/*
 * MIT License
 *
 * Copyright (c) 2020-present Cloudogu GmbH and Contributors
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

package sonia.scm.server;

import org.eclipse.jetty.server.Connector;
import org.eclipse.jetty.server.ForwardedRequestCustomizer;
import org.eclipse.jetty.server.Handler;
import org.eclipse.jetty.server.HttpConfiguration;
import org.eclipse.jetty.server.HttpConnectionFactory;
import org.eclipse.jetty.server.SecureRequestCustomizer;
import org.eclipse.jetty.server.Server;
import org.eclipse.jetty.server.ServerConnector;
import org.eclipse.jetty.server.SslConnectionFactory;
import org.eclipse.jetty.server.handler.HandlerCollection;
import org.eclipse.jetty.util.resource.ResourceCollection;
import org.eclipse.jetty.util.ssl.SslContextFactory;
import org.eclipse.jetty.webapp.WebAppContext;

import java.net.URL;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.List;

public final class ServerConfiguration {

  @SuppressWarnings("java:S1075") // not a real uri
  private static final String DEFAULT_CONTEXT_PATH = "/scm";
  private final ServerConfigYaml configYaml;
  private Path testTempDir;

  public ServerConfiguration() {
    this.configYaml = new ServerConfigParser().parse();
  }

  // Visible for testing
  public ServerConfiguration(URL configFile, Path tempDir) {
    this.configYaml = new ServerConfigParser().parse(configFile);
    this.testTempDir = tempDir;
  }

  public void configureServer(Server server) {
    try {
      configureHttp(server);
      configureHandler(server);
      if (configYaml.getHttps().getKeyStorePath() != null && !configYaml.getHttps().getKeyStorePath().isEmpty()) {
        configureSSL(server);
      }
    } catch (Exception ex) {
      throw new ScmServerException("error during server configuration", ex);
    }
  }

  private void configureSSL(Server server) {
    SslContextFactory.Server sslServer = new SslContextFactory.Server();
    ServerConfigYaml.SSLConfig https = configYaml.getHttps();
    sslServer.setKeyStorePath(https.getKeyStorePath());
    sslServer.setKeyStorePassword(https.getKeyStorePassword());
    sslServer.setKeyStoreType(https.getKeyStoreType());

    sslServer.setIncludeProtocols("TLSv1.2", "TLSv1.3");
    sslServer.setIncludeCipherSuites(
      "TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384",
      "TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384",
      "TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256",
      "TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256",
      "TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256",
      "TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256",
      "TLS_DHE_RSA_WITH_AES_256_GCM_SHA384",
      "TLS_DHE_RSA_WITH_AES_128_GCM_SHA256");
    sslServer.setUseCipherSuitesOrder(false);
    HttpConfiguration sslHttpConfig = new HttpConfiguration(createCustomHttpConfig());
    sslHttpConfig.addCustomizer(new SecureRequestCustomizer(
        false,
        true,
        -1,
        false
      )
    );
    ServerConnector sslConnector = new ServerConnector(server, (
      new SslConnectionFactory(sslServer, "http/1.1")),
      new HttpConnectionFactory(sslHttpConfig));
    sslConnector.setHost(configYaml.getAddressBinding());
    sslConnector.setPort(https.getSslPort());
    server.addConnector(sslConnector);
  }

  private void configureHttp(Server server) {
    HttpConfiguration httpConfig = createCustomHttpConfig();
    redirectHttpToHttps(httpConfig);
    ServerConnector connector = new ServerConnector(server, new HttpConnectionFactory(httpConfig));
    System.out.println("Set http address binding to " + configYaml.getAddressBinding());
    connector.setHost(configYaml.getAddressBinding());
    System.out.println("Set http port to " + configYaml.getPort());
    connector.setPort(configYaml.getPort());
    server.addConnector(connector);
  }

