require 'typesafe_enum'

module BerkeleyLibrary
  module AV
    module Types
      class FileType < TypesafeEnum::Base

        # ############################################################
        # Non-enum constants

        # Supported extensions for MP3 files
        MP3_EXTENSIONS = ['.mp3'].freeze
        # Supported extensions for MP4 files, per https://www.wowza.com/docs/understanding-protocols-and-formats-supported-by-wowza-streaming-engine#supported-media-file-formats-for-vod-streaming
        MP4_EXTENSIONS = %w[.mp4 .f4v .mov .m4a .m4v .mp4a .mp4v .3gp .3g2].freeze

        # ############################################################
        # Initializer

        # rubocop:disable Metrics/ParameterLists
        def initialize(key, player_tag, mime_type, label: nil, prefix: nil, extensions: [])
          raise_if_duplicate(extensions)

          @player_tag = player_tag
          @mime_type = mime_type
          @label = label || player_tag.capitalize
          @prefix = prefix || key.to_s.downcase
          @extensions = extensions

          super(key)
        end

        # rubocop:enable Metrics/ParameterLists

        # ############################################################
        # Accessors and instance methods

        attr_reader :player_tag, :mime_type, :label, :prefix, :extensions

        def to_s
          value.to_s
        end

        private

        # ############################################################
        # Private methods

        def raise_if_duplicate(extensions)
          FileType.each do |t|
            next if (dups = extensions & t.extensions).empty?

            raise(ArgumentError, "#{FileType}::#{t.key} already covers extensions #{dups.join(', ')}") if t
          end
        end

        # ############################################################
        # Enum members

        new(:MP3, 'audio', 'application/x-mpegURL', extensions: MP3_EXTENSIONS)
        new(:MP4, 'video', 'video/mp4', extensions: MP4_EXTENSIONS)
        new(:UNKNOWN, 'object', 'application/octet-stream', label: 'Unknown')

        # ############################################################
        # Class methods

        class << self
          # Returns the AV file type for the specified path
          #
          # @param path [String]
          # @return [FileType] The file type, or FileType::UNKNOWN if the type cannot be determined
          def for_path(path)
            extension = path && File.extname(path)
            by_extension[extension] || FileType::UNKNOWN
          end

          def by_extension
            @by_extension ||= FileType.flat_map { |t| t.extensions.map { |x| [x, t] } }.to_h
          end

        end
      end
    end
  end
end