# frozen_string_literal: true

module Repubmark
  module Elems
    class CodeBlock < Base
      parents :Canvas

      attr_reader :syntax, :str, :indent

      def initialize(parent, syntax, str, indent: 0)
        super parent

        self.syntax = syntax
        self.str = str
        self.indent = indent
      end

      #################
      # Basic methods #
      #################

      def to_html = highlighted_str

      def to_gemtext
        [
          "```\n",
          "#{str.strip}\n",
          "```\n",
        ].join.freeze
      end

    private

      def syntax=(syntax)
        return @syntax = nil if syntax.nil?

        unless syntax.instance_of? Symbol
          raise TypeError, "Expected #{Symbol}, got #{syntax.class}"
        end

        @syntax = syntax
      end

      def str=(str)
        str = String(str).freeze
        raise 'Expected non-blank string' if str.strip.empty?

        @str = str
      end

      def indent=(indent)
        @indent = Integer indent
        raise 'Expected non-negative number' if @indent.negative?
      end

      def highlighted_str
        @highlighted_str ||= Highlight.call syntax, transformed_str
      end

      def transformed_str
        @transformed_str ||=
          str.lines.map { |line| "#{indentation}#{line}" }.join.freeze
      end

      def indentation
        @indentation ||= (' ' * indent).freeze
      end
    end
  end
end