redis.rb

# frozen_string_literal: true

require "monitor"
require_relative "redis/errors"

class Redis
  class << self
    attr_reader :exists_returns_integer

    def exists_returns_integer=(value)
      unless value
        message = "`Redis#exists(key)` will return an Integer by default in redis-rb 4.3. The option to explicitly " \
          "disable this behaviour via `Redis.exists_returns_integer` will be removed in 5.0. You should use " \
          "`exists?` instead."

        ::Kernel.warn(message)
      end

      @exists_returns_integer = value
    end

    attr_writer :current
  end

  def self.current
    @current ||= Redis.new
  end

  include MonitorMixin

  # Create a new client instance
  #
  # @param [Hash] options
  # @option options [String] :url (value of the environment variable REDIS_URL) a Redis URL, for a TCP connection:
  #   `redis://:[password]@[hostname]:[port]/[db]` (password, port and database are optional), for a unix socket
  #    connection: `unix://[path to Redis socket]`. This overrides all other options.
  # @option options [String] :host ("127.0.0.1") server hostname
  # @option options [Integer] :port (6379) server port
  # @option options [String] :path path to server socket (overrides host and port)
  # @option options [Float] :timeout (5.0) timeout in seconds
  # @option options [Float] :connect_timeout (same as timeout) timeout for initial connect in seconds
  # @option options [String] :username Username to authenticate against server
  # @option options [String] :password Password to authenticate against server
  # @option options [Integer] :db (0) Database to select after initial connect
  # @option options [Symbol] :driver Driver to use, currently supported: `:ruby`, `:hiredis`, `:synchrony`
  # @option options [String] :id ID for the client connection, assigns name to current connection by sending
  #   `CLIENT SETNAME`
  # @option options [Hash, Integer] :tcp_keepalive Keepalive values, if Integer `intvl` and `probe` are calculated
  #   based on the value, if Hash `time`, `intvl` and `probes` can be specified as a Integer
  # @option options [Integer] :reconnect_attempts Number of attempts trying to connect
  # @option options [Boolean] :inherit_socket (false) Whether to use socket in forked process or not
  # @option options [Array] :sentinels List of sentinels to contact
  # @option options [Symbol] :role (:master) Role to fetch via Sentinel, either `:master` or `:slave`
  # @option options [Array<String, Hash{Symbol => String, Integer}>] :cluster List of cluster nodes to contact
  # @option options [Boolean] :replica Whether to use readonly replica nodes in Redis Cluster or not
  # @option options [Class] :connector Class of custom connector
  #
  # @return [Redis] a new client instance
  def initialize(options = {})
    @options = options.dup
    @cluster_mode = options.key?(:cluster)
    client = @cluster_mode ? Cluster : Client
    @original_client = @client = client.new(options)
    @queue = Hash.new { |h, k| h[k] = [] }

    super() # Monitor#initialize
  end

  def synchronize
    mon_synchronize { yield(@client) }
  end

  # Run code with the client reconnecting
  def with_reconnect(val = true, &blk)
    synchronize do |client|
      client.with_reconnect(val, &blk)
    end
  end

  # Run code without the client reconnecting
  def without_reconnect(&blk)
    with_reconnect(false, &blk)
  end

  # Test whether or not the client is connected
  def connected?
    @original_client.connected?
  end

  # Disconnect the client as quickly and silently as possible.
  def close
    @original_client.disconnect
  end
  alias disconnect! close

  # Sends a command to Redis and returns its reply.
  #
  # Replies are converted to Ruby objects according to the RESP protocol, so
  # you can expect a Ruby array, integer or nil when Redis sends one. Higher
  # level transformations, such as converting an array of pairs into a Ruby
  # hash, are up to consumers.
  #
  # Redis error replies are raised as Ruby exceptions.
  def call(*command)
    synchronize do |client|
      client.call(command)
    end
  end

  # Queues a command for pipelining.
  #
  # Commands in the queue are executed with the Redis#commit method.
  #
  # See http://redis.io/topics/pipelining for more details.
  #
  def queue(*command)
    synchronize do
      @queue[Thread.current.object_id] << command
    end
  end

  # Sends all commands in the queue.
  #
  # See http://redis.io/topics/pipelining for more details.
  #
  def commit
    synchronize do |client|
      begin
        pipeline = Pipeline.new(client)
        @queue[Thread.current.object_id].each do |command|
          pipeline.call(command)
        end

        client.call_pipelined(pipeline)
      ensure
        @queue.delete(Thread.current.object_id)
      end
    end
  end

  def _client
    @client
  end

  # Authenticate to the server.
  #
  # @param [Array<String>] args includes both username and password
  #   or only password
  # @return [String] `OK`
  # @see https://redis.io/commands/auth AUTH command
  def auth(*args)
    synchronize do |client|
      client.call([:auth, *args])
    end
  end

  # Change the selected database for the current connection.
  #
  # @param [Integer] db zero-based index of the DB to use (0 to 15)
  # @return [String] `OK`
  def select(db)
    synchronize do |client|
      client.db = db
      client.call([:select, db])
    end
  end

  # Ping the server.
  #
  # @param [optional, String] message
  # @return [String] `PONG`
  def ping(message = nil)
    synchronize do |client|
      client.call([:ping, message].compact)
    end
  end

  # Echo the given string.
  #
  # @param [String] value
  # @return [String]
  def echo(value)
    synchronize do |client|
      client.call([:echo, value])
    end
  end

  # Close the connection.
  #
  # @return [String] `OK`
  def quit
    synchronize do |client|
      begin
        client.call([:quit])
      rescue ConnectionError
      ensure
        client.disconnect
      end
    end
  end

  # Asynchronously rewrite the append-only file.
  #
  # @return [String] `OK`
  def bgrewriteaof
    synchronize do |client|
      client.call([:bgrewriteaof])
    end
  end

  # Asynchronously save the dataset to disk.
  #
  # @return [String] `OK`
  def bgsave
    synchronize do |client|
      client.call([:bgsave])
    end
  end

  # Get or set server configuration parameters.
  #
  # @param [Symbol] action e.g. `:get`, `:set`, `:resetstat`
  # @return [String, Hash] string reply, or hash when retrieving more than one
  #   property with `CONFIG GET`
  def config(action, *args)
    synchronize do |client|
      client.call([:config, action] + args) do |reply|
        if reply.is_a?(Array) && action == :get
          Hashify.call(reply)
        else
          reply
        end
      end
    end
  end

  # Manage client connections.
  #
  # @param [String, Symbol] subcommand e.g. `kill`, `list`, `getname`, `setname`
  # @return [String, Hash] depends on subcommand
  def client(subcommand = nil, *args)
    synchronize do |client|
      client.call([:client, subcommand] + args) do |reply|
        if subcommand.to_s == "list"
          reply.lines.map do |line|
            entries = line.chomp.split(/[ =]/)
            Hash[entries.each_slice(2).to_a]
          end
        else
          reply
        end
      end
    end
  end

  # Return the number of keys in the selected database.
  #
  # @return [Integer]
  def dbsize
    synchronize do |client|
      client.call([:dbsize])
    end
  end

  def debug(*args)
    synchronize do |client|
      client.call([:debug] + args)
    end
  end

  # Remove all keys from all databases.
  #
  # @param [Hash] options
  #   - `:async => Boolean`: async flush (default: false)
  # @return [String] `OK`
  def flushall(options = nil)
    synchronize do |client|
      if options && options[:async]
        client.call(%i[flushall async])
      else
        client.call([:flushall])
      end
    end
  end

  # Remove all keys from the current database.
  #
  # @param [Hash] options
  #   - `:async => Boolean`: async flush (default: false)
  # @return [String] `OK`
  def flushdb(options = nil)
    synchronize do |client|
      if options && options[:async]
        client.call(%i[flushdb async])
      else
        client.call([:flushdb])
      end
    end
  end

  # Get information and statistics about the server.
  #
  # @param [String, Symbol] cmd e.g. "commandstats"
  # @return [Hash<String, String>]
  def info(cmd = nil)
    synchronize do |client|
      client.call([:info, cmd].compact) do |reply|
        if reply.is_a?(String)
          reply = HashifyInfo.call(reply)

          if cmd && cmd.to_s == "commandstats"
            # Extract nested hashes for INFO COMMANDSTATS
            reply = Hash[reply.map do |k, v|
              v = v.split(",").map { |e| e.split("=") }
              [k[/^cmdstat_(.*)$/, 1], Hash[v]]
            end]
          end
        end

        reply
      end
    end
  end

  # Get the UNIX time stamp of the last successful save to disk.
  #
  # @return [Integer]
  def lastsave
    synchronize do |client|
      client.call([:lastsave])
    end
  end

  # Listen for all requests received by the server in real time.
  #
  # There is no way to interrupt this command.
  #
  # @yield a block to be called for every line of output
  # @yieldparam [String] line timestamp and command that was executed
  def monitor(&block)
    synchronize do |client|
      client.call_loop([:monitor], &block)
    end
  end

  # Synchronously save the dataset to disk.
  #
  # @return [String]
  def save
    synchronize do |client|
      client.call([:save])
    end
  end

  # Synchronously save the dataset to disk and then shut down the server.
  def shutdown
    synchronize do |client|
      client.with_reconnect(false) do
        begin
          client.call([:shutdown])
        rescue ConnectionError
          # This means Redis has probably exited.
          nil
        end
      end
    end
  end

  # Make the server a slave of another instance, or promote it as master.
  def slaveof(host, port)
    synchronize do |client|
      client.call([:slaveof, host, port])
    end
  end

  # Interact with the slowlog (get, len, reset)
  #
  # @param [String] subcommand e.g. `get`, `len`, `reset`
  # @param [Integer] length maximum number of entries to return
  # @return [Array<String>, Integer, String] depends on subcommand
  def slowlog(subcommand, length = nil)
    synchronize do |client|
      args = [:slowlog, subcommand]
      args << length if length
      client.call args
    end
  end

  # Internal command used for replication.
  def sync
    synchronize do |client|
      client.call([:sync])
    end
  end

  # Return the server time.
  #
  # @example
  #   r.time # => [ 1333093196, 606806 ]
  #
  # @return [Array<Integer>] tuple of seconds since UNIX epoch and
  #   microseconds in the current second
  def time
    synchronize do |client|
      client.call([:time]) do |reply|
        reply&.map(&:to_i)
      end
    end
  end

  # Remove the expiration from a key.
  #
  # @param [String] key
  # @return [Boolean] whether the timeout was removed or not
  def persist(key)
    synchronize do |client|
      client.call([:persist, key], &Boolify)
    end
  end

  # Set a key's time to live in seconds.
  #
  # @param [String] key
  # @param [Integer] seconds time to live
  # @return [Boolean] whether the timeout was set or not
  def expire(key, seconds)
    synchronize do |client|
      client.call([:expire, key, seconds], &Boolify)
    end
  end

  # Set the expiration for a key as a UNIX timestamp.
  #
  # @param [String] key
  # @param [Integer] unix_time expiry time specified as a UNIX timestamp
  # @return [Boolean] whether the timeout was set or not
  def expireat(key, unix_time)
    synchronize do |client|
      client.call([:expireat, key, unix_time], &Boolify)
    end
  end

  # Get the time to live (in seconds) for a key.
  #
  # @param [String] key
  # @return [Integer] remaining time to live in seconds.
  #
  # In Redis 2.6 or older the command returns -1 if the key does not exist or if
  # the key exist but has no associated expire.
  #
  # Starting with Redis 2.8 the return value in case of error changed:
  #
  #     - The command returns -2 if the key does not exist.
  #     - The command returns -1 if the key exists but has no associated expire.
  def ttl(key)
    synchronize do |client|
      client.call([:ttl, key])
    end
  end

  # Set a key's time to live in milliseconds.
  #
  # @param [String] key
  # @param [Integer] milliseconds time to live
  # @return [Boolean] whether the timeout was set or not
  def pexpire(key, milliseconds)
    synchronize do |client|
      client.call([:pexpire, key, milliseconds], &Boolify)
    end
  end

  # Set the expiration for a key as number of milliseconds from UNIX Epoch.
  #
  # @param [String] key
  # @param [Integer] ms_unix_time expiry time specified as number of milliseconds from UNIX Epoch.
  # @return [Boolean] whether the timeout was set or not
  def pexpireat(key, ms_unix_time)
    synchronize do |client|
      client.call([:pexpireat, key, ms_unix_time], &Boolify)
    end
  end

  # Get the time to live (in milliseconds) for a key.
  #
  # @param [String] key
  # @return [Integer] remaining time to live in milliseconds
  # In Redis 2.6 or older the command returns -1 if the key does not exist or if
  # the key exist but has no associated expire.
  #
  # Starting with Redis 2.8 the return value in case of error changed:
  #
  #     - The command returns -2 if the key does not exist.
  #     - The command returns -1 if the key exists but has no associated expire.
  def pttl(key)
    synchronize do |client|
      client.call([:pttl, key])
    end
  end

  # Return a serialized version of the value stored at a key.
  #
  # @param [String] key
  # @return [String] serialized_value
  def dump(key)
    synchronize do |client|
      client.call([:dump, key])
    end
  end

