rubyfmt on rubyfmt.rb

#!/usr/bin/env ruby
require "ripper"
require "stringio"
require "pp"

LineMetadata = Struct.new(:comment_blocks)

class Line
  attr_accessor(:parts)
  def initialize(parts)
    @comments = []
    @parts = parts
  end

  def push_comment(comment)
    @comments << comment
  end

  def has_comment?
    [email protected]?
  end

  def <<(item)
    @parts << item
  end

  def string_length
    @parts.join("").length
  end

  def empty?
    @parts.empty?
  end

  def to_s
    build = @parts.join("")

    unless @comments.empty?
      build = "#{@comments.join("\n")}\n#{build}"
    end

    build
  end

  def strip_trailing_newlines
    while @parts.last == "\n"
      @parts.pop
    end
  end

  def remove_redundant_indents
    @parts.shift if @parts[0] == ""
  end

  def ends_with_newline?
    @parts.last == "\n"
  end

  def is_only_a_newline?
    @parts == ["\n"]
  end

  def contains_end?
    @parts.any? { |x| x == :end }
  end

  def contains_def?
    @parts.any? { |x| x == :def }
  end

  def contains_do?
    @parts.any? { |x| x == :do }
  end

  def contains_if?
    @parts.any? { |x| x == :if }
  end

  def contains_else?
    @parts.any? { |x| x == :else }
  end

  def contains_unless?
    @parts.any? { |x| x == :unless }
  end

  def declares_private?
    @parts.any? { |x| x == "private" } && @parts.length == 3
  end

  def declares_require?
    @parts.any? { |x| x == "require" } && @parts.none? { |x| x == "}" }
  end

  def declares_class_or_module?
    @parts.any? { |x| x == :class || x == :module }
  end

  def contains_while?
    @parts.any? { |x| x == :while }
  end

  def surpresses_blankline?
    contains_def? || contains_do? || contains_while? || contains_if? || contains_else?
  end
end

def want_blankline?(line, next_line)
  return unless next_line
  return true if line.contains_end? && !next_line.contains_end?
  return true if next_line.contains_do? && !line.surpresses_blankline?
  return true if (next_line.contains_if? || next_line.contains_unless?) && !line.surpresses_blankline?
  return true if line.declares_private?
  return true if line.declares_require? && !next_line.declares_require?
  return true if !line.declares_class_or_module? && next_line.has_comment?
  return true if !line.declares_class_or_module? && next_line.declares_class_or_module?
end

class ParserState
  attr_accessor(:depth_stack, :start_of_line, :line, :string_concat_position, :surpress_one_paren)
  attr_reader(:heredoc_strings)
  attr_reader(:result)
  attr_accessor(:render_queue)
  attr_reader(:comments_hash)
  attr_reader(:depth_stack)
  def initialize(result, line_metadata)
    @surpress_comments_stack = [false]
    @surpress_one_paren = false
    @result = result
    @depth_stack = [0]
    @start_of_line = [true]
    @render_queue = []
    @line = Line.new([])
    @current_orig_line_number = 0
    @comments_hash = line_metadata.comment_blocks
    @conditional_indent = [0]
    @heredoc_strings = []
    @string_concat_position = []
  end

  def self.with_depth_stack(output, from:)
    i = new(output, LineMetadata.new({}))
    i.depth_stack = from.depth_stack.dup
    i
  end

  def with_surpress_comments(value, &blk)
    @surpress_comments_stack << value
    blk.call
    @surpress_comments_stack.pop
  end

  def push_heredoc_content(symbol, indent, inner_string_components)
    buf = StringIO.new
    next_ps = ParserState.new(buf, LineMetadata.new({}))
    next_ps.depth_stack = depth_stack.dup
    format_inner_string(next_ps, inner_string_components, :heredoc)
    next_ps.emit_newline
    next_ps.write
    buf.rewind

    # buf gets an extra newline on the end, trim it
    @heredoc_strings << [
      symbol,
      indent,
      buf.read[0...-1],
    ]

    next_ps.heredoc_strings.each do |s|
      @heredoc_strings << s
    end
  end

  def with_start_of_line(value, &blk)
    start_of_line << value
    blk.call
    start_of_line.pop
  end

  def start_string_concat
    push_conditional_indent(:string) if @string_concat_position.empty?
    @string_concat_position << Object.new
  end

  def end_string_concat
    @string_concat_position.pop
    pop_conditional_indent if @string_concat_position.empty?
  end

  def on_line(line_number, skip=false)
    if line_number != @current_orig_line_number
      @arrays_on_line = -1
    end

    while !comments_hash.empty? && comments_hash.keys.sort.first < line_number
      key = comments_hash.keys.sort.first
      comment = comments_hash.delete(key)
      @line.push_comment(comment) unless @surpress_comments_stack.last
    end

    @current_orig_line_number = line_number
  end

  def write
    on_line(100000000000000)
    clear_empty_trailing_lines
    lines = render_queue
    clear_double_spaces(lines)
    add_valid_blanklines(lines)

    lines.each do |line|
      line.remove_redundant_indents
    end

    ensure_file_ends_with_exactly_one_newline(lines)
    result.write("\n")
    result.flush
  end

  def emit_while
    line << :while
  end

  def emit_indent
    spaces = (@conditional_indent.last) + (2 * @depth_stack.last)
    line << " " * spaces
  end

  def emit_slash
    line << "\\"
  end

  def emit_else
    line << :else
  end

  def emit_elsif
    line << "elsif"
  end

  def push_conditional_indent(type)
    if line.empty?
      @conditional_indent << 2 * @depth_stack.last
    else
      if type == :conditional
        @conditional_indent << 2 * @depth_stack.last
      elsif type == :string
        @conditional_indent << line.string_length
      end
    end

    @depth_stack << 0
  end

  def pop_conditional_indent
    @conditional_indent.pop
    @depth_stack.pop
  end

  def emit_comma_space
    line << ", "
  end

  def emit_return
    line << :return
  end

  def ensure_file_ends_with_exactly_one_newline(lines)
    lines.each_with_index do |line, i|
      if i == lines.length - 1
        line.strip_trailing_newlines
      end

      result.write(line)
    end
  end

  def add_valid_blanklines(lines)
    line = lines.first
    next_index = 1
    while next_index < lines.length
      if want_blankline?(line, lines[next_index])
        lines.insert(next_index, Line.new(["\n"]))
        next_index += 1
      end

      line = lines[next_index]
      next_index += 1
    end
  end

  def clear_double_spaces(lines)
    line = lines.first
    next_index = 1
    while next_index < lines.length
      while line.ends_with_newline? && lines[next_index] && lines[next_index].is_only_a_newline?
        lines.delete_at(next_index)
      end

      line = lines[next_index]
      next_index += 1
    end
  end

  def clear_empty_trailing_lines
    while render_queue.last == []
      render_queue.pop
    end

    while render_queue.last == ["\n"]
      render_queue.pop
    end
  end

  def emit_def(def_name)
    line << :def
    line << " #{def_name}"
  end

  def emit_params_list(params_list)
  end

  def emit_binary(symbol)
    line << " #{symbol} "
  end

  def emit_end
    emit_newline
    emit_indent if start_of_line.last
    line << :end
  end

  def emit_space
    line << " "
  end

  def emit_do
    line << :do
  end

  def emit_newline
    line << "\n"
    render_queue << line
    self.line = Line.new([])
    render_heredocs
  end

  def emit_dot
    line << "."
  end

  def emit_lonely_operator
    line << "&."
  end

  def emit_ident(ident)
    line << ident
  end

  def emit_op(op)
    line << op
  end

  def emit_int(int)
    emit_indent if start_of_line.last
    line << int
  end

  def emit_var_ref(ref)
    emit_indent if start_of_line.last
    line << ref
  end

  def emit_open_paren
    line << "("
  end

  def emit_close_paren
    line << ")"
  end

  def new_block(&blk)
    depth_stack[-1] += 1
    with_start_of_line(true, &blk)
    depth_stack[-1] -= 1
  end

