# frozen_string_literal: true
module MetalArchives
  ##
  # Abstract model class
  #
  class BaseModel
    ##
    # Generic shallow copy constructor
    #
    def initialize(hash = {})
      raise Errors::NotImplementedError, 'no :id property in model' unless respond_to? :id?, true

      hash.each do |property, value|
        instance_variable_set("@#{property}", value) if self.class.properties.include? property
      end
    end

    ##
    # Returns true if two objects have the same type and id
    #
    def ==(obj)
      obj.instance_of?(self.class) && id ==(obj.id)
    end

    ##
    # Fetch, parse and load the data
    #
    # [Raises]
    # - rdoc-ref:MetalArchives::Errors::InvalidIDError when no id
    # - rdoc-ref:MetalArchives::Errors::APIError when receiving a status code >= 400 (except 404)
    #
    def load!
      raise Errors::InvalidIDError, 'no id present' unless !!id

      # Use constructor to set attributes
      initialize assemble

      # Set empty properties to nil
      self.class.properties.each do |prop|
        instance_variable_set("@#{prop}", nil) unless instance_variable_defined? "@#{prop}"
      end

      @loaded = true
      self.class.cache[id] = self
    rescue => e
      # Don't cache invalid requests
      self.class.cache.delete id
      raise e
    end

    ##
    # Whether or not the object is currently loaded
    #
    def loaded?
      !@loaded.nil?
    end

    ##
    # Whether or not the object is currently cached
    #
    def cached?
      loaded? && self.class.cache.include?(id)
    end

    protected

      ##
      # Fetch the data and assemble the model
      #
      # Override this method
      #
      # [Raises]
      # - rdoc-ref:MetalArchives::Errors::InvalidIDError when no or invalid id
      # - rdoc-ref:MetalArchives::Errors::APIError when receiving a status code >= 400 (except 404)
      #
    def assemble
      raise Errors::NotImplementedError, 'method :assemble not implemented'
    end

    class << self
      ##
      # +Array+ of declared properties
      #
      attr_accessor :properties

      ##
      # Get class-level object cache
      #
      def cache
        @cache ||= MetalArchives::LRUCache.new MetalArchives.config.cache_size
      end

      protected

        ##
        # Defines a model property.
        #
        # [+name+]
        #     Name of the property
        #
        # [+opts+]
        #   [+type+]
        #       Data type of property (a constant)
        #
        #       Default: +String+
        #
        #   [+multiple+]
        #       Whether or not the property has multiple values (which
        #       turns it into an +Array+ of +type+)
        #
      def property(name, opts = {})
        (@properties ||= []) << name

        # property
        define_method(name) do
          load! unless instance_variable_defined?("@#{name}") || name == :id
          instance_variable_get("@#{name}")
        end

        # property?
        define_method("#{name}?") do
          load! unless instance_variable_defined?("@#{name}") || name == :id

          property = instance_variable_get("@#{name}")
          property.respond_to?(:empty?) ? !property.empty? : !!property
        end

        # property=
        define_method("#{name}=") do |value|
          if value.nil?
            instance_variable_set "@#{name}", value
            return
          end

          # Check value type
          type = opts[:type] || String
          if opts[:multiple]
            raise MetalArchives::Errors::TypeError, "invalid type #{value.class}, must be Array for #{name}" unless value.is_a? Array
            value.each do |val|
              raise MetalArchives::Errors::TypeError, "invalid type #{val.class}, must be #{type} for #{name}" unless val.is_a? type
            end
          else
            raise MetalArchives::Errors::TypeError, "invalid type #{value.class}, must be #{type} for #{name}" unless value.is_a? type
          end

          instance_variable_set "@#{name}", value
        end
      end

        ##
        # Defines a model enum property.
        #
        # [+name+]
        #     Name of the property
        #
        # [+opts+]
        #   [+values+]
        #       Required. An array of possible values
        #
        #   [+multiple+]
        #       Whether or not the property has multiple values (which
        #       turns it into an +Array+ of +type+)
        #
      def enum(name, opts)
        raise ArgumentError, 'opts[:values] is required' unless opts and opts[:values]

        (@properties ||= []) << name

        # property
        define_method(name) do
          load! unless instance_variable_defined?("@#{name}")
          instance_variable_get("@#{name}")
        end

        # property?
        define_method("#{name}?") do
          load! unless instance_variable_defined?("@#{name}")

          property = instance_variable_get("@#{name}")
          property.respond_to?(:empty?) ? !property.empty? : !!property
        end

        # property=
        define_method("#{name}=") do |value|
          # Check enum type
          if opts[:multiple]
            raise MetalArchives::Errors::TypeError, "invalid enum value #{value}, must be Array for #{name}" unless value.is_a? Array
            value.each do |val|
              raise MetalArchives::Errors::TypeError, "invalid enum value #{val} for #{name}" unless opts[:values].include? val
            end
          else
            raise MetalArchives::Errors::TypeError, "invalid enum value #{value} for #{name}" unless opts[:values].include? value
          end

          instance_variable_set name, value
        end
      end

        ##
        # Defines a model boolean property. This method is an alias for <tt>enum name, :values => [true, false]</tt>
        #
        # [+name+]
        #     Name of the property
        #
        # [+opts+]
        #   [+multiple+]
        #       Whether or not the property has multiple values (which
        #       turns it into an +Array+ of +type+)
        #
      def boolean(name, opts = {})
        enum name, opts.merge(:values => [true, false])
      end
    end
  end
end