Carc.in: http://carc.in/#/r/dxv

optimize.cr

require "colorize"

# I think a pure regex solution isn't possible unfortunately
# This regex is still reall handy becomes you can
# go from escape code group to escape code and get the text in between
FORMAT_GROUPS_REG = /(?:\e\[(?:(?:[0-9]{1,3});)*(?:[0-9]{1,3})m)+([^\e]+)/
# Procues something like #<MatchData "\e[33;1m\e[99mT" 1:"T">

# This now exctracts the styles from the groups of escape codes
# This is a number either followed by a 'm' or a ';'
FORMAT_REG = /([0-9]{1,3})[;m]/

# To figure out if e.g. the number 33 'overwrites' a current active number of '93'
# We have to know wether both are of the same type (fg, bg or text style)
FG_COLORS = [] of Int32
{% for name in Colorize::Object::COLORS %}
  FG_COLORS << Colorize::Object::FORE_{{name.upcase.id}}.to_i
{% end %}

BG_COLORS = [] of Int32
{% for name in Colorize::Object::COLORS %}
  BG_COLORS << Colorize::Object::BACK_{{name.upcase.id}}.to_i
{% end %}

TEXT_STYLES = [1, 4]

def optimize input
  output = ""


  current_format = {
    :fg => -1,
    :bg => -1,
    :style => -1
  }

  s = "Splitted:\n"
  input.scan(FORMAT_GROUPS_REG).each do |match|
    if match
      text = match[1] || ""
      styles = match[0].scan(FORMAT_REG).map {|match| match[1].to_s.to_i}
      s += "\t'#{text}' #{styles}" # debug only

      this_format = {} of Symbol => Int32
      styles.each do |style|
        # This could be done in a less readable way
        # By iterating over an array [:fg, :bg, :style]
        if FG_COLORS.includes? style
          this_format[:fg] = style
        elsif BG_COLORS.includes? style
          this_format[:bg] = style
        elsif TEXT_STYLES.includes? style
          this_format[:style] = style
        elsif style == 0
          # Just set every value to 0
          # This could be done in a less readable way by
          # Including 0 in the fg_color, BG_COLORS, TEXT_STYLES array.
          this_format[:fg] =  this_format[:bg] = this_format[:style] = 0

        else
          raise Exception.new "Don't know what to do with style code '#{style}'"
        end
      end

      s += " => #{this_format.values}"
      s_helper = [] of Colorize::Object(Int32)

      changed_styles = [] of Int32

      this_format.each_with_index do |format_type, value|
        # If has changed, update current_format and save to write to output string later
        if current_format[format_type] != value
          current_format[format_type] = value
          changed_styles << value
          s_helper << value.colorize.green
        else
          s_helper << value.colorize.red
        end
      end

      # \e[0m is translated to :fg, :bg, :style => 0
      # And we don't want multiple zeroes
      changed_styles.uniq!

      s += " => #{s_helper}\n"

      # Write changed style to output string
      output += "\e[#{changed_styles.join(";")}m" if changed_styles.length > 0
      output += text
    end
  end

  puts s,""
  puts "Input: #{input.inspect}\n"
  puts "Output: #{output.inspect}\n"
  puts "Input:  #{input}\e[0m\n"
  puts "Output: #{output}\e[0m\n"
  
  output
end



input = "\e[33;1m\e[95mT\e[33;1me\e[33;4ms\e[33mt \e[4mTest \e[0m\e[34mTest \e[33m Test"
optimize(input)
puts

optimize("\e[44m \e[44m \e[44m \e[44m \e[44m \e[44m \e[44m \e[44m \e[44m \e[44m \e[44m ")