  def dedent(&blk)
    depth_stack[-1] -= 1
    with_start_of_line(true, &blk)
    depth_stack[-1] += 1
  end

  def emit_open_block_arg_list
    line << "|"
  end

  def emit_close_block_arg_list
    line << "|"
  end

  def emit_double_quote
    line << "\""
  end

  def emit_module_keyword
    line << :module
  end

  def emit_class_keyword
    line << :class
  end

  def emit_const(const)
    line << const
  end

  def emit_double_colon
    line << "::"
  end

  def emit_symbol(symbol)
    line << ":#{symbol}"
  end

  def render_heredocs(skip=false)
    while !heredoc_strings.empty?
      symbol, indent, string = heredoc_strings.pop

      unless render_queue[-1] && render_queue[-1].ends_with_newline?
        line << "\n"
      end

      if string.end_with?("\n")
        string = string[0...-1]
      end

      line << string
      emit_newline

      if indent
        emit_indent
      end

      emit_ident(symbol)

      if !skip
        emit_newline
      end
    end
  end
end

def format_block_params_list(ps, params_list)
  ps.emit_open_block_arg_list
  ps.emit_params_list(params_list)
  ps.emit_close_block_arg_list
end

def format_until(ps, rest)
  conditional, expressions = rest
  ps.emit_indent if ps.start_of_line.last
  ps.emit_ident("until")
  ps.emit_space

  ps.with_start_of_line(false) do
    format_expression(ps, conditional)
  end

  ps.emit_newline

  (expressions || []).each do |expr|
    ps.new_block do
      format_expression(ps, expr)
    end
  end

  ps.emit_end
  ps.emit_newline
end

def format_def(ps, rest)
  def_expression, params, body = rest
  def_name = def_expression[1]
  line_number = def_expression.last.first
  ps.on_line(line_number)
  params = rest[1]
  body = rest[2]
  ps.emit_indent
  ps.emit_def(def_name)
  format_params(ps, params, "(", ")")
  ps.emit_newline

  ps.new_block do
    format_expression(ps, body)
  end

  ps.emit_end
  ps.emit_newline
  ps.emit_newline
end

def format_required_params(ps, required_params)
  return if required_params.empty?

  ps.with_start_of_line(false) do
    required_params.each_with_index do |expr, index|
      format_expression(ps, expr)

      if index != required_params.length - 1
        ps.emit_comma_space
      end
    end
  end
end

def format_optional_params(ps, optional_params)
  ps.with_start_of_line(false) do
    optional_params.each_with_index do |param, i|
      left, right = param
      format_expression(ps, left)
      ps.emit_ident("=")
      format_expression(ps, right)

      if i != optional_params.length - 1
        ps.emit_ident(", ")
      end
    end
  end
end

def format_kwargs(ps, kwargs)
  return if kwargs.empty?

  kwargs.each_with_index do |kwarg, index|
    label, false_or_expr = kwarg
    raise("got non label in kwarg") if label[0] != :@label
    ps.emit_ident(label[1])

    ps.with_start_of_line(false) do
      if false_or_expr
        ps.emit_space
      end

      format_expression(ps, false_or_expr) if false_or_expr
    end

    ps.emit_ident(", ") if index != kwargs.length - 1
  end
end

def format_rest_params(ps, rest_params)
  return if rest_params.empty?
  ps.emit_ident("*")
  return if rest_params[1].nil?
  rest_param, expr = rest_params
  raise("got bad rest_params") if rest_param != :rest_param

  ps.with_start_of_line(false) do
    format_expression(ps, expr)
  end
end

def format_blockarg(ps, blockarg)
  return if blockarg.empty?
  _, expr = blockarg

  ps.with_start_of_line(false) do
    ps.emit_ident("&")
    format_expression(ps, expr)
  end
end

def format_params(ps, params, open_delim, close_delim)
  return if params.nil?

  if params[0] == :paren || params[0] == :block_var
    params = params[1]
  end

  have_any_params = params[1..-1].any? { |x| !x.nil? }

  if have_any_params
    ps.emit_ident(open_delim)
  end

  bad_params = params[4..-1].any? { |x| !x.nil? }
  bad_params = false if params[5]
  bad_params = false if params[7]
  raise("dont know how to deal with a params list") if bad_params
  required_params = params[1] || []
  optional_params = params[2] || []
  rest_params = params[3] || []
  kwargs = params[5] || []
  block_arg = params[7] || []
  emission_order = [
    required_params,
    optional_params,
    rest_params,
    kwargs,
    block_arg,
  ]
  format_required_params(ps, required_params)
  did_emit = !emission_order.shift.empty?
  have_more = emission_order.map { |x| !x.empty? }.any?
  ps.emit_ident(", ") if did_emit && have_more
  format_optional_params(ps, optional_params)
  did_emit = !emission_order.shift.empty?
  have_more = emission_order.map { |x| !x.empty? }.any?
  ps.emit_ident(", ") if did_emit && have_more
  format_rest_params(ps, rest_params)
  did_emit = !emission_order.shift.empty?
  have_more = emission_order.map { |x| !x.empty? }.any?
  ps.emit_ident(", ") if did_emit && have_more
  format_kwargs(ps, kwargs)
  did_emit = !emission_order.shift.empty?
  have_more = emission_order.map { |x| !x.empty? }.any?
  ps.emit_ident(", ") if did_emit && have_more
  format_blockarg(ps, block_arg)

  if have_any_params
    ps.emit_ident(close_delim)
  end
end

def format_void_expression(ps, rest)
end

def format_opassign(ps, rest)
  head, op, tail = rest
  ps.emit_indent if ps.start_of_line.last

  ps.with_start_of_line(false) do
    format_expression(ps, head)
    ps.emit_space
    ps.emit_op(op[1])
    ps.emit_space
    format_expression(ps, tail)
  end

  ps.emit_newline if ps.start_of_line.last
end

def format_assign_expression(ps, rest)
  head, tail = rest
  ps.emit_indent if ps.start_of_line.last

  ps.with_start_of_line(false) do
    format_expression(ps, head)
    ps.emit_space
    ps.emit_op("=")
    ps.emit_space
    format_expression(ps, tail)
  end

  ps.emit_newline if ps.start_of_line.last
end

def format_method_add_block(ps, rest)
  raise("got non 2 length rest in add block") if rest.count != 2
  left, block_body = rest
  ps.emit_indent if ps.start_of_line.last

  ps.with_start_of_line(false) do
    format_expression(ps, left)
  end

  ps.emit_space
  format_expression(ps, block_body)
  ps.emit_newline if ps.start_of_line.last
end

def format_int(ps, rest)
  int = rest[0]
  ps.emit_int(int)
end

def format_var_ref(ps, rest)
  ref = rest[0][1]
  line_number = rest[0][2][0]
  ps.on_line(line_number)
  ps.emit_var_ref(ref)
  ps.emit_newline if ps.start_of_line.last
end

def format_binary(ps, rest)
  ps.emit_indent if ps.start_of_line.last

  ps.with_start_of_line(false) do
    format_expression(ps, rest[0])
    ps.emit_binary("#{rest[1].to_s}")
    format_expression(ps, rest[2])
  end

  ps.emit_newline if ps.start_of_line.last
end

def format_do_block(ps, rest)
  raise("got bad block #{rest.inspect}") if rest.length != 2
  params, body = rest
  ps.emit_do
  format_params(ps, params, " |", "|")
  ps.emit_newline

