// Copyright (C) 2012 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.pgm.init;

import com.google.gerrit.launcher.GerritLauncher;
import com.google.gerrit.pgm.util.ConsoleUI;
import com.google.gerrit.server.config.SitePaths;
import com.google.gerrit.server.plugins.PluginLoader;
import com.google.inject.Inject;
import com.google.inject.Singleton;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.util.Enumeration;
import java.util.jar.Attributes;
import java.util.jar.JarFile;
import java.util.jar.Manifest;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;

@Singleton
public class InitPlugins implements InitStep {
  private final static String PLUGIN_DIR = "WEB-INF/plugins/";
  private final static String JAR = ".jar";

  private final ConsoleUI ui;
  private final SitePaths site;

  @Inject
  InitPlugins(final ConsoleUI ui, final SitePaths site) {
    this.ui = ui;
    this.site = site;
  }

  @Override
  public void run() throws Exception {
    ui.header("Plugins");

    final File myWar;
    try {
      myWar = GerritLauncher.getDistributionArchive();
    } catch (FileNotFoundException e) {
      System.err.println("warn: Cannot find gerrit.war");
      return;
    }

    boolean foundPlugin = false;
    try {
      final ZipFile zf = new ZipFile(myWar);
      try {
        final Enumeration<? extends ZipEntry> e = zf.entries();
        while (e.hasMoreElements()) {
          final ZipEntry ze = e.nextElement();
          if (ze.isDirectory()) {
            continue;
          }

          if (ze.getName().startsWith(PLUGIN_DIR) && ze.getName().endsWith(JAR)) {
            if (!foundPlugin) {
              if (!ui.yesno(false, "Prompt to install core plugins")) {
                return;
              }
              foundPlugin = true;
            }

            final String pluginJarName = new File(ze.getName()).getName();
            final String pluginName = pluginJarName.substring(0,  pluginJarName.length() - JAR.length());

            final InputStream in = zf.getInputStream(ze);
            try {
              final File tmpPlugin = PluginLoader.storeInTemp(pluginName, in, site);
              final String pluginVersion = getVersion(tmpPlugin);

              if (!ui.yesno(false, "Install plugin %s version %s", pluginName,
                  pluginVersion)) {
                tmpPlugin.delete();
                continue;
              }

              final File plugin = new File(site.plugins_dir, pluginJarName);
              if (plugin.exists()) {
                final String installedPluginVersion = getVersion(plugin);
                if (!ui.yesno(false,
                    "version %s is already installed, overwrite it",
                    installedPluginVersion)) {
                  tmpPlugin.delete();
                  continue;
                }
                if (!plugin.delete()) {
                  throw new IOException("Failed to delete plugin " + pluginName
                      + ": " + plugin.getAbsolutePath());
                }
              }
              if (!tmpPlugin.renameTo(plugin)) {
                throw new IOException("Failed to install plugin " + pluginName
                    + ": " + tmpPlugin.getAbsolutePath() + " -> "
                    + plugin.getAbsolutePath());
              }
            } finally {
              in.close();
            }
          }
        }
      } finally {
        zf.close();
      }
    } catch (IOException e) {
      throw new IOException("Failure during plugin installation", e);
    }

    if (!foundPlugin) {
      ui.message("No plugins found.");
    }
  }

  private static String getVersion(final File plugin) throws IOException {
    final JarFile jarFile = new JarFile(plugin);
    try {
      final Manifest manifest = jarFile.getManifest();
      final Attributes main = manifest.getMainAttributes();
      return main.getValue(Attributes.Name.IMPLEMENTATION_VERSION);
    } finally {
      jarFile.close();
    }
  }
}