// Copyright 2016 The Domain Registry Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package google.registry.module.frontend;

import static java.util.Arrays.asList;

import com.google.common.base.Function;
import com.google.common.collect.FluentIterable;
import google.registry.monitoring.metrics.MetricReporter;
import google.registry.request.RequestHandler;
import google.registry.request.RequestModule;
import google.registry.util.FormattingLogger;
import java.io.IOException;
import java.lang.reflect.Method;
import java.security.Security;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.bouncycastle.jce.provider.BouncyCastleProvider;

/** Servlet that should handle all requests to our "default" App Engine module. */
public final class FrontendServlet extends HttpServlet {

  private static final FrontendComponent component = DaggerFrontendComponent.create();
  private static final MetricReporter metricReporter = component.metricReporter();
  private static final FormattingLogger logger = FormattingLogger.getLoggerForCallerClass();

  private static final RequestHandler<FrontendRequestComponent> requestHandler =
      RequestHandler.create(FrontendRequestComponent.class, FluentIterable
          .from(asList(FrontendRequestComponent.class.getMethods()))
          .transform(new Function<Method, Method>() {
            @Override
            public Method apply(Method method) {
              method.setAccessible(true);  // Make App Engine's security manager happy.
              return method;
            }}));

  @Override
  public void init() {
    Security.addProvider(new BouncyCastleProvider());

    try {
      metricReporter.startAsync().awaitRunning(10, TimeUnit.SECONDS);
      logger.info("Started up MetricReporter");
    } catch (TimeoutException timeoutException) {
      logger.severefmt("Failed to initialize MetricReporter: %s", timeoutException);
    }
  }

  @Override
  public void destroy() {
    try {
      metricReporter.stopAsync().awaitTerminated(10, TimeUnit.SECONDS);
      logger.info("Shut down MetricReporter");
    } catch (TimeoutException timeoutException) {
      logger.severefmt("Failed to stop MetricReporter: %s", timeoutException);
    }
  }

  @Override
  public void service(HttpServletRequest req, HttpServletResponse rsp) throws IOException {
    requestHandler.handleRequest(req, rsp, component.startRequest(new RequestModule(req, rsp)));
  }
}