module Scrivito
  # This class represents a CMS obj class. Obj classes can be created, updated and all properties
  # can be read. The class also provides methods to find obj classes. The attributes of an obj class
  # are defined by {Scrivito::Attribute} instances.
  #
  # @api public
  class ObjClass
    include ModelIdentity

    class << self
      # Returns all the obj classes.
      #
      # @api public
      #
      # @example Find all obj classes in the current {Scrivito::Workspace}.
      #   ObjClass.all
      #
      # @return [Array<Scrivito::ObjClass>]
      def all
        Workspace.current.obj_classes.to_a
      end

      # Finds an obj class by its name.
      #
      # @api public
      #
      # @example Find the obj class named "Homepage" in the current {Scrivito::Workspace}.
      #   ObjClass.find('Homepage')
      #
      # @param [String] name The name of the obj class.
      # @return [Scrivito::ObjClass]
      # @raise [Scrivito::ResourceNotFound] Raised when no obj class with the given +name+ can be found.
      def find(name)
        obj_class = Workspace.current.obj_classes[name]

        unless obj_class
          raise ResourceNotFound, "Could not find '#{ObjClass}' with name '#{name}'."
        end

        obj_class
      end

      # Creates a new obj class and persists it in the CMS.
      #
      # @api public
      #
      # This allows you to set the different properties of an obj class by
      # providing a hash with the property names as keys and the values you want
      # to set as values. Attributes can be either given as {Scrivito::Attribute} instances or as
      # an attribute property hash.
      #
      # @example Create a non-binary obj class.
      #   ObjClass.create(name: 'Homepage', is_binary: false)
      #
      # @example Create a binary obj class.
      #   ObjClass.create(name: 'Image', is_binary: true)
      #
      # @example Create an obj class with attributes passed in as an Array of attribute property hashes.
      #   ObjClass.create(name: 'Blog', attributes: [
      #     { name: 'headline', type: :string },
      #     { name: 'category', type: :enum, values: %w(tech social) },
      #   ])
      #
      # @example Create an obj class with attributes passed in as an Array of {Scrivito::Attribute} instances.
      #   ObjClass.create(name: 'Blog', attributes: [
      #     Attribute.new(name: 'headline', type: :string),
      #     Attribute.new(name: 'category', type: :enum, values: %w(tech social)),
      #   ])
      #
      # @param [Hash] properties
      # @option properties [String] :name The name of the obj class.
      # @option properties [Boolean] :is_binary Is this a binary or non-binary obj class?
      # @option properties [Boolean] :is_active Is it possible to create instances of this obj class?
      # @option properties [Array<Scrivito::Attribute>, Array<Hash>] :attributes A list of
      #   attributes for this obj class. Can be either a list of attribute instances or attribute
      #   property hashes.
      #
      # @return [Scrivito::ObjClass]
      def create(properties)
        properties = properties.with_indifferent_access

        unless properties.has_key?(:is_binary)
          raise ScrivitoError, 'The "is_binary" property is mandatory. Please provide' \
            ' a hash containing an "is_binary" key with true or false value.'
        end

        if properties[:attributes]
          properties[:attributes].map! do |attribute|
            attribute.respond_to?(:to_cms_rest_api) ? attribute : Attribute.new(attribute)
          end
        end

        workspace = Workspace.current
        raw_obj_class_data = workspace.api_request(:post, '/obj_classes',
            obj_class: format_properties_for_cms(properties))
        new(ObjClassData.new(raw_obj_class_data), workspace)
      end

      private

      # Formats obj class properties into a CMS REST API format.
      # @param [Hash] properties
      # @return [Hash] Properties formated for the CMS.
      def format_properties_for_cms(properties)
        params = properties.dup

        if params.has_key?(:is_binary)
          params[:type] = params.delete(:is_binary) ? :generic : :publication
        end

        if params.has_key?(:attributes)
          params[:attributes] = params[:attributes].map(&:to_cms_rest_api)
        end

        params
      end
    end

    # Initializes a new obj class. It expects the CMS backend representation of an obj class.
    #
    # See {ObjClass.create} for a detailed overview of how to set properties.
    #
    # @param [Hash] obj_class_data
    # @param [Workspace,NilClass] workspace
    # @raise [Scrivito::ScrivitoError]
    # @return [Scrivito::ObjClass]
    def initialize(obj_class_data, workspace)
      update_obj_class_data(obj_class_data)
      @workspace = workspace
    end

    # @!attribute [r] id
    #   @api public
    #   @return [String] unique identifier of this obj class
    # @!attribute [r] name
    #   @api public
    #   @return [String] the name of this obj class
    # @!attribute [r] is_active
    #   @api public
    #   @return [Boolean] whether instances can be created with this obj class
    # @!attribute [r] is_binary
    #   @api public
    #   @return [Boolean] whether instances of this class are binary, e.g. images or PDFs
    delegate :id, :name, :is_active, :is_binary, to: :obj_class_data

    alias_method :active?, :is_active
    alias_method :binary?, :is_binary

    # @api public
    # @return [Scrivito::AttributeCollection] the attributes of this obj class.
    #
    # @example Find an attribute named "locale" for the obj class "Homepage".
    #   ObjClass.find('Homepage').attributes['locale']
    #
    # @example Add a new +string+ attribute named "headline" to the "Homepage" obj class by providing an attribute property hash.
    #   ObjClass.find('Homepage').attributes.add(name: 'headline', type: :string)
    #
    # @example Add a new +enum+ attribute named "category" to the "Homepage" obj class by providing an attribute instance.
    #   attribute = Attribute.new(name: 'category', type: :enum, values: %w(tech social))
    #   ObjClass.find('Homepage').attributes.add(attribute)
    #
    # @example Iterate over the list of attributes from the obj class "Homepage" and print their name and type.
    #   ObjClass.find('Homepage').attributes.each do |attribute|
    #     puts "#{attribute.name}:#{attribute.type}"
    #   end
    attr_reader :attributes

    # Updates this obj class and persists the changes in the CMS. It is not possible to
    # update the +name+ or +is_binary+ property.
    #
    # @api public
    #
    # See {Scrivito::ObjClass.create} for a detailed overview of
    # what properties are allowed and how to set them.
    #
    # @param [Hash] properties
    #
    # @raise [ScrivitoError] Raised when trying to change +name+ or +is_binary+.
    #
    # @return [nil]
    def update(properties)
      params = properties.with_indifferent_access

      if params.has_key?(:is_binary)
        raise ScrivitoError, "#{self.class} does not support changing 'is_binary'. Please remove" \
          " the key from the properties."
      end

      if params.has_key?(:name)
        raise ScrivitoError, "#{self.class} does not support changing 'name'. Please remove" \
          " the key from the properties."
      end

      if params.has_key?(:attributes)
        params[:attributes].map! do |attribute|
          attribute = Attribute.new(attribute) unless attribute.respond_to?(:to_cms_rest_api)
          attribute.obj_class = self
          attribute.to_cms_rest_api
        end
      end

      raw_obj_class_data = workspace.api_request(:put, "/obj_classes/#{name}", obj_class: params)
      update_obj_class_data(ObjClassData.new(raw_obj_class_data))
      workspace.reload

      nil
    end

    def update_obj_class_data(obj_class_data)
      @obj_class_data = obj_class_data
      update_attributes
    end

    private

    attr_reader :obj_class_data, :workspace

    def update_attributes
      attributes = @obj_class_data.attributes.map do |attribute_data|
        attribute = Attribute.new(attribute_data)
        attribute.obj_class = self
        attribute
      end
      @attributes = AttributeCollection.new(self, attributes)
    end
  end
end