    # in ruby 2.5 blocks are bodystmts because blocks support
    # ```
    # foo do
    # rescue
    # end
    # ```
    #
    # style rescues now
  ps.new_block do
    if body[0] == :bodystmt
      format_expression(ps, body)
    else
      body.each do |expr|
        format_expression(ps, expr)
      end
    end
  end

  ps.with_start_of_line(true) do
    ps.emit_end
  end
end

def format_method_add_arg(ps, rest)
  type, call_rest = rest.first, rest.drop(1)
  ps.emit_indent if ps.start_of_line.last

  ps.with_start_of_line(false) do
    format_expression(ps, type)
  end

  raise("got call rest longer than one") if call_rest.length > 1
  args_list = call_rest[0]
  emitted_paren = false

  if args_list[0] == :arg_paren
    args_list = args_list[1]

    if args_list.count == 1
      args_list = args_list.first
    end

    if !args_list.empty?
      emitted_paren = true
      ps.emit_open_paren
      ps.surpress_one_paren = true
    end

  elsif args_list[0] == :args_add_block
  elsif args_list.empty?
  else
    raise("got non call paren args list")
  end

  ps.with_start_of_line(!emitted_paren) do
    next if args_list.empty?
    case args_list[0]
    when :args_add_block, :command_call, :command, :vcall
      format_expression(ps, args_list) unless args_list.empty?
    else
      format_list_like_thing(ps, [args_list], single_line = true)
    end
  end

  if emitted_paren
    ps.emit_close_paren
  end

  ps.emit_newline if ps.start_of_line.last
end

def format_command(ps, rest)

  # this is definitely wrong
  ident = rest[0]
  have_require = {
    :"@ident" => lambda {
      ps.emit_indent if ps.start_of_line.last
      ps.emit_ident(ident[1])
      ident[1] == "require"

    },
  }.fetch(rest[0][0]).call
  args_list = rest[1]

  if args_list.count == 1
    args_list = args_list[0]
  end

  ps.with_start_of_line(false) do
    if !args_list.nil? && args_list[0] == :command_call
      ps.emit_space
    end

    if have_require
      ps.emit_ident(" ")
    end

    ps.surpress_one_paren = have_require
    format_expression(ps, args_list)
  end

  ps.emit_newline if ps.start_of_line.last
end

def format_vcall(ps, rest)
  raise("didn't get exactly one part") if rest.count != 1
  raise("didn't get an ident") if rest[0][0] != :"@ident"
  ps.emit_indent if ps.start_of_line.last
  ps.emit_ident(rest[0][1])
  ps.emit_newline if ps.start_of_line.last
end

def format_tstring_content(ps, rest)
  ps.emit_ident(rest[1])
  ps.on_line(rest[2][0])
end

def format_inner_string(ps, parts, type)
  parts = parts.dup

  parts.each_with_index do |part, idx|
    case part[0]
    when :@tstring_content
      ps.emit_ident(part[1])
      ps.on_line(part[2][0])
    when :string_embexpr
      ps.emit_ident("\#{")

      ps.with_start_of_line(false) do
        format_expression(ps, part[1][0])
      end

      ps.emit_ident("}")
      on_line_skip = type == :heredoc && parts[idx + 1] && parts[idx + 1][0] == :@tstring_content && parts[idx + 1][1].start_with?("\n")

      if on_line_skip
        ps.render_heredocs(true)
      end

    else
      raise("dont't know how to do this #{part[0].inspect}")
    end
  end
end

def format_heredoc_string_literal(ps, rest)
  ps.emit_indent if ps.start_of_line.last

  ps.with_surpress_comments(true) do
    heredoc_type = rest[0][1][0]
    heredoc_symbol = rest[0][1][1]
    ps.emit_ident(heredoc_type)
    ps.emit_ident(heredoc_symbol)
    string_parts = rest[1]

    #the 1 that we drop here is the literal symbol :string_content
    inner_string_components = string_parts.drop(1)
    components = inner_string_components
    ps.push_heredoc_content(heredoc_symbol, heredoc_type.include?("~"), components)
  end
end

def format_string_literal(ps, rest)
  return format_heredoc_string_literal(ps, rest) if rest[0][0] == :heredoc_string_literal
  items = rest[0]
  parts = nil

  if items[0] == :string_content
    _, parts = items[0], items[1..-1]
  else
    parts = items
  end

  ps.emit_indent if ps.start_of_line.last
  ps.emit_double_quote
  format_inner_string(ps, parts, :quoted)
  ps.emit_double_quote
  ps.emit_newline if ps.start_of_line.last && ps.string_concat_position.empty?
end

def format_xstring_literal(ps, rest)
  items = rest[0]
  parts = nil

  if items[0] == :string_content
    _, parts = items[0], items[1..-1]
  else
    parts = items
  end

  ps.emit_indent if ps.start_of_line.last
  ps.emit_ident("`")
  format_inner_string(ps, parts, :quoted)
  ps.emit_ident("`")
  ps.emit_newline if ps.start_of_line.last && ps.string_concat_position.empty?
end

def format_module(ps, rest)
  module_name = rest[0]
  ps.emit_indent
  ps.emit_module_keyword
  ps.start_of_line << false
  ps.emit_space
  format_expression(ps, module_name)
  ps.start_of_line.pop
  ps.emit_newline

  ps.new_block do
    exprs = rest[1][1]

    exprs.each do |expr|
      format_expression(ps, expr)
    end
  end

  ps.emit_end
  ps.emit_newline if ps.start_of_line.last
end

def format_fcall(ps, rest)

  # this is definitely wrong
  raise("omg") if rest.length != 1
  {
    :@ident => lambda {
      ps.emit_indent if ps.start_of_line.last
      ps.emit_ident(rest[0][1])
    },
    :@const => lambda {
      ps.emit_indent if ps.start_of_line.last
      ps.emit_const(rest[0][1])
    },
  }.fetch(rest[0][0]).call
end

def format_class(ps, rest)
  class_name = rest[0]
  ps.emit_indent
  ps.emit_class_keyword

  ps.with_start_of_line(false) do
    ps.emit_space
    format_expression(ps, class_name)
  end

  if rest[1] != nil
    ps.emit_ident(" < ")
    ps.start_of_line << false
    format_expression(ps, rest[1])
    ps.start_of_line.pop
  end

  ps.emit_newline

  ps.new_block do
    exprs = rest[2][1]

    exprs.each do |expr|
      format_expression(ps, expr)
    end
  end

  ps.emit_end
  ps.emit_newline if ps.start_of_line.last
end

def format_const_path_ref(ps, rest)
  expr, const = rest
  ps.start_of_line << false
  format_expression(ps, expr)
  ps.emit_double_colon
  raise("cont a non const") if const[0] != :"@const"
  ps.emit_const(const[1])
  ps.start_of_line.pop

  if ps.start_of_line.last
    ps.emit_newline
  end
end

def format_call(ps, rest)
  raise("got non 3 length rest") if rest.length != 3
  front = rest[0]
  dot = rest[1]
  back = rest[2]
  ps.emit_indent if ps.start_of_line.last
  line_number = back.last.first
  ps.on_line(line_number)
  ps.start_of_line << false
  format_expression(ps, front)
  case
  when is_normal_dot(dot)
    ps.emit_dot
  when dot == :"&."
    ps.emit_lonely_operator
  else
    raise("got unrecognised dot")
  end

  format_expression(ps, back)
  ps.start_of_line.pop
  ps.emit_newline if ps.start_of_line.last
end

def format_ident(ps, ident)
  ps.emit_indent if ps.start_of_line.last
  ps.emit_ident(ident[0])
end

def format_symbol_literal(ps, literal)
  ps.emit_indent if ps.start_of_line.last

  ps.with_start_of_line(false) do
    if literal[0][0] == :@ident
      format_expression(ps, literal[0])
    elsif literal[0][0] == :symbol
      ps.emit_ident(":")
      format_expression(ps, literal[0][1])
    else
      raise("didn't get ident in right position") if literal[0][1][0] != :"@ident"
      ps.emit_symbol(literal[0][1][1])
    end
  end

  ps.emit_newline if ps.start_of_line.last
end

def is_normal_dot(candidate)
  candidate == :"." || (candidate.is_a?(Array) && candidate[0] == :@period)
end

