module Strutta
  # The Strutta Games object is the master of all other API objects (Rounds, Flow, Entries, Participants)
  # The above objects are instantiated in association with a Games object, as each belong to a Game in the Strutta API
  # The above objects also have all their API requests forwarded through this object to Strutta::API
  class Games
    attr_accessor :master, :id

    # Initializes the Strutta::Games object
    #
    # @param id [Integer, nil] Game id
    # @param master [Strutta::API] Master Strutta::API object
    # @return [Strutta::Games] instantiated Strutta::Games object
    def initialize(id = nil, master)
      @id = id
      @root_path = 'games'
      @master = master
    end

    # Forwards an API call to @master
    #
    # @param method [String] the required HTTP method
    # @param url [String] URL for the call
    # @param params [Hash] Parameters for the call
    # @return [Hash] Parsed body of the response
    def call(method, url, params = {})
      @master.call(method, url, params)
    end

    # Polymorphic GET Index request
    #
    # @param resource_path [String, nil] the GET index path for the requesting object
    #  See Strutta::APIObject#all
    # @return [Hash] Parsed body of the response
    def all(params = {}, resource_path = nil)
      verify_no_id(@id) unless resource_path
      call('get', "#{@root_path}/#{resource_path}", params)
    end

    # Polymorphic GET single object request
    #
    # @param resource_path [String, nil] the GET path for the requesting object
    #  See Strutta::APIObject#get
    # @return [Hash] Parsed body of the response
    def get(params = {}, resource_path = '')
      verify_id(@id, Errors::GAME_ID_REQUIRED)
      call('get', "#{@root_path}/#{@id}/#{resource_path}", params)
    end

    # Polymorphic POST request
    #
    # @param resource_path [String, nil] the POST path for the requesting object
    #  See Strutta::APIObject#create
    # @return [Hash] Parsed body of the response
    def create(params = {}, resource_path = nil)
      verify_no_id(@id) unless resource_path
      call('post', "#{@root_path}/#{resource_path}", params)
    end

    # Polymorphic PATCH request
    #
    # @param resource_path [String, nil] the PATCH path for the requesting object
    #  See Strutta::APIObject#update
    # @return [Hash] Parsed body of the response
    def update(params, resource_path = nil)
      verify_id(@id, Errors::GAME_ID_REQUIRED)
      call('patch', "#{@root_path}/#{@id}/#{resource_path}", params)
    end

    # Polymorphic DELETE request
    #
    # @param resource_path [String, nil] the DELETE path for the requesting object
    #  See Strutta::APIObject#delete
    # @return [Hash] Parsed body of the response
    def delete(resource_path = nil)
      verify_id(@id, Errors::GAME_ID_REQUIRED)
      call('delete', "#{@root_path}/#{@id}/#{resource_path}", {})
    end

    # Instantiates a Strutta::Rounds object with reference to this Game
    #
    # @param id [Integer, nil] the ID of the Round
    # @return [Strutta::Rounds] The instantiated Strutta::Rounds object
    def rounds(id = nil)
      verify_id(@id, Errors::GAME_ID_REQUIRED)
      Rounds.new id, self
    end

    # Instantiates a Strutta::Participants object with reference to this Game
    #
    # @param id [Integer, nil] the ID of the Participant
    # @return [Strutta::Participants] The instantiated Strutta::Participants object
    def participants(id = nil)
      verify_id(@id, Errors::GAME_ID_REQUIRED)
      Participants.new id, self
    end

    # Instantiates a Strutta::Flow object with reference to this Game
    #
    # @param id [Integer, nil] Flows do not have Ids. This is here simply for consistency, and will result in error of used.
    # @return [Strutta::Flow] The instantiated Strutta::Flow object
    def flow(id = nil)
      verify_id(@id, Errors::GAME_ID_REQUIRED)
      Flow.new id, self
    end

    # Instantiates a Strutta::Entries object with reference to this Game
    #
    # @param id [Integer, nil] the ID of the Entry
    # @return [Strutta::Entries] The instantiated Strutta::Entries object
    def entries(id = nil)
      verify_id(@id, Errors::GAME_ID_REQUIRED)
      Entries.new id, self
    end

    # Instantiates a Strutta::Points object with reference to this Game
    #
    # @param id [Integer, nil] Point IDs are not used by this API. This is here simply for consistency, and will result in error of used.
    # @return [Strutta::Entries] The instantiated Strutta::Points object
    def points(id = nil)
      verify_id(@id, Errors::GAME_ID_REQUIRED)
      Points.new id, self
    end

    # Instantiates a Strutta::Moderation object with reference to this Game
    #
    # @param id [Integer, nil] Moderation do not have Ids. This is here simply for consistency, and will result in error of used.
    # @return [Strutta::Entries] The instantiated Strutta::Moderation object
    def moderation(id = nil)
      verify_id(@id, Errors::GAME_ID_REQUIRED)
      Moderation.new id, self
    end

    # Instantiates a Strutta::Judging object with reference to this Game
    #
    # @param id [Integer, nil] Judging does not have Ids. This is here simply for consistency, and will result in error of used.
    # @return [Strutta::Entries] The instantiated Strutta::Judging object
    def judging(id = nil)
      verify_id(@id, Errors::GAME_ID_REQUIRED)
      Judging.new id, self
    end

    # Confirm that an id exists for a request
    #
    # @param id [Integer] the ID of the objec
    # @param message [String] Error message if no id exists
    # @return [nil] nil if id exists, Error otherwise
    def verify_id(id, message)
      fail Errors::ObjectIDRequired, message unless id
    end

    # Confirm that no id exists for a request
    #
    # @param id [Integer] the ID of the objec
    # @return [nil] nil if no id exists, Error otherwise
    def verify_no_id(id)
      fail Errors::ObjectIDNotAllowed, Errors::OBJECT_NOT_ALLOWED if id
    end
  end
end