test_source_tree_rewriter.rb

# frozen_string_literal: true

require 'helper'

class TestSourceTreeRewriter < Minitest::Test
  module Setup
    def setup
      @buf = Parser::Source::Buffer.new('(rewriter)',
        source: 'puts(:hello, :world)')

      @hello = range(5, 6)
      @ll = range(8, 2)
      @comma_space = range(11,2)
      @world = range(13,6)
      @whole = range(0, @buf.source.length)
    end

    def range(from, len = nil)
      from, len = from.begin, from.end - from.begin unless len
      Parser::Source::Range.new(@buf, from, from + len)
    end
  end

  include Setup

  # Returns either:
  #  - yield rewriter
  #  - [diagnostic, ...] (Diagnostics)
  #  - Parser::ClobberingError
  #
  def build(actions, **policy)
    diagnostics = []
    diags = -> { diagnostics.flatten.map(&:strip).join("\n") }
    rewriter = Parser::Source::TreeRewriter.new(@buf, **policy)
    rewriter.diagnostics.consumer = -> diag { diagnostics << diag.render }
    actions.each do |action, range, *args|
      rewriter.public_send(action, range, *args)
    end
    if diagnostics.empty?
      yield rewriter
    else
      diags.call
    end
  rescue ::Parser::ClobberingError => _e
    [::Parser::ClobberingError, diags.call]
  end

  # Returns either:
  #  - String (Normal operation)
  #  - [diagnostic, ...] (Diagnostics)
  #  - Parser::ClobberingError
  #
  def apply(actions, **policy)
    build(actions, **policy) { |rewriter| rewriter.process }
  end

  # Expects ordered actions to be grouped together
  def check_actions(expected, grouped_actions, **policy)
    grouped_actions.permutation do |sequence|
      # [action, [action, action]]  => [action, action, action]
      # except we can't use flatten because "action" are arrays themselves
      actions = sequence.flat_map { |group| group.first.is_a?(Array) ? group : [group] }
      assert_equal(expected, apply(actions, **policy))
    end
  end

  def assert_actions_result(expected, *actions, **rest)
    if expected == :raise
      diagnostic = rest.values.first
      check_actions([::Parser::ClobberingError, diagnostic], actions)
    elsif rest.empty?
      check_actions(expected, actions)
    else
      policy, diagnostic = rest.first
      check_actions(expected, actions, policy => :accept)
      check_actions(diagnostic, actions, policy => :warn)
      diagnostic.gsub!(/warning: /, 'error: ')
      check_actions([::Parser::ClobberingError, diagnostic], actions, policy => :raise)
    end
  end

  ### Simple cases

  def test_remove
    assert_actions_result 'puts(, :world)', [:remove, @hello]
  end

  def test_insert_before
    assert_actions_result 'puts(:hello, 42, :world)', [:insert_before, @world, '42, ']
  end

  def test_insert_after
    assert_actions_result 'puts(:hello, 42, :world)', [:insert_after, @hello, ', 42']
  end

  def test_wrap
    assert_actions_result 'puts([:hello], :world)', [:wrap, @hello, '[', ']']
  end

  def test_replace
    assert_actions_result 'puts(:hi, :world)', [:replace, @hello, ':hi']
  end

  #
  # All other cases, as per doc
  #

  def test_crossing_non_deletions
    check = [
      [:wrap, '(', ')'],
      [:remove],
      [:replace, 'xx'],
    ]
    check.combination(2) do |(action, *args), (action_b, *args_b)|
      next if action == :remove && action_b == :remove
      assert_actions_result :raise,
                            [[action, @hello.join(@comma_space), *args],
                             [action_b, @world.join(@comma_space), *args_b]],
                            diagnostic: <<-DIAGNOSTIC.chomp
(rewriter):1:12: error: the rewriting action on:
(rewriter):1: puts(:hello, :world)
(rewriter):1:            ^~~~~~~~
(rewriter):1:6: error: is crossing that on:
(rewriter):1: puts(:hello, :world)
(rewriter):1:      ^~~~~~~~
DIAGNOSTIC
    end
  end


  def test_crossing_deletions
    assert_actions_result 'puts()',
                          [[:remove, @hello.join(@comma_space)],
                           [:remove, @world.join(@comma_space)]],
                          crossing_deletions: <<-DIAGNOSTIC.chomp
(rewriter):1:12: warning: the deletion of:
(rewriter):1: puts(:hello, :world)
(rewriter):1:            ^~~~~~~~
(rewriter):1:6: warning: is crossing:
(rewriter):1: puts(:hello, :world)
(rewriter):1:      ^~~~~~~~
DIAGNOSTIC
  end

