/*
 * 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.vcs.impl;

import com.intellij.ProjectTopics;
import com.intellij.openapi.application.ApplicationManager;
import com.intellij.openapi.application.ModalityState;
import com.intellij.openapi.components.ProjectComponent;
import com.intellij.openapi.module.Module;
import com.intellij.openapi.module.ModuleManager;
import com.intellij.openapi.project.ModuleAdapter;
import com.intellij.openapi.project.Project;
import com.intellij.openapi.roots.ModuleRootEvent;
import com.intellij.openapi.roots.ModuleRootListener;
import com.intellij.openapi.roots.ModuleRootManager;
import com.intellij.openapi.startup.StartupManager;
import com.intellij.openapi.ui.Messages;
import com.intellij.openapi.util.Pair;
import com.intellij.openapi.util.io.FileUtil;
import com.intellij.openapi.vcs.AbstractVcs;
import com.intellij.openapi.vcs.ProjectLevelVcsManager;
import com.intellij.openapi.vcs.VcsBundle;
import com.intellij.openapi.vcs.VcsDirectoryMapping;
import com.intellij.openapi.vfs.VirtualFile;
import com.intellij.util.messages.MessageBus;
import com.intellij.util.messages.MessageBusConnection;
import org.jetbrains.annotations.NonNls;
import org.jetbrains.annotations.NotNull;

import java.util.*;

/**
 * @author yole
 */
public class ModuleVcsDetector implements ProjectComponent {
  private final Project myProject;
  private final MessageBus myMessageBus;
  private final ProjectLevelVcsManagerImpl myVcsManager;
  private MessageBusConnection myConnection;

  public ModuleVcsDetector(final Project project, final MessageBus messageBus, final ProjectLevelVcsManager vcsManager) {
    myProject = project;
    myMessageBus = messageBus;
    myVcsManager = (ProjectLevelVcsManagerImpl) vcsManager;
  }

  @Override
  public void projectOpened() {
    if (ApplicationManager.getApplication().isUnitTestMode()) return;
    
    final StartupManager manager = StartupManager.getInstance(myProject);
    manager.registerStartupActivity(new Runnable() {
      @Override
      public void run() {
        if (myVcsManager.needAutodetectMappings()) {
          autoDetectVcsMappings(true);
        }
        myVcsManager.updateActiveVcss();
      }
    });
    manager.registerPostStartupActivity(new Runnable() {
      @Override
      public void run() {
        if (myMessageBus != null) {
          myConnection = myMessageBus.connect();
          final MyModulesListener listener = new MyModulesListener();
          myConnection.subscribe(ProjectTopics.MODULES, listener);
          myConnection.subscribe(ProjectTopics.PROJECT_ROOTS, listener);
        }
      }
    });
  }

  private class MyModulesListener extends ModuleAdapter implements ModuleRootListener {
    private final List<Pair<String, VcsDirectoryMapping>> myMappingsForRemovedModules = new ArrayList<Pair<String, VcsDirectoryMapping>>();

    @Override
    public void beforeRootsChange(ModuleRootEvent event) {
      myMappingsForRemovedModules.clear();
    }

    @Override
    public void rootsChanged(ModuleRootEvent event) {
      for (Pair<String, VcsDirectoryMapping> mapping : myMappingsForRemovedModules) {
        promptRemoveMapping(mapping.first, mapping.second);
      }
      // the check calculates to true only before user has done any change to mappings, i.e. in case modules are detected/added automatically
      // on start etc (look inside)
      if (myVcsManager.needAutodetectMappings()) {
        autoDetectVcsMappings(false);
      }
    }

    @Override
    public void moduleAdded(final Project project, final Module module) {
      myMappingsForRemovedModules.removeAll(getMappings(module));
      autoDetectModuleVcsMapping(module);
    }

    @Override
    public void beforeModuleRemoved(final Project project, final Module module) {
      myMappingsForRemovedModules.addAll(getMappings(module));
    }
  }

  @Override
  public void projectClosed() {
  }

  @Override
  @NonNls
  @NotNull
  public String getComponentName() {
    return "ModuleVcsDetector";
  }

