/*
 * Copyright 2000-2014 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.openapi.roots.impl;

import com.intellij.ProjectTopics;
import com.intellij.openapi.Disposable;
import com.intellij.openapi.diagnostic.Logger;
import com.intellij.openapi.fileTypes.FileTypeEvent;
import com.intellij.openapi.fileTypes.FileTypeListener;
import com.intellij.openapi.fileTypes.FileTypeManager;
import com.intellij.openapi.module.Module;
import com.intellij.openapi.module.ModuleManager;
import com.intellij.openapi.progress.ProgressManager;
import com.intellij.openapi.project.Project;
import com.intellij.openapi.roots.*;
import com.intellij.openapi.util.Disposer;
import com.intellij.openapi.vfs.VirtualFile;
import com.intellij.openapi.vfs.VirtualFileManager;
import com.intellij.openapi.vfs.newvfs.BulkFileListener;
import com.intellij.openapi.vfs.newvfs.NewVirtualFile;
import com.intellij.openapi.vfs.newvfs.events.VFileEvent;
import com.intellij.util.IncorrectOperationException;
import com.intellij.util.Query;
import com.intellij.util.containers.ConcurrentIntObjectMap;
import com.intellij.util.containers.StripedLockIntObjectConcurrentHashMap;
import com.intellij.util.messages.MessageBusConnection;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;
import org.jetbrains.annotations.TestOnly;
import org.jetbrains.jps.model.module.JpsModuleSourceRootType;

import java.util.Arrays;
import java.util.Collections;
import java.util.List;

public class DirectoryIndexImpl extends DirectoryIndex {
  private static final Logger LOG = Logger.getInstance("#com.intellij.openapi.roots.impl.DirectoryIndexImpl");

  private final Project myProject;
  private final MessageBusConnection myConnection;

  private volatile boolean myDisposed = false;
  private volatile RootIndex myRootIndex = null;

  public DirectoryIndexImpl(@NotNull Project project) {
    myProject = project;
    myConnection = project.getMessageBus().connect(project);
    subscribeToFileChanges();
    markContentRootsForRefresh();
    Disposer.register(project, new Disposable() {
      @Override
      public void dispose() {
        myDisposed = true;
        myRootIndex = null;
      }
    });
  }

  protected void subscribeToFileChanges() {
    myConnection.subscribe(FileTypeManager.TOPIC, new FileTypeListener.Adapter() {
      @Override
      public void fileTypesChanged(@NotNull FileTypeEvent event) {
        myRootIndex = null;
      }
    });

    myConnection.subscribe(ProjectTopics.PROJECT_ROOTS, new ModuleRootAdapter() {
      @Override
      public void rootsChanged(ModuleRootEvent event) {
        myRootIndex = null;
      }
    });

    myConnection.subscribe(VirtualFileManager.VFS_CHANGES, new BulkFileListener() {
      @Override
      public void before(@NotNull List<? extends VFileEvent> events) {
      }

      @Override
      public void after(@NotNull List<? extends VFileEvent> events) {
        RootIndex rootIndex = myRootIndex;
        if (rootIndex != null && rootIndex.resetOnEvents(events)) {
          myRootIndex = null;
        }
      }
    });
  }

  protected void markContentRootsForRefresh() {
    Module[] modules = ModuleManager.getInstance(myProject).getModules();
    for (Module module : modules) {
      VirtualFile[] contentRoots = ModuleRootManager.getInstance(module).getContentRoots();
      for (VirtualFile contentRoot : contentRoots) {
        if (contentRoot instanceof NewVirtualFile) {
          ((NewVirtualFile)contentRoot).markDirtyRecursively();
        }
      }
    }
  }

  protected void dispatchPendingEvents() {
    myConnection.deliverImmediately();
  }

  @Override
  @NotNull
  public Query<VirtualFile> getDirectoriesByPackageName(@NotNull String packageName, boolean includeLibrarySources) {
    return getRootIndex().getDirectoriesByPackageName(packageName, includeLibrarySources);
  }

  @NotNull
  private RootIndex getRootIndex() {
    RootIndex rootIndex = myRootIndex;
    if (rootIndex == null) {
      myRootIndex = rootIndex = new RootIndex(myProject, createRootInfoCache());
    }
    return rootIndex;
  }

  protected RootIndex.InfoCache createRootInfoCache() {
    return new RootIndex.InfoCache() {
      // Upsource can't use int-mapping because different files may have the same id there
      private final ConcurrentIntObjectMap<DirectoryInfo> myInfoCache = new StripedLockIntObjectConcurrentHashMap<DirectoryInfo>();
      @Override
      public void cacheInfo(@NotNull VirtualFile dir, @NotNull DirectoryInfo info) {
        myInfoCache.put(((NewVirtualFile)dir).getId(), info);
      }