  # Create a key using the serialized value, previously obtained using DUMP.
  #
  # @param [String] key
  # @param [String] ttl
  # @param [String] serialized_value
  # @param [Hash] options
  #   - `:replace => Boolean`: if false, raises an error if key already exists
  # @raise [Redis::CommandError]
  # @return [String] `"OK"`
  def restore(key, ttl, serialized_value, replace: nil)
    args = [:restore, key, ttl, serialized_value]
    args << 'REPLACE' if replace

    synchronize do |client|
      client.call(args)
    end
  end

  # Transfer a key from the connected instance to another instance.
  #
  # @param [String, Array<String>] key
  # @param [Hash] options
  #   - `:host => String`: host of instance to migrate to
  #   - `:port => Integer`: port of instance to migrate to
  #   - `:db => Integer`: database to migrate to (default: same as source)
  #   - `:timeout => Integer`: timeout (default: same as connection timeout)
  #   - `:copy => Boolean`: Do not remove the key from the local instance.
  #   - `:replace => Boolean`: Replace existing key on the remote instance.
  # @return [String] `"OK"`
  def migrate(key, options)
    args = [:migrate]
    args << (options[:host] || raise(':host not specified'))
    args << (options[:port] || raise(':port not specified'))
    args << (key.is_a?(String) ? key : '')
    args << (options[:db] || @client.db).to_i
    args << (options[:timeout] || @client.timeout).to_i
    args << 'COPY' if options[:copy]
    args << 'REPLACE' if options[:replace]
    args += ['KEYS', *key] if key.is_a?(Array)

    synchronize { |client| client.call(args) }
  end

  # Delete one or more keys.
  #
  # @param [String, Array<String>] keys
  # @return [Integer] number of keys that were deleted
  def del(*keys)
    keys.flatten!(1)
    return 0 if keys.empty?

    synchronize do |client|
      client.call([:del] + keys)
    end
  end

  # Unlink one or more keys.
  #
  # @param [String, Array<String>] keys
  # @return [Integer] number of keys that were unlinked
  def unlink(*keys)
    synchronize do |client|
      client.call([:unlink] + keys)
    end
  end

  # Determine how many of the keys exists.
  #
  # @param [String, Array<String>] keys
  # @return [Integer]
  def exists(*keys)
    if !Redis.exists_returns_integer && keys.size == 1
      if Redis.exists_returns_integer.nil?
        message = "`Redis#exists(key)` will return an Integer in redis-rb 4.3. `exists?` returns a boolean, you " \
          "should use it instead. To opt-in to the new behavior now you can set Redis.exists_returns_integer =  " \
          "true. To disable this message and keep the current (boolean) behaviour of 'exists' you can set " \
          "`Redis.exists_returns_integer = false`, but this option will be removed in 5.0. " \
          "(#{::Kernel.caller(1, 1).first})\n"

        ::Kernel.warn(message)
      end

      exists?(*keys)
    else
      _exists(*keys)
    end
  end

  def _exists(*keys)
    synchronize do |client|
      client.call([:exists, *keys])
    end
  end

  # Determine if any of the keys exists.
  #
  # @param [String, Array<String>] keys
  # @return [Boolean]
  def exists?(*keys)
    synchronize do |client|
      client.call([:exists, *keys]) do |value|
        value > 0
      end
    end
  end

  # Find all keys matching the given pattern.
  #
  # @param [String] pattern
  # @return [Array<String>]
  def keys(pattern = "*")
    synchronize do |client|
      client.call([:keys, pattern]) do |reply|
        if reply.is_a?(String)
          reply.split(" ")
        else
          reply
        end
      end
    end
  end

  # Move a key to another database.
  #
  # @example Move a key to another database
  #   redis.set "foo", "bar"
  #     # => "OK"
  #   redis.move "foo", 2
  #     # => true
  #   redis.exists "foo"
  #     # => false
  #   redis.select 2
  #     # => "OK"
  #   redis.exists "foo"
  #     # => true
  #   redis.get "foo"
  #     # => "bar"
  #
  # @param [String] key
  # @param [Integer] db
  # @return [Boolean] whether the key was moved or not
  def move(key, db)
    synchronize do |client|
      client.call([:move, key, db], &Boolify)
    end
  end

  def object(*args)
    synchronize do |client|
      client.call([:object] + args)
    end
  end

  # Return a random key from the keyspace.
  #
  # @return [String]
  def randomkey
    synchronize do |client|
      client.call([:randomkey])
    end
  end

  # Rename a key. If the new key already exists it is overwritten.
  #
  # @param [String] old_name
  # @param [String] new_name
  # @return [String] `OK`
  def rename(old_name, new_name)
    synchronize do |client|
      client.call([:rename, old_name, new_name])
    end
  end

  # Rename a key, only if the new key does not exist.
  #
  # @param [String] old_name
  # @param [String] new_name
  # @return [Boolean] whether the key was renamed or not
  def renamenx(old_name, new_name)
    synchronize do |client|
      client.call([:renamenx, old_name, new_name], &Boolify)
    end
  end

  # Sort the elements in a list, set or sorted set.
  #
  # @example Retrieve the first 2 elements from an alphabetically sorted "list"
  #   redis.sort("list", :order => "alpha", :limit => [0, 2])
  #     # => ["a", "b"]
  # @example Store an alphabetically descending list in "target"
  #   redis.sort("list", :order => "desc alpha", :store => "target")
  #     # => 26
  #
  # @param [String] key
  # @param [Hash] options
  #   - `:by => String`: use external key to sort elements by
  #   - `:limit => [offset, count]`: skip `offset` elements, return a maximum
  #   of `count` elements
  #   - `:get => [String, Array<String>]`: single key or array of keys to
  #   retrieve per element in the result
  #   - `:order => String`: combination of `ASC`, `DESC` and optionally `ALPHA`
  #   - `:store => String`: key to store the result at
  #
  # @return [Array<String>, Array<Array<String>>, Integer]
  #   - when `:get` is not specified, or holds a single element, an array of elements
  #   - when `:get` is specified, and holds more than one element, an array of
  #   elements where every element is an array with the result for every
  #   element specified in `:get`
  #   - when `:store` is specified, the number of elements in the stored result
  def sort(key, by: nil, limit: nil, get: nil, order: nil, store: nil)
    args = [:sort, key]
    args << "BY" << by if by

    if limit
      args << "LIMIT"
      args.concat(limit)
    end

    get = Array(get)
    get.each do |item|
      args << "GET" << item
    end

    args.concat(order.split(" ")) if order
    args << "STORE" << store if store

    synchronize do |client|
      client.call(args) do |reply|
        if get.size > 1 && !store
          reply.each_slice(get.size).to_a if reply
        else
          reply
        end
      end
    end
  end

  # Determine the type stored at key.
  #
  # @param [String] key
  # @return [String] `string`, `list`, `set`, `zset`, `hash` or `none`
  def type(key)
    synchronize do |client|
      client.call([:type, key])
    end
  end

  # Decrement the integer value of a key by one.
  #
  # @example
  #   redis.decr("value")
  #     # => 4
  #
  # @param [String] key
  # @return [Integer] value after decrementing it
  def decr(key)
    synchronize do |client|
      client.call([:decr, key])
    end
  end

  # Decrement the integer value of a key by the given number.
  #
  # @example
  #   redis.decrby("value", 5)
  #     # => 0
  #
  # @param [String] key
  # @param [Integer] decrement
  # @return [Integer] value after decrementing it
  def decrby(key, decrement)
    synchronize do |client|
      client.call([:decrby, key, decrement])
    end
  end

  # Increment the integer value of a key by one.
  #
  # @example
  #   redis.incr("value")
  #     # => 6
  #
  # @param [String] key
  # @return [Integer] value after incrementing it
  def incr(key)
    synchronize do |client|
      client.call([:incr, key])
    end
  end

  # Increment the integer value of a key by the given integer number.
  #
  # @example
  #   redis.incrby("value", 5)
  #     # => 10
  #
  # @param [String] key
  # @param [Integer] increment
  # @return [Integer] value after incrementing it
  def incrby(key, increment)
    synchronize do |client|
      client.call([:incrby, key, increment])
    end
  end

  # Increment the numeric value of a key by the given float number.
  #
  # @example
  #   redis.incrbyfloat("value", 1.23)
  #     # => 1.23
  #
  # @param [String] key
  # @param [Float] increment
  # @return [Float] value after incrementing it
  def incrbyfloat(key, increment)
    synchronize do |client|
      client.call([:incrbyfloat, key, increment], &Floatify)
    end
  end

  # Set the string value of a key.
  #
  # @param [String] key
  # @param [String] value
  # @param [Hash] options
  #   - `:ex => Integer`: Set the specified expire time, in seconds.
  #   - `:px => Integer`: Set the specified expire time, in milliseconds.
  #   - `:nx => true`: Only set the key if it does not already exist.
  #   - `:xx => true`: Only set the key if it already exist.
  #   - `:keepttl => true`: Retain the time to live associated with the key.
  # @return [String, Boolean] `"OK"` or true, false if `:nx => true` or `:xx => true`
  def set(key, value, ex: nil, px: nil, nx: nil, xx: nil, keepttl: nil)
    args = [:set, key, value.to_s]
    args << "EX" << ex if ex
    args << "PX" << px if px
    args << "NX" if nx
    args << "XX" if xx
    args << "KEEPTTL" if keepttl

    synchronize do |client|
      if nx || xx
        client.call(args, &BoolifySet)
      else
        client.call(args)
      end
    end
  end

  # Set the time to live in seconds of a key.
  #
  # @param [String] key
  # @param [Integer] ttl
  # @param [String] value
  # @return [String] `"OK"`
  def setex(key, ttl, value)
    synchronize do |client|
      client.call([:setex, key, ttl, value.to_s])
    end
  end

  # Set the time to live in milliseconds of a key.
  #
  # @param [String] key
  # @param [Integer] ttl
  # @param [String] value
  # @return [String] `"OK"`
  def psetex(key, ttl, value)
    synchronize do |client|
      client.call([:psetex, key, ttl, value.to_s])
    end
  end

  # Set the value of a key, only if the key does not exist.
  #
  # @param [String] key
  # @param [String] value
  # @return [Boolean] whether the key was set or not
  def setnx(key, value)
    synchronize do |client|
      client.call([:setnx, key, value.to_s], &Boolify)
    end
  end

  # Set one or more values.
  #
  # @example
  #   redis.mset("key1", "v1", "key2", "v2")
  #     # => "OK"
  #
  # @param [Array<String>] args array of keys and values
  # @return [String] `"OK"`
  #
  # @see #mapped_mset
  def mset(*args)
    synchronize do |client|
      client.call([:mset] + args)
    end
  end

  # Set one or more values.
  #
  # @example
  #   redis.mapped_mset({ "f1" => "v1", "f2" => "v2" })
  #     # => "OK"
  #
  # @param [Hash] hash keys mapping to values
  # @return [String] `"OK"`
  #
  # @see #mset
  def mapped_mset(hash)
    mset(hash.to_a.flatten)
  end

  # Set one or more values, only if none of the keys exist.
  #
  # @example
  #   redis.msetnx("key1", "v1", "key2", "v2")
  #     # => true
  #
  # @param [Array<String>] args array of keys and values
  # @return [Boolean] whether or not all values were set
  #
  # @see #mapped_msetnx
  def msetnx(*args)
    synchronize do |client|
      client.call([:msetnx, *args], &Boolify)
    end
  end

  # Set one or more values, only if none of the keys exist.
  #
  # @example
  #   redis.mapped_msetnx({ "key1" => "v1", "key2" => "v2" })
  #     # => true
  #
  # @param [Hash] hash keys mapping to values
  # @return [Boolean] whether or not all values were set
  #
  # @see #msetnx
  def mapped_msetnx(hash)
    msetnx(hash.to_a.flatten)
  end

  # Get the value of a key.
  #
  # @param [String] key
  # @return [String]
  def get(key)
    synchronize do |client|
      client.call([:get, key])
    end
  end

  # Get the values of all the given keys.
  #
  # @example
  #   redis.mget("key1", "key2")
  #     # => ["v1", "v2"]
  #
  # @param [Array<String>] keys
  # @return [Array<String>] an array of values for the specified keys
  #
  # @see #mapped_mget
  def mget(*keys, &blk)
    synchronize do |client|
      client.call([:mget, *keys], &blk)
    end
  end

  # Get the values of all the given keys.
  #
  # @example
  #   redis.mapped_mget("key1", "key2")
  #     # => { "key1" => "v1", "key2" => "v2" }
  #
  # @param [Array<String>] keys array of keys
  # @return [Hash] a hash mapping the specified keys to their values
  #
  # @see #mget
  def mapped_mget(*keys)
    mget(*keys) do |reply|
      if reply.is_a?(Array)
        Hash[keys.zip(reply)]
      else
        reply
      end
    end
  end

  # Overwrite part of a string at key starting at the specified offset.
  #
  # @param [String] key
  # @param [Integer] offset byte offset
  # @param [String] value
  # @return [Integer] length of the string after it was modified
  def setrange(key, offset, value)
    synchronize do |client|
      client.call([:setrange, key, offset, value.to_s])
    end
  end

  # Get a substring of the string stored at a key.
  #
  # @param [String] key
  # @param [Integer] start zero-based start offset
  # @param [Integer] stop zero-based end offset. Use -1 for representing
  #   the end of the string
  # @return [Integer] `0` or `1`
  def getrange(key, start, stop)
    synchronize do |client|
      client.call([:getrange, key, start, stop])
    end
  end

  # Sets or clears the bit at offset in the string value stored at key.
  #
  # @param [String] key
  # @param [Integer] offset bit offset
  # @param [Integer] value bit value `0` or `1`
  # @return [Integer] the original bit value stored at `offset`
  def setbit(key, offset, value)
    synchronize do |client|
      client.call([:setbit, key, offset, value])
    end
  end

  # Returns the bit value at offset in the string value stored at key.
  #
  # @param [String] key
  # @param [Integer] offset bit offset
  # @return [Integer] `0` or `1`
  def getbit(key, offset)
    synchronize do |client|
      client.call([:getbit, key, offset])
    end
  end