  @Override
  public void initComponent() {
  }

  @Override
  public void disposeComponent() {
    if (myConnection != null) {
      myConnection.disconnect();
    }
  }

  private void autoDetectVcsMappings(final boolean tryMapPieces) {
    Set<AbstractVcs> usedVcses = new HashSet<AbstractVcs>();
    Map<VirtualFile, AbstractVcs> vcsMap = new HashMap<VirtualFile, AbstractVcs>();
    final ModuleManager moduleManager = ModuleManager.getInstance(myProject);
    for(Module module: moduleManager.getModules()) {
      final VirtualFile[] files = ModuleRootManager.getInstance(module).getContentRoots();
      for(VirtualFile file: files) {
        AbstractVcs contentRootVcs = myVcsManager.findVersioningVcs(file);
        if (contentRootVcs != null) {
          vcsMap.put(file, contentRootVcs);
        }
        usedVcses.add(contentRootVcs);
      }
    }
    if (usedVcses.size() == 1) {
      // todo I doubt this is correct, see IDEA-50527
      final AbstractVcs[] abstractVcses = usedVcses.toArray(new AbstractVcs[1]);
      final Module[] modules = moduleManager.getModules();
      final Set<String> contentRoots = new HashSet<String>();
      for (Module module : modules) {
        final VirtualFile[] roots = ModuleRootManager.getInstance(module).getContentRoots();
        for (VirtualFile root : roots) {
          contentRoots.add(root.getPath());
        }
      }

      if (abstractVcses [0] != null) {
        final List<VcsDirectoryMapping> vcsDirectoryMappings = new ArrayList<VcsDirectoryMapping>(myVcsManager.getDirectoryMappings());
        for (Iterator<VcsDirectoryMapping> iterator = vcsDirectoryMappings.iterator(); iterator.hasNext();) {
          final VcsDirectoryMapping mapping = iterator.next();
          if (! contentRoots.contains(mapping.getDirectory())) {
            iterator.remove();
          }
        }
        myVcsManager.setAutoDirectoryMapping("", abstractVcses [0].getName());
        for (VcsDirectoryMapping mapping : vcsDirectoryMappings) {
          myVcsManager.removeDirectoryMapping(mapping);
        }
        myVcsManager.cleanupMappings();
      }
    }
    else if (tryMapPieces) {
      for(Map.Entry<VirtualFile, AbstractVcs> entry: vcsMap.entrySet()) {
        myVcsManager.setAutoDirectoryMapping(entry.getKey().getPath(), entry.getValue() == null ? "" : entry.getValue().getName());
      }
      myVcsManager.cleanupMappings();
    }
  }

  private void autoDetectModuleVcsMapping(final Module module) {
    boolean mappingsUpdated = false;
    final VirtualFile[] files = ModuleRootManager.getInstance(module).getContentRoots();
    for(VirtualFile file: files) {
      AbstractVcs vcs = myVcsManager.findVersioningVcs(file);
      if (vcs != null && vcs != myVcsManager.getVcsFor(file)) {
        myVcsManager.setAutoDirectoryMapping(file.getPath(), vcs.getName());
        mappingsUpdated = true;
      }
    }
    if (mappingsUpdated) {
      myVcsManager.cleanupMappings();
    }
  }

  private List<Pair<String, VcsDirectoryMapping>> getMappings(final Module module) {
    List<Pair<String, VcsDirectoryMapping>> result = new ArrayList<Pair<String, VcsDirectoryMapping>>();
    final VirtualFile[] files = ModuleRootManager.getInstance(module).getContentRoots();
    final String moduleName = module.getName();
    for(final VirtualFile file: files) {
      for(final VcsDirectoryMapping mapping: myVcsManager.getDirectoryMappings()) {
        if (FileUtil.toSystemIndependentName(mapping.getDirectory()).equals(file.getPath())) {
          result.add(Pair.create(moduleName, mapping));
          break;
        }
      }
    }
    return result;
  }

  private void promptRemoveMapping(final String moduleName, final VcsDirectoryMapping mapping) {
    ApplicationManager.getApplication().invokeLater(new Runnable() {
      @Override
      public void run() {
        if (myProject.isDisposed()) return;
        final String msg = VcsBundle.message("vcs.root.remove.prompt", FileUtil.toSystemDependentName(mapping.getDirectory()), moduleName);
        int rc = Messages.showYesNoDialog(myProject, msg, VcsBundle.message("vcs.root.remove.title"), Messages.getQuestionIcon());
        if (rc == Messages.YES) {
          myVcsManager.removeDirectoryMapping(mapping);
        }
      }
    }, ModalityState.NON_MODAL);
  }
}