//Copyright (C) 2011 The Android Open Source Project
//
// 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 com.google.gerrit.httpd.auth.container;

import com.google.gerrit.common.PageLinks;
import com.google.gerrit.server.config.CanonicalWebUrl;
import com.google.inject.Inject;
import com.google.inject.Provider;
import com.google.inject.Singleton;

import java.io.IOException;

import javax.annotation.Nullable;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet bound to {@code /login/*} to redirect after client SSL certificate
 * login.
 * <p>
 * When using client SSL certificate one should normally never see the sign in
 * dialog. However, this will happen if users session gets invalidated in some
 * way. Like in other authentication types, we need to force page to fully
 * reload in order to initialize a new session and create a valid xsrfKey.
 */
@Singleton
public class HttpsClientSslCertLoginServlet extends HttpServlet {
  private static final long serialVersionUID = 1L;

  private final Provider<String> urlProvider;

  @Inject
  public HttpsClientSslCertLoginServlet(@CanonicalWebUrl @Nullable final Provider<String> urlProvider) {
    this.urlProvider = urlProvider;
  }

  @Override
  protected void doGet(final HttpServletRequest req,
      final HttpServletResponse rsp) throws IOException {
    final StringBuilder rdr = new StringBuilder();
    rdr.append(urlProvider.get());
    rdr.append('#');
    rdr.append(getToken(req));

    rsp.setHeader("Expires", "Fri, 01 Jan 1980 00:00:00 GMT");
    rsp.setHeader("Pragma", "no-cache");
    rsp.setHeader("Cache-Control", "no-cache, must-revalidate");
    rsp.sendRedirect(rdr.toString());
  }

  private String getToken(final HttpServletRequest req) {
    String token = req.getPathInfo();
    if (token == null || token.isEmpty()) {
      token = PageLinks.MINE;
    }
    return token;
  }
}