  # Append a value to a key.
  #
  # @param [String] key
  # @param [String] value value to append
  # @return [Integer] length of the string after appending
  def append(key, value)
    synchronize do |client|
      client.call([:append, key, value])
    end
  end

  # Count the number of set bits in a range of the string value stored at key.
  #
  # @param [String] key
  # @param [Integer] start start index
  # @param [Integer] stop stop index
  # @return [Integer] the number of bits set to 1
  def bitcount(key, start = 0, stop = -1)
    synchronize do |client|
      client.call([:bitcount, key, start, stop])
    end
  end

  # Perform a bitwise operation between strings and store the resulting string in a key.
  #
  # @param [String] operation e.g. `and`, `or`, `xor`, `not`
  # @param [String] destkey destination key
  # @param [String, Array<String>] keys one or more source keys to perform `operation`
  # @return [Integer] the length of the string stored in `destkey`
  def bitop(operation, destkey, *keys)
    synchronize do |client|
      client.call([:bitop, operation, destkey, *keys])
    end
  end

  # Return the position of the first bit set to 1 or 0 in a string.
  #
  # @param [String] key
  # @param [Integer] bit whether to look for the first 1 or 0 bit
  # @param [Integer] start start index
  # @param [Integer] stop stop index
  # @return [Integer] the position of the first 1/0 bit.
  #                  -1 if looking for 1 and it is not found or start and stop are given.
  def bitpos(key, bit, start = nil, stop = nil)
    raise(ArgumentError, 'stop parameter specified without start parameter') if stop && !start

    synchronize do |client|
      command = [:bitpos, key, bit]
      command << start if start
      command << stop if stop
      client.call(command)
    end
  end

  # Set the string value of a key and return its old value.
  #
  # @param [String] key
  # @param [String] value value to replace the current value with
  # @return [String] the old value stored in the key, or `nil` if the key
  #   did not exist
  def getset(key, value)
    synchronize do |client|
      client.call([:getset, key, value.to_s])
    end
  end

  # Get the value of key and delete the key. This command is similar to GET,
  # except for the fact that it also deletes the key on success.
  #
  # @param [String] key
  # @return [String] the old value stored in the key, or `nil` if the key
  #   did not exist
  def getdel(key)
    synchronize do |client|
      client.call([:getdel, key])
    end
  end

  # Get the value of key and optionally set its expiration. GETEX is similar to
  # GET, but is a write command with additional options. When no options are
  # provided, GETEX behaves like GET.
  #
  # @param [String] key
  # @param [Hash] options
  #   - `:ex => Integer`: Set the specified expire time, in seconds.
  #   - `:px => Integer`: Set the specified expire time, in milliseconds.
  #   - `:exat => true`: Set the specified Unix time at which the key will
  #      expire, in seconds.
  #   - `:pxat => true`: Set the specified Unix time at which the key will
  #      expire, in milliseconds.
  #   - `:persist => true`: Remove the time to live associated with the key.
  # @return [String] The value of key, or nil when key does not exist.
  def getex(key, ex: nil, px: nil, exat: nil, pxat: nil, persist: false)
    args = [:getex, key]
    args << "EX" << ex if ex
    args << "PX" << px if px
    args << "EXAT" << exat if exat
    args << "PXAT" << pxat if pxat
    args << "PERSIST" if persist

    synchronize do |client|
      client.call(args)
    end
  end

  # Get the length of the value stored in a key.
  #
  # @param [String] key
  # @return [Integer] the length of the value stored in the key, or 0
  #   if the key does not exist
  def strlen(key)
    synchronize do |client|
      client.call([:strlen, key])
    end
  end

  # Get the length of a list.
  #
  # @param [String] key
  # @return [Integer]
  def llen(key)
    synchronize do |client|
      client.call([:llen, key])
    end
  end

  # Prepend one or more values to a list, creating the list if it doesn't exist
  #
  # @param [String] key
  # @param [String, Array<String>] value string value, or array of string values to push
  # @return [Integer] the length of the list after the push operation
  def lpush(key, value)
    synchronize do |client|
      client.call([:lpush, key, value])
    end
  end

  # Prepend a value to a list, only if the list exists.
  #
  # @param [String] key
  # @param [String] value
  # @return [Integer] the length of the list after the push operation
  def lpushx(key, value)
    synchronize do |client|
      client.call([:lpushx, key, value])
    end
  end

  # Append one or more values to a list, creating the list if it doesn't exist
  #
  # @param [String] key
  # @param [String, Array<String>] value string value, or array of string values to push
  # @return [Integer] the length of the list after the push operation
  def rpush(key, value)
    synchronize do |client|
      client.call([:rpush, key, value])
    end
  end

  # Append a value to a list, only if the list exists.
  #
  # @param [String] key
  # @param [String] value
  # @return [Integer] the length of the list after the push operation
  def rpushx(key, value)
    synchronize do |client|
      client.call([:rpushx, key, value])
    end
  end

  # Remove and get the first elements in a list.
  #
  # @param [String] key
  # @param [Integer] count number of elements to remove
  # @return [String, Array<String>] the values of the first elements
  def lpop(key, count = nil)
    synchronize do |client|
      command = [:lpop, key]
      command << count if count
      client.call(command)
    end
  end

  # Remove and get the last elements in a list.
  #
  # @param [String] key
  # @param [Integer] count number of elements to remove
  # @return [String, Array<String>] the values of the last elements
  def rpop(key, count = nil)
    synchronize do |client|
      command = [:rpop, key]
      command << count if count
      client.call(command)
    end
  end

  # Remove the last element in a list, append it to another list and return it.
  #
  # @param [String] source source key
  # @param [String] destination destination key
  # @return [nil, String] the element, or nil when the source key does not exist
  def rpoplpush(source, destination)
    synchronize do |client|
      client.call([:rpoplpush, source, destination])
    end
  end

  def _bpop(cmd, args, &blk)
    timeout = if args.last.is_a?(Hash)
      options = args.pop
      options[:timeout]
    elsif args.last.respond_to?(:to_int)
      # Issue deprecation notice in obnoxious mode...
      args.pop.to_int
    end

    timeout ||= 0

    if args.size > 1
      # Issue deprecation notice in obnoxious mode...
    end

    keys = args.flatten

    synchronize do |client|
      command = [cmd, keys, timeout]
      timeout += client.timeout if timeout > 0
      client.call_with_timeout(command, timeout, &blk)
    end
  end

  # Remove and get the first element in a list, or block until one is available.
  #
  # @example With timeout
  #   list, element = redis.blpop("list", :timeout => 5)
  #     # => nil on timeout
  #     # => ["list", "element"] on success
  # @example Without timeout
  #   list, element = redis.blpop("list")
  #     # => ["list", "element"]
  # @example Blocking pop on multiple lists
  #   list, element = redis.blpop(["list", "another_list"])
  #     # => ["list", "element"]
  #
  # @param [String, Array<String>] keys one or more keys to perform the
  #   blocking pop on
  # @param [Hash] options
  #   - `:timeout => Integer`: timeout in seconds, defaults to no timeout
  #
  # @return [nil, [String, String]]
  #   - `nil` when the operation timed out
  #   - tuple of the list that was popped from and element was popped otherwise
  def blpop(*args)
    _bpop(:blpop, args)
  end

  # Remove and get the last element in a list, or block until one is available.
  #
  # @param [String, Array<String>] keys one or more keys to perform the
  #   blocking pop on
  # @param [Hash] options
  #   - `:timeout => Integer`: timeout in seconds, defaults to no timeout
  #
  # @return [nil, [String, String]]
  #   - `nil` when the operation timed out
  #   - tuple of the list that was popped from and element was popped otherwise
  #
  # @see #blpop
  def brpop(*args)
    _bpop(:brpop, args)
  end

  # Pop a value from a list, push it to another list and return it; or block
  # until one is available.
  #
  # @param [String] source source key
  # @param [String] destination destination key
  # @param [Hash] options
  #   - `:timeout => Integer`: timeout in seconds, defaults to no timeout
  #
  # @return [nil, String]
  #   - `nil` when the operation timed out
  #   - the element was popped and pushed otherwise
  def brpoplpush(source, destination, deprecated_timeout = 0, timeout: deprecated_timeout)
    synchronize do |client|
      command = [:brpoplpush, source, destination, timeout]
      timeout += client.timeout if timeout > 0
      client.call_with_timeout(command, timeout)
    end
  end

  # Get an element from a list by its index.
  #
  # @param [String] key
  # @param [Integer] index
  # @return [String]
  def lindex(key, index)
    synchronize do |client|
      client.call([:lindex, key, index])
    end
  end

  # Insert an element before or after another element in a list.
  #
  # @param [String] key
  # @param [String, Symbol] where `BEFORE` or `AFTER`
  # @param [String] pivot reference element
  # @param [String] value
  # @return [Integer] length of the list after the insert operation, or `-1`
  #   when the element `pivot` was not found
  def linsert(key, where, pivot, value)
    synchronize do |client|
      client.call([:linsert, key, where, pivot, value])
    end
  end

  # Get a range of elements from a list.
  #
  # @param [String] key
  # @param [Integer] start start index
  # @param [Integer] stop stop index
  # @return [Array<String>]
  def lrange(key, start, stop)
    synchronize do |client|
      client.call([:lrange, key, start, stop])
    end
  end

  # Remove elements from a list.
  #
  # @param [String] key
  # @param [Integer] count number of elements to remove. Use a positive
  #   value to remove the first `count` occurrences of `value`. A negative
  #   value to remove the last `count` occurrences of `value`. Or zero, to
  #   remove all occurrences of `value` from the list.
  # @param [String] value
  # @return [Integer] the number of removed elements
  def lrem(key, count, value)
    synchronize do |client|
      client.call([:lrem, key, count, value])
    end
  end

  # Set the value of an element in a list by its index.
  #
  # @param [String] key
  # @param [Integer] index
  # @param [String] value
  # @return [String] `OK`
  def lset(key, index, value)
    synchronize do |client|
      client.call([:lset, key, index, value])
    end
  end

  # Trim a list to the specified range.
  #
  # @param [String] key
  # @param [Integer] start start index
  # @param [Integer] stop stop index
  # @return [String] `OK`
  def ltrim(key, start, stop)
    synchronize do |client|
      client.call([:ltrim, key, start, stop])
    end
  end

  # Get the number of members in a set.
  #
  # @param [String] key
  # @return [Integer]
  def scard(key)
    synchronize do |client|
      client.call([:scard, key])
    end
  end

  # Add one or more members to a set.
  #
  # @param [String] key
  # @param [String, Array<String>] member one member, or array of members
  # @return [Boolean, Integer] `Boolean` when a single member is specified,
  #   holding whether or not adding the member succeeded, or `Integer` when an
  #   array of members is specified, holding the number of members that were
  #   successfully added
  def sadd(key, member)
    synchronize do |client|
      client.call([:sadd, key, member]) do |reply|
        if member.is_a? Array
          # Variadic: return integer
          reply
        else
          # Single argument: return boolean
          Boolify.call(reply)
        end
      end
    end
  end

  # Remove one or more members from a set.
  #
  # @param [String] key
  # @param [String, Array<String>] member one member, or array of members
  # @return [Boolean, Integer] `Boolean` when a single member is specified,
  #   holding whether or not removing the member succeeded, or `Integer` when an
  #   array of members is specified, holding the number of members that were
  #   successfully removed
  def srem(key, member)
    synchronize do |client|
      client.call([:srem, key, member]) do |reply|
        if member.is_a? Array
          # Variadic: return integer
          reply
        else
          # Single argument: return boolean
          Boolify.call(reply)
        end
      end
    end
  end

  # Remove and return one or more random member from a set.
  #
  # @param [String] key
  # @return [String]
  # @param [Integer] count
  def spop(key, count = nil)
    synchronize do |client|
      if count.nil?
        client.call([:spop, key])
      else
        client.call([:spop, key, count])
      end
    end
  end

  # Get one or more random members from a set.
  #
  # @param [String] key
  # @param [Integer] count
  # @return [String]
  def srandmember(key, count = nil)
    synchronize do |client|
      if count.nil?
        client.call([:srandmember, key])
      else
        client.call([:srandmember, key, count])
      end
    end
  end

  # Move a member from one set to another.
  #
  # @param [String] source source key
  # @param [String] destination destination key
  # @param [String] member member to move from `source` to `destination`
  # @return [Boolean]
  def smove(source, destination, member)
    synchronize do |client|
      client.call([:smove, source, destination, member], &Boolify)
    end
  end

  # Determine if a given value is a member of a set.
  #
  # @param [String] key
  # @param [String] member
  # @return [Boolean]
  def sismember(key, member)
    synchronize do |client|
      client.call([:sismember, key, member], &Boolify)
    end
  end

  # Get all the members in a set.
  #
  # @param [String] key
  # @return [Array<String>]
  def smembers(key)
    synchronize do |client|
      client.call([:smembers, key])
    end
  end

  # Subtract multiple sets.
  #
  # @param [String, Array<String>] keys keys pointing to sets to subtract
  # @return [Array<String>] members in the difference
  def sdiff(*keys)
    synchronize do |client|
      client.call([:sdiff, *keys])
    end
  end

  # Subtract multiple sets and store the resulting set in a key.
  #
  # @param [String] destination destination key
  # @param [String, Array<String>] keys keys pointing to sets to subtract
  # @return [Integer] number of elements in the resulting set
  def sdiffstore(destination, *keys)
    synchronize do |client|
      client.call([:sdiffstore, destination, *keys])
    end
  end

