/*
 * Copyright 2016 The Bazel Authors. All rights reserved.
 *
 * 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.google.idea.blaze.base.sync.projectstructure;

import com.google.common.annotations.VisibleForTesting;
import com.google.common.collect.Lists;
import com.google.common.collect.Sets;
import com.google.idea.blaze.base.io.FileAttributeProvider;
import com.google.idea.blaze.base.scope.BlazeContext;
import com.google.idea.blaze.base.scope.output.PrintOutput;
import com.google.idea.blaze.base.settings.BlazeImportSettings;
import com.google.idea.blaze.base.sync.BlazeSyncPlugin;
import com.intellij.ide.highlighter.ModuleFileType;
import com.intellij.openapi.application.ApplicationManager;
import com.intellij.openapi.diagnostic.Logger;
import com.intellij.openapi.module.ModifiableModuleModel;
import com.intellij.openapi.module.Module;
import com.intellij.openapi.module.ModuleManager;
import com.intellij.openapi.module.ModuleType;
import com.intellij.openapi.project.Project;
import com.intellij.openapi.roots.CompilerModuleExtension;
import com.intellij.openapi.roots.ModifiableRootModel;
import com.intellij.openapi.roots.ModuleRootManager;
import com.intellij.openapi.roots.impl.ModifiableModelCommitter;
import com.intellij.openapi.vfs.VfsUtil;
import com.intellij.openapi.vfs.VirtualFile;

import javax.annotation.Nullable;
import java.io.File;
import java.io.IOException;
import java.util.Collection;
import java.util.List;
import java.util.Set;

/**
 * Module editor implementation.
 */
public class ModuleEditorImpl implements BlazeSyncPlugin.ModuleEditor {
  private static final Logger LOG = Logger.getInstance(ModuleEditorImpl.class.getName());
  private static final String EXTERNAL_SYSTEM_ID_KEY = "external.system.id";
  private static final String EXTERNAL_SYSTEM_ID_VALUE = "Blaze";

  private final Project project;
  private final ModifiableModuleModel moduleModel;
  private final File imlDirectory;
  private final Set<String> moduleNames = Sets.newHashSet();
  @VisibleForTesting
  public Collection<ModifiableRootModel> modifiableModels = Lists.newArrayList();

  public ModuleEditorImpl(Project project, BlazeImportSettings importSettings) {
    this.project = project;
    this.moduleModel = ModuleManager.getInstance(project).getModifiableModel();

    this.imlDirectory = getImlDirectory(importSettings);
    if (!FileAttributeProvider.getInstance().exists(imlDirectory)) {
      if (!imlDirectory.mkdirs()) {
        LOG.error("Could not make directory: " + imlDirectory.getPath());
      }
    }
  }

  @Override
  public boolean registerModule(String moduleName) {
    boolean hasModule = moduleModel.findModuleByName(moduleName) != null;
    if (hasModule) {
      moduleNames.add(moduleName);
    }
    return hasModule;
  }

  @Override
  public Module createModule(String moduleName, ModuleType moduleType) {
    Module module = moduleModel.findModuleByName(moduleName);
    if (module == null) {
      File imlFile = new File(imlDirectory, moduleName + ModuleFileType.DOT_DEFAULT_EXTENSION);
      removeImlFile(imlFile);
      module = moduleModel.newModule(imlFile.getPath(), moduleType.getId());
      module.setOption(EXTERNAL_SYSTEM_ID_KEY, EXTERNAL_SYSTEM_ID_VALUE);
    }
    module.setOption(Module.ELEMENT_TYPE, moduleType.getId());
    moduleNames.add(moduleName);
    return module;
  }

  @Override
  public ModifiableRootModel editModule(Module module) {
    ModifiableRootModel modifiableModel = ModuleRootManager.getInstance(module).getModifiableModel();
    modifiableModels.add(modifiableModel);

    modifiableModel.clear();
    modifiableModel.inheritSdk();
    CompilerModuleExtension compilerSettings = modifiableModel.getModuleExtension(CompilerModuleExtension.class);
    if (compilerSettings != null) {
      compilerSettings.inheritCompilerOutputPath(false);
    }

    return modifiableModel;
  }

  @Override
  @Nullable
  public Module findModule(String moduleName) {
    return moduleModel.findModuleByName(moduleName);
  }

  public void commitWithGc(BlazeContext context) {
    List<Module> orphanModules = Lists.newArrayList();
    for (Module module : ModuleManager.getInstance(project).getModules()) {
      if (!moduleNames.contains(module.getName())) {
        orphanModules.add(module);
      }
    }
    if (orphanModules.size() > 0) {
      context.output(new PrintOutput(
        String.format("Removing %d dead modules", orphanModules.size()))
      );
      for (Module module : orphanModules) {
        if (module.isDisposed()) {
          continue;
        }
        moduleModel.disposeModule(module);
        File imlFile = new File(module.getModuleFilePath());
        removeImlFile(imlFile);
      }
    }

    context.output(new PrintOutput(
      String.format("Workspace has %s modules", modifiableModels.size())
    ));

    commit();
  }

  @Override
  public void commit() {
    ModifiableModelCommitter.multiCommit(modifiableModels, moduleModel);
  }

  private File getImlDirectory(BlazeImportSettings importSettings) {
    return new File(
      new File(importSettings.getProjectDataDirectory(), ModuleDataStorage.DATA_SUBDIRECTORY),
      ModuleDataStorage.MODULE_DATA_SUBDIRECTORY
    );
  }

  // Delete using the virtual file to ensure that IntelliJ properly updates its index. Otherwise, it is possible for IntelliJ to read the
  // old IML file from its index and behave unpredictably (like failing to save the new IML files to disk).
  private static void removeImlFile(final File imlFile) {
    final VirtualFile imlVirtualFile = VfsUtil.findFileByIoFile(imlFile, true);
    if (imlVirtualFile != null && imlVirtualFile.exists()) {
      ApplicationManager.getApplication().runWriteAction(new Runnable() {
        @Override
        public void run() {
          try {
            imlVirtualFile.delete(this);
          }
          catch (IOException e) {
            LOG.warn(String.format("Could not delete file: %s, will try to continue anyway.", imlVirtualFile.getPath()), e);
          }
        }
      });
    }
  }
}