      @Override
      public DirectoryInfo getCachedInfo(@NotNull VirtualFile dir) {
        return myInfoCache.get(((NewVirtualFile)dir).getId());
      }
    };
  }

  @TestOnly
  public void checkConsistency() {
    getRootIndex().checkConsistency();
  }

  @Override
  public DirectoryInfo getInfoForDirectory(@NotNull VirtualFile dir) {
    DirectoryInfo info = getInfoForFile(dir);
    return info.isInProject() ? info : null;
  }

  @NotNull
  @Override
  public DirectoryInfo getInfoForFile(@NotNull VirtualFile file) {
    checkAvailability();
    dispatchPendingEvents();

    if (!(file instanceof NewVirtualFile)) return NonProjectDirectoryInfo.NOT_SUPPORTED_VIRTUAL_FILE_IMPLEMENTATION;

    return getRootIndex().getInfoForFile(file);
  }

  @Override
  @Nullable
  public JpsModuleSourceRootType<?> getSourceRootType(@NotNull DirectoryInfo info) {
    if (info.isInModuleSource()) {
      return getRootIndex().getSourceRootType(info);
    }
    return null;
  }

  @Override
  public String getPackageName(@NotNull VirtualFile dir) {
    checkAvailability();
    if (!(dir instanceof NewVirtualFile)) return null;

    return getRootIndex().getPackageName(dir);
  }

  @NotNull
  @Override
  public OrderEntry[] getOrderEntries(@NotNull DirectoryInfo info) {
    checkAvailability();
    return getRootIndex().getOrderEntries(info);
  }

  @TestOnly
  void assertConsistency(DirectoryInfo info) {
    OrderEntry[] entries = getOrderEntries(info);
    for (int i = 1; i < entries.length; i++) {
      assert RootIndex.BY_OWNER_MODULE.compare(entries[i - 1], entries[i]) <= 0;
    }
  }

  private void checkAvailability() {
    if (myDisposed) {
      ProgressManager.checkCanceled();
      LOG.error("Directory index is already disposed for " + myProject);
    }
  }

  @NotNull
  private static OrderEntry createFakeOrderEntry(@NotNull final Module ownerModule) {
    return new OrderEntry() {
      @NotNull
      @Override
      public VirtualFile[] getFiles(OrderRootType type) {
        throw new IncorrectOperationException();
      }

      @NotNull
      @Override
      public String[] getUrls(OrderRootType rootType) {
        throw new IncorrectOperationException();
      }

      @NotNull
      @Override
      public String getPresentableName() {
        throw new IncorrectOperationException();
      }

      @Override
      public boolean isValid() {
        throw new IncorrectOperationException();
      }

      @NotNull
      @Override
      public Module getOwnerModule() {
        return ownerModule;
      }

      @Override
      public <R> R accept(RootPolicy<R> policy, @Nullable R initialValue) {
        throw new IncorrectOperationException();
      }

      @Override
      public int compareTo(@NotNull OrderEntry o) {
        throw new IncorrectOperationException();
      }

      @Override
      public boolean isSynthetic() {
        throw new IncorrectOperationException();
      }
    };
  }

  @Override
  @Nullable
  OrderEntry findOrderEntryWithOwnerModule(@NotNull DirectoryInfo info, @NotNull Module ownerModule) {
    OrderEntry[] entries = getOrderEntries(info);
    if (entries.length < 10) {
      for (OrderEntry entry : entries) {
        if (entry.getOwnerModule() == ownerModule) return entry;
      }
      return null;
    }
    int index = Arrays.binarySearch(entries, createFakeOrderEntry(ownerModule), RootIndex.BY_OWNER_MODULE);
    return index < 0 ? null : entries[index];
  }

  @Override
  @NotNull
  List<OrderEntry> findAllOrderEntriesWithOwnerModule(@NotNull DirectoryInfo info, @NotNull Module ownerModule) {
    OrderEntry[] entries = getOrderEntries(info);
    if (entries.length == 0) return Collections.emptyList();

    if (entries.length == 1) {
      OrderEntry entry = entries[0];
      return entry.getOwnerModule() == ownerModule ? Arrays.asList(entries) : Collections.<OrderEntry>emptyList();
    }
    int index = Arrays.binarySearch(entries, createFakeOrderEntry(ownerModule), RootIndex.BY_OWNER_MODULE);
    if (index < 0) {
      return Collections.emptyList();
    }
    int firstIndex = index;
    while (firstIndex - 1 >= 0 && entries[firstIndex - 1].getOwnerModule() == ownerModule) {
      firstIndex--;
    }
    int lastIndex = index + 1;
    while (lastIndex < entries.length && entries[lastIndex].getOwnerModule() == ownerModule) {
      lastIndex++;
    }

    OrderEntry[] subArray = new OrderEntry[lastIndex - firstIndex];
    System.arraycopy(entries, firstIndex, subArray, 0, lastIndex - firstIndex);

    return Arrays.asList(subArray);
  }
}