  # Intersect multiple sets.
  #
  # @param [String, Array<String>] keys keys pointing to sets to intersect
  # @return [Array<String>] members in the intersection
  def sinter(*keys)
    synchronize do |client|
      client.call([:sinter, *keys])
    end
  end

  # Intersect multiple sets and store the resulting set in a key.
  #
  # @param [String] destination destination key
  # @param [String, Array<String>] keys keys pointing to sets to intersect
  # @return [Integer] number of elements in the resulting set
  def sinterstore(destination, *keys)
    synchronize do |client|
      client.call([:sinterstore, destination, *keys])
    end
  end

  # Add multiple sets.
  #
  # @param [String, Array<String>] keys keys pointing to sets to unify
  # @return [Array<String>] members in the union
  def sunion(*keys)
    synchronize do |client|
      client.call([:sunion, *keys])
    end
  end

  # Add multiple sets and store the resulting set in a key.
  #
  # @param [String] destination destination key
  # @param [String, Array<String>] keys keys pointing to sets to unify
  # @return [Integer] number of elements in the resulting set
  def sunionstore(destination, *keys)
    synchronize do |client|
      client.call([:sunionstore, destination, *keys])
    end
  end

  # Get the number of members in a sorted set.
  #
  # @example
  #   redis.zcard("zset")
  #     # => 4
  #
  # @param [String] key
  # @return [Integer]
  def zcard(key)
    synchronize do |client|
      client.call([:zcard, key])
    end
  end

  # Add one or more members to a sorted set, or update the score for members
  # that already exist.
  #
  # @example Add a single `[score, member]` pair to a sorted set
  #   redis.zadd("zset", 32.0, "member")
  # @example Add an array of `[score, member]` pairs to a sorted set
  #   redis.zadd("zset", [[32.0, "a"], [64.0, "b"]])
  #
  # @param [String] key
  # @param [[Float, String], Array<[Float, String]>] args
  #   - a single `[score, member]` pair
  #   - an array of `[score, member]` pairs
  # @param [Hash] options
  #   - `:xx => true`: Only update elements that already exist (never
  #   add elements)
  #   - `:nx => true`: Don't update already existing elements (always
  #   add new elements)
  #   - `:ch => true`: Modify the return value from the number of new
  #   elements added, to the total number of elements changed (CH is an
  #   abbreviation of changed); changed elements are new elements added
  #   and elements already existing for which the score was updated
  #   - `:incr => true`: When this option is specified ZADD acts like
  #   ZINCRBY; only one score-element pair can be specified in this mode
  #
  # @return [Boolean, Integer, Float]
  #   - `Boolean` when a single pair is specified, holding whether or not it was
  #   **added** to the sorted set.
  #   - `Integer` when an array of pairs is specified, holding the number of
  #   pairs that were **added** to the sorted set.
  #   - `Float` when option :incr is specified, holding the score of the member
  #   after incrementing it.
  def zadd(key, *args, nx: nil, xx: nil, ch: nil, incr: nil)
    command = [:zadd, key]
    command << "NX" if nx
    command << "XX" if xx
    command << "CH" if ch
    command << "INCR" if incr

    synchronize do |client|
      if args.size == 1 && args[0].is_a?(Array)
        # Variadic: return float if INCR, integer if !INCR
        client.call(command + args[0], &(incr ? Floatify : nil))
      elsif args.size == 2
        # Single pair: return float if INCR, boolean if !INCR
        client.call(command + args, &(incr ? Floatify : Boolify))
      else
        raise ArgumentError, "wrong number of arguments"
      end
    end
  end

  # Increment the score of a member in a sorted set.
  #
  # @example
  #   redis.zincrby("zset", 32.0, "a")
  #     # => 64.0
  #
  # @param [String] key
  # @param [Float] increment
  # @param [String] member
  # @return [Float] score of the member after incrementing it
  def zincrby(key, increment, member)
    synchronize do |client|
      client.call([:zincrby, key, increment, member], &Floatify)
    end
  end

  # Remove one or more members from a sorted set.
  #
  # @example Remove a single member from a sorted set
  #   redis.zrem("zset", "a")
  # @example Remove an array of members from a sorted set
  #   redis.zrem("zset", ["a", "b"])
  #
  # @param [String] key
  # @param [String, Array<String>] member
  #   - a single member
  #   - an array of members
  #
  # @return [Boolean, Integer]
  #   - `Boolean` when a single member is specified, holding whether or not it
  #   was removed from the sorted set
  #   - `Integer` when an array of pairs is specified, holding the number of
  #   members that were removed to the sorted set
  def zrem(key, member)
    synchronize do |client|
      client.call([:zrem, key, member]) do |reply|
        if member.is_a? Array
          # Variadic: return integer
          reply
        else
          # Single argument: return boolean
          Boolify.call(reply)
        end
      end
    end
  end

  # Removes and returns up to count members with the highest scores in the sorted set stored at key.
  #
  # @example Popping a member
  #   redis.zpopmax('zset')
  #   #=> ['b', 2.0]
  # @example With count option
  #   redis.zpopmax('zset', 2)
  #   #=> [['b', 2.0], ['a', 1.0]]
  #
  # @params key [String] a key of the sorted set
  # @params count [Integer] a number of members
  #
  # @return [Array<String, Float>] element and score pair if count is not specified
  # @return [Array<Array<String, Float>>] list of popped elements and scores
  def zpopmax(key, count = nil)
    synchronize do |client|
      members = client.call([:zpopmax, key, count].compact, &FloatifyPairs)
      count.to_i > 1 ? members : members.first
    end
  end

  # Removes and returns up to count members with the lowest scores in the sorted set stored at key.
  #
  # @example Popping a member
  #   redis.zpopmin('zset')
  #   #=> ['a', 1.0]
  # @example With count option
  #   redis.zpopmin('zset', 2)
  #   #=> [['a', 1.0], ['b', 2.0]]
  #
  # @params key [String] a key of the sorted set
  # @params count [Integer] a number of members
  #
  # @return [Array<String, Float>] element and score pair if count is not specified
  # @return [Array<Array<String, Float>>] list of popped elements and scores
  def zpopmin(key, count = nil)
    synchronize do |client|
      members = client.call([:zpopmin, key, count].compact, &FloatifyPairs)
      count.to_i > 1 ? members : members.first
    end
  end

  # Removes and returns up to count members with the highest scores in the sorted set stored at keys,
  #   or block until one is available.
  #
  # @example Popping a member from a sorted set
  #   redis.bzpopmax('zset', 1)
  #   #=> ['zset', 'b', 2.0]
  # @example Popping a member from multiple sorted sets
  #   redis.bzpopmax('zset1', 'zset2', 1)
  #   #=> ['zset1', 'b', 2.0]
  #
  # @params keys [Array<String>] one or multiple keys of the sorted sets
  # @params timeout [Integer] the maximum number of seconds to block
  #
  # @return [Array<String, String, Float>] a touple of key, member and score
  # @return [nil] when no element could be popped and the timeout expired
  def bzpopmax(*args)
    _bpop(:bzpopmax, args) do |reply|
      reply.is_a?(Array) ? [reply[0], reply[1], Floatify.call(reply[2])] : reply
    end
  end

  # Removes and returns up to count members with the lowest scores in the sorted set stored at keys,
  #   or block until one is available.
  #
  # @example Popping a member from a sorted set
  #   redis.bzpopmin('zset', 1)
  #   #=> ['zset', 'a', 1.0]
  # @example Popping a member from multiple sorted sets
  #   redis.bzpopmin('zset1', 'zset2', 1)
  #   #=> ['zset1', 'a', 1.0]
  #
  # @params keys [Array<String>] one or multiple keys of the sorted sets
  # @params timeout [Integer] the maximum number of seconds to block
  #
  # @return [Array<String, String, Float>] a touple of key, member and score
  # @return [nil] when no element could be popped and the timeout expired
  def bzpopmin(*args)
    _bpop(:bzpopmin, args) do |reply|
      reply.is_a?(Array) ? [reply[0], reply[1], Floatify.call(reply[2])] : reply
    end
  end

  # Get the score associated with the given member in a sorted set.
  #
  # @example Get the score for member "a"
  #   redis.zscore("zset", "a")
  #     # => 32.0
  #
  # @param [String] key
  # @param [String] member
  # @return [Float] score of the member
  def zscore(key, member)
    synchronize do |client|
      client.call([:zscore, key, member], &Floatify)
    end
  end

  # Return a range of members in a sorted set, by index.
  #
  # @example Retrieve all members from a sorted set
  #   redis.zrange("zset", 0, -1)
  #     # => ["a", "b"]
  # @example Retrieve all members and their scores from a sorted set
  #   redis.zrange("zset", 0, -1, :with_scores => true)
  #     # => [["a", 32.0], ["b", 64.0]]
  #
  # @param [String] key
  # @param [Integer] start start index
  # @param [Integer] stop stop index
  # @param [Hash] options
  #   - `:with_scores => true`: include scores in output
  #
  # @return [Array<String>, Array<[String, Float]>]
  #   - when `:with_scores` is not specified, an array of members
  #   - when `:with_scores` is specified, an array with `[member, score]` pairs
  def zrange(key, start, stop, withscores: false, with_scores: withscores)
    args = [:zrange, key, start, stop]

    if with_scores
      args << "WITHSCORES"
      block = FloatifyPairs
    end

    synchronize do |client|
      client.call(args, &block)
    end
  end

  # Return a range of members in a sorted set, by index, with scores ordered
  # from high to low.
  #
  # @example Retrieve all members from a sorted set
  #   redis.zrevrange("zset", 0, -1)
  #     # => ["b", "a"]
  # @example Retrieve all members and their scores from a sorted set
  #   redis.zrevrange("zset", 0, -1, :with_scores => true)
  #     # => [["b", 64.0], ["a", 32.0]]
  #
  # @see #zrange
  def zrevrange(key, start, stop, withscores: false, with_scores: withscores)
    args = [:zrevrange, key, start, stop]

    if with_scores
      args << "WITHSCORES"
      block = FloatifyPairs
    end

    synchronize do |client|
      client.call(args, &block)
    end
  end

  # Determine the index of a member in a sorted set.
  #
  # @param [String] key
  # @param [String] member
  # @return [Integer]
  def zrank(key, member)
    synchronize do |client|
      client.call([:zrank, key, member])
    end
  end

  # Determine the index of a member in a sorted set, with scores ordered from
  # high to low.
  #
  # @param [String] key
  # @param [String] member
  # @return [Integer]
  def zrevrank(key, member)
    synchronize do |client|
      client.call([:zrevrank, key, member])
    end
  end

  # Remove all members in a sorted set within the given indexes.
  #
  # @example Remove first 5 members
  #   redis.zremrangebyrank("zset", 0, 4)
  #     # => 5
  # @example Remove last 5 members
  #   redis.zremrangebyrank("zset", -5, -1)
  #     # => 5
  #
  # @param [String] key
  # @param [Integer] start start index
  # @param [Integer] stop stop index
  # @return [Integer] number of members that were removed
  def zremrangebyrank(key, start, stop)
    synchronize do |client|
      client.call([:zremrangebyrank, key, start, stop])
    end
  end

  # Count the members, with the same score in a sorted set, within the given lexicographical range.
  #
  # @example Count members matching a
  #   redis.zlexcount("zset", "[a", "[a\xff")
  #     # => 1
  # @example Count members matching a-z
  #   redis.zlexcount("zset", "[a", "[z\xff")
  #     # => 26
  #
  # @param [String] key
  # @param [String] min
  #   - inclusive minimum is specified by prefixing `(`
  #   - exclusive minimum is specified by prefixing `[`
  # @param [String] max
  #   - inclusive maximum is specified by prefixing `(`
  #   - exclusive maximum is specified by prefixing `[`
  #
  # @return [Integer] number of members within the specified lexicographical range
  def zlexcount(key, min, max)
    synchronize do |client|
      client.call([:zlexcount, key, min, max])
    end
  end