  def test_multiple_actions
    assert_actions_result 'puts({:hello => [:everybody]})',
                          [:replace, @comma_space, ' => '],
                          [:wrap, @hello.join(@world), '{', '}'],
                          [:replace, @world, ':everybody'],
                          [:wrap, @world, '[', ']']
  end

  def test_wraps_same_range
    assert_actions_result 'puts([(:hello)], :world)',
                           [[:wrap, @hello, '(', ')'],
                            [:wrap, @hello, '[', ']']]
  end

  def test_inserts_on_empty_ranges
    assert_actions_result 'puts({x}:hello[y], :world)',
      [:insert_before, @hello.begin, '{'],
      [:replace, @hello.begin, 'x'],
      [:insert_after, @hello.begin, '}'],
      [:insert_before, @hello.end, '['],
      [:replace, @hello.end, 'y'],
      [:insert_after, @hello.end, ']']
  end

  def test_replace_same_range
    assert_actions_result 'puts(:hey, :world)',
                           [[:replace, @hello, ':hi'],
                            [:replace, @hello, ':hey']],
                           different_replacements: <<-DIAGNOSTIC.chomp
(rewriter):1:6: warning: different replacements: :hey vs :hi
(rewriter):1: puts(:hello, :world)
(rewriter):1:      ^~~~~~
DIAGNOSTIC
  end

  def test_swallowed_insertions
    assert_actions_result 'puts(:hi)',
                           [[:wrap, @hello.adjust(begin_pos: 1), '__', '__'],
                            [:replace, @world.adjust(end_pos: -2), 'xx'],
                            [:replace, @hello.join(@world), ':hi']],
                           swallowed_insertions: <<-DIAGNOSTIC.chomp
(rewriter):1:6: warning: this replacement:
(rewriter):1: puts(:hello, :world)
(rewriter):1:      ^~~~~~~~~~~~~~
(rewriter):1:7: warning: swallows some inner rewriting actions:
(rewriter):1: puts(:hello, :world)
(rewriter):1:       ^~~~~  ~~~~
DIAGNOSTIC
  end

  def test_out_of_range_ranges
    rewriter = Parser::Source::TreeRewriter.new(@buf)
    assert_raises(IndexError) { rewriter.insert_before(range(0, 100), 'hola') }
  end

  def test_empty
    rewriter = Parser::Source::TreeRewriter.new(@buf)
    assert_equal true, rewriter.empty?

    # This is a trivial wrap
    rewriter.wrap(range(2,3), '', '')
    assert_equal true, rewriter.empty?

    # This is a trivial deletion
    rewriter.remove(range(2,0))
    assert_equal true, rewriter.empty?

    rewriter.remove(range(2,3))
    assert_equal false, rewriter.empty?
  end

  # splits array into two groups, yield all such possible pairs of groups
  # each_split([1, 2, 3, 4]) yields [1, 2], [3, 4];
  #                            then [1, 3], [2, 4]
  #                                 ...
  #                     and finally [3, 4], [1, 2]
  def each_split(array)
    n = array.size
    first_split_size = n.div(2)
    splitting = (0...n).to_set
    splitting.to_a.combination(first_split_size) do |indices|
      yield array.values_at(*indices),
            array.values_at(*(splitting - indices))
    end
  end

  # Checks that `actions+extra` give the same result when
  # made in order or from subgroups that are later merged.
  # The `extra` actions are always added at the end of the second group.
  #
  def check_all_merge_possibilities(actions, extra, **policy)
    expected = apply(actions + extra, **policy)

    each_split(actions) do |actions_1, actions_2|
      build(actions_1, **policy) do |rewriter_1|
        build(actions_2 + extra, **policy) do |rewriter_2|
          result = rewriter_1.merge(rewriter_2).process
          assert_equal(expected, result,
            "Group 1: #{actions_1.inspect}\n\n" +
            "Group 2: #{(actions_2 + extra).inspect}"
          )
        end
      end
    end
  end

  def test_merge
    check_all_merge_possibilities([
      [:wrap, @whole, '<', '>'],
      [:replace, @comma_space, ' => '],
      [:wrap, @hello, '!', '!'],
      # Following two wraps must have same value as they
      # will be applied in different orders...
      [:wrap, @hello.join(@world), '{', '}'],
      [:wrap, @hello.join(@world), '{', '}'],
      [:remove, @ll],
      [:replace, @world, ':everybody'],
      [:wrap, @world, '[', ']']
    ],
    [ # ... but this one is always going to be applied last (extra)
      [:wrap, @hello.join(@world), '@', '@'],
    ])
  end

