require 'repertoire/media/exceptions/unknown_media'

module Repertoire
  module Media
    #
    # Returns the +Hash+ of all registered Media types.
    #
    def Media.types
      @@media_types ||= {}
    end

    #
    # Returns +true+ if there is a Media type registered with the matching 
    # _name_.
    #
    def Media.supports?(name)
      Media.types.has_key?(name.to_sym)
    end

    #
    # Returns the Media type with the matching _name_.
    #
    def Media.get(name)
      name = name.to_sym

      unless Media.supports?(name)
        raise(UnknownMedia,"media type #{name} is not registered",caller)
      end

      return Media.types[name]
    end

    #
    # Returns the +Hash+ of all registered Media types and their associated
    # URI schemes.
    #
    def Media.schemes
      @@media_schemes ||= {}
    end

    #
    # Returns an +Array+ of all registered URI schemes.
    #
    def Media.registered_schemes
      Media.schemes.keys
    end

    #
    # Returns +true+ if a Media type was registered for the specified
    # _scheme_, returns +false+ otherwise.
    #
    def Media.supports_scheme?(scheme)
      Media.schemes.has_key?(scheme.to_s)
    end

    #
    # Returns the Media type that was registered for the specified _scheme_.
    #
    def Media.supports_scheme(name)
      name = name.to_s

      unless Media.supports_scheme?(name)
        raise(UnknownMedia,"media type for scheme #{name.dump} is not registered",caller)
      end

      return Media.schemes[name]
    end

    #
    # Returns the +Hash+ of all registered Media types and their
    # associated media storage directories.
    #
    def Media.directories
      @@media_directories ||= {}
    end

    #
    # Returns an +Array+ of all registered directories.
    #
    def Media.registered_directories
      Media.directories.keys
    end

    #
    # Returns +true+ if a Media type was registered with the specified
    # _directory_, returns +false+ otherwise.
    #
    def Media.recognizes_directory?(name)
      Media.directories.has_key?(name.to_s)
    end

    #
    # Returns the Media type that was registered for the specified
    # _directory_.
    #
    def Media.recognizes_directory(name)
      name = name.to_s

      unless Media.recognizes_directory?(name)
        raise(UnknownMedia,"media type for directory #{name.dump} is not registered",caller)
      end

      return Media.directories[name]
    end

    #
    # Get the Media type that was registered for the scheme of the
    # specified _uri_.
    #
    def Media.guess_from_uri(uri)
      Media.supports_scheme(uri.to_s.scan(/^[^:\/@]+:/).first.chop)
    end

    #
    # Attempts to determine the correct Media type for the specified _path_.
    #
    def Media.guess_from_path(path)
      path = File.expand_path(path)

      Media.directories.each do |directory,media|
        if File.directory?(File.join(path,directory))
          return media
        end
      end

      raise(UnknownMedia,"the media type for #{path.dump} is unknown",caller)
    end
  end
end