  # Return a range of members with the same score in a sorted set, by lexicographical ordering
  #
  # @example Retrieve members matching a
  #   redis.zrangebylex("zset", "[a", "[a\xff")
  #     # => ["aaren", "aarika", "abagael", "abby"]
  # @example Retrieve the first 2 members matching a
  #   redis.zrangebylex("zset", "[a", "[a\xff", :limit => [0, 2])
  #     # => ["aaren", "aarika"]
  #
  # @param [String] key
  # @param [String] min
  #   - inclusive minimum is specified by prefixing `(`
  #   - exclusive minimum is specified by prefixing `[`
  # @param [String] max
  #   - inclusive maximum is specified by prefixing `(`
  #   - exclusive maximum is specified by prefixing `[`
  # @param [Hash] options
  #   - `:limit => [offset, count]`: skip `offset` members, return a maximum of
  #   `count` members
  #
  # @return [Array<String>, Array<[String, Float]>]
  def zrangebylex(key, min, max, limit: nil)
    args = [:zrangebylex, key, min, max]

    if limit
      args << "LIMIT"
      args.concat(limit)
    end

    synchronize do |client|
      client.call(args)
    end
  end

  # Return a range of members with the same score in a sorted set, by reversed lexicographical ordering.
  # Apart from the reversed ordering, #zrevrangebylex is similar to #zrangebylex.
  #
  # @example Retrieve members matching a
  #   redis.zrevrangebylex("zset", "[a", "[a\xff")
  #     # => ["abbygail", "abby", "abagael", "aaren"]
  # @example Retrieve the last 2 members matching a
  #   redis.zrevrangebylex("zset", "[a", "[a\xff", :limit => [0, 2])
  #     # => ["abbygail", "abby"]
  #
  # @see #zrangebylex
  def zrevrangebylex(key, max, min, limit: nil)
    args = [:zrevrangebylex, key, max, min]

    if limit
      args << "LIMIT"
      args.concat(limit)
    end

    synchronize do |client|
      client.call(args)
    end
  end

  # Return a range of members in a sorted set, by score.
  #
  # @example Retrieve members with score `>= 5` and `< 100`
  #   redis.zrangebyscore("zset", "5", "(100")
  #     # => ["a", "b"]
  # @example Retrieve the first 2 members with score `>= 0`
  #   redis.zrangebyscore("zset", "0", "+inf", :limit => [0, 2])
  #     # => ["a", "b"]
  # @example Retrieve members and their scores with scores `> 5`
  #   redis.zrangebyscore("zset", "(5", "+inf", :with_scores => true)
  #     # => [["a", 32.0], ["b", 64.0]]
  #
  # @param [String] key
  # @param [String] min
  #   - inclusive minimum score is specified verbatim
  #   - exclusive minimum score is specified by prefixing `(`
  # @param [String] max
  #   - inclusive maximum score is specified verbatim
  #   - exclusive maximum score is specified by prefixing `(`
  # @param [Hash] options
  #   - `:with_scores => true`: include scores in output
  #   - `:limit => [offset, count]`: skip `offset` members, return a maximum of
  #   `count` members
  #
  # @return [Array<String>, Array<[String, Float]>]
  #   - when `:with_scores` is not specified, an array of members
  #   - when `:with_scores` is specified, an array with `[member, score]` pairs
  def zrangebyscore(key, min, max, withscores: false, with_scores: withscores, limit: nil)
    args = [:zrangebyscore, key, min, max]

    if with_scores
      args << "WITHSCORES"
      block = FloatifyPairs
    end

    if limit
      args << "LIMIT"
      args.concat(limit)
    end

    synchronize do |client|
      client.call(args, &block)
    end
  end

  # Return a range of members in a sorted set, by score, with scores ordered
  # from high to low.
  #
  # @example Retrieve members with score `< 100` and `>= 5`
  #   redis.zrevrangebyscore("zset", "(100", "5")
  #     # => ["b", "a"]
  # @example Retrieve the first 2 members with score `<= 0`
  #   redis.zrevrangebyscore("zset", "0", "-inf", :limit => [0, 2])
  #     # => ["b", "a"]
  # @example Retrieve members and their scores with scores `> 5`
  #   redis.zrevrangebyscore("zset", "+inf", "(5", :with_scores => true)
  #     # => [["b", 64.0], ["a", 32.0]]
  #
  # @see #zrangebyscore
  def zrevrangebyscore(key, max, min, withscores: false, with_scores: withscores, limit: nil)
    args = [:zrevrangebyscore, key, max, min]

    if with_scores
      args << "WITHSCORES"
      block = FloatifyPairs
    end

    if limit
      args << "LIMIT"
      args.concat(limit)
    end

    synchronize do |client|
      client.call(args, &block)
    end
  end

  # Remove all members in a sorted set within the given scores.
  #
  # @example Remove members with score `>= 5` and `< 100`
  #   redis.zremrangebyscore("zset", "5", "(100")
  #     # => 2
  # @example Remove members with scores `> 5`
  #   redis.zremrangebyscore("zset", "(5", "+inf")
  #     # => 2
  #
  # @param [String] key
  # @param [String] min
  #   - inclusive minimum score is specified verbatim
  #   - exclusive minimum score is specified by prefixing `(`
  # @param [String] max
  #   - inclusive maximum score is specified verbatim
  #   - exclusive maximum score is specified by prefixing `(`
  # @return [Integer] number of members that were removed
  def zremrangebyscore(key, min, max)
    synchronize do |client|
      client.call([:zremrangebyscore, key, min, max])
    end
  end

  # Count the members in a sorted set with scores within the given values.
  #
  # @example Count members with score `>= 5` and `< 100`
  #   redis.zcount("zset", "5", "(100")
  #     # => 2
  # @example Count members with scores `> 5`
  #   redis.zcount("zset", "(5", "+inf")
  #     # => 2
  #
  # @param [String] key
  # @param [String] min
  #   - inclusive minimum score is specified verbatim
  #   - exclusive minimum score is specified by prefixing `(`
  # @param [String] max
  #   - inclusive maximum score is specified verbatim
  #   - exclusive maximum score is specified by prefixing `(`
  # @return [Integer] number of members in within the specified range
  def zcount(key, min, max)
    synchronize do |client|
      client.call([:zcount, key, min, max])
    end
  end

  # Return the intersection of multiple sorted sets
  #
  # @example Retrieve the intersection of `2*zsetA` and `1*zsetB`
  #   redis.zinter("zsetA", "zsetB", :weights => [2.0, 1.0])
  #     # => ["v1", "v2"]
  # @example Retrieve the intersection of `2*zsetA` and `1*zsetB`, and their scores
  #   redis.zinter("zsetA", "zsetB", :weights => [2.0, 1.0], :with_scores => true)
  #     # => [["v1", 3.0], ["v2", 6.0]]
  #
  # @param [String, Array<String>] keys one or more keys to intersect
  # @param [Hash] options
  #   - `:weights => [Float, Float, ...]`: weights to associate with source
  #   sorted sets
  #   - `:aggregate => String`: aggregate function to use (sum, min, max, ...)
  #   - `:with_scores => true`: include scores in output
  #
  # @return [Array<String>, Array<[String, Float]>]
  #   - when `:with_scores` is not specified, an array of members
  #   - when `:with_scores` is specified, an array with `[member, score]` pairs
  def zinter(*keys, weights: nil, aggregate: nil, with_scores: false)
    args = [:zinter, keys.size, *keys]

    if weights
      args << "WEIGHTS"
      args.concat(weights)
    end

    args << "AGGREGATE" << aggregate if aggregate

    if with_scores
      args << "WITHSCORES"
      block = FloatifyPairs
    end

    synchronize do |client|
      client.call(args, &block)
    end
  end

  # Intersect multiple sorted sets and store the resulting sorted set in a new
  # key.
  #
  # @example Compute the intersection of `2*zsetA` with `1*zsetB`, summing their scores
  #   redis.zinterstore("zsetC", ["zsetA", "zsetB"], :weights => [2.0, 1.0], :aggregate => "sum")
  #     # => 4
  #
  # @param [String] destination destination key
  # @param [Array<String>] keys source keys
  # @param [Hash] options
  #   - `:weights => [Float, Float, ...]`: weights to associate with source
  #   sorted sets
  #   - `:aggregate => String`: aggregate function to use (sum, min, max, ...)
  # @return [Integer] number of elements in the resulting sorted set
  def zinterstore(destination, keys, weights: nil, aggregate: nil)
    args = [:zinterstore, destination, keys.size, *keys]

    if weights
      args << "WEIGHTS"
      args.concat(weights)
    end

    args << "AGGREGATE" << aggregate if aggregate

    synchronize do |client|
      client.call(args)
    end
  end

  # Add multiple sorted sets and store the resulting sorted set in a new key.
  #
  # @example Compute the union of `2*zsetA` with `1*zsetB`, summing their scores
  #   redis.zunionstore("zsetC", ["zsetA", "zsetB"], :weights => [2.0, 1.0], :aggregate => "sum")
  #     # => 8
  #
  # @param [String] destination destination key
  # @param [Array<String>] keys source keys
  # @param [Hash] options
  #   - `:weights => [Float, Float, ...]`: weights to associate with source
  #   sorted sets
  #   - `:aggregate => String`: aggregate function to use (sum, min, max, ...)
  # @return [Integer] number of elements in the resulting sorted set
  def zunionstore(destination, keys, weights: nil, aggregate: nil)
    args = [:zunionstore, destination, keys.size, *keys]

    if weights
      args << "WEIGHTS"
      args.concat(weights)
    end

    args << "AGGREGATE" << aggregate if aggregate

    synchronize do |client|
      client.call(args)
    end
  end

  # Get the number of fields in a hash.
  #
  # @param [String] key
  # @return [Integer] number of fields in the hash
  def hlen(key)
    synchronize do |client|
      client.call([:hlen, key])
    end
  end

  # Set one or more hash values.
  #
  # @example
  #   redis.hset("hash", "f1", "v1", "f2", "v2") # => 2
  #   redis.hset("hash", { "f1" => "v1", "f2" => "v2" }) # => 2
  #
  # @param [String] key
  # @param [Array<String> | Hash<String, String>] attrs array or hash of fields and values
  # @return [Integer] The number of fields that were added to the hash
  def hset(key, *attrs)
    attrs = attrs.first.flatten if attrs.size == 1 && attrs.first.is_a?(Hash)

    synchronize do |client|
      client.call([:hset, key, *attrs])
    end
  end

  # Set the value of a hash field, only if the field does not exist.
  #
  # @param [String] key
  # @param [String] field
  # @param [String] value
  # @return [Boolean] whether or not the field was **added** to the hash
  def hsetnx(key, field, value)
    synchronize do |client|
      client.call([:hsetnx, key, field, value], &Boolify)
    end
  end

  # Set one or more hash values.
  #
  # @example
  #   redis.hmset("hash", "f1", "v1", "f2", "v2")
  #     # => "OK"
  #
  # @param [String] key
  # @param [Array<String>] attrs array of fields and values
  # @return [String] `"OK"`
  #
  # @see #mapped_hmset
  def hmset(key, *attrs)
    synchronize do |client|
      client.call([:hmset, key] + attrs)
    end
  end

  # Set one or more hash values.
  #
  # @example
  #   redis.mapped_hmset("hash", { "f1" => "v1", "f2" => "v2" })
  #     # => "OK"
  #
  # @param [String] key
  # @param [Hash] hash a non-empty hash with fields mapping to values
  # @return [String] `"OK"`
  #
  # @see #hmset
  def mapped_hmset(key, hash)
    hmset(key, hash.to_a.flatten)
  end

  # Get the value of a hash field.
  #
  # @param [String] key
  # @param [String] field
  # @return [String]
  def hget(key, field)
    synchronize do |client|
      client.call([:hget, key, field])
    end
  end

  # Get the values of all the given hash fields.
  #
  # @example
  #   redis.hmget("hash", "f1", "f2")
  #     # => ["v1", "v2"]
  #
  # @param [String] key
  # @param [Array<String>] fields array of fields
  # @return [Array<String>] an array of values for the specified fields
  #
  # @see #mapped_hmget
  def hmget(key, *fields, &blk)
    synchronize do |client|
      client.call([:hmget, key] + fields, &blk)
    end
  end

  # Get the values of all the given hash fields.
  #
  # @example
  #   redis.mapped_hmget("hash", "f1", "f2")
  #     # => { "f1" => "v1", "f2" => "v2" }
  #
  # @param [String] key
  # @param [Array<String>] fields array of fields
  # @return [Hash] a hash mapping the specified fields to their values
  #
  # @see #hmget
  def mapped_hmget(key, *fields)
    hmget(key, *fields) do |reply|
      if reply.is_a?(Array)
        Hash[fields.zip(reply)]
      else
        reply
      end
    end
  end

  # Delete one or more hash fields.
  #
  # @param [String] key
  # @param [String, Array<String>] field
  # @return [Integer] the number of fields that were removed from the hash
  def hdel(key, *fields)
    synchronize do |client|
      client.call([:hdel, key, *fields])
    end
  end

  # Determine if a hash field exists.
  #
  # @param [String] key
  # @param [String] field
  # @return [Boolean] whether or not the field exists in the hash
  def hexists(key, field)
    synchronize do |client|
      client.call([:hexists, key, field], &Boolify)
    end
  end

  # Increment the integer value of a hash field by the given integer number.
  #
  # @param [String] key
  # @param [String] field
  # @param [Integer] increment
  # @return [Integer] value of the field after incrementing it
  def hincrby(key, field, increment)
    synchronize do |client|
      client.call([:hincrby, key, field, increment])
    end
  end

  # Increment the numeric value of a hash field by the given float number.
  #
  # @param [String] key
  # @param [String] field
  # @param [Float] increment
  # @return [Float] value of the field after incrementing it
  def hincrbyfloat(key, field, increment)
    synchronize do |client|
      client.call([:hincrbyfloat, key, field, increment], &Floatify)
    end
  end

  # Get all the fields in a hash.
  #
  # @param [String] key
  # @return [Array<String>]
  def hkeys(key)
    synchronize do |client|
      client.call([:hkeys, key])
    end
  end

  # Get all the values in a hash.
  #
  # @param [String] key
  # @return [Array<String>]
  def hvals(key)
    synchronize do |client|
      client.call([:hvals, key])
    end
  end

  # Get all the fields and values in a hash.
  #
  # @param [String] key
  # @return [Hash<String, String>]
  def hgetall(key)
    synchronize do |client|
      client.call([:hgetall, key], &Hashify)
    end
  end

  # Post a message to a channel.
  def publish(channel, message)
    synchronize do |client|
      client.call([:publish, channel, message])
    end
  end

  def subscribed?
    synchronize do |client|
      client.is_a? SubscribedClient
    end
  end

  # Listen for messages published to the given channels.
  def subscribe(*channels, &block)
    synchronize do |_client|
      _subscription(:subscribe, 0, channels, block)
    end
  end

  # Listen for messages published to the given channels. Throw a timeout error
  # if there is no messages for a timeout period.
  def subscribe_with_timeout(timeout, *channels, &block)
    synchronize do |_client|
      _subscription(:subscribe_with_timeout, timeout, channels, block)
    end
  end

  # Stop listening for messages posted to the given channels.
  def unsubscribe(*channels)
    synchronize do |client|
      raise "Can't unsubscribe if not subscribed." unless subscribed?

