/*
 * 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.psi.stubs;

import com.intellij.openapi.application.ApplicationManager;
import com.intellij.openapi.application.ModalityState;
import com.intellij.openapi.diagnostic.Logger;
import com.intellij.openapi.editor.Document;
import com.intellij.openapi.fileEditor.FileDocumentManager;
import com.intellij.openapi.project.DumbService;
import com.intellij.openapi.project.Project;
import com.intellij.openapi.vfs.VirtualFile;
import com.intellij.psi.search.GlobalSearchScopes;
import com.intellij.util.indexing.FileBasedIndex;
import com.intellij.util.indexing.FileContent;
import com.intellij.util.indexing.FileContentImpl;
import com.intellij.util.indexing.IndexingStamp;
import org.jetbrains.annotations.Nullable;

import java.io.IOException;
import java.util.List;

/**
 * @author yole
 */
public class StubTreeLoaderImpl extends StubTreeLoader {
  private static final Logger LOG = Logger.getInstance("#com.intellij.psi.stubs.StubTreeLoaderImpl");

  @Nullable
  public StubTree readOrBuild(Project project, final VirtualFile vFile) {
    final StubTree fromIndices = readFromVFile(project, vFile);
    if (fromIndices != null) {
      return fromIndices;
    }

    if (!StubUpdatingIndex.canHaveStub(vFile)) {
      return null;
    }

    try {
      final FileContent fc = new FileContentImpl(vFile, vFile.contentsToByteArray());
      fc.putUserData(FileBasedIndex.PROJECT, project);
      final StubElement element = StubUpdatingIndex.buildStubTree(fc);
      if (element instanceof PsiFileStub) {
        return new StubTree((PsiFileStub)element);
      }
    }
    catch (IOException e) {
      throw new RuntimeException(e);
    }

    return null;
  }

  @Nullable
  public StubTree readFromVFile(Project project, final VirtualFile vFile) {
    if (DumbService.getInstance(project).isDumb()) {
      return null;
    }

    final int id = Math.abs(FileBasedIndex.getFileId(vFile));
    if (id > 0) {
      final List<SerializedStubTree> datas = FileBasedIndex.getInstance().getValues(StubUpdatingIndex.INDEX_ID, id, GlobalSearchScopes
          .fileScope(project, vFile));
      final int size = datas.size();

      if (size == 1) {
        StubElement stub = datas.get(0).getStub();
        return new StubTree((PsiFileStub)stub);
      }
      else if (size != 0) {
        LOG.error("Twin stubs: " + vFile.getPresentableUrl() + " has " + size + " stub versions. Should only have one. id=" + id);

        ApplicationManager.getApplication().invokeLater(new Runnable() {
          public void run() {
            final Document doc = FileDocumentManager.getInstance().getCachedDocument(vFile);
            if (doc != null) {
              FileDocumentManager.getInstance().saveDocument(doc);
            }
          }
        }, ModalityState.NON_MODAL);

        FileBasedIndex.getInstance().requestReindex(vFile);
      }
    }

    return null;
  }

  @Override
  public void rebuildStubTree(VirtualFile virtualFile) {
    FileBasedIndex.getInstance().requestReindex(virtualFile);
  }

  @Override
  public long getStubTreeTimestamp(VirtualFile vFile) {
    return IndexingStamp.getIndexStamp(vFile, StubUpdatingIndex.INDEX_ID);
  }
}