/*
 * Copyright 2000-2012 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.impl.file.impl;

import com.intellij.ProjectTopics;
import com.intellij.ide.highlighter.JavaClassFileType;
import com.intellij.openapi.Disposable;
import com.intellij.openapi.diagnostic.Logger;
import com.intellij.openapi.project.Project;
import com.intellij.openapi.roots.*;
import com.intellij.openapi.util.Comparing;
import com.intellij.openapi.vfs.VirtualFile;
import com.intellij.openapi.vfs.VirtualFileWithId;
import com.intellij.psi.*;
import com.intellij.psi.impl.PsiManagerEx;
import com.intellij.psi.impl.file.PsiPackageImpl;
import com.intellij.psi.impl.java.stubs.index.JavaFullClassNameIndex;
import com.intellij.psi.search.GlobalSearchScope;
import com.intellij.psi.util.PsiUtilCore;
import com.intellij.util.Query;
import com.intellij.util.containers.ConcurrentHashMap;
import com.intellij.util.containers.ContainerUtil;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;
import org.jetbrains.jps.model.java.JavaModuleSourceRootTypes;

import java.util.*;

/**
 * Author: dmitrylomov
 */
public class JavaFileManagerImpl implements JavaFileManager, Disposable {
  private static final Logger LOG = Logger.getInstance("#com.intellij.psi.impl.file.impl.JavaFileManagerImpl");
  private final ConcurrentHashMap<GlobalSearchScope, PsiClass> myCachedObjectClassMap = new ConcurrentHashMap<GlobalSearchScope, PsiClass>();
  private final PsiManagerEx myManager;
  private volatile Set<String> myNontrivialPackagePrefixes = null;
  private boolean myDisposed = false;
  private final PackageIndex myPackageIndex;

  public JavaFileManagerImpl(Project project) {
    myManager = (PsiManagerEx)PsiManager.getInstance(project);
    myPackageIndex = PackageIndex.getInstance(myManager.getProject());
    project.getMessageBus().connect().subscribe(ProjectTopics.PROJECT_ROOTS, new ModuleRootAdapter() {
      @Override
      public void rootsChanged(final ModuleRootEvent event) {
        myNontrivialPackagePrefixes = null;
      }
    });

    myManager.registerRunnableToRunOnChange(new Runnable() {
      @Override
      public void run() {
        myCachedObjectClassMap.clear();
      }
    });
  }

  @Override
  public void dispose() {
    myDisposed = true;
    myCachedObjectClassMap.clear();
  }

  @Override
  @Nullable
  public PsiPackage findPackage(@NotNull String packageName) {
    Query<VirtualFile> dirs = myPackageIndex.getDirsByPackageName(packageName, true);
    if (dirs.findFirst() == null) return null;
    return new PsiPackageImpl(myManager, packageName);
  }

  @Override
  public PsiClass[] findClasses(@NotNull String qName, @NotNull final GlobalSearchScope scope) {
    final Collection<PsiClass> classes = JavaFullClassNameIndex.getInstance().get(qName.hashCode(), myManager.getProject(), scope);
    if (classes.isEmpty()) return PsiClass.EMPTY_ARRAY;
    List<PsiClass> result = new ArrayList<PsiClass>(classes.size());
    for (PsiClass aClass : classes) {
      final String qualifiedName = aClass.getQualifiedName();
      if (qualifiedName == null || !qualifiedName.equals(qName)) continue;

      PsiUtilCore.ensureValid(aClass);
      PsiFile file = aClass.getContainingFile();
      if (file == null) {
        throw new AssertionError("No file for class: " + aClass + " of " + aClass.getClass());
      }

      VirtualFile vFile = file.getVirtualFile();
      if (!hasAcceptablePackage(vFile)) continue;

      result.add(aClass);
    }

    int count = result.size();
    if (count == 0) return PsiClass.EMPTY_ARRAY;
    if (count == 1) return new PsiClass[] {result.get(0)};

