require 'uri'

module SpreeClient
  module API
    class V1
      class Resources
        # Spree API client instance.
        # @return [SpreeClient::API::V1]
        attr_reader :api
        # Every method caches the response so it can be inspected afterwards.
        # @return [HTTParty::Response] The API response
        attr_reader :response
        # @return [Hash]
        attr_reader :default_args

        # Initialize
        #
        # @param [SpreeClient::API::V1] :api An API client instance
        def initialize(**args)
          @api = args.delete :api
          @default_args = args
        end

        # Initialize a new resource
        #
        # @param [Hash] Attributes
        # @return [Struct]
        def new(**args)
          resource_class.new **args
        end

        # Gets all products or filter with params
        #
        # Filters:
        #
        # ids: comma-separated list of IDs
        # q: Ransack search params (mutually exclusive with ids)
        #
        # Pagination:
        #
        # page: page number
        # per_page: results per page
        #
        # @param [Hash] Query params
        def index(**q)
          @response = api.class.get endpoint(q),
                                    query: q.slice(:ids, :q, :page, :per_page),
                                    headers: api.headers

          response.ok?
        end

        # Get a single product by ID
        def show(resource)
          @response = api.class.get endpoint(resource), headers: api.headers

          response.ok?
        end

        # Creates a resource
        #
        # @see SpreeClient::API::V1#headers
        # @param [Struct,Hash] Model instance
        # @return [Boolean]
        def create(resource)
          resource = new **resource unless resource.is_a? resource_class

          @response = api.class.post endpoint(resource),
                                     body: params(resource),
                                     headers: api.headers

          response.created?
        end

        # Updates a resource
        #
        # @see SpreeClient::API::V1#headers
        # @param [Struct,Hash]
        # @return [Boolean]
        def update(resource)
          resource = new resource unless resource.is_a? resource_class

          @response = api.class.patch endpoint(resource),
                                      body: params(resource),
                                      headers: api.headers

          response.ok?
        end

        # Deletes a resource
        #
        # @see SpreeClient::API::V1#headers
        # @param [Struct,Hash]
        # @return [Boolean]
        def delete(resource)
          @response = spree.class.delete endpoint(resource), headers: api.headers

          response.no_content?
        end

        private

        # Strong parameters
        #
        # @see SpreeClient#authenticity_token
        # @param [Struct,Nil]
        # @return [Hash]
        def params(resource = nil)
          { resource_name => default_args.merge(resource.to_h.compact) }.to_json
        end

        # Backend endpoint
        #
        # @param [Struct]
        # @return [String]
        def endpoint(resource = {})
          endpoint = self.class::ENDPOINT + (resource.dig(:id) ? '/:id' : '')

          parameterize_with endpoint, resource
        end

        # Generates a URL with :parameter replaced with values
        # 
        # @param [String]
        # @param [Struct,Hash]
        def parameterize_with(endpoint, resource = {})
          default_args.merge(resource.to_h.compact).inject(endpoint) do |e, pair|
            e.gsub ':' + pair.first.to_s, pair.last.to_s
          end + '.json'
        end

        def resource_class
          self.class::RESOURCE
        end

        def resource_name
          self.class::NAME
        end
      end
    end
  end
end