require 'polytrix/documentation/code_segmenter'

module Polytrix
  module Documentation
    module Helpers
      module CodeHelper
        class ReStructuredTextHelper
          def self.code_block(source, language)
            buffer = StringIO.new
            buffer.puts ".. code-block:: #{language}"
            indented_source = source.lines.map do|line|
              "  #{line}"
            end.join("\n")
            buffer.puts indented_source
            buffer.string
          end
        end
        class MarkdownHelper
          def self.code_block(source, language)
            buffer = StringIO.new
            buffer.puts "```#{language}"
            buffer.puts source
            buffer.puts '```'
            buffer.string
          end
        end
        def initialize(*args)
          @segmenter = Polytrix::Documentation::CodeSegmenter.new
          super
        end

        def source
          File.read source_file
        end

        def code_block(source_code, language, opts = { format: :markdown })
          case opts[:format]
          when :rst
            ReStructuredTextHelper.code_block source_code, language
          when :markdown
            MarkdownHelper.code_block source_code, language
          else
            fail IllegalArgumentError, "Unknown format: #{format}"
          end
        end

        # Loses proper indentation on comments
        def snippet_after(matcher)
          segments = @segmenter.segment(source)
          buffer = StringIO.new
          segment = segments.find do |s|
            doc_segment_content = s.first.join
            doc_segment_content.match matcher
          end
          buffer.print segment[1].join "\n" if segment # return code segment
          buffer.string
        end

        def snippet_between(before_matcher, after_matcher)
          segments = @segmenter.segment(source)
          start_segment = find_segment_index segments, before_matcher
          end_segment   = find_segment_index segments, after_matcher
          buffer = StringIO.new
          if start_segment && end_segment
            segments[start_segment...end_segment].each do |segment|
              buffer.puts @segmenter.comment(segment[0]) unless segment == segments[start_segment]
              buffer.puts segment[1].join
            end
          end
          buffer.puts "\n"
          buffer.string
        end

        private

        def find_segment_index(segments, matcher)
          segments.find_index do |s|
            doc_segment_content = s.first.join
            doc_segment_content.match matcher
          end
        end
      end
    end
  end
end