require_relative 'exchange_handler'
require_relative '../hash_methods'
require_relative '../not_found_errors'
require_relative '../accessors'
require_relative '../interpreter'
require 'json'
require 'nori'

module Soaspec

  # Accessors specific to REST handler
  module RestAccessors

    # Defines method 'base_url_value' containing base URL used in REST requests
    # @param [String] url Base Url to use in REST requests. Suburl is appended to this
    def base_url(url)
      define_method('base_url_value') do
        url
      end
    end
  end

  # Wraps around Savon client defining default values dependent on the soap request
  class RestHandler < ExchangeHandler
    extend Soaspec::RestAccessors
    extend Soaspec::Accessors

    # Savon client used to make SOAP calls
    attr_accessor :client
    # SOAP Operation to use by default
    attr_accessor :operation

    # Set through following method. Base URL in REST requests.
    def base_url_value
      nil
    end

    # Add values to here when extending this class to have default REST options.
    # See rest client resource at https://github.com/rest-client/rest-client for details
    # @return [Hash] Options adding to & overriding defaults
    def rest_resource_options
      {
      }
    end

    # Setup object to handle communicating with a particular SOAP WSDL
    # @param [Hash] specific_options Options defining SOAP request. WSDL, authentication
    def initialize(name, specific_options = {})
      raise "Base URL not set! Please set in class with 'base_url' method" unless base_url_value
      options = rest_resource_options
      options.merge!(specific_options)
      @resource = RestClient::Resource.new(base_url_value, options) # @resource[url_extension].get
      super
    end

    # Used in together with Exchange request that passes such override parameters
    # @param [Hash] override_parameters Params to characterize REST request
    # @param_value [params] Extra parameters (E.g. headers)
    # @param_value [suburl] URL appended to base_url of clss
    # @param_value [method] REST method (get, post, etc)
    def make_request(override_parameters)
      test_values = override_parameters
      test_values[:params] ||= {}
      test_values[:suburl] = test_values[:suburl].to_s if test_values[:suburl]

      @resource_used = test_values[:suburl] ? @resource[test_values[:suburl]] : @resource

      begin
      response = case test_values[:method]
      when :post
        unless test_values[:payload]
          test_values[:payload] = JSON.generate(test_values[:body]).to_s if test_values[:body]
        end
        @resource_used.send(test_values[:method].to_s, test_values[:payload], test_values[:params])
      else
        @resource_used.send(test_values[:method].to_s, test_values[:params])
      end
      rescue RestClient::ExceptionWithResponse => e
        response = e.response
      end
      Soaspec::SpecLogger.add_to(response)
      response
    end

    # @param [Hash] format Format of expected result. Ignored for this
    # @return [Object] Generic body to be displayed in error messages
    def response_body(response, format: :hash)
      extract_hash response
    end

    def include_in_body?(response, expected)
      response.body.include? expected
    end

    # Whether the request found the desired value or not
    def found?(response)
      status_code_for(response) != 404
    end

    # Convert XML or JSON response into a Hash
    # @param [String] response Response as a String (either in XML or JSON)
    # @return [Hash]
    def extract_hash(response)
      raise ArgumentError("Empty Body. Can't assert on it") if response.body.empty?
      case Interpreter.response_type_for response
      when :json
        JSON.parse(response.body).transform_keys_to_symbols
      when :xml
        parser = Nori.new(convert_tags_to: lambda { |tag| tag.snakecase.to_sym })
        parser.parse(response.body)
      else
        raise "Neither XML nor JSON detected. It is #{type}. Don't know how to parse It is #{response.body}"
      end
    end

    # @return [Boolean] Whether response contains expected value
    def include_value?(response, expected)
      extract_hash(response).include_value? expected
    end

    # @return [Boolean] Whether response body contains expected key
    def include_key?(response, expected)
      extract_hash(response).include_key? expected
    end

    # @return [Integer] HTTP Status code for response
    def status_code_for(response)
      response.code
    end

    # Override this to specify elements that must be present in the response
    # Will be used in 'success_scenarios' shared examples
    # @return [Array] Array of symbols specifying element names
    def mandatory_elements
      []
    end

    # Override this to specify xpath results that must be present in the response
    # Will be used in 'success_scenarios' shared examples
    # @return [Hash] Hash of 'xpath' => 'expected value' pairs
    def mandatory_xpath_values
      {}
    end

    # Attributes set at the root XML element of SOAP request
    def root_attributes
      nil
    end

    # Returns the value at the provided xpath
    # @param [Exchange] exchange
    # @param [String] xpath
    # @return [String] Value inside element found through Xpath
    def xpath_value_for(exchange: nil, xpath: nil)
      raise ArgumentError unless exchange && xpath
      response = exchange.response
      raise "Can't perform XPATH if response is not XML" unless Interpreter.response_type_for(response) == :xml
      result =
        if Soaspec::Environment.strip_namespaces? && !xpath.include?(':')
          temp_doc = Nokogiri.parse response.body
          temp_doc.remove_namespaces!
          temp_doc.xpath(xpath).first
        else
          Nokogiri.parse(response.body).xpath(xpath).first
        end
      raise NoElementAtXpath, "No value at Xpath '#{xpath}'" unless result
      result.inner_text
    end

    # Based on a exchange, return the value at the provided xpath
    # If the path does not begin with a '/', a '//' is added to it
    # @param [Exchange] exchange
    # @param [Object] path Xpath or other path identifying how to find element
    # @return [String] Value at Xpath
    def value_from_path(exchange, path)
      case Interpreter.response_type_for(exchange.response)
      when :xml
        path = '//' + path if path[0] != '/'
        xpath_value_for(exchange: exchange, xpath: path)
      when :json
        hash = extract_hash exchange.response
        value = hash.dig(*path)
        raise NoElementInHash, "Element in #{hash} not found with path '#{path}'" unless value
        value
      else
        raise 'Unrecognised response message. Neither xml nor json detected'
      end

    end

  end
end