      client.unsubscribe(*channels)
    end
  end

  # Listen for messages published to channels matching the given patterns.
  def psubscribe(*channels, &block)
    synchronize do |_client|
      _subscription(:psubscribe, 0, channels, block)
    end
  end

  # Listen for messages published to channels matching the given patterns.
  # Throw a timeout error if there is no messages for a timeout period.
  def psubscribe_with_timeout(timeout, *channels, &block)
    synchronize do |_client|
      _subscription(:psubscribe_with_timeout, timeout, channels, block)
    end
  end

  # Stop listening for messages posted to channels matching the given patterns.
  def punsubscribe(*channels)
    synchronize do |client|
      raise "Can't unsubscribe if not subscribed." unless subscribed?

      client.punsubscribe(*channels)
    end
  end

  # Inspect the state of the Pub/Sub subsystem.
  # Possible subcommands: channels, numsub, numpat.
  def pubsub(subcommand, *args)
    synchronize do |client|
      client.call([:pubsub, subcommand] + args)
    end
  end

  # Watch the given keys to determine execution of the MULTI/EXEC block.
  #
  # Using a block is optional, but is necessary for thread-safety.
  #
  # An `#unwatch` is automatically issued if an exception is raised within the
  # block that is a subclass of StandardError and is not a ConnectionError.
  #
  # @example With a block
  #   redis.watch("key") do
  #     if redis.get("key") == "some value"
  #       redis.multi do |multi|
  #         multi.set("key", "other value")
  #         multi.incr("counter")
  #       end
  #     else
  #       redis.unwatch
  #     end
  #   end
  #     # => ["OK", 6]
  #
  # @example Without a block
  #   redis.watch("key")
  #     # => "OK"
  #
  # @param [String, Array<String>] keys one or more keys to watch
  # @return [Object] if using a block, returns the return value of the block
  # @return [String] if not using a block, returns `OK`
  #
  # @see #unwatch
  # @see #multi
  def watch(*keys)
    synchronize do |client|
      res = client.call([:watch, *keys])

      if block_given?
        begin
          yield(self)
        rescue ConnectionError
          raise
        rescue StandardError
          unwatch
          raise
        end
      else
        res
      end
    end
  end

  # Forget about all watched keys.
  #
  # @return [String] `OK`
  #
  # @see #watch
  # @see #multi
  def unwatch
    synchronize do |client|
      client.call([:unwatch])
    end
  end

  def pipelined
    synchronize do |prior_client|
      begin
        @client = Pipeline.new(prior_client)
        yield(self)
        prior_client.call_pipeline(@client)
      ensure
        @client = prior_client
      end
    end
  end

  # Mark the start of a transaction block.
  #
  # Passing a block is optional.
  #
  # @example With a block
  #   redis.multi do |multi|
  #     multi.set("key", "value")
  #     multi.incr("counter")
  #   end # => ["OK", 6]
  #
  # @example Without a block
  #   redis.multi
  #     # => "OK"
  #   redis.set("key", "value")
  #     # => "QUEUED"
  #   redis.incr("counter")
  #     # => "QUEUED"
  #   redis.exec
  #     # => ["OK", 6]
  #
  # @yield [multi] the commands that are called inside this block are cached
  #   and written to the server upon returning from it
  # @yieldparam [Redis] multi `self`
  #
  # @return [String, Array<...>]
  #   - when a block is not given, `OK`
  #   - when a block is given, an array with replies
  #
  # @see #watch
  # @see #unwatch
  def multi
    synchronize do |prior_client|
      if !block_given?
        prior_client.call([:multi])
      else
        begin
          @client = Pipeline::Multi.new(prior_client)
          yield(self)
          prior_client.call_pipeline(@client)
        ensure
          @client = prior_client
        end
      end
    end
  end

  # Execute all commands issued after MULTI.
  #
  # Only call this method when `#multi` was called **without** a block.
  #
  # @return [nil, Array<...>]
  #   - when commands were not executed, `nil`
  #   - when commands were executed, an array with their replies
  #
  # @see #multi
  # @see #discard
  def exec
    synchronize do |client|
      client.call([:exec])
    end
  end

  # Discard all commands issued after MULTI.
  #
  # Only call this method when `#multi` was called **without** a block.
  #
  # @return [String] `"OK"`
  #
  # @see #multi
  # @see #exec
  def discard
    synchronize do |client|
      client.call([:discard])
    end
  end

  # Control remote script registry.
  #
  # @example Load a script
  #   sha = redis.script(:load, "return 1")
  #     # => <sha of this script>
  # @example Check if a script exists
  #   redis.script(:exists, sha)
  #     # => true
  # @example Check if multiple scripts exist
  #   redis.script(:exists, [sha, other_sha])
  #     # => [true, false]
  # @example Flush the script registry
  #   redis.script(:flush)
  #     # => "OK"
  # @example Kill a running script
  #   redis.script(:kill)
  #     # => "OK"
  #
  # @param [String] subcommand e.g. `exists`, `flush`, `load`, `kill`
  # @param [Array<String>] args depends on subcommand
  # @return [String, Boolean, Array<Boolean>, ...] depends on subcommand
  #
  # @see #eval
  # @see #evalsha
  def script(subcommand, *args)
    subcommand = subcommand.to_s.downcase

    if subcommand == "exists"
      synchronize do |client|
        arg = args.first

        client.call([:script, :exists, arg]) do |reply|
          reply = reply.map { |r| Boolify.call(r) }

          if arg.is_a?(Array)
            reply
          else
            reply.first
          end
        end
      end
    else
      synchronize do |client|
        client.call([:script, subcommand] + args)
      end
    end
  end

  def _eval(cmd, args)
    script = args.shift
    options = args.pop if args.last.is_a?(Hash)
    options ||= {}

    keys = args.shift || options[:keys] || []
    argv = args.shift || options[:argv] || []

    synchronize do |client|
      client.call([cmd, script, keys.length] + keys + argv)
    end
  end

  # Evaluate Lua script.
  #
  # @example EVAL without KEYS nor ARGV
  #   redis.eval("return 1")
  #     # => 1
  # @example EVAL with KEYS and ARGV as array arguments
  #   redis.eval("return { KEYS, ARGV }", ["k1", "k2"], ["a1", "a2"])
  #     # => [["k1", "k2"], ["a1", "a2"]]
  # @example EVAL with KEYS and ARGV in a hash argument
  #   redis.eval("return { KEYS, ARGV }", :keys => ["k1", "k2"], :argv => ["a1", "a2"])
  #     # => [["k1", "k2"], ["a1", "a2"]]
  #
  # @param [Array<String>] keys optional array with keys to pass to the script
  # @param [Array<String>] argv optional array with arguments to pass to the script
  # @param [Hash] options
  #   - `:keys => Array<String>`: optional array with keys to pass to the script
  #   - `:argv => Array<String>`: optional array with arguments to pass to the script
  # @return depends on the script
  #
  # @see #script
  # @see #evalsha
  def eval(*args)
    _eval(:eval, args)
  end

  # Evaluate Lua script by its SHA.
  #
  # @example EVALSHA without KEYS nor ARGV
  #   redis.evalsha(sha)
  #     # => <depends on script>
  # @example EVALSHA with KEYS and ARGV as array arguments
  #   redis.evalsha(sha, ["k1", "k2"], ["a1", "a2"])
  #     # => <depends on script>
  # @example EVALSHA with KEYS and ARGV in a hash argument
  #   redis.evalsha(sha, :keys => ["k1", "k2"], :argv => ["a1", "a2"])
  #     # => <depends on script>
  #
  # @param [Array<String>] keys optional array with keys to pass to the script
  # @param [Array<String>] argv optional array with arguments to pass to the script
  # @param [Hash] options
  #   - `:keys => Array<String>`: optional array with keys to pass to the script
  #   - `:argv => Array<String>`: optional array with arguments to pass to the script
  # @return depends on the script
  #
  # @see #script
  # @see #eval
  def evalsha(*args)
    _eval(:evalsha, args)
  end

  def _scan(command, cursor, args, match: nil, count: nil, type: nil, &block)
    # SSCAN/ZSCAN/HSCAN already prepend the key to +args+.

    args << cursor
    args << "MATCH" << match if match
    args << "COUNT" << count if count
    args << "TYPE" << type if type

    synchronize do |client|
      client.call([command] + args, &block)
    end
  end

  # Scan the keyspace
  #
  # @example Retrieve the first batch of keys
  #   redis.scan(0)
  #     # => ["4", ["key:21", "key:47", "key:42"]]
  # @example Retrieve a batch of keys matching a pattern
  #   redis.scan(4, :match => "key:1?")
  #     # => ["92", ["key:13", "key:18"]]
  # @example Retrieve a batch of keys of a certain type
  #   redis.scan(92, :type => "zset")
  #     # => ["173", ["sortedset:14", "sortedset:78"]]
  #
  # @param [String, Integer] cursor the cursor of the iteration
  # @param [Hash] options
  #   - `:match => String`: only return keys matching the pattern
  #   - `:count => Integer`: return count keys at most per iteration
  #   - `:type => String`: return keys only of the given type
  #
  # @return [String, Array<String>] the next cursor and all found keys
  def scan(cursor, **options)
    _scan(:scan, cursor, [], **options)
  end

  # Scan the keyspace
  #
  # @example Retrieve all of the keys (with possible duplicates)
  #   redis.scan_each.to_a
  #     # => ["key:21", "key:47", "key:42"]
  # @example Execute block for each key matching a pattern
  #   redis.scan_each(:match => "key:1?") {|key| puts key}
  #     # => key:13
  #     # => key:18
  # @example Execute block for each key of a type
  #   redis.scan_each(:type => "hash") {|key| puts redis.type(key)}
  #     # => "hash"
  #     # => "hash"
  #
  # @param [Hash] options
  #   - `:match => String`: only return keys matching the pattern
  #   - `:count => Integer`: return count keys at most per iteration
  #   - `:type => String`: return keys only of the given type
  #
  # @return [Enumerator] an enumerator for all found keys
  def scan_each(**options, &block)
    return to_enum(:scan_each, **options) unless block_given?

    cursor = 0
    loop do
      cursor, keys = scan(cursor, **options)
      keys.each(&block)
      break if cursor == "0"
    end
  end

  # Scan a hash
  #
  # @example Retrieve the first batch of key/value pairs in a hash
  #   redis.hscan("hash", 0)
  #
  # @param [String, Integer] cursor the cursor of the iteration
  # @param [Hash] options
  #   - `:match => String`: only return keys matching the pattern
  #   - `:count => Integer`: return count keys at most per iteration
  #
  # @return [String, Array<[String, String]>] the next cursor and all found keys
  def hscan(key, cursor, **options)
    _scan(:hscan, cursor, [key], **options) do |reply|
      [reply[0], reply[1].each_slice(2).to_a]
    end
  end

  # Scan a hash
  #
  # @example Retrieve all of the key/value pairs in a hash
  #   redis.hscan_each("hash").to_a
  #   # => [["key70", "70"], ["key80", "80"]]
  #
  # @param [Hash] options
  #   - `:match => String`: only return keys matching the pattern
  #   - `:count => Integer`: return count keys at most per iteration
  #
  # @return [Enumerator] an enumerator for all found keys
  def hscan_each(key, **options, &block)
    return to_enum(:hscan_each, key, **options) unless block_given?

    cursor = 0
    loop do
      cursor, values = hscan(key, cursor, **options)
      values.each(&block)
      break if cursor == "0"
    end
  end

  # Scan a sorted set
  #
  # @example Retrieve the first batch of key/value pairs in a hash
  #   redis.zscan("zset", 0)
  #
  # @param [String, Integer] cursor the cursor of the iteration
  # @param [Hash] options
  #   - `:match => String`: only return keys matching the pattern
  #   - `:count => Integer`: return count keys at most per iteration
  #
  # @return [String, Array<[String, Float]>] the next cursor and all found
  #   members and scores
  def zscan(key, cursor, **options)
    _scan(:zscan, cursor, [key], **options) do |reply|
      [reply[0], FloatifyPairs.call(reply[1])]
    end
  end

  # Scan a sorted set
  #
  # @example Retrieve all of the members/scores in a sorted set
  #   redis.zscan_each("zset").to_a
  #   # => [["key70", "70"], ["key80", "80"]]
  #
  # @param [Hash] options
  #   - `:match => String`: only return keys matching the pattern
  #   - `:count => Integer`: return count keys at most per iteration
  #
  # @return [Enumerator] an enumerator for all found scores and members
  def zscan_each(key, **options, &block)
    return to_enum(:zscan_each, key, **options) unless block_given?

    cursor = 0
    loop do
      cursor, values = zscan(key, cursor, **options)
      values.each(&block)
      break if cursor == "0"
    end
  end

  # Scan a set
  #
  # @example Retrieve the first batch of keys in a set
  #   redis.sscan("set", 0)
  #
  # @param [String, Integer] cursor the cursor of the iteration
  # @param [Hash] options
  #   - `:match => String`: only return keys matching the pattern
  #   - `:count => Integer`: return count keys at most per iteration
  #
  # @return [String, Array<String>] the next cursor and all found members
  def sscan(key, cursor, **options)
    _scan(:sscan, cursor, [key], **options)
  end

  # Scan a set
  #
  # @example Retrieve all of the keys in a set
  #   redis.sscan_each("set").to_a
  #   # => ["key1", "key2", "key3"]
  #
  # @param [Hash] options
  #   - `:match => String`: only return keys matching the pattern
  #   - `:count => Integer`: return count keys at most per iteration
  #
  # @return [Enumerator] an enumerator for all keys in the set
  def sscan_each(key, **options, &block)
    return to_enum(:sscan_each, key, **options) unless block_given?

