# frozen_string_literal: true

require 'active_support/core_ext/hash/slice'
require 'json-schema'
require 'json'
require 'open_api/rswag/specs/extended_schema'

module OpenApi
  module Rswag
    module Specs
      class ResponseValidator
        def initialize(config = ::OpenApi::Rswag::Specs.config)
          @config = config
        end

        def validate!(metadata, response)
          swagger_doc = @config.get_swagger_doc(metadata[:swagger_doc])

          validate_code!(metadata, response)
          validate_headers!(metadata, response.headers)
          validate_body!(metadata, swagger_doc, response.body)
        end

        private

        def validate_code!(metadata, response)
          expected = metadata[:response][:code].to_s
          if response.code != expected
            raise UnexpectedResponse,
                  "Expected response code '#{response.code}' to match '#{expected}'\n" \
                "Response body: #{response.body}"
          end
        end

        def validate_headers!(metadata, headers)
          expected = (metadata[:response][:headers] || {}).keys
          expected.each do |name|
            raise UnexpectedResponse, "Expected response header #{name} to be present" if headers[name.to_s].nil?
          end
        end

        def validate_body!(metadata, swagger_doc, body)
          test_schemas = extract_schemas(metadata)
          return if test_schemas.nil? || test_schemas.empty?

          components = swagger_doc[:components] || {}
          components_schemas = { components: { schemas: components[:schemas] } }

          validation_schema = test_schemas[:schema] # response_schema
                                  .merge('$schema' => 'http://tempuri.org/rswag/specs/extended_schema')
                                  .merge(components_schemas)
          
          errors = JSON::Validator.fully_validate(validation_schema, body)
          raise UnexpectedResponse, "Expected response body to match schema: #{errors[0]}" if errors.any?
        end

        def extract_schemas(metadata)
          metadata[:operation] = {produces: []} if metadata[:operation].nil?
          produces = Array(metadata[:operation][:produces])

          producer_content = produces.first || 'application/json'
          response_content = metadata[:response][:content] || {producer_content => {}}
          response_content[producer_content]
        end
      end

      class UnexpectedResponse < StandardError; end
    end
  end
end