easy-going-rails/lib/semantic/ansi_wrapper.rb

require_relative 'ansi_colors'

module Semantic
  # AnsiWrapper cares about Ansi Colour Code \e[...
  class AnsiWrapper
    include AnsiColors

    TAB_TO_SPACES = 2

    def self.wrap(text, length, prefix = '', continuation = prefix)
      if visible_length(prefix) != visible_length(continuation)
        raise "continuation <#{continuation.inspect}> should have the same length as prefix <#{prefix.inspect}>"
      end
      return unless text

      text = text.gsub("\t", ' ' * TAB_TO_SPACES)

      lines = split_text_to_lines(text, length - visible_length(prefix))
      lines = inject_continuation_and_ansi_colors_to_lines(lines, prefix, continuation)
      lines.join("\n")
    end

    private_class_method def self.inject_continuation_and_ansi_colors_to_lines(lines, prefix, continuation)
      last_ansi = ''
      lines.each_with_index.map do |line, index|
        current = index.zero? ? prefix : continuation
        current += last_ansi unless last_ansi.empty? || last_ansi == CLEAR
        current += line

        last_ansi = scan_for_actual_ansi(line, last_ansi)

        current += CLEAR if last_ansi.empty? || last_ansi != CLEAR
        current
      end
    end

    private_class_method def self.scan_for_actual_ansi(line, last_ansi)
      line.scan(ANSI_REGEX).each do |match|
        ansi_code = match.to_s
        if ansi_code == CLEAR
          last_ansi = CLEAR
        else
          last_ansi += ansi_code
        end
      end
      last_ansi
    end

    private_class_method def self.split_text_to_lines(text, length)
      lines = text.split("\n")
      sublines = lines.map do |line|
        visible_length(line) > length ? visible_split(line, length) : [line]
      end
      sublines.flatten
    end

    private_class_method def self.visible_length(line)
      raise 'line should not contain carriage return character!' if line.match "\n"

      ansi_code_length = line.scan(ANSI_REGEX).map(&:length).sum
      line.length - ansi_code_length
    end

    # TODO: might be refactored with less complexity
    private_class_method def self.visible_split(line, length, stack = '') # rubocop:disable Metrics/AbcSize,Metrics/MethodLength
      before, ansi_code, after = line.partition(ANSI_REGEX)
      stack_length = visible_length(stack)
      visible_length = before.length + stack_length
      if visible_length == length
        ["#{stack}#{before}#{ansi_code}"] + visible_split(after, length)
      elsif visible_length > length
        first_line = stack + before[0...length - stack_length]
        tail = before[length - stack_length..] + ansi_code + after
        [first_line] + visible_split(tail, length)
      elsif ansi_code.length.positive?
        visible_split(after, length, "#{stack}#{before}#{ansi_code}")
      else
        ["#{stack}#{before}#{ansi_code}"]
      end
    end
  end
end