  private void redirectHttpToHttps(HttpConfiguration httpConfig) {
    ServerConfigYaml.SSLConfig https = configYaml.getHttps();
    if (configYaml.getHttps().isRedirectHttpToHttps()) {
      httpConfig.setSecurePort(https.getSslPort());
      httpConfig.setSecureScheme("https");
    }
  }

  private void configureHandler(Server server) {
    HandlerCollection handlerCollection = new HandlerCollection();
    handlerCollection.setHandlers(new Handler[]{createWebAppContext(), createDocRoot()});
    server.setHandler(handlerCollection);
  }

  private WebAppContext createWebAppContext() {
    WebAppContext webApp = new WebAppContext();
    webApp.setContextPath(configYaml.getContextPath());
    // disable directory listings
    webApp.setInitParameter("org.eclipse.jetty.servlet.Default.dirAllowed", "false");

    String baseDir = resolveBaseDir();
    webApp.setWar(baseDir + "/var/webapp/scm-webapp.war");
    String tempDir = configYaml.getTempDir();
    webApp.setTempDirectory(tempDir.startsWith("/") ? Paths.get(tempDir, "webapp").toFile() : Paths.get(baseDir, tempDir).toFile());
    return webApp;
  }

  private WebAppContext createDocRoot() {
    WebAppContext docRoot = new WebAppContext();
    docRoot.setContextPath("/");
    String baseDir = resolveBaseDir();
    docRoot.setBaseResource(new ResourceCollection(new String[]{baseDir + "/var/webapp/docroot"}));
    String tempDir = configYaml.getTempDir();
    docRoot.setTempDirectory(tempDir.startsWith("/") ? Paths.get(tempDir, "work/docroot").toFile() : Paths.get(baseDir, tempDir).toFile());
    return docRoot;
  }

  private HttpConfiguration createCustomHttpConfig() {
    HttpConfiguration httpConfig = new HttpConfiguration();
    System.out.println("Set http request header size to " + configYaml.getHttpHeaderSize());
    httpConfig.setRequestHeaderSize(configYaml.getHttpHeaderSize());
    System.out.println("Set http response header size to " + configYaml.getHttpHeaderSize());
    httpConfig.setResponseHeaderSize(configYaml.getHttpHeaderSize());
    httpConfig.setSendServerVersion(false);
    System.out.println("Set forward request customizer: " + configYaml.isForwardHeadersEnabled());
    if (configYaml.isForwardHeadersEnabled()) {
      httpConfig.addCustomizer(new ForwardedRequestCustomizer());
    }
    return httpConfig;
  }

  public List<Listener> getListeners() {
    List<Listener> listeners = new ArrayList<>();

    Server server = new Server();
    configureServer(server);

    String contextPath = findContextPath(server.getHandlers());
    if (contextPath == null) {
      contextPath = DEFAULT_CONTEXT_PATH;
    }

    for (Connector connector : server.getConnectors()) {
      if (connector instanceof ServerConnector) {
        ServerConnector serverConnector = (ServerConnector) connector;
        String scheme = "http";
        String protocol = serverConnector.getDefaultProtocol();
        if ("SSL".equalsIgnoreCase(protocol) || "TLS".equalsIgnoreCase(protocol)) {
          scheme = "https";
        }
        listeners.add(new Listener(scheme, serverConnector.getPort(), contextPath));
      }
    }

    return listeners;
  }


  private String resolveBaseDir() {
    return testTempDir != null ? testTempDir.toString() : System.getProperty("baseDir", ".");
  }

  private String findContextPath(Handler[] handlers) {
    for (Handler handler : handlers) {
      if (handler instanceof WebAppContext) {
        return ((WebAppContext) handler).getContextPath();
      } else if (handler instanceof HandlerCollection) {
        String contextPath = findContextPath(((HandlerCollection) handler).getHandlers());
        if (contextPath != null) {
          return contextPath;
        }
      }
    }
    return null;
  }
}