def format_command_call(ps, expression)
  ps.emit_indent if ps.start_of_line.last
  left, dot, right, args = expression

  ps.with_start_of_line(false) do
    format_expression(ps, left)
    raise("got something other than a dot") if !is_normal_dot(dot)
    ps.emit_dot
    format_expression(ps, right)
    ps.emit_open_paren
    ps.surpress_one_paren = true
    format_expression(ps, args)
    ps.emit_close_paren
  end

  ps.emit_newline if ps.start_of_line.last
end

def format_list_like_thing_items(ps, args_list, single_line)
  return false if args_list.nil?
  emitted_args = false

  args_list[0].each_with_index do |expr, idx|
    raise("this is bad") if expr[0] == :tstring_content

    if !single_line
      ps.emit_indent
      ps.start_of_line << false
    end

    format_expression(ps, expr)

    if single_line
      ps.emit_comma_space unless idx == args_list[0].count - 1
    else
      ps.emit_ident(",")
      ps.emit_newline
      ps.start_of_line.pop
    end

    emitted_args = true
  end

  emitted_args
end

# format_list_like_thing takes any inner construct (like array items, or an
# args list, and formats them).
def format_list_like_thing(ps, args_list, single_line=true)
  emitted_args = false
  return false if args_list.nil? || args_list[0].nil?

  if args_list[0][0] != :args_add_star
    emitted_args = format_list_like_thing_items(ps, args_list, single_line)
  else
    _, args_list, call = args_list[0]
    args_list = [args_list]
    emitted_args = format_list_like_thing_items(ps, args_list, single_line)
    emit_extra_separator(ps, single_line, emitted_args)
    ps.emit_ident("*")
    emitted_args = true

    ps.with_start_of_line(false) do
      format_expression(ps, call)
    end

    if !single_line
      ps.emit_ident(",")
      ps.emit_newline
    end
  end

  emitted_args
end

def emit_extra_separator(ps, single_line, emitted_args)
  return unless emitted_args

  if single_line
    ps.emit_comma_space
  else
    ps.emit_indent
  end
end

def format_args_add_block(ps, args_list)
  surpress_paren = ps.surpress_one_paren
  ps.surpress_one_paren = false
  ps.emit_open_paren unless surpress_paren
  ps.start_of_line << false
  emitted_args = format_list_like_thing(ps, args_list)

  if args_list[1]
    ps.emit_ident(", ") if emitted_args
    ps.emit_ident("&")
    format_expression(ps, args_list[1])
  end

  ps.emit_close_paren unless surpress_paren
  ps.start_of_line.pop
end

def format_const_ref(ps, expression)
  raise("got more tahn one thing in const ref") if expression.length != 1
  format_expression(ps, expression[0])
end

def format_const(ps, expression)
  line_number = expression.last.first
  ps.on_line(line_number)
  raise("didn't get exactly a const") if expression.length != 2
  ps.emit_indent if ps.start_of_line.last
  ps.emit_const(expression[0])
end

def format_defs(ps, rest)
  head, period, tail, params, body = rest
  ps.emit_indent if ps.start_of_line.last
  ps.emit_ident("def")
  ps.emit_space
  ps.start_of_line << false
  format_expression(ps, head)
  ps.emit_dot
  format_expression(ps, tail)
  format_params(ps, params, "(", ")")
  ps.emit_newline
  ps.start_of_line.pop

  ps.new_block do
    format_expression(ps, body)
  end

  ps.emit_end
  ps.emit_newline if ps.start_of_line.last
end

def format_kw(ps, rest)
  ps.emit_ident(rest[0])
  ps.on_line(rest.last.first)
end

def format_rescue(ps, rescue_part)
  return if rescue_part.nil?
  _, rescue_class, rescue_capture, rescue_expressions, next_rescue = rescue_part

  ps.dedent do
    ps.emit_indent
    ps.emit_ident("rescue")

    ps.with_start_of_line(false) do
      if !rescue_class.nil? || !rescue_capture.nil?
        ps.emit_space
      end

      if !rescue_class.nil?
        if rescue_class.count == 1
          rescue_class = rescue_class[0]
        end

        format_expression(ps, rescue_class)
      end

      if !rescue_class.nil? && !rescue_capture.nil?
        ps.emit_space
      end

      if !rescue_capture.nil?
        ps.emit_ident("=> ")
        format_expression(ps, rescue_capture)
      end
    end
  end

  if !rescue_expressions.nil?
    ps.emit_newline

    ps.with_start_of_line(true) do
      rescue_expressions.each do |expr|
        format_expression(ps, expr)
      end
    end
  end

  format_rescue(ps, next_rescue) unless next_rescue.nil?
end

def format_ensure(ps, ensure_part)
  return if ensure_part.nil?
  _, ensure_expressions = ensure_part

  ps.dedent do
    ps.emit_indent
    ps.emit_ident("ensure")
  end

  if !ensure_expressions.nil?
    ps.emit_newline

    ps.with_start_of_line(true) do
      ensure_expressions.each do |expr|
        format_expression(ps, expr)
      end
    end
  end
end

def format_else(ps, else_part)
  return if else_part.nil?

  exprs = if RUBY_VERSION.to_f > 2.5
    else_part
  else
    _, a = else_part
    a
  end

  ps.dedent do
    ps.emit_indent
    ps.emit_else
  end

  if !exprs.nil?
    ps.emit_newline

    ps.with_start_of_line(true) do
      exprs.each do |expr|
        format_expression(ps, expr)
      end
    end
  end
end

def format_bodystmt(ps, rest, inside_begin=false)
  expressions = rest[0]
  rescue_part = rest[1]
  else_part = rest[2]
  ensure_part = rest[3]

  if rest[4..-1].any? { |x| x != nil }
    raise("got something other than a nil in a format body statement")
  end

  expressions.each do |line|
    format_expression(ps, line)
  end

  format_rescue(ps, rescue_part)
  format_else(ps, else_part)
  format_ensure(ps, ensure_part)
end

def format_if_mod(ps, rest)
  format_conditional_mod(ps, rest, "if")
end

def format_unless_mod(ps, rest)
  format_conditional_mod(ps, rest, "unless")
end

def format_conditional_mod(ps, rest, conditional_type)
  conditional, guarded_expression = rest
  ps.emit_indent if ps.start_of_line.last
  ps.start_of_line << false
  format_expression(ps, guarded_expression)
  ps.emit_space
  ps.emit_ident(conditional_type)
  ps.emit_space
  format_expression(ps, conditional)
  ps.start_of_line.pop
  ps.emit_newline if ps.start_of_line.last
end

def format_return(ps, rest)
  raise("got wrong size return args") if rest.length != 1
  raise("didn't get args add block to return") if rest.first.first != :args_add_block
  ps.emit_indent if ps.start_of_line.last
  ps.start_of_line << false
  ps.emit_return
  ps.emit_space
  format_list_like_thing(ps, rest.first[1...-1], true)
  ps.start_of_line.pop
  ps.emit_newline if ps.start_of_line.last
end

def format_conditional_parts(ps, further_conditionals)
  return if further_conditionals.nil?
  type = further_conditionals[0]
  case type
  when :else
    _, body = further_conditionals
    ps.emit_indent
    ps.emit_else
    ps.emit_newline

    ps.with_start_of_line(true) do
      ps.new_block do
        body.each do |expr|
          format_expression(ps, expr)
        end
      end
    end

  when :elsif
    _, cond, body, further_conditionals = further_conditionals
    ps.emit_indent
    ps.emit_elsif
    ps.emit_space
    ps.start_of_line << false
    format_expression(ps, cond)
    ps.start_of_line.pop
    ps.emit_newline
    ps.start_of_line << true

    ps.new_block do
      body.each do |expr|
        format_expression(ps, expr)
      end
    end

