require 'open-uri'
require 'pact/consumer_contract'
require 'pact/provider/rspec/matchers'
require 'pact/provider/test_methods'
require 'pact/provider/configuration'

module Pact
  module Provider
    module RSpec

      module InstanceMethods
        def app
          Pact.configuration.provider.app
        end
      end

      module ClassMethods

        include ::RSpec::Core::DSL

        def honour_pactfile pactfile_uri, options = {}
          #TODO change puts to use output stream
          puts "Reading pact at #{pactfile_uri}"
          puts "Filtering interactions by: #{options[:criteria]}" if options[:criteria] && options[:criteria].any?
          consumer_contract = Pact::ConsumerContract.from_json(read_pact_from(pactfile_uri, options))
          ::RSpec.describe "Verifying a pact between #{consumer_contract.consumer.name} and #{consumer_contract.provider.name}", :pactfile_uri => pactfile_uri do
            honour_consumer_contract consumer_contract, options
          end
        end

        def honour_consumer_contract consumer_contract, options = {}
          describe_consumer_contract consumer_contract, options.merge({:consumer => consumer_contract.consumer.name})
        end

        private

        def describe_consumer_contract consumer_contract, options
          consumer_interactions(consumer_contract, options).each do |interaction|
            describe_interaction_with_provider_state interaction, options
          end
        end

        def consumer_interactions(consumer_contract, options)
          if options[:criteria].nil?
            consumer_contract.interactions
          else
            consumer_contract.find_interactions options[:criteria]
          end
        end

        def describe_interaction_with_provider_state interaction, options
          if interaction.provider_state
            describe "Given #{interaction.provider_state}" do
              describe_interaction interaction, options
            end
          else
            describe_interaction interaction, options
          end
        end

        def describe_interaction interaction, options

          metadata = {
            :pact => :verify,
            :pact_interaction => interaction,
            :pact_interaction_example_description => interaction_description_for_rerun_command(interaction)
          }

          describe description_for(interaction), metadata do

            describe "with #{interaction.request.method_and_path}" do

              interaction_context = InteractionContext.new

              before do | example |
                interaction_context.run_once :before do
                  Pact.configuration.logger.info "Running example '#{Pact::RSpec.full_description(example)}'"
                  set_up_provider_state interaction.provider_state, options[:consumer]
                  replay_interaction interaction
                  interaction_context.last_response = last_response
                end
              end

              after do
                interaction_context.run_once :after do
                  tear_down_provider_state interaction.provider_state, options[:consumer]
                end
              end

              describe_response Pact::Term.unpack_regexps(interaction.response), interaction_context

            end

          end

        end

        def describe_response expected_response, interaction_context

          describe "returns a response which" do

            include Pact::RSpec::Matchers

            let(:expected_response_status) { expected_response['status'] }
            let(:expected_response_body) { expected_response['body'] }
            let(:response) { interaction_context.last_response }
            let(:response_status) { response.status }
            let(:response_body) { parse_body_from_response(response) }
            let(:differ) { Pact.configuration.body_differ_for_content_type diff_content_type }
            let(:diff_formatter) { Pact.configuration.diff_formatter_for_content_type diff_content_type }
            let(:expected_content_type) { Pact::Headers.new(expected_response['headers'] || {})['Content-Type'] }
            let(:actual_content_type) { response.headers['Content-Type']}
            let(:diff_content_type) { String === expected_content_type ? expected_content_type : actual_content_type } # expected_content_type may be a Regexp
            let(:diff_options) { { with: differ, diff_formatter: diff_formatter } }

            if expected_response['status']
              it "has status code #{expected_response['status']}" do
                expect(response_status).to eql expected_response_status
              end
            end

            if expected_response['headers']
              describe "includes headers" do
                expected_response['headers'].each do |name, expected_header_value|
                  it "\"#{name}\" with value #{expected_header_value.inspect}" do
                    header_value = response.headers[name]
                    expect(header_value).to match_header(name, expected_header_value)
                  end
                end
              end
            end

            if expected_response['body']
              it "has a matching body" do
                expect(response_body).to match_term expected_response_body, diff_options
              end
            end
          end
        end

        def description_for interaction
          interaction.provider_state ? interaction.description : interaction.description.capitalize
        end

        def interaction_description_for_rerun_command interaction
          description_for(interaction).capitalize + ( interaction.provider_state ? " given #{interaction.provider_state}" : "")
        end

        def read_pact_from uri, options = {}
          Pact::PactFile.read(uri, options)
        end

      end

      # The "arrange" and "act" parts of the test really only need to be run once,
      # however, stubbing is not supported in before :all, so this is a
      # wee hack to enable before :all like functionality using before :each.
      # In an ideal world, the test setup and execution should be quick enough for
      # the difference between :all and :each to be unnoticable, but the annoying
      # reality is, sometimes it does make a difference. This is for you, V!

      class InteractionContext

        attr_accessor :last_response

        def initialize
          @already_run = []
        end

        def run_once hook
          unless @already_run.include?(hook)
            yield
            @already_run << hook
          end
        end

      end
    end
  end
end