    ContainerUtil.quickSort(result, new Comparator<PsiClass>() {
      @Override
      public int compare(PsiClass o1, PsiClass o2) {
        return scope.compare(o2.getContainingFile().getVirtualFile(), o1.getContainingFile().getVirtualFile());
      }
    });

    return result.toArray(new PsiClass[count]);
  }

  @Override
  @Nullable
  public PsiClass findClass(@NotNull String qName, @NotNull GlobalSearchScope scope) {
    LOG.assertTrue(!myDisposed);

    if (CommonClassNames.JAVA_LANG_OBJECT.equals(qName)) { // optimization
      PsiClass cached = myCachedObjectClassMap.get(scope);
      if (cached == null) {
        cached = findClassInIndex(qName, scope);
        if (cached != null) {
          cached = myCachedObjectClassMap.cacheOrGet(scope, cached);
        }
      }

      return cached;
    }

    return findClassInIndex(qName, scope);
  }

  @Nullable
  private PsiClass findClassInIndex(String qName, GlobalSearchScope scope) {
    VirtualFile bestFile = null;
    PsiClass bestClass = null;
    final Collection<PsiClass> classes = JavaFullClassNameIndex.getInstance().get(qName.hashCode(), myManager.getProject(), scope);

    for (PsiClass aClass : classes) {
      PsiFile file = aClass.getContainingFile();
      if (file == null) {
        LOG.error("aClass=" + aClass + " of class " + aClass.getClass() + "; valid=" + aClass.isValid());
        continue;
      }
      final boolean valid = aClass.isValid();
      VirtualFile vFile = file.getVirtualFile();
      if (!valid) {
        LOG.error("Invalid class " + aClass + "; " +
                  file + (file.isValid() ? "" : " (invalid)") +
                  "; virtualFile:" + vFile +
                  (vFile != null && !vFile.isValid() ? " (invalid)" : "") +
                  "; id=" + (vFile == null ? 0 : ((VirtualFileWithId)vFile).getId()),
                  new PsiInvalidElementAccessException(aClass));
        continue;
      }

      final String qualifiedName = aClass.getQualifiedName();
      if (qualifiedName == null || !qualifiedName.equals(qName)) continue;


      if (!hasAcceptablePackage(vFile)) continue;
      if (bestFile == null || scope.compare(vFile, bestFile) > 0) {
        bestFile = vFile;
        bestClass = aClass;
      }
    }
    return bestClass;
  }

  private boolean hasAcceptablePackage(final VirtualFile vFile) {
    if (vFile.getFileType() == JavaClassFileType.INSTANCE) {
      // See IDEADEV-5626
      final VirtualFile root = ProjectRootManager.getInstance(myManager.getProject()).getFileIndex().getClassRootForFile(vFile);
      VirtualFile parent = vFile.getParent();
      final PsiNameHelper nameHelper = JavaPsiFacade.getInstance(myManager.getProject()).getNameHelper();
      while (parent != null && !Comparing.equal(parent, root)) {
        if (!nameHelper.isIdentifier(parent.getName())) return false;
        parent = parent.getParent();
      }
    }

    return true;
  }

  @Override
  public Collection<String> getNonTrivialPackagePrefixes() {
    Set<String> names = myNontrivialPackagePrefixes;
    if (names == null) {
      names = new HashSet<String>();
      final ProjectRootManager rootManager = ProjectRootManager.getInstance(myManager.getProject());
      final List<VirtualFile> sourceRoots = rootManager.getModuleSourceRoots(JavaModuleSourceRootTypes.SOURCES);
      final ProjectFileIndex fileIndex = rootManager.getFileIndex();
      for (final VirtualFile sourceRoot : sourceRoots) {
        final String packageName = fileIndex.getPackageNameByDirectory(sourceRoot);
        if (packageName != null && !packageName.isEmpty()) {
          names.add(packageName);
        }
      }
      myNontrivialPackagePrefixes = names;
    }
    return names;
  }

}