    cursor = 0
    loop do
      cursor, keys = sscan(key, cursor, **options)
      keys.each(&block)
      break if cursor == "0"
    end
  end

  # Add one or more members to a HyperLogLog structure.
  #
  # @param [String] key
  # @param [String, Array<String>] member one member, or array of members
  # @return [Boolean] true if at least 1 HyperLogLog internal register was altered. false otherwise.
  def pfadd(key, member)
    synchronize do |client|
      client.call([:pfadd, key, member], &Boolify)
    end
  end

  # Get the approximate cardinality of members added to HyperLogLog structure.
  #
  # If called with multiple keys, returns the approximate cardinality of the
  # union of the HyperLogLogs contained in the keys.
  #
  # @param [String, Array<String>] keys
  # @return [Integer]
  def pfcount(*keys)
    synchronize do |client|
      client.call([:pfcount] + keys)
    end
  end

  # Merge multiple HyperLogLog values into an unique value that will approximate the cardinality of the union of
  # the observed Sets of the source HyperLogLog structures.
  #
  # @param [String] dest_key destination key
  # @param [String, Array<String>] source_key source key, or array of keys
  # @return [Boolean]
  def pfmerge(dest_key, *source_key)
    synchronize do |client|
      client.call([:pfmerge, dest_key, *source_key], &BoolifySet)
    end
  end

  # Adds the specified geospatial items (latitude, longitude, name) to the specified key
  #
  # @param [String] key
  # @param [Array] member arguemnts for member or members: longitude, latitude, name
  # @return [Integer] number of elements added to the sorted set
  def geoadd(key, *member)
    synchronize do |client|
      client.call([:geoadd, key, *member])
    end
  end

  # Returns geohash string representing position for specified members of the specified key.
  #
  # @param [String] key
  # @param [String, Array<String>] member one member or array of members
  # @return [Array<String, nil>] returns array containg geohash string if member is present, nil otherwise
  def geohash(key, member)
    synchronize do |client|
      client.call([:geohash, key, member])
    end
  end

  # Query a sorted set representing a geospatial index to fetch members matching a
  # given maximum distance from a point
  #
  # @param [Array] args key, longitude, latitude, radius, unit(m|km|ft|mi)
  # @param ['asc', 'desc'] sort sort returned items from the nearest to the farthest
  #   or the farthest to the nearest relative to the center
  # @param [Integer] count limit the results to the first N matching items
  # @param ['WITHDIST', 'WITHCOORD', 'WITHHASH'] options to return additional information
  # @return [Array<String>] may be changed with `options`

  def georadius(*args, **geoptions)
    geoarguments = _geoarguments(*args, **geoptions)

    synchronize do |client|
      client.call([:georadius, *geoarguments])
    end
  end

  # Query a sorted set representing a geospatial index to fetch members matching a
  # given maximum distance from an already existing member
  #
  # @param [Array] args key, member, radius, unit(m|km|ft|mi)
  # @param ['asc', 'desc'] sort sort returned items from the nearest to the farthest or the farthest
  #   to the nearest relative to the center
  # @param [Integer] count limit the results to the first N matching items
  # @param ['WITHDIST', 'WITHCOORD', 'WITHHASH'] options to return additional information
  # @return [Array<String>] may be changed with `options`

  def georadiusbymember(*args, **geoptions)
    geoarguments = _geoarguments(*args, **geoptions)

    synchronize do |client|
      client.call([:georadiusbymember, *geoarguments])
    end
  end

  # Returns longitude and latitude of members of a geospatial index
  #
  # @param [String] key
  # @param [String, Array<String>] member one member or array of members
  # @return [Array<Array<String>, nil>] returns array of elements, where each
  #   element is either array of longitude and latitude or nil
  def geopos(key, member)
    synchronize do |client|
      client.call([:geopos, key, member])
    end
  end

  # Returns the distance between two members of a geospatial index
  #
  # @param [String ]key
  # @param [Array<String>] members
  # @param ['m', 'km', 'mi', 'ft'] unit
  # @return [String, nil] returns distance in spefied unit if both members present, nil otherwise.
  def geodist(key, member1, member2, unit = 'm')
    synchronize do |client|
      client.call([:geodist, key, member1, member2, unit])
    end
  end

  # Returns the stream information each subcommand.
  #
  # @example stream
  #   redis.xinfo(:stream, 'mystream')
  # @example groups
  #   redis.xinfo(:groups, 'mystream')
  # @example consumers
  #   redis.xinfo(:consumers, 'mystream', 'mygroup')
  #
  # @param subcommand [String] e.g. `stream` `groups` `consumers`
  # @param key        [String] the stream key
  # @param group      [String] the consumer group name, required if subcommand is `consumers`
  #
  # @return [Hash]        information of the stream if subcommand is `stream`
  # @return [Array<Hash>] information of the consumer groups if subcommand is `groups`
  # @return [Array<Hash>] information of the consumers if subcommand is `consumers`
  def xinfo(subcommand, key, group = nil)
    args = [:xinfo, subcommand, key, group].compact
    synchronize do |client|
      client.call(args) do |reply|
        case subcommand.to_s.downcase
        when 'stream'              then Hashify.call(reply)
        when 'groups', 'consumers' then reply.map { |arr| Hashify.call(arr) }
        else reply
        end
      end
    end
  end

  # Add new entry to the stream.
  #
  # @example Without options
  #   redis.xadd('mystream', f1: 'v1', f2: 'v2')
  # @example With options
  #   redis.xadd('mystream', { f1: 'v1', f2: 'v2' }, id: '0-0', maxlen: 1000, approximate: true)
  #
  # @param key   [String] the stream key
  # @param entry [Hash]   one or multiple field-value pairs
  # @param opts  [Hash]   several options for `XADD` command
  #
  # @option opts [String]  :id          the entry id, default value is `*`, it means auto generation
  # @option opts [Integer] :maxlen      max length of entries
  # @option opts [Boolean] :approximate whether to add `~` modifier of maxlen or not
  #
  # @return [String] the entry id
  def xadd(key, entry, approximate: nil, maxlen: nil, id: '*')
    args = [:xadd, key]
    if maxlen
      args << "MAXLEN"
      args << "~" if approximate
      args << maxlen
    end
    args << id
    args.concat(entry.to_a.flatten)
    synchronize { |client| client.call(args) }
  end

  # Trims older entries of the stream if needed.
  #
  # @example Without options
  #   redis.xtrim('mystream', 1000)
  # @example With options
  #   redis.xtrim('mystream', 1000, approximate: true)
  #
  # @param key         [String]  the stream key
  # @param mexlen      [Integer] max length of entries
  # @param approximate [Boolean] whether to add `~` modifier of maxlen or not
  #
  # @return [Integer] the number of entries actually deleted
  def xtrim(key, maxlen, approximate: false)
    args = [:xtrim, key, 'MAXLEN', (approximate ? '~' : nil), maxlen].compact
    synchronize { |client| client.call(args) }
  end

  # Delete entries by entry ids.
  #
  # @example With splatted entry ids
  #   redis.xdel('mystream', '0-1', '0-2')
  # @example With arrayed entry ids
  #   redis.xdel('mystream', ['0-1', '0-2'])
  #
  # @param key [String]        the stream key
  # @param ids [Array<String>] one or multiple entry ids
  #
  # @return [Integer] the number of entries actually deleted
  def xdel(key, *ids)
    args = [:xdel, key].concat(ids.flatten)
    synchronize { |client| client.call(args) }
  end

  # Fetches entries of the stream in ascending order.
  #
  # @example Without options
  #   redis.xrange('mystream')
  # @example With a specific start
  #   redis.xrange('mystream', '0-1')
  # @example With a specific start and end
  #   redis.xrange('mystream', '0-1', '0-3')
  # @example With count options
  #   redis.xrange('mystream', count: 10)
  #
  # @param key [String]  the stream key
  # @param start [String]  first entry id of range, default value is `-`
  # @param end [String]  last entry id of range, default value is `+`
  # @param count [Integer] the number of entries as limit
  #
  # @return [Array<Array<String, Hash>>] the ids and entries pairs
  def xrange(key, start = '-', range_end = '+', count: nil)
    args = [:xrange, key, start, range_end]
    args.concat(['COUNT', count]) if count
    synchronize { |client| client.call(args, &HashifyStreamEntries) }
  end

  # Fetches entries of the stream in descending order.
  #
  # @example Without options
  #   redis.xrevrange('mystream')
  # @example With a specific end
  #   redis.xrevrange('mystream', '0-3')
  # @example With a specific end and start
  #   redis.xrevrange('mystream', '0-3', '0-1')
  # @example With count options
  #   redis.xrevrange('mystream', count: 10)
  #
  # @param key [String]  the stream key
  # @param end [String]  first entry id of range, default value is `+`
  # @param start [String]  last entry id of range, default value is `-`
  # @params count [Integer] the number of entries as limit
  #
  # @return [Array<Array<String, Hash>>] the ids and entries pairs
  def xrevrange(key, range_end = '+', start = '-', count: nil)
    args = [:xrevrange, key, range_end, start]
    args.concat(['COUNT', count]) if count
    synchronize { |client| client.call(args, &HashifyStreamEntries) }
  end

  # Returns the number of entries inside a stream.
  #
  # @example With key
  #   redis.xlen('mystream')
  #
  # @param key [String] the stream key
  #
  # @return [Integer] the number of entries
  def xlen(key)
    synchronize { |client| client.call([:xlen, key]) }
  end

  # Fetches entries from one or multiple streams. Optionally blocking.
  #
  # @example With a key
  #   redis.xread('mystream', '0-0')
  # @example With multiple keys
  #   redis.xread(%w[mystream1 mystream2], %w[0-0 0-0])
  # @example With count option
  #   redis.xread('mystream', '0-0', count: 2)
  # @example With block option
  #   redis.xread('mystream', '$', block: 1000)
  #
  # @param keys  [Array<String>] one or multiple stream keys
  # @param ids   [Array<String>] one or multiple entry ids
  # @param count [Integer]       the number of entries as limit per stream
  # @param block [Integer]       the number of milliseconds as blocking timeout
  #
  # @return [Hash{String => Hash{String => Hash}}] the entries
  def xread(keys, ids, count: nil, block: nil)
    args = [:xread]
    args << 'COUNT' << count if count
    args << 'BLOCK' << block.to_i if block
    _xread(args, keys, ids, block)
  end

  # Manages the consumer group of the stream.
  #
  # @example With `create` subcommand
  #   redis.xgroup(:create, 'mystream', 'mygroup', '$')
  # @example With `setid` subcommand
  #   redis.xgroup(:setid, 'mystream', 'mygroup', '$')
  # @example With `destroy` subcommand
  #   redis.xgroup(:destroy, 'mystream', 'mygroup')
  # @example With `delconsumer` subcommand
  #   redis.xgroup(:delconsumer, 'mystream', 'mygroup', 'consumer1')
  #
  # @param subcommand     [String] `create` `setid` `destroy` `delconsumer`
  # @param key            [String] the stream key
  # @param group          [String] the consumer group name
  # @param id_or_consumer [String]
  #   * the entry id or `$`, required if subcommand is `create` or `setid`
  #   * the consumer name, required if subcommand is `delconsumer`
  # @param mkstream [Boolean] whether to create an empty stream automatically or not
  #
  # @return [String] `OK` if subcommand is `create` or `setid`
  # @return [Integer] effected count if subcommand is `destroy` or `delconsumer`
  def xgroup(subcommand, key, group, id_or_consumer = nil, mkstream: false)
    args = [:xgroup, subcommand, key, group, id_or_consumer, (mkstream ? 'MKSTREAM' : nil)].compact
    synchronize { |client| client.call(args) }
  end

  # Fetches a subset of the entries from one or multiple streams related with the consumer group.
  # Optionally blocking.
  #
  # @example With a key
  #   redis.xreadgroup('mygroup', 'consumer1', 'mystream', '>')
  # @example With multiple keys
  #   redis.xreadgroup('mygroup', 'consumer1', %w[mystream1 mystream2], %w[> >])
  # @example With count option
  #   redis.xreadgroup('mygroup', 'consumer1', 'mystream', '>', count: 2)
  # @example With block option
  #   redis.xreadgroup('mygroup', 'consumer1', 'mystream', '>', block: 1000)
  # @example With noack option
  #   redis.xreadgroup('mygroup', 'consumer1', 'mystream', '>', noack: true)
  #
  # @param group    [String]        the consumer group name
  # @param consumer [String]        the consumer name
  # @param keys     [Array<String>] one or multiple stream keys
  # @param ids      [Array<String>] one or multiple entry ids
  # @param opts     [Hash]          several options for `XREADGROUP` command
  #
  # @option opts [Integer] :count the number of entries as limit
  # @option opts [Integer] :block the number of milliseconds as blocking timeout
  # @option opts [Boolean] :noack whether message loss is acceptable or not
  #
  # @return [Hash{String => Hash{String => Hash}}] the entries
  def xreadgroup(group, consumer, keys, ids, count: nil, block: nil, noack: nil)
    args = [:xreadgroup, 'GROUP', group, consumer]
    args << 'COUNT' << count if count
    args << 'BLOCK' << block.to_i if block
    args << 'NOACK' if noack
    _xread(args, keys, ids, block)
  end