    ps.start_of_line.pop
    ps.emit_newline
    format_conditional_parts(ps, further_conditionals)
  when nil
  else
    raise("didn't get a known type in format conditional parts")
  end
end

def format_unless(ps, expression)
  format_conditional(ps, expression, :unless)
end

def format_if(ps, expression)
  format_conditional(ps, expression, :if)
end

def format_conditional(ps, expression, kind)
  if_conditional, body, further_conditionals = expression[0], expression[1], expression[2]
  ps.emit_indent if ps.start_of_line.last

  ps.with_start_of_line(false) do
    ps.emit_ident(kind)
    ps.emit_space
    format_expression(ps, if_conditional)
  end

  ps.emit_newline

  ps.new_block do
    body.each do |expr|
      format_expression(ps, expr)
    end
  end

  ps.with_start_of_line(true) do
    ps.emit_newline
    format_conditional_parts(ps, further_conditionals || [])
    ps.emit_end
  end

  ps.emit_newline if ps.start_of_line.last
end

def format_var_field(ps, rest)
  raise("didn't get exactly one thing") if rest.length != 1
  format_expression(ps, rest[0])
end

def format_ivar(ps, rest)
  ps.emit_indent if ps.start_of_line.last
  ps.emit_ident(rest[0])
end

def format_top_const_ref(ps, rest)
  raise("got bad top const ref") if rest.length != 1
  ps.emit_indent if ps.start_of_line.last
  ps.emit_double_colon
  ps.emit_ident(rest[0][1])
end

def format_super(ps, rest)
  return if rest.nil?
  raise("got bad super") if rest.length != 1
  args = rest[0]

  if rest[0][0] == :arg_paren
    args = rest[0][1]
  end

  raise("nope args") if args != nil && args[0] != :args_add_block
  ps.emit_indent if ps.start_of_line.last
  ps.emit_ident("super")

  if args.nil?
    ps.emit_open_paren
    ps.emit_close_paren
  else
    ps.with_start_of_line(false) do
      format_expression(ps, args)
    end
  end

  ps.emit_newline if ps.start_of_line.last
end

def format_zsuper(ps, rest)
  ps.emit_indent if ps.start_of_line.last
  ps.emit_ident("super")
  ps.emit_newline if ps.start_of_line.last
end

def format_array_fast_path(ps, rest)
  single_statement = rest[0] && rest[0].length == 1

  if single_statement
    ps.emit_ident("[")

    ps.with_start_of_line(false) do
      format_list_like_thing(ps, rest, true)
    end

    ps.emit_ident("]")
  else
    ps.emit_ident("[")
    ps.emit_newline unless rest.first.nil?

    ps.new_block do
      format_list_like_thing(ps, rest, false)
    end

    ps.emit_indent unless rest.first.nil?
    ps.emit_ident("]")
  end
end

def format_array(ps, rest)
  ps.emit_indent if ps.start_of_line.last

  if Parser.is_percent_array?(rest)
    ps.emit_ident(Parser.percent_symbol_for(rest))
    ps.emit_ident("[")

    ps.with_start_of_line(false) do
      parts = rest[0][1]

      parts.each.with_index do |expr, index|
        expr = [expr] if expr[0] == :@tstring_content
        format_inner_string(ps, expr, :array)
        ps.emit_space if index != parts.length - 1
      end
    end

    ps.emit_ident("]")
  else
    format_array_fast_path(ps, rest)
  end

  ps.emit_newline if ps.start_of_line.last
end

def format_unary(ps, rest)
  raise("got non size two unary") if rest.count != 2
  op, tail = rest
  ps.emit_indent if ps.start_of_line.last
  ps.emit_ident(op.to_s.gsub("@", ""))
  ps.start_of_line << false
  format_expression(ps, tail)
  ps.start_of_line.pop
  ps.emit_newline if ps.start_of_line.last
end

def format_cvar(ps, rest)
  ps.emit_indent if ps.start_of_line.last
  ps.emit_ident(rest[0])
  ps.emit_newline if ps.start_of_line.last
end

def format_string_concat(ps, rest)
  ps.start_string_concat
  parts, string = rest
  ps.emit_indent if ps.start_of_line.last
  format_expression(ps, parts)
  ps.emit_space
  ps.emit_slash
  ps.emit_newline

  ps.with_start_of_line(true) do
    format_expression(ps, string)
  end

  ps.emit_newline if ps.start_of_line.last
  ps.end_string_concat
end

def format_paren(ps, rest)
  raise("didn't get len 1 paren") if rest.length != 1
  ps.emit_indent if ps.start_of_line.last
  ps.emit_ident("(")

  if rest[0].length == 1
    format_expression(ps, rest[0][0])
  else
    format_expression(ps, rest[0])
  end

  ps.emit_ident(")")
  ps.emit_newline if ps.start_of_line.last
end

def format_begin(ps, expression)
  begin_body, rc, rb, eb = expression

  # I originally named these variables thinking they were 'rescue class'
  # 'rescue block' and 'ensure block' but they are not, those positions
  # are attached to the :bodystmt inside the begin
  raise("get better at begins") if rc != nil || rb != nil || eb != nil
  raise("begin body was not a bodystmt") if begin_body[0] != :bodystmt
  ps.emit_indent if ps.start_of_line.last
  ps.emit_ident("begin")
  ps.emit_newline

  ps.new_block do
    format_bodystmt(ps, begin_body[1..-1], inside_begin = true)
  end

  ps.with_start_of_line(true) do
    ps.emit_end
    ps.emit_newline
  end
end

def format_brace_block(ps, expression)
  raise("didn't get right array in brace block") if expression.length != 2
  params, body = expression
  output = StringIO.new
  next_ps = ParserState.with_depth_stack(output, from: ps)

  ps.new_block do
    body.each do |expr|
      format_expression(next_ps, expr)
    end
  end

  multiline = next_ps.render_queue.length > 1
  bv, params, f = params
  raise("got something other than block var") if bv != :block_var && bv != nil
  raise("got something other than false") if f != false && f != nil
  ps.emit_ident("{")

  unless bv.nil?
    ps.emit_space
    format_params(ps, params, "|", "|")
  end

  if multiline
    ps.emit_newline
  else
    ps.emit_space
  end

  ps.new_block do
    ps.with_start_of_line(multiline) do
      body.each do |expr|
        format_expression(ps, expr)
      end
    end
  end

  if multiline
    ps.emit_indent
  else
    ps.emit_space
  end

  ps.emit_ident("}")
  ps.emit_newline if ps.start_of_line.last
end

def format_float(ps, expression)
  ps.emit_ident(expression[0])
end

def format_ifop(ps, expression)
  raise("got a non 3 item ternary") if expression.length != 3
  conditional, left, right = expression
  ps.emit_indent if ps.start_of_line.last

  ps.with_start_of_line(false) do
    format_expression(ps, conditional)
    ps.emit_space
    ps.emit_ident("?")
    ps.emit_space
    format_expression(ps, left)

    if right != nil
      ps.emit_space
      ps.emit_ident(":")
      ps.emit_space
      format_expression(ps, right)
    end
  end

  ps.emit_newline if ps.start_of_line.last
end

def format_assocs(ps, assocs, newlines=true)
  assocs.each_with_index do |assoc, idx|
    ps.emit_indent if newlines

    ps.with_start_of_line(false) do
      if assoc[0] == :assoc_new
        if assoc[1][0] == :@label
          ps.emit_ident(assoc[1][1])
          ps.emit_space
        else
          format_expression(ps, assoc[1])
          ps.emit_space
          ps.emit_ident("=>")
          ps.emit_space
        end

        format_expression(ps, assoc[2])

        if newlines
          ps.emit_ident(",")
          ps.emit_newline
        elsif idx != assocs.length - 1
          ps.emit_ident(",")
          ps.emit_space
        end

      else
        raise("got non assoc_new in hash literal")
      end
    end
  end
end

