Clean up argument parsing.

rustfmt.toml

@@ -0,0 +1,79 @@
+## This is copied from https://github.com/rust-bitcoin/rust-bitcoin/blob/master/rustfmt.toml
+
+hard_tabs = false
+tab_spaces = 4
+newline_style = "Auto"
+indent_style = "Block"
+
+max_width = 100 # This is number of characters.
+# `use_small_heuristics` is ignored if the granular width config values are explicitly set.
+use_small_heuristics = "Max"    # "Max" == All granular width settings same as `max_width`.
+# # Granular width configuration settings. These are percentages of `max_width`.
+# fn_call_width = 60
+# attr_fn_like_width = 70
+# struct_lit_width = 18
+# struct_variant_width = 35
+# array_width = 60
+# chain_width = 60
+# single_line_if_else_max_width = 50
+
+wrap_comments = false
+format_code_in_doc_comments = false
+comment_width = 100             # Default 80
+normalize_comments = false
+normalize_doc_attributes = false
+format_strings = false
+format_macro_matchers = false
+format_macro_bodies = true
+hex_literal_case = "Preserve"
+empty_item_single_line = true
+struct_lit_single_line = true
+fn_single_line = true           # Default false
+where_single_line = false
+imports_indent = "Block"
+imports_layout = "Mixed"
+imports_granularity = "Module"     # Default "Preserve"
+group_imports = "StdExternalCrate" # Default "Preserve"
+reorder_imports = true
+reorder_modules = true
+reorder_impl_items = false
+type_punctuation_density = "Wide"
+space_before_colon = false
+space_after_colon = true
+spaces_around_ranges = false
+binop_separator = "Front"
+remove_nested_parens = true
+combine_control_expr = true
+overflow_delimited_expr = false
+struct_field_align_threshold = 0
+enum_discrim_align_threshold = 0
+match_arm_blocks = false        # Default true
+match_arm_leading_pipes = "Never"
+force_multiline_blocks = false
+fn_args_layout = "Tall"
+brace_style = "SameLineWhere"
+control_brace_style = "AlwaysSameLine"
+trailing_semicolon = true
+trailing_comma = "Vertical"
+match_block_trailing_comma = false
+blank_lines_upper_bound = 1
+blank_lines_lower_bound = 0
+edition = "2018"
+version = "One"
+inline_attribute_width = 0
+format_generated_files = true
+merge_derives = true
+use_try_shorthand = false
+use_field_init_shorthand = false
+force_explicit_abi = true
+condense_wildcard_suffixes = false
+color = "Auto"
+required_version = "1.5.1"
+unstable_features = false
+disable_all_formatting = false
+skip_children = false
+hide_parse_errors = false
+error_on_line_overflow = false
+error_on_unformatted = false
+emit_mode = "Files"
+make_backup = false

src/args.rs

@@ -0,0 +1,73 @@
+use std::{ffi::OsString, fmt, num::ParseIntError};
+
+use crate::{ScheduledChannel, ScheduledPayJoin};
+
+/// CLI argument errors.
+#[derive(Debug)]
+pub(crate) enum ArgError {
+    /// Argument not UTF-8
+    NotUTF8(OsString),
+    /// Parse feerate error
+    FeeRateError(ParseIntError),
+    /// Parse node address error
+    InvalidNodeAddress(ln_types::p2p_address::ParseError),
+    /// Parse bitcoin amount error
+    InvalidBitcoinAmount(bitcoin::util::amount::ParseAmountError),
+    /// Wallet amount error
+    InvalidWalletAmount(bitcoin::util::amount::ParseAmountError),
+}
+
+impl fmt::Display for ArgError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        // TODO: Do this properly.
+        write!(f, "invalid arguments: {:?}", self)
+    }
+}
+
+impl std::error::Error for ArgError {}
+
+/// Parses arguments in `[fee_rate] [(<p2p_addr>, <sats_amount>)...] [wallet_amount]`
+pub(crate) fn parse_args<A>(args: A) -> Result<Option<ScheduledPayJoin>, ArgError>
+where
+    A: Iterator<Item = OsString>,
+{
+    // ensure all args are utf8
+    let args = args
+        .map(|arg| arg.into_string())
+        .collect::<Result<Vec<_>, _>>()
+        .map_err(ArgError::NotUTF8)?;
+
+    // first argument is fee rate
+    let fee_rate = match args.get(0) {
+        Some(fee_rate_str) => fee_rate_str.parse::<u64>().map_err(ArgError::FeeRateError)?,
+        None => return Ok(None),
+    };
+
+    // return None if no remaining args.
+    let mut args = match args.get(1..) {
+        Some(args) => args.iter(),
+        None => return Ok(None),
+    };
+
+    // parse scheduled channel arguments: pairs of (addr, amount)
+    let mut channels = Vec::with_capacity(args.len() / 2);
+
+    // the remaining single argument is the wallet amount in satoshis (if any)
+    let wallet_amount = loop {
+        match (args.next(), args.next()) {
+            // we have a pair of arguments, interpret it as a scheduled channel (p2p addr, amount)
+            (Some(addr), Some(amount)) => {
+                channels.push(ScheduledChannel::from_args(addr, amount)?);
+            }
+            // if there is a remaining single argument, it is the wallet amount
+            (Some(amount), None) => {
+                break bitcoin::Amount::from_str_in(amount, bitcoin::Denomination::Satoshi)
+                    .map_err(ArgError::InvalidWalletAmount)?
+            }
+            // if there is no remaining single argument, the wallet amount is 0
+            _ => break bitcoin::Amount::ZERO,
+        }
+    };
+
+    Ok(Some(ScheduledPayJoin { wallet_amount, channels, fee_rate }))
+}