module Neo4j
  module Server
    class CypherResponse
      attr_reader :data, :columns, :error_msg, :error_status, :error_code, :response

      class ResponseError < StandardError
        attr_reader :status, :code

        def initialize(msg, status, code)
          super(msg)
          @status = status
          @code = code
        end
      end


      class HashEnumeration
        include Enumerable
        extend Forwardable
        def_delegator :@response, :error_msg
        def_delegator :@response, :error_status
        def_delegator :@response, :error_code
        def_delegator :@response, :columns
        def_delegator :@response, :struct

        def initialize(response, query)
          @response = response
          @query = query
        end

        def to_s
          @query
        end

        def inspect
          "Enumerable query: '#{@query}'"
        end

        def each(&block)
          @response.each_data_row do |row|
            yield(row.each_with_index.each_with_object(struct.new) do |(value, i), result|
              result[columns[i].to_sym] = value
            end)
          end
        end
      end

      def to_struct_enumeration(cypher = '')
        HashEnumeration.new(self, cypher)
      end

      def to_node_enumeration(cypher = '', session = Neo4j::Session.current)
        Enumerator.new do |yielder|
          @result_index = 0
          to_struct_enumeration(cypher).each do |row|
            @row_index = 0
            yielder << row.each_pair.each_with_object(@struct.new) do |(column, value), result|
              result[column] = map_row_value(value, session)
              @row_index += 1
            end
            @result_index += 1
          end
        end
      end

      def map_row_value(value, session)
        if value.is_a?(Hash)
          hash_value_as_object(value, session)
        elsif value.is_a?(Array)
          value.map { |v| map_row_value(v, session) }
        else
          value
        end
      end

      def hash_value_as_object(value, session)
        return value unless value['labels'] || value['type'] || transaction_response?

        is_node, data =  if transaction_response?
                           add_transaction_entity_id
                           [!mapped_rest_data['start'], mapped_rest_data]
                         elsif value['labels'] || value['type']
                           add_entity_id(value)
                           [value['labels'], value]
                         end
        (is_node ? CypherNode : CypherRelationship).new(session, data).wrapper
      end

      attr_reader :struct

      def initialize(response, uncommited = false)
        @response = response
        @uncommited = uncommited
      end

      def entity_data(id = nil)
        if @uncommited
          data = @data.first['row'].first
          data.is_a?(Hash) ? {'data' => data, 'id' => id} : data
        else
          data = @data[0][0]
          data.is_a?(Hash) ? add_entity_id(data) : data
        end
      end

      def first_data(id = nil)
        if @uncommited
          data = @data.first['row'].first
          # data.is_a?(Hash) ? {'data' => data, 'id' => id} : data
        else
          data = @data[0][0]
          data.is_a?(Hash) ? add_entity_id(data) : data
        end
      end

      def add_entity_id(data)
        data.merge!('id' => self.class.id_from_url(data['self']))
      end

      def add_transaction_entity_id
        mapped_rest_data.merge!('id' => mapped_rest_data['self'].split('/').last.to_i)
      end

      def error?
        !!@error
      end

      def data?
        !response.body['data'].nil?
      end

      def raise_unless_response_code(code)
        fail "Response code #{response.status}, expected #{code} for #{response.headers['location']}, #{response.body}" unless response.status == code
      end

      def each_data_row
        if @uncommited
          data.each { |r| yield r['row'] }
        else
          data.each { |r| yield r }
        end
      end

      def set_data(data, columns)
        @data = data
        @columns = columns
        @struct = columns.empty? ? Object.new : Struct.new(*columns.map(&:to_sym))
        self
      end

      def set_error(error_msg, error_status, error_core)
        @error = true
        @error_msg = error_msg
        @error_status = error_status
        @error_code = error_core
        self
      end

      def raise_error
        fail 'Tried to raise error without an error' unless @error
        fail ResponseError.new(@error_msg, @error_status, @error_code)
      end

      def raise_cypher_error
        fail 'Tried to raise error without an error' unless @error
        fail Neo4j::Session::CypherError.new(@error_msg, @error_code, @error_status)
      end


      def self.create_with_no_tx(response)
        case response.status
        when 200
          CypherResponse.new(response).set_data(response.body['data'], response.body['columns'])
        when 400
          CypherResponse.new(response).set_error(response.body['message'], response.body['exception'], response.body['fullname'])
        else
          fail "Unknown response code #{response.status} for #{response.env[:url]}"
        end
      end

      def self.create_with_tx(response)
        fail "Unknown response code #{response.status} for #{response.request_uri}" unless response.status == 200

        first_result = response.body['results'][0]
        cr = CypherResponse.new(response, true)

        if response.body['errors'].empty?
          cr.set_data(first_result['data'], first_result['columns'])
        else
          first_error = response.body['errors'].first
          cr.set_error(first_error['message'], first_error['status'], first_error['code'])
        end
        cr
      end

      def transaction_response?
        response.respond_to?('body') && !response.body['commit'].nil?
      end

      def rest_data
        @result_index = @row_index = 0
        mapped_rest_data
      end

      def rest_data_with_id
        rest_data.merge!('id' => mapped_rest_data['self'].split('/').last.to_i)
      end

      class << self
        def id_from_url(url)
          url.split('/')[-1].to_i
        end
      end

      private

      attr_reader :row_index

      attr_reader :result_index

      def mapped_rest_data
        response.body['results'][0]['data'][result_index]['rest'][row_index]
      end
    end
  end
end