QutBioacoustics/baw-workers

module BawWorkers
  module Storage
    # Provides access to audio cache storage.
    class AudioCache
      include BawWorkers::Storage::Common

      public

      # Create a new BawWorkers::Storage::AudioCache.
      # @param [Array<String>] storage_paths
      # @return [void]
      def initialize(storage_paths)
        # array of top-level folder paths to store cached audio
        @storage_paths = storage_paths
        @separator = '_'
        @extension_indicator = '.'
      end

      # Get the file name
      # @param [Hash] opts
      # @return [String] file name for stored file
      def file_name(opts)
        validate_uuid(opts)
        validate_start_offset(opts)
        validate_end_offset(opts)
        validate_channel(opts)
        validate_sample_rate(opts)
        validate_format(opts)

        result = opts[:uuid].to_s + @separator +
            opts[:start_offset].to_f.to_s + @separator +
            opts[:end_offset].to_f.to_s + @separator +
            opts[:channel].to_i.to_s + @separator +
            opts[:sample_rate].to_i.to_s +
            @extension_indicator + opts[:format].trim('.', '').to_s
        result.downcase
      end

      # Get file names
      # @param [Hash] opts
      # @return [Array<String>]
      def file_names(opts)
        [file_name(opts)]
      end

      # Construct the partial path to an audio cache file.
      # @param [Hash] opts
      # @return [String] partial path to audio cache  file.
      def partial_path(opts)
        validate_uuid(opts)

        # prepend first two chars of uuid
        opts[:uuid][0, 2].downcase
      end

      # Extract information from a file name.
      # @param [String] file_path
      # @return [Hash] info
      def parse_file_path(file_path)

        file_name = File.basename(file_path)
        file_name_split = file_name.split('_')

        sample_rate, format = file_name_split[4].split('.')

        opts = {
            uuid: file_name_split[0],
            start_offset: file_name_split[1].to_f,
            end_offset: file_name_split[2].to_f,
            channel: file_name_split[3].to_i,
            sample_rate: sample_rate.to_i,
            format: format,
        }

        validate_uuid(opts)
        validate_start_offset(opts)
        validate_end_offset(opts)
        validate_channel(opts)
        validate_sample_rate(opts)
        validate_format(opts)

        opts
      end

    end
  end
end