def format_hash(ps, expression)
  ps.emit_indent if ps.start_of_line.last

  if expression == [nil]
    ps.emit_ident("{}")
  elsif expression[0][0] == :assoclist_from_args
    assocs = expression[0][1]
    ps.emit_ident("{")
    ps.emit_newline

    ps.new_block do
      format_assocs(ps, assocs)
    end

    ps.emit_indent
    ps.emit_ident("}")
  else
    raise("omg")
  end

  ps.emit_newline if ps.start_of_line.last
end

def format_aref_field(ps, expression)
  raise("got bad aref field") if expression.length != 2
  expression, sqb_args = expression
  ps.emit_indent if ps.start_of_line.last

  ps.with_start_of_line(false) do
    format_expression(ps, expression)
    ps.emit_ident("[")
    ps.surpress_one_paren = true
    format_expression(ps, sqb_args)
    ps.emit_ident("]")
  end
end

def format_aref(ps, expression)
  raise("got bad aref") if expression.length != 2
  expression, sqb_args = expression
  ps.emit_indent if ps.start_of_line.last

  ps.with_start_of_line(false) do
    format_expression(ps, expression)
    ps.emit_ident("[")
    ps.surpress_one_paren = true
    format_expression(ps, sqb_args)
    ps.emit_ident("]")
  end

  ps.emit_newline if ps.start_of_line.last
end

def format_bare_assoc_hash(ps, expression)
  if expression[0][0][0] == :assoc_splat
    ps.emit_ident("**")
    assoc_expr = expression[0][0][1]

    ps.with_start_of_line(false) do
      format_expression(ps, assoc_expr)
    end

  else
    ps.new_block do
      format_assocs(ps, expression[0], newlines = false)
    end
  end
end

def format_defined(ps, rest)
  ps.emit_indent if ps.start_of_line.last
  ps.emit_ident("defined?")
  ps.emit_open_paren
  format_expression(ps, rest[0])
  ps.emit_close_paren
  ps.emit_newline if ps.start_of_line.last
end

def format_return0(ps, rest)
  ps.emit_indent if ps.start_of_line.last
  ps.emit_ident("return")
  ps.emit_newline if ps.start_of_line.last
end

def format_massign(ps, expression)
  ps.emit_indent if ps.start_of_line.last

  ps.with_start_of_line(false) do
    assigns, rhs = expression

    if assigns[0] == :mlhs_add_star
      assigns, last = [
        assigns[1],
        assigns[2],
      ]
      item = last
      assigns << [
        :rest_param,
        item,
      ]
    end

    assigns.each_with_index do |assign, index|
      format_expression(ps, assign)
      ps.emit_ident(", ") if index != assigns.length - 1
    end

    ps.emit_ident(" = ")
    format_expression(ps, rhs)
  end

  ps.emit_newline if ps.start_of_line.last
end

def format_yield(ps, expression)
  ps.emit_indent if ps.start_of_line.last
  ps.emit_ident("yield")

  if expression.first.first != :paren
    ps.emit_space
  end

  ps.with_start_of_line(false) do
    ps.surpress_one_paren = true
    format_expression(ps, expression.first)
  end

  ps.emit_newline if ps.start_of_line.last
end

def format_regexp_literal(ps, expression)
  parts, re_end = expression
  re_delimiters = case re_end[3][0]
  when "%"
    [
      "%r#{re_end[3][2]}",
      re_end[1],
    ]
  when "/"
    [
      "/",
      "/",
    ]
  else
    raise("got unknown regular expression")
  end

  ps.emit_indent if ps.start_of_line.last
  ps.emit_ident(re_delimiters[0])
  format_inner_string(ps, parts, :regexp)
  ps.emit_ident(re_delimiters[1])

  if re_end[1].length > 1
    extra_chars = re_end[1][1..-1]
    ps.emit_ident(extra_chars)
  end

  ps.emit_newline if ps.start_of_line.last
end

def format_alias(ps, expression)
  ps.emit_indent if ps.start_of_line.last
  first, last = expression
  ps.emit_ident("alias ")

  ps.with_start_of_line(false) do
    format_expression(ps, first)
    ps.emit_space
    format_expression(ps, last)
  end

  ps.emit_newline if ps.start_of_line.last
end

def format_field(ps, rest)
  format_call(ps, rest)
end

def format_mrhs_new_from_args(ps, expression)
  ps.emit_indent if ps.start_of_line.last
  parts, tail = expression

  ps.with_start_of_line(false) do
    parts.each do |expr|
      format_expression(ps, expr)
      ps.emit_ident(", ")
    end

    format_expression(ps, tail)
  end

  ps.emit_newline if ps.start_of_line.last
end

def format_dot2(ps, expression)
  left, right = expression
  ps.emit_indent if ps.start_of_line.last

  ps.with_start_of_line(false) do
    format_expression(ps, left)
    ps.emit_ident("..")
    format_expression(ps, right)
  end

  ps.emit_newline if ps.start_of_line.last
end

def format_dot3(ps, expression)
  left, right = expression
  ps.emit_indent if ps.start_of_line.last

  ps.with_start_of_line(false) do
    format_expression(ps, left)
    ps.emit_ident("...")
    format_expression(ps, right)
  end

  ps.emit_newline if ps.start_of_line.last
end

def format_yield0(ps, expression)
  ps.emit_indent if ps.start_of_line.last
  ps.emit_ident("yield")
  ps.emit_newline if ps.start_of_line.last
end

def format_op(ps, expression)
  ps.emit_ident(expression[0])
end

def format_case_parts(ps, case_parts)
  return if case_parts.nil?
  type = case_parts[0]

  if type == :when
    _, conditional, body, case_parts = case_parts
    ps.emit_indent
    ps.emit_ident("when ")

    ps.with_start_of_line(false) do
      format_list_like_thing_items(ps, [conditional], true)
    end

    ps.emit_newline

    ps.new_block do
      body.each do |expr|
        format_expression(ps, expr)
      end
    end

    format_case_parts(ps, case_parts)
  elsif type == :else
    _, body = case_parts
    ps.emit_indent
    ps.emit_else
    ps.emit_newline

    ps.new_block do
      body.each do |expr|
        format_expression(ps, expr)
      end
    end

  else
    raise("got got bad case")
  end
end

def format_case(ps, rest)
  case_expr, case_parts = rest
  ps.emit_indent if ps.start_of_line.last
  ps.emit_ident("case")

  if !case_expr.nil?
    ps.with_start_of_line(false) do
      ps.emit_space
      format_expression(ps, case_expr)
    end
  end

  ps.emit_newline
  format_case_parts(ps, case_parts)

  ps.with_start_of_line(true) do
    ps.emit_end
  end

  ps.emit_newline
end

def format_gvar(ps, rest)
  ps.emit_indent if ps.start_of_line.last
  ps.emit_ident(rest[0])
end

def format_sclass(ps, rest)
  arrow_expr, statements = rest
  ps.emit_indent if ps.start_of_line.last
  ps.emit_ident("class << ")

  ps.with_start_of_line(false) do
    format_expression(ps, arrow_expr)
  end

  ps.emit_newline

  ps.new_block do
    format_expression(ps, statements)
  end

  ps.emit_end
  ps.emit_newline if ps.start_of_line.last
end

def format_empty_kwd(ps, expression, keyword)
  raise("omg #{expression}") if !expression.flatten.empty?
  ps.emit_indent if ps.start_of_line.last
  ps.emit_ident(keyword)
  ps.emit_newline if ps.start_of_line.last
end

def format_while_mod(ps, rest)
  while_conditional, while_expr = rest
  ps.emit_indent if ps.start_of_line.last

  ps.with_start_of_line(false) do
    format_expression(ps, while_expr)
    ps.emit_ident(" while ")
    format_expression(ps, while_conditional)
  end

  ps.emit_newline if ps.start_of_line.last
end

def format_mlhs(ps, expression)
  ps.emit_open_paren

  ps.with_start_of_line(false) do
    expression.each_with_index do |expr, index|
      format_expression(ps, expr)