  def representation_example
    Parser::Source::TreeRewriter.new(@buf)
      .wrap(range(1...10), '(', ')')
      .insert_after(range(2...6), '!')
      .replace(range(2...4), 'foo')
      .remove(range(5...6))
  end

  def test_nested_actions
    result = representation_example.as_nested_actions

    assert_equal( [ [:wrap, 1...10, '(', ')'],
                    [:wrap, 2...6, '', '!'],  # aka "insert_after"
                    [:replace, 2...4, 'foo'],
                    [:replace, 5...6, ''],  # aka "removal"
                  ],
                  result.each {|arr| arr[1] = arr[1].to_range }
                )
  end

  def test_ordered_replacements
    result = representation_example.as_replacements

    assert_equal( [ [ 1...1, '('],
                    [ 2...4, 'foo'],
                    [ 5...6, ''],
                    [ 6...6, '!'],
                    [ 10...10, ')'],
                  ],
                  result.map {|r, s| [r.to_range, s]}
                )
  end
end

class TestSourceTreeRewriterImport < Minitest::Test
  include TestSourceTreeRewriter::Setup
  def setup
    super
    @buf2 = Parser::Source::Buffer.new('(rewriter 2)',
      source: ':hello')

    @rewriter = Parser::Source::TreeRewriter.new(@buf)

    @rewriter2 = Parser::Source::TreeRewriter.new(@buf2)

    @hello2 = range2(0, 6)
    @ll2 = range2(3, 2)
  end

  def range2(from, len)
    Parser::Source::Range.new(@buf2, from, from + len)
  end

  def test_import_with_offset
    @rewriter2.wrap(@hello2, '[', ']')
    @rewriter.wrap(@hello.join(@world), '{', '}')
    @rewriter.import!(@rewriter2, offset: @hello.begin_pos)
    assert_equal 'puts({[:hello], :world})', @rewriter.process
  end

  def test_import_with_offset_from_bigger_source
    @rewriter2.wrap(@ll2, '[', ']')
    @rewriter.wrap(@hello, '{', '}')
    @rewriter2.import!(@rewriter, offset: -@hello.begin_pos)
    assert_equal '{:he[ll]o}', @rewriter2.process
  end

  def test_import_with_offset_and_self
    @rewriter.wrap(@ll, '[', ']')
    @rewriter.import!(@rewriter, offset: +3)
    @rewriter.replace(range(8,1), '**')
    assert_equal 'puts(:he[**l]o[, ]:world)', @rewriter.process
    @rewriter.import!(@rewriter, offset: -6)
    assert_equal 'pu[**s]([:h]e[**l]o[, ]:world)', @rewriter.process
  end

  def test_import_with_invalid_offset
    @rewriter.wrap(@ll, '[', ']')
    m = @rewriter.dup.import!(@rewriter, offset: -@ll.begin_pos)
    assert_equal '[pu]ts(:he[ll]o, :world)', m.process
    off = @buf.source.size - @ll.end_pos
    m = @rewriter.dup.import!(@rewriter, offset: off)
    assert_equal 'puts(:he[ll]o, :worl[d)]', m.process
    assert_raises { @rewriter.import!(@rewriter, offset: -@ll.begin_pos - 1) }
    assert_raises { @rewriter.import!(@rewriter, offset: off + 1) }
    assert_equal 'puts(:he[ll]o, :world)', @rewriter.process # Test atomicity of import!
  end

  def test_empty_import
    assert_equal @rewriter, @rewriter.import!(@rewriter2)
    assert_equal @rewriter, @rewriter.import!(@rewriter, offset: 42)
  end

  def test_inspect
    assert_equal '#<Parser::Source::TreeRewriter (rewriter): empty>', @rewriter.inspect
    @rewriter.insert_before(@hello, '[')
    @rewriter.replace(@ll, 'xxx')
    @rewriter.remove(@comma_space)
    assert_equal '#<Parser::Source::TreeRewriter (rewriter): +"["@5, ^"xxx"@8...10, -11...13>', @rewriter.inspect
    @rewriter.insert_before(@hello, '{')
    @rewriter.remove(@world)
    assert_equal '#<Parser::Source::TreeRewriter (rewriter): +"{["@5, ^"xxx"@8...10, -11...13, …>', @rewriter.inspect
  end
end