/*
 * 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.projectview;

import com.google.common.collect.Lists;
import com.google.idea.blaze.base.projectview.parser.ProjectViewParser;
import com.google.idea.blaze.base.scope.BlazeContext;
import com.google.idea.blaze.base.settings.BlazeImportSettings;
import com.google.idea.blaze.base.settings.BlazeImportSettingsManager;
import com.google.idea.blaze.base.sync.data.BlazeDataStorage;
import com.google.idea.blaze.base.sync.workspace.WorkspacePathResolver;
import com.google.idea.blaze.base.util.SerializationUtil;
import com.intellij.openapi.diagnostic.Logger;
import com.intellij.openapi.project.Project;
import java.io.File;
import java.io.IOException;
import java.util.List;
import javax.annotation.Nullable;
import org.jetbrains.annotations.NotNull;

/** Project view manager implementation. */
/** Stores mutable per-project user settings. */
final class ProjectViewManagerImpl extends ProjectViewManager {

  private static final Logger logger = Logger.getInstance(ProjectViewManagerImpl.class);
  private static final String CACHE_FILE_NAME = "project.view.dat";

  private final Project project;
  @Nullable private ProjectViewSet projectViewSet;
  private boolean projectViewSetLoaded = false;

  public ProjectViewManagerImpl(@NotNull Project project) {
    this.project = project;
  }

  @Nullable
  @Override
  public ProjectViewSet getProjectViewSet() {
    if (projectViewSet == null && !projectViewSetLoaded) {
      ProjectViewSet loadedProjectViewSet = null;
      try {
        BlazeImportSettings importSettings =
            BlazeImportSettingsManager.getInstance(project).getImportSettings();
        if (importSettings == null) {
          return null;
        }
        File file = getCacheFile(project, importSettings);

        List<ClassLoader> classLoaders = Lists.newArrayList();
        classLoaders.add(getClass().getClassLoader());
        classLoaders.add(Thread.currentThread().getContextClassLoader());
        loadedProjectViewSet = (ProjectViewSet) SerializationUtil.loadFromDisk(file, classLoaders);
      } catch (IOException e) {
        logger.info(e);
      }
      this.projectViewSet = loadedProjectViewSet;
      this.projectViewSetLoaded = true;
    }
    return projectViewSet;
  }

  @Override
  public ProjectViewSet reloadProjectView(
      BlazeContext context, WorkspacePathResolver workspacePathResolver) {
    BlazeImportSettings importSettings =
        BlazeImportSettingsManager.getInstance(project).getImportSettings();
    assert importSettings != null;
    assert importSettings.getProjectViewFile() != null;
    File projectViewFile = new File(importSettings.getProjectViewFile());
    ProjectViewParser parser = new ProjectViewParser(context, workspacePathResolver);
    parser.parseProjectView(projectViewFile