/*
 * Copyright 2000-2011 JetBrains s.r.o.
 *
 * 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.intellij.framework.detection.impl;

import com.intellij.framework.FrameworkType;
import com.intellij.framework.detection.FrameworkDetector;
import com.intellij.openapi.application.ApplicationManager;
import com.intellij.openapi.application.PathManager;
import com.intellij.openapi.diagnostic.Logger;
import com.intellij.openapi.fileTypes.FileType;
import com.intellij.openapi.util.io.FileUtil;
import com.intellij.util.containers.MultiMap;
import gnu.trove.TIntObjectHashMap;
import gnu.trove.TObjectIntHashMap;
import org.jetbrains.annotations.NotNull;

import java.io.*;
import java.util.*;

/**
 * @author nik
 */
public class FrameworkDetectorRegistryImpl extends FrameworkDetectorRegistry {
  private static final Logger LOG = Logger.getInstance("#com.intellij.framework.detection.impl.FrameworkDetectorRegistryImpl");
  private static final int REGISTRY_VERSION = 0;
  private TObjectIntHashMap<String> myDetectorIds;
  private TIntObjectHashMap<FrameworkDetector> myDetectorById;
  private MultiMap<FileType, Integer> myDetectorsByFileType;
  private int myDetectorsVersion;

  public FrameworkDetectorRegistryImpl() {
    loadDetectors();
    if (!ApplicationManager.getApplication().isUnitTestMode()) {
      saveDetectors();
    }
  }

  private void loadDetectors() {
    Map<String, FrameworkDetector> newDetectors = new HashMap<String, FrameworkDetector>();
    for (FrameworkDetector detector : FrameworkDetector.EP_NAME.getExtensions()) {
      newDetectors.put(detector.getDetectorId(), detector);
    }

    myDetectorIds = new TObjectIntHashMap<String>();
    final File file = getDetectorsRegistryFile();
    int maxId = REGISTRY_VERSION;
    if (file.exists()) {
      LOG.debug("loading framework detectors registry from " + file.getAbsolutePath());
      List<String> unknownIds = new ArrayList<String>();
      boolean versionChanged = false;
      try {
        DataInputStream input = new DataInputStream(new BufferedInputStream(new FileInputStream(file)));
        try {
          input.readInt();
          myDetectorsVersion = input.readInt();
          int size = input.readInt();
          while (size-- > REGISTRY_VERSION) {
            final String stringId = input.readUTF();
            int intId = input.readInt();
            maxId = Math.max(maxId, intId);
            final int version = input.readInt();
            final FrameworkDetector detector = newDetectors.remove(stringId);
            if (detector != null) {
              if (version != detector.getDetectorVersion()) {
                LOG.info("Version of framework detector '" + stringId + "' changed: " + version + " -> " + detector.getDetectorVersion());
                versionChanged = true;
              }
              myDetectorIds.put(stringId, intId);
            }
            else {
              unknownIds.add(stringId);
            }
          }
        }
        finally {
          input.close();
        }
      }
      catch (IOException e) {
        LOG.info(e);
      }
      if (!unknownIds.isEmpty()) {
        LOG.debug("Unknown framework detectors: " + unknownIds);
      }
      if (versionChanged || !newDetectors.isEmpty()) {
        if (!newDetectors.isEmpty()) {
          LOG.info("New framework detectors: " + newDetectors.keySet());
        }
        myDetectorsVersion++;
        LOG.info("Framework detection index version changed to " + myDetectorsVersion);
      }
    }
    int nextId = maxId+1;
    for (String newDetector : newDetectors.keySet()) {
      myDetectorIds.put(newDetector, nextId++);
    }
    myDetectorById = new TIntObjectHashMap<FrameworkDetector>();
    myDetectorsByFileType = new MultiMap<FileType, Integer>();
    for (FrameworkDetector detector : FrameworkDetector.EP_NAME.getExtensions()) {
      final int id = myDetectorIds.get(detector.getDetectorId());
      myDetectorsByFileType.putValue(detector.getFileType(), id);
      myDetectorById.put(id, detector);
      LOG.debug("'" + detector.getDetectorId() + "' framework detector: id = " + id);
    }
  }

  private void saveDetectors() {
    final File file = getDetectorsRegistryFile();
    FileUtil.createIfDoesntExist(file);
    try {
      DataOutputStream output = new DataOutputStream(new BufferedOutputStream(new FileOutputStream(file)));
      try {
        output.writeInt(REGISTRY_VERSION);
        output.writeInt(myDetectorsVersion);
        final FrameworkDetector[] detectors = FrameworkDetector.EP_NAME.getExtensions();
        output.writeInt(detectors.length);
        for (FrameworkDetector detector : detectors) {
          output.writeUTF(detector.getDetectorId());
          output.writeInt(myDetectorIds.get(detector.getDetectorId()));
          output.writeInt(detector.getDetectorVersion());
        }
      }
      finally {
        output.close();
      }
    }
    catch (IOException e) {
      LOG.info(e);
    }
  }

  private static File getDetectorsRegistryFile() {
    return new File(getDetectionDirPath() + File.separator + "detectors-registry.dat");
  }

  public static String getDetectionDirPath() {
    return PathManager.getSystemPath() + File.separator + "frameworks" + File.separator + "detection";
  }

  @Override
  public FrameworkType findFrameworkType(@NotNull String typeId) {
    for (FrameworkType type : getFrameworkTypes()) {
      if (typeId.equals(type.getId())) {
        return type;
      }
    }
    return null;
  }

  @NotNull
  @Override
  public List<? extends FrameworkType> getFrameworkTypes() {
    final List<FrameworkType> types = new ArrayList<FrameworkType>();
    for (FrameworkDetector detector : FrameworkDetector.EP_NAME.getExtensions()) {
      types.add(detector.getFrameworkType());
    }
    return types;
  }

  @Override
  public int getDetectorsVersion() {
    return myDetectorsVersion;
  }

  @Override
  public int getDetectorId(@NotNull FrameworkDetector detector) {
    return myDetectorIds.get(detector.getDetectorId());
  }

  @Override
  public FrameworkDetector getDetectorById(int id) {
    return myDetectorById.get(id);
  }

  @NotNull
  @Override
  public Collection<Integer> getDetectorIds(@NotNull FileType fileType) {
    return myDetectorsByFileType.get(fileType);
  }

  @Override
  public Collection<Integer> getAllDetectorIds() {
    final int[] ids = myDetectorIds.getValues();
    final List<Integer> result = new ArrayList<Integer>();
    for (int id : ids) {
      result.add(id);
    }
    return result;
  }
}