  # Removes one or multiple entries from the pending entries list of a stream consumer group.
  #
  # @example With a entry id
  #   redis.xack('mystream', 'mygroup', '1526569495631-0')
  # @example With splatted entry ids
  #   redis.xack('mystream', 'mygroup', '0-1', '0-2')
  # @example With arrayed entry ids
  #   redis.xack('mystream', 'mygroup', %w[0-1 0-2])
  #
  # @param key   [String]        the stream key
  # @param group [String]        the consumer group name
  # @param ids   [Array<String>] one or multiple entry ids
  #
  # @return [Integer] the number of entries successfully acknowledged
  def xack(key, group, *ids)
    args = [:xack, key, group].concat(ids.flatten)
    synchronize { |client| client.call(args) }
  end

  # Changes the ownership of a pending entry
  #
  # @example With splatted entry ids
  #   redis.xclaim('mystream', 'mygroup', 'consumer1', 3600000, '0-1', '0-2')
  # @example With arrayed entry ids
  #   redis.xclaim('mystream', 'mygroup', 'consumer1', 3600000, %w[0-1 0-2])
  # @example With idle option
  #   redis.xclaim('mystream', 'mygroup', 'consumer1', 3600000, %w[0-1 0-2], idle: 1000)
  # @example With time option
  #   redis.xclaim('mystream', 'mygroup', 'consumer1', 3600000, %w[0-1 0-2], time: 1542866959000)
  # @example With retrycount option
  #   redis.xclaim('mystream', 'mygroup', 'consumer1', 3600000, %w[0-1 0-2], retrycount: 10)
  # @example With force option
  #   redis.xclaim('mystream', 'mygroup', 'consumer1', 3600000, %w[0-1 0-2], force: true)
  # @example With justid option
  #   redis.xclaim('mystream', 'mygroup', 'consumer1', 3600000, %w[0-1 0-2], justid: true)
  #
  # @param key           [String]        the stream key
  # @param group         [String]        the consumer group name
  # @param consumer      [String]        the consumer name
  # @param min_idle_time [Integer]       the number of milliseconds
  # @param ids           [Array<String>] one or multiple entry ids
  # @param opts          [Hash]          several options for `XCLAIM` command
  #
  # @option opts [Integer] :idle       the number of milliseconds as last time it was delivered of the entry
  # @option opts [Integer] :time       the number of milliseconds as a specific Unix Epoch time
  # @option opts [Integer] :retrycount the number of retry counter
  # @option opts [Boolean] :force      whether to create the pending entry to the pending entries list or not
  # @option opts [Boolean] :justid     whether to fetch just an array of entry ids or not
  #
  # @return [Hash{String => Hash}] the entries successfully claimed
  # @return [Array<String>]        the entry ids successfully claimed if justid option is `true`
  def xclaim(key, group, consumer, min_idle_time, *ids, **opts)
    args = [:xclaim, key, group, consumer, min_idle_time].concat(ids.flatten)
    args.concat(['IDLE',       opts[:idle].to_i])  if opts[:idle]
    args.concat(['TIME',       opts[:time].to_i])  if opts[:time]
    args.concat(['RETRYCOUNT', opts[:retrycount]]) if opts[:retrycount]
    args << 'FORCE'                                if opts[:force]
    args << 'JUSTID'                               if opts[:justid]
    blk = opts[:justid] ? Noop : HashifyStreamEntries
    synchronize { |client| client.call(args, &blk) }
  end

  # Transfers ownership of pending stream entries that match the specified criteria.
  #
  # @example Claim next pending message stuck > 5 minutes  and mark as retry
  #   redis.xautoclaim('mystream', 'mygroup', 'consumer1', 3600000, '0-0')
  # @example Claim 50 next pending messages stuck > 5 minutes  and mark as retry
  #   redis.xclaim('mystream', 'mygroup', 'consumer1', 3600000, '0-0', count: 50)
  # @example Claim next pending message stuck > 5 minutes and don't mark as retry
  #   redis.xclaim('mystream', 'mygroup', 'consumer1', 3600000, '0-0', justid: true)
  # @example Claim next pending message after this id stuck > 5 minutes  and mark as retry
  #   redis.xautoclaim('mystream', 'mygroup', 'consumer1', 3600000, '1641321233-0')
  #
  # @param key           [String]        the stream key
  # @param group         [String]        the consumer group name
  # @param consumer      [String]        the consumer name
  # @param min_idle_time [Integer]       the number of milliseconds
  # @param start         [String]        entry id to start scanning from or 0-0 for everything
  # @param count         [Integer]       number of messages to claim (default 1)
  # @param justid        [Boolean]       whether to fetch just an array of entry ids or not.
  #                                      Does not increment retry count when true
  #
  # @return [Hash{String => Hash}] the entries successfully claimed
  # @return [Array<String>]        the entry ids successfully claimed if justid option is `true`
  def xautoclaim(key, group, consumer, min_idle_time, start, count: nil, justid: false)
    args = [:xautoclaim, key, group, consumer, min_idle_time, start]
    if count
      args << 'COUNT' << count.to_s
    end
    args << 'JUSTID' if justid
    blk = justid ? HashifyStreamAutoclaimJustId : HashifyStreamAutoclaim
    synchronize { |client| client.call(args, &blk) }
  end

  # Fetches not acknowledging pending entries
  #
  # @example With key and group
  #   redis.xpending('mystream', 'mygroup')
  # @example With range options
  #   redis.xpending('mystream', 'mygroup', '-', '+', 10)
  # @example With range and consumer options
  #   redis.xpending('mystream', 'mygroup', '-', '+', 10, 'consumer1')
  #
  # @param key      [String]  the stream key
  # @param group    [String]  the consumer group name
  # @param start    [String]  start first entry id of range
  # @param end      [String]  end   last entry id of range
  # @param count    [Integer] count the number of entries as limit
  # @param consumer [String]  the consumer name
  #
  # @return [Hash]        the summary of pending entries
  # @return [Array<Hash>] the pending entries details if options were specified
  def xpending(key, group, *args)
    command_args = [:xpending, key, group]
    case args.size
    when 0, 3, 4
      command_args.concat(args)
    else
      raise ArgumentError, "wrong number of arguments (given #{args.size + 2}, expected 2, 5 or 6)"
    end

    summary_needed = args.empty?
    blk = summary_needed ? HashifyStreamPendings : HashifyStreamPendingDetails
    synchronize { |client| client.call(command_args, &blk) }
  end

  # Interact with the sentinel command (masters, master, slaves, failover)
  #
  # @param [String] subcommand e.g. `masters`, `master`, `slaves`
  # @param [Array<String>] args depends on subcommand
  # @return [Array<String>, Hash<String, String>, String] depends on subcommand
  def sentinel(subcommand, *args)
    subcommand = subcommand.to_s.downcase
    synchronize do |client|
      client.call([:sentinel, subcommand] + args) do |reply|
        case subcommand
        when "get-master-addr-by-name"
          reply
        else
          if reply.is_a?(Array)
            if reply[0].is_a?(Array)
              reply.map(&Hashify)
            else
              Hashify.call(reply)
            end
          else
            reply
          end
        end
      end
    end
  end

  # Sends `CLUSTER *` command to random node and returns its reply.
  #
  # @see https://redis.io/commands#cluster Reference of cluster command
  #
  # @param subcommand [String, Symbol] the subcommand of cluster command
  #   e.g. `:slots`, `:nodes`, `:slaves`, `:info`
  #
  # @return [Object] depends on the subcommand
  def cluster(subcommand, *args)
    subcommand = subcommand.to_s.downcase
    block = case subcommand
    when 'slots'
      HashifyClusterSlots
    when 'nodes'
      HashifyClusterNodes
    when 'slaves'
      HashifyClusterSlaves
    when 'info'
      HashifyInfo
    else
      Noop
    end

    # @see https://github.com/antirez/redis/blob/unstable/src/redis-trib.rb#L127 raw reply expected
    block = Noop unless @cluster_mode

    synchronize do |client|
      client.call([:cluster, subcommand] + args, &block)
    end
  end

  # Sends `ASKING` command to random node and returns its reply.
  #
  # @see https://redis.io/topics/cluster-spec#ask-redirection ASK redirection
  #
  # @return [String] `'OK'`
  def asking
    synchronize { |client| client.call(%i[asking]) }
  end

  def id
    @original_client.id
  end

  def inspect
    "#<Redis client v#{Redis::VERSION} for #{id}>"
  end

  def dup
    self.class.new(@options)
  end

  def connection
    return @original_client.connection_info if @cluster_mode

    {
      host: @original_client.host,
      port: @original_client.port,
      db: @original_client.db,
      id: @original_client.id,
      location: @original_client.location
    }
  end

  def method_missing(command, *args) # rubocop:disable Style/MissingRespondToMissing
    synchronize do |client|
      client.call([command] + args)
    end
  end

  private

  # Commands returning 1 for true and 0 for false may be executed in a pipeline
  # where the method call will return nil. Propagate the nil instead of falsely
  # returning false.
  Boolify = lambda { |value|
    case value
    when 1
      true
    when 0
      false
    else
      value
    end
  }

  BoolifySet = lambda { |value|
    case value
    when "OK"
      true
    when nil
      false
    else
      value
    end
  }

  Hashify = lambda { |value|
    if value.respond_to?(:each_slice)
      value.each_slice(2).to_h
    else
      value
    end
  }

  Floatify = lambda { |value|
    case value
    when "inf"
      Float::INFINITY
    when "-inf"
      -Float::INFINITY
    when String
      Float(value)
    else
      value
    end
  }

  FloatifyPairs = lambda { |value|
    return value unless value.respond_to?(:each_slice)

    value.each_slice(2).map do |member, score|
      [member, Floatify.call(score)]
    end
  }

  HashifyInfo = lambda { |reply|
    lines = reply.split("\r\n").grep_v(/^(#|$)/)
    lines.map! { |line| line.split(':', 2) }
    lines.compact!
    lines.to_h
  }

  HashifyStreams = lambda { |reply|
    case reply
    when nil
      {}
    else
      reply.map { |key, entries| [key, HashifyStreamEntries.call(entries)] }.to_h
    end
  }

  EMPTY_STREAM_RESPONSE = [nil].freeze
  private_constant :EMPTY_STREAM_RESPONSE

  HashifyStreamEntries = lambda { |reply|
    reply.compact.map do |entry_id, values|
      [entry_id, values&.each_slice(2)&.to_h]
    end
  }

  HashifyStreamAutoclaim = lambda { |reply|
    {
      'next' => reply[0],
      'entries' => reply[1].map { |entry| [entry[0], entry[1].each_slice(2).to_h] }
    }
  }

  HashifyStreamAutoclaimJustId = lambda { |reply|
    {
      'next' => reply[0],
      'entries' => reply[1]
    }
  }

  HashifyStreamPendings = lambda { |reply|
    {
      'size' => reply[0],
      'min_entry_id' => reply[1],
      'max_entry_id' => reply[2],
      'consumers' => reply[3].nil? ? {} : reply[3].to_h
    }
  }

  HashifyStreamPendingDetails = lambda { |reply|
    reply.map do |arr|
      {
        'entry_id' => arr[0],
        'consumer' => arr[1],
        'elapsed' => arr[2],
        'count' => arr[3]
      }
    end
  }

  HashifyClusterNodeInfo = lambda { |str|
    arr = str.split(' ')
    {
      'node_id' => arr[0],
      'ip_port' => arr[1],
      'flags' => arr[2].split(','),
      'master_node_id' => arr[3],
      'ping_sent' => arr[4],
      'pong_recv' => arr[5],
      'config_epoch' => arr[6],
      'link_state' => arr[7],
      'slots' => arr[8].nil? ? nil : Range.new(*arr[8].split('-'))
    }
  }

  HashifyClusterSlots = lambda { |reply|
    reply.map do |arr|
      first_slot, last_slot = arr[0..1]
      master = { 'ip' => arr[2][0], 'port' => arr[2][1], 'node_id' => arr[2][2] }
      replicas = arr[3..-1].map { |r| { 'ip' => r[0], 'port' => r[1], 'node_id' => r[2] } }
      {
        'start_slot' => first_slot,
        'end_slot' => last_slot,
        'master' => master,
        'replicas' => replicas
      }
    end
  }

  HashifyClusterNodes = lambda { |reply|
    reply.split(/[\r\n]+/).map { |str| HashifyClusterNodeInfo.call(str) }
  }

  HashifyClusterSlaves = lambda { |reply|
    reply.map { |str| HashifyClusterNodeInfo.call(str) }
  }

  Noop = ->(reply) { reply }

  def _geoarguments(*args, options: nil, sort: nil, count: nil)
    args.push sort if sort
    args.push 'count', count if count
    args.push options if options
    args
  end

  def _subscription(method, timeout, channels, block)
    return @client.call([method] + channels) if subscribed?

    begin
      original, @client = @client, SubscribedClient.new(@client)
      if timeout > 0
        @client.send(method, timeout, *channels, &block)
      else
        @client.send(method, *channels, &block)
      end
    ensure
      @client = original
    end
  end

  def _xread(args, keys, ids, blocking_timeout_msec)
    keys = keys.is_a?(Array) ? keys : [keys]
    ids = ids.is_a?(Array) ? ids : [ids]
    args << 'STREAMS'
    args.concat(keys)
    args.concat(ids)

    synchronize do |client|
      if blocking_timeout_msec.nil?
        client.call(args, &HashifyStreams)
      elsif blocking_timeout_msec.to_f.zero?
        client.call_without_timeout(args, &HashifyStreams)
      else
        timeout = client.timeout.to_f + blocking_timeout_msec.to_f / 1000.0
        client.call_with_timeout(args, timeout, &HashifyStreams)
      end
    end
  end
end

require_relative "redis/version"
require_relative "redis/connection"
require_relative "redis/client"
require_relative "redis/cluster"
require_relative "redis/pipeline"
require_relative "redis/subscribe"