tartrazine/src/formatters/ansi.cr

require "../formatter"

module Tartrazine
  def self.to_ansi(text : String, language : String,
                   theme : String = "default-dark",
                   line_numbers : Bool = false) : String
    Tartrazine::Ansi.new(
      theme: Tartrazine.theme(theme),
      line_numbers: line_numbers
    ).format(text, Tartrazine.lexer(name: language))
  end

  class Ansi < Formatter
    property? line_numbers : Bool = false

    def initialize(@theme : Theme = Tartrazine.theme("default-dark"), @line_numbers : Bool = false)
    end

    private def line_label(i : Int32) : String
      "#{i + 1}".rjust(4).ljust(5)
    end

    def format(text : String, lexer : BaseLexer, outp : IO) : Nil
      tokenizer = lexer.tokenizer(text)
      i = 0
      outp << line_label(i) if line_numbers?
      tokenizer.each do |token|
        outp << colorize(token[:value], token[:type])
        if token[:value].includes?("\n")
          i += 1
          outp << line_label(i) if line_numbers?
        end
      end
    end

    def colorize(text : String, token : String) : String
      style = theme.styles.fetch(token, nil)
      return text if style.nil?
      if theme.styles.has_key?(token)
        s = theme.styles[token]
      else
        # Themes don't contain information for each specific
        # token type. However, they may contain information
        # for a parent style. Worst case, we go to the root
        # (Background) style.
        s = theme.styles[theme.style_parents(token).reverse.find { |parent|
          theme.styles.has_key?(parent)
        }]
      end
      colorized = text.colorize
      s.color.try { |col| colorized = colorized.fore(col.colorize) }
      # Intentionally not setting background color
      colorized.mode(:bold) if s.bold
      colorized.mode(:italic) if s.italic
      colorized.mode(:underline) if s.underline
      colorized.to_s
    end
  end
end