      if index != expression.length - 1
        ps.emit_comma_space
      end
    end
  end

  ps.emit_close_paren
end

def format_dyna_symbol(ps, rest)
  ps.emit_indent if ps.start_of_line.last
  ps.emit_ident(":")

  ps.with_start_of_line(false) do
    format_string_literal(ps, rest)
  end

  ps.emit_newline if ps.start_of_line.last
end

def format_rest_param(ps, rest)
  ps.emit_indent if ps.start_of_line.last
  ps.emit_ident("*")

  ps.with_start_of_line(false) do
    format_expression(ps, rest[0])
  end

  ps.emit_newline if ps.start_of_line.last
end

def format_undef(ps, rest)
  ps.emit_indent if ps.start_of_line.last
  ps.emit_ident("undef ")

  ps.with_start_of_line(false) do
    format_expression(ps, rest[0][0])
  end

  ps.emit_newline if ps.start_of_line.last
end

# mlhs_paren occurs when a block arg has parenthesisation for array unpacking
# e.g. do |a, (b, c, (d, e))|. it is illegal to call this function with
# start_of_line.last == true
def format_mlhs_paren(ps, rest)
  raise if ps.start_of_line.last
  ps.emit_ident("(")

  ps.with_start_of_line(false) do
    rest[0].each_with_index do |item, idx|
      case item[1][0]
      when Array
        format_mlhs_paren(ps, [item[1]])
      when :@ident
        ps.emit_ident(item[1][1])
      else
        raise("got a bad mlhs paren")
      end

      ps.emit_comma_space unless idx == rest[0].count - 1
    end
  end

  ps.emit_ident(")")
end

def format_mrhs_add_star(ps, expression)
  ps.emit_indent if ps.start_of_line.last

  ps.with_start_of_line(false) do
    ps.emit_ident("*")
    format_expression(ps, expression.last)
  end

  ps.emit_newline if ps.start_of_line.last
end

def format_while(ps, rest)
  condition, expressions = rest
  ps.emit_indent if ps.start_of_line.last
  ps.emit_while
  ps.emit_ident(" ")

  ps.with_start_of_line(false) do
    format_expression(ps, condition)
  end

  ps.emit_newline

  ps.new_block do
    expressions.each do |expression|
      ps.with_start_of_line(true) do
        format_expression(ps, expression)
      end

      ps.emit_newline
    end
  end

  ps.emit_end
  ps.emit_newline if ps.start_of_line.last
end

def format_lambda(ps, rest)
  ps.emit_indent if ps.start_of_line.last
  params, body = rest
  ps.emit_ident("->")

  if params[0] == :paren
    params = params[1]
  end

  ps.emit_space if params.drop(1).any?
  format_params(ps, params, "(", ")")

  delim = if body[0] == :bodystmt
    [
      "do",
      "end",
    ]
  else
    [
      "{",
      "}",
    ]
  end

  # lambdas typically are a single statement, so line breaking them would
  # be masochistic
  if delim[0] == "{" && body.length == 1
    ps.emit_ident(" { ")

    ps.with_start_of_line(false) do
      format_expression(ps, body[0])
    end

    ps.emit_ident(" }")
  else
    ps.emit_ident(" #{delim[0]}")
    ps.emit_newline

    ps.new_block do
      if body[0] != :bodystmt
        body.each do |expr|
          format_expression(ps, expr)
          ps.emit_newline
        end

      else
        format_bodystmt(ps, body.drop(1))
      end
    end

    ps.emit_ident(delim[1])
  end

  ps.emit_newline if ps.start_of_line.last
end

def format_rescue_mod(ps, expression)
  expression, rescue_clause = expression
  ps.emit_indent if ps.start_of_line.last

  ps.with_start_of_line(false) do
    format_expression(ps, expression)
    ps.emit_ident(" rescue ")
    format_expression(ps, rescue_clause)
  end

  ps.emit_newline if ps.start_of_line.last
end

def format_backref(ps, expression)
  ps.emit_indent if ps.start_of_line.last
  ps.emit_ident(expression[0])
  ps.on_line(expression[1][0])
  ps.emit_newline if ps.start_of_line.last
end

def format_break(ps, expression)
  ps.emit_indent if ps.start_of_line.last
  ps.emit_ident("break")

  if expression[0] && expression[0][1]
    ps.emit_ident(" ")

    ps.with_start_of_line(false) do
      format_expression(ps, expression[0][1][0])
    end
  end

  ps.emit_newline if ps.start_of_line.last
end

def format_expression(ps, expression)
  type, rest = expression[0], expression[1...expression.length]
  line_re = /(\[\d+, \d+\])/
  line_number = line_re.match(rest.inspect)

  if line_number != nil
    line_number = line_number.to_s.split(",")[0].gsub("[", "").to_i
    ps.on_line(line_number)
  end

