module Cucover
  class Store
    def initialize(cache = DiskCache.new)
      @cache = cache
    end

    def latest_recordings
      recordings.keys.map{ |file_colon_line| latest_recording(file_colon_line) }
    end

    def latest_recording(file_colon_line)
      recordings[file_colon_line].sort{ |x, y| x.end_time <=> y.end_time }.last
    end

    def keep!(recording_data)
      Cucover.logger.debug("Storing recording of #{recording_data.file_colon_line}")
      recordings[recording_data.file_colon_line] << recording_data
      @cache.save(@recordings)
    end

    def recordings_covering(source_file)
      latest_recordings.select { |r| r.covers_file?(source_file) }
    end

    def recordings
      ensure_recordings_loaded!
      @recordings
    end

    private

    def ensure_recordings_loaded!
      return if @recordings

      if @recordings = @cache.load
        Cucover.logger.debug("Loaded #{@recordings.length} recording(s)")
      else
        Cucover.logger.debug("Starting with no existing coverage data.")
        @recordings = Recordings.new
      end
    end

    class Recordings < Hash
      def [](key)
        self[key] = [] if super.nil?
        super
      end
    end

    class DiskCache
      def save(recordings)
        Cucover.logger.debug("Saving #{recordings.length} recording(s) to #{data_file}")
        File.open(data_file, 'w') { |f| f.puts Marshal.dump(recordings) }
      end

      def load
        return unless File.exists?(data_file)

        Cucover.logger.debug("Reading existing coverage data from #{data_file}")
        File.open(data_file) { |f| Marshal.load(f) }
      end

      private

      def data_file
        Dir.pwd + '/cucover.data'
      end
    end
  end
end