require 'active_support/core_ext/hash/deep_merge'
require 'rspec/core/formatters/base_text_formatter'
require 'swagger_helper'

module Rswag
  module Specs
    class SwaggerFormatter

      # NOTE: rspec 2.x support
      if RSPEC_VERSION > 2
        ::RSpec::Core::Formatters.register self, :example_group_finished, :stop
      end

      def initialize(output)
        @output = output
        @swagger_root = ::RSpec.configuration.swagger_root
        raise ConfigurationError, 'Missing swagger_root. See swagger_helper.rb' if @swagger_root.nil?
        @swagger_docs = ::RSpec.configuration.swagger_docs || []
        raise ConfigurationError, 'Missing swagger_docs. See swagger_helper.rb' if @swagger_docs.empty?

        @output.puts 'Generating Swagger docs ...'
      end

      def example_group_finished(notification)
        # NOTE: rspec 2.x support
        if RSPEC_VERSION > 2
          metadata = notification.group.metadata
        else
          metadata = notification.metadata
        end

        return unless metadata.has_key?(:response)
        swagger_doc = get_swagger_doc(metadata[:swagger_doc])
        swagger_doc.deep_merge!(metadata_to_swagger(metadata))
      end

      def stop(notification=nil)
        @swagger_docs.each do |url_path, doc|
          file_path = File.join(@swagger_root, url_path)
          dirname = File.dirname(file_path)
          FileUtils.mkdir_p dirname unless File.exists?(dirname)

          File.open(file_path, 'w') do |file|
            file.write(JSON.pretty_generate(doc))
          end

          @output.puts "Swagger doc generated at #{file_path}"
        end
      end

      private

      def get_swagger_doc(tag)
        return @swagger_docs.values.first if tag.nil?
        raise ConfigurationError, "Unknown swagger_doc '#{tag}'" unless @swagger_docs.has_key?(tag)
        @swagger_docs[tag]
      end

      def metadata_to_swagger(metadata)
        response_code = metadata[:response][:code]
        response = metadata[:response].reject { |k,v| k == :code }
        verb = metadata[:operation][:verb]
        operation = metadata[:operation]
          .reject { |k,v| k == :verb }
          .merge(responses: { response_code => response })

        {
          paths: {
            metadata[:path] => {
              verb => operation
            }
          }
        }
      end
    end

    class ConfigurationError < StandardError; end
  end
end