  {
    :return => lambda { |ps, rest| format_return(ps, rest) },
    :def => lambda { |ps, rest| format_def(ps, rest) },
    :void_stmt => lambda { |ps, rest| format_void_expression(ps, rest) },
    :assign => lambda { |ps, rest| format_assign_expression(ps, rest) },
    :method_add_block => lambda { |ps, rest| format_method_add_block(ps, rest) },
    :@int => lambda { |ps, rest| format_int(ps, rest) },
    :var_ref => lambda { |ps, rest| format_var_ref(ps, rest) },
    :do_block => lambda { |ps, rest| format_do_block(ps, rest) },
    :binary => lambda { |ps, rest| format_binary(ps, rest) },
    :command => lambda { |ps, rest| format_command(ps, rest) },
    :method_add_arg => lambda { |ps, rest| format_method_add_arg(ps, rest) },
    :vcall => lambda { |ps, rest| format_vcall(ps, rest) },
    :fcall => lambda { |ps, rest| format_fcall(ps, rest) },
    :string_literal => lambda { |ps, rest| format_string_literal(ps, rest) },
    :module => lambda { |ps, rest| format_module(ps, rest) },
    :class => lambda { |ps, rest| format_class(ps, rest) },
    :call => lambda { |ps, rest| format_call(ps, rest) },
    :const_path_ref => lambda { |ps, rest| format_const_path_ref(ps, rest) },
    :@ident => lambda { |ps, rest| format_ident(ps, rest) },
    :symbol_literal => lambda { |ps, rest| format_symbol_literal(ps, rest) },
    :command_call => lambda { |ps, rest| format_command_call(ps, rest) },
    :const_ref => lambda { |ps, rest| format_const_ref(ps, rest) },
    :"@const" => lambda { |ps, rest| format_const(ps, rest) },
    :defs => lambda { |ps, rest| format_defs(ps, rest) },
    :@kw => lambda { |ps, rest| format_kw(ps, rest) },
    :bodystmt => lambda { |ps, rest| format_bodystmt(ps, rest) },
    :if_mod => lambda { |ps, rest| format_if_mod(ps, rest) },
    :unless_mod => lambda { |ps, rest| format_unless_mod(ps, rest) },
    :if => lambda { |ps, rest| format_if(ps, rest) },
    :opassign => lambda { |ps, rest| format_opassign(ps, rest) },
    :var_field => lambda { |ps, rest| format_var_field(ps, rest) },
    :@ivar => lambda { |ps, rest| format_ivar(ps, rest) },
    :top_const_ref => lambda { |ps, rest| format_top_const_ref(ps, rest) },
    :super => lambda { |ps, rest| format_super(ps, rest) },
    :zsuper => lambda { |ps, rest| format_zsuper(ps, rest) },
    :array => lambda { |ps, rest| format_array(ps, rest) },
    :unary => lambda { |ps, rest| format_unary(ps, rest) },
    :paren => lambda { |ps, rest| format_paren(ps, rest) },
    :string_concat => lambda { |ps, rest| format_string_concat(ps, rest) },
    :unless => lambda { |ps, rest| format_unless(ps, rest) },
    :begin => lambda { |ps, rest| format_begin(ps, rest) },
    :brace_block => lambda { |ps, rest| format_brace_block(ps, rest) },
    :@float => lambda { |ps, rest| format_float(ps, rest) },
    :ifop => lambda { |ps, rest| format_ifop(ps, rest) },
    :hash => lambda { |ps, rest| format_hash(ps, rest) },
    :aref_field => lambda { |ps, rest| format_aref_field(ps, rest) },
    :aref => lambda { |ps, rest| format_aref(ps, rest) },
    :args_add_block => lambda { |ps, rest| format_args_add_block(ps, rest) },
    :bare_assoc_hash => lambda { |ps, rest| format_bare_assoc_hash(ps, rest) },
    :defined => lambda { |ps, rest| format_defined(ps, rest) },
    :until => lambda { |ps, rest| format_until(ps, rest) },
    :return0 => lambda { |ps, rest| format_return0(ps, rest) },
    :massign => lambda { |ps, rest| format_massign(ps, rest) },
    :yield => lambda { |ps, rest| format_yield(ps, rest) },
    :regexp_literal => lambda { |ps, rest| format_regexp_literal(ps, rest) },
    :alias => lambda { |ps, rest| format_alias(ps, rest) },
    :field => lambda { |ps, rest| format_field(ps, rest) },
    :mrhs_new_from_args => lambda { |ps, rest| format_mrhs_new_from_args(ps, rest) },
    :dot2 => lambda { |ps, rest| format_dot2(ps, rest) },
    :dot3 => lambda { |ps, rest| format_dot3(ps, rest) },
    :yield0 => lambda { |ps, rest| format_yield0(ps, rest) },
    :@op => lambda { |ps, rest| format_op(ps, rest) },
    :case => lambda { |ps, rest| format_case(ps, rest) },
    :@gvar => lambda { |ps, rest| format_gvar(ps, rest) },
    :sclass => lambda { |ps, rest| format_sclass(ps, rest) },
    :retry => lambda { |ps, rest| format_empty_kwd(ps, rest, "retry") },
    :break => lambda { |ps, rest| format_break(ps, rest) },
    :next => lambda { |ps, rest| format_empty_kwd(ps, rest, "next") },
    :while_mod => lambda { |ps, rest| format_while_mod(ps, rest) },
    :mlhs => lambda { |ps, rest| format_mlhs(ps, rest) },
    :dyna_symbol => lambda { |ps, rest| format_dyna_symbol(ps, rest) },
    :rest_param => lambda { |ps, rest| format_rest_param(ps, rest) },
    :undef => lambda { |ps, rest| format_undef(ps, rest) },
    :@cvar => lambda { |ps, rest| format_cvar(ps, rest) },
    :mlhs_paren => lambda { |ps, rest| format_mlhs_paren(ps, rest) },
    :mrhs_add_star => lambda { |ps, rest| format_mrhs_add_star(ps, rest) },
    :while => lambda { |ps, rest| format_while(ps, rest) },
    :lambda => lambda { |ps, rest| format_lambda(ps, rest) },
    :rescue_mod => lambda { |ps, rest| format_rescue_mod(ps, rest) },
    :xstring_literal => lambda { |ps, rest| format_xstring_literal(ps, rest) },
    :@backref => lambda { |ps, rest| format_backref(ps, rest) },
  }.fetch(type).call(ps, rest)
end

def format_program(line_metadata, sexp, result)
  program, expressions = sexp
  ps = ParserState.new(result, line_metadata)

  expressions.each do |expression|
    format_expression(ps, expression)
  end

  ps.write
end

def extract_line_metadata(file_data)
  comment_blocks = {}

  file_data.split("\n").each_with_index do |line, index|
    comment_blocks[index] = line if /^ *#/ === line
  end

  LineMetadata.new(comment_blocks)
end

class Parser < Ripper::SexpBuilderPP
  ARRAY_SYMBOLS = {
    qsymbols: "%i",
    qwords: "%w",
    symbols: "%I",
    words: "%W",
  }.freeze
  def self.is_percent_array?(rest)
    return false if rest.nil?
    return false if rest[0].nil?
    ARRAY_SYMBOLS.include?(rest[0][0])
  end

  def self.percent_symbol_for(rest)
    ARRAY_SYMBOLS[rest[0][0]]
  end

  def initialize(file_data)
    super(file_data)
    @file_lines = file_data.split("\n")

    # heredoc stack is the stack of identified heredocs
    @heredoc_stack = []

    # next_heredoc_stack is the type identifiers of the next heredocs, that
    # we haven't emitted yet
    @next_heredoc_stack = []
    @heredoc_regex = /(<<[-~]?)(.*$)/
    @next_comment_delete = []
    @comments_delete = []
    @regexp_stack = []
  end

  attr_reader(:comments_delete)
  private

  ARRAY_SYMBOLS.each do |event, symbol|
    define_method(:"on_#{event}_new") do
      [
        event,
        [],
        [
          lineno,
          column,
        ],
      ]
    end

    define_method(:"on_#{event}_add") do |parts, part|
      parts.tap do |node|
        node[1] << part
      end
    end
  end

  def on_heredoc_beg(*args, &blk)
    heredoc_parts = @heredoc_regex.match(args[0]).captures
    raise("bad heredoc") unless heredoc_parts.select { |x| x != nil }.count == 2
    @next_heredoc_stack.push(heredoc_parts)
    @next_comment_delete.push(lineno)
    super
  end

  def on_heredoc_end(*args, &blk)
    @heredoc_stack.push(@next_heredoc_stack.pop)
    start_com = @next_comment_delete.pop
    end_com = lineno
    @comments_delete.push([
      start_com,
      end_com,
    ])
    super
  end

  def fixup_tstring_content_for_double_quotes(string)
    string.gsub!("\\\\", "__RUBYFMT_SAFE_QUAD")
    string.gsub!("\\", "\\\\\\\\")
    string.gsub!("\"", "\\\"")
    string.gsub!("__RUBYFMT_SAFE_QUAD", "\\\\\\\\")
  end

  def on_string_literal(*args, &blk)
    if @heredoc_stack.last
      heredoc_parts = @heredoc_stack.pop
      args.insert(0, [
        :heredoc_string_literal,
        heredoc_parts,
      ])
    else
      quote = [@file_lines[lineno - 1].bytes[column - 1]].pack("c*")

      if quote == "'"
        (args || []).each do |part|
          next if part[1].nil?
          case part[1][0]
          when :@tstring_content
            fixup_tstring_content_for_double_quotes(part[1][1])
          else
            raise("got non tstring content in single string")
          end
        end

      elsif quote == ")"

        (args[0][1..-1] || []).each do |part|
          next if part.nil?
          case part[0]
          when :@tstring_content
            fixup_tstring_content_for_double_quotes(part[1])
          when :string_embexpr
          else

            # this is fine
            raise("got something bad in %q string")
          end
        end

      elsif quote == "\""
      else
        raise("what even is this string type #{quote}")
      end
    end

    super
  end

  def on_regexp_beg(re_part)
    @regexp_stack << re_part
  end

  def on_regexp_literal(*args)
    args[1] << @regexp_stack.pop
    super(*args)
  end
end

def main
  file_data = ARGF.read
  file_data = file_data.gsub("\r\n", "\n")
  line_metadata = extract_line_metadata(file_data)
  parser = Parser.new(file_data)
  sexp = parser.parse

  if ENV["RUBYFMT_DEBUG"] == "2"
    require "pry"

    binding.pry
  end

  if parser.error?
    if ENV["RUBYFMT_DEBUG"] == "2"
      require "pry"

      binding.pry
    end

    raise(parser.error)
  end

  parser.comments_delete.each do |(start, last)|
    line_metadata.comment_blocks.reject! { |k, v| k >= start && k <= last }
  end

  format_program(line_metadata, sexp, $stdout)
end

main