module IRB::NestingParser

# File irb/nesting_parser.rb, line 193
def open_tokens(tokens)
  # scan_opens without block will return a list of open tokens at last token position
  scan_opens(tokens)
end

# File irb/nesting_parser.rb, line 212
def parse_by_line(tokens)
  line_tokens = []
  prev_opens = []
  min_depth = 0
  output = []
  last_opens = scan_opens(tokens) do |t, opens|
    depth = t == opens.last&.first ? opens.size - 1 : opens.size
    min_depth = depth if depth < min_depth
    if t.tok.include?("\n")
      t.tok.each_line do |line|
        line_tokens << [t, line]
        next if line[-1] != "\n"
        next_opens = opens.map(&:first)
        output << [line_tokens, prev_opens, next_opens, min_depth]
        prev_opens = next_opens
        min_depth = prev_opens.size
        line_tokens = []
      end
    else
      line_tokens << [t, t.tok]
    end
  end
  output << [line_tokens, prev_opens, last_opens, min_depth] if line_tokens.any?
  output
end

# File irb/nesting_parser.rb, line 8
def scan_opens(tokens)
  opens = []
  pending_heredocs = []
  first_token_on_line = true
  tokens.each do |t|
    skip = false
    last_tok, state, args = opens.last
    case state
    when :in_alias_undef
      skip = t.event == :on_kw
    when :in_unquoted_symbol
      unless IGNORE_TOKENS.include?(t.event)
        opens.pop
        skip = true
      end
    when :in_lambda_head
      opens.pop if t.event == :on_tlambeg || (t.event == :on_kw && t.tok == 'do')
    when :in_method_head
      unless IGNORE_TOKENS.include?(t.event)
        next_args = []
        body = nil
        if args.include?(:receiver)
          case t.event
          when :on_lparen, :on_ivar, :on_gvar, :on_cvar
            # def (receiver). | def @ivar. | def $gvar. | def @@cvar.
            next_args << :dot
          when :on_kw
            case t.tok
            when 'self', 'true', 'false', 'nil'
              # def self(arg) | def self.
              next_args.push(:arg, :dot)
            else
              # def if(arg)
              skip = true
              next_args << :arg
            end
          when :on_op, :on_backtick
            # def +(arg)
            skip = true
            next_args << :arg
          when :on_ident, :on_const
            # def a(arg) | def a.
            next_args.push(:arg, :dot)
          end
        end
        if args.include?(:dot)
          # def receiver.name
          next_args << :name if t.event == :on_period || (t.event == :on_op && t.tok == '::')
        end
        if args.include?(:name)
          if %i[on_ident on_const on_op on_kw on_backtick].include?(t.event)
            # def name(arg) | def receiver.name(arg)
            next_args << :arg
            skip = true
          end
        end
        if args.include?(:arg)
          case t.event
          when :on_nl, :on_semicolon
            # def receiver.f;
            body = :normal
          when :on_lparen
            # def receiver.f()
            next_args << :eq
          else
            if t.event == :on_op && t.tok == '='
              # def receiver.f =
              body = :oneliner
            else
              # def receiver.f arg
              next_args << :arg_without_paren
            end
          end
        end
        if args.include?(:eq)
          if t.event == :on_op && t.tok == '='
            body = :oneliner
          else
            body = :normal
          end
        end
        if args.include?(:arg_without_paren)
          if %i[on_semicolon on_nl].include?(t.event)
            # def f a;
            body = :normal
          else
            # def f a, b
            next_args << :arg_without_paren
          end
        end
        if body == :oneliner
          opens.pop
        elsif body
          opens[-1] = [last_tok, nil]
        else
          opens[-1] = [last_tok, :in_method_head, next_args]
        end
      end
    when :in_for_while_until_condition
      if t.event == :on_semicolon || t.event == :on_nl || (t.event == :on_kw && t.tok == 'do')
        skip = true if t.event == :on_kw && t.tok == 'do'
        opens[-1] = [last_tok, nil]
      end
    end

    unless skip
      case t.event
      when :on_kw
        case t.tok
        when 'begin', 'class', 'module', 'do', 'case'
          opens << [t, nil]
        when 'end'
          opens.pop
        when 'def'
          opens << [t, :in_method_head, [:receiver, :name]]
        when 'if', 'unless'
          unless t.state.allbits?(Ripper::EXPR_LABEL)
            opens << [t, nil]
          end
        when 'while', 'until'
          unless t.state.allbits?(Ripper::EXPR_LABEL)
            opens << [t, :in_for_while_until_condition]
          end
        when 'ensure', 'rescue'
          unless t.state.allbits?(Ripper::EXPR_LABEL)
            opens.pop
            opens << [t, nil]
          end
        when 'alias'
          opens << [t, :in_alias_undef, 2]
        when 'undef'
          opens << [t, :in_alias_undef, 1]
        when 'elsif', 'else', 'when'
          opens.pop
          opens << [t, nil]
        when 'for'
          opens << [t, :in_for_while_until_condition]
        when 'in'
          if last_tok&.event == :on_kw && %w[case in].include?(last_tok.tok) && first_token_on_line
            opens.pop
            opens << [t, nil]
          end
        end
      when :on_tlambda
        opens << [t, :in_lambda_head]
      when :on_lparen, :on_lbracket, :on_lbrace, :on_tlambeg, :on_embexpr_beg, :on_embdoc_beg
        opens << [t, nil]
      when :on_rparen, :on_rbracket, :on_rbrace, :on_embexpr_end, :on_embdoc_end
        opens.pop
      when :on_heredoc_beg
        pending_heredocs << t
      when :on_heredoc_end
        opens.pop
      when :on_backtick
        opens << [t, nil] unless t.state == Ripper::EXPR_ARG
      when :on_tstring_beg, :on_words_beg, :on_qwords_beg, :on_symbols_beg, :on_qsymbols_beg, :on_regexp_beg
        opens << [t, nil]
      when :on_tstring_end, :on_regexp_end, :on_label_end
        opens.pop
      when :on_symbeg
        if t.tok == ':'
          opens << [t, :in_unquoted_symbol]
        else
          opens << [t, nil]
        end
      end
    end
    if t.event == :on_nl || t.event == :on_semicolon
      first_token_on_line = true
    elsif t.event != :on_sp
      first_token_on_line = false
    end
    if pending_heredocs.any? && t.tok.include?("\n")
      pending_heredocs.reverse_each { |t| opens << [t, nil] }
      pending_heredocs = []
    end
    if opens.last && opens.last[1] == :in_alias_undef && !IGNORE_TOKENS.include?(t.event) && t.event != :on_heredoc_end
      tok, state, arg = opens.pop
      opens << [tok, state, arg - 1] if arg >= 1
    end
    yield t, opens if block_given?
  end
  opens.map(&:first) + pending_heredocs.reverse
end