// 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.googlesource.gerrit.plugins.scripting.scala;

import com.google.gerrit.extensions.annotations.PluginName;
import com.google.gerrit.server.plugins.InvalidPluginException;
import com.google.gerrit.server.plugins.ServerPlugin;
import com.google.gerrit.server.plugins.ServerPluginProvider;
import com.google.inject.Inject;
import com.google.inject.Provider;
import com.google.inject.Singleton;

import org.eclipse.jgit.internal.storage.file.FileSnapshot;

import java.nio.file.Path;

/**
 * Scala scripting plugins.
 *
 * Allows to define a Groovy class to implement any type of Gerrit plugin.
 *
 * Example of Scala SSH Plugin (hello-1.0.scala):
 * ------------------------------------------------ TBD
 *
 * The above example add a "hello scala" command to Gerrit SSH interface that
 * displays "Hello Gerrit from Scala !"
 *
 * import com.google.gerrit.sshd._
 * import com.google.gerrit.extensions.annotations._
 *
 * @Export("scala")
 * class MyClass extends SshCommand {
 *   override def run = stdout println "Hello Gerrit from Scala!"
 * }
 *
 */
@Singleton
class ScalaPluginProvider implements ServerPluginProvider {
  public static final String SCALA_EXTENSION = ".scala";

  private final Provider<ScalaPluginScriptEngine> scriptEngineProvider;
  private final String providerPluginName;

  @Inject
  public ScalaPluginProvider(
      Provider<ScalaPluginScriptEngine> scriptEngineProvider,
      @PluginName String providerPluginName) {
    this.scriptEngineProvider = scriptEngineProvider;
    this.providerPluginName = providerPluginName;
  }

  @Override
  public ServerPlugin get(Path srcFile,
      FileSnapshot snapshot, PluginDescription description)
      throws InvalidPluginException {
    ScalaPluginScriptEngine scriptEngine = scriptEngineProvider.get();
    String name = getPluginName(srcFile);
    return new ServerPlugin(name, description.canonicalUrl, description.user, srcFile,
        snapshot, new ScalaPluginScanner(name, srcFile, scriptEngine),
        description.dataDir, scriptEngine.getClassLoader());
  }

  @Override
  public boolean handles(Path srcFile) {
    return srcFile.toString().toLowerCase().endsWith(SCALA_EXTENSION);
  }

  @Override
  public String getPluginName(Path srcFile) {
    String srcFileName = srcFile.getFileName().toString();
    int endPos = srcFileName.lastIndexOf('-');
    if (endPos == -1) {
      endPos = srcFileName.lastIndexOf('.');
    }
    return srcFileName.substring(0, endPos);
  }

  @Override
  public String getProviderPluginName() {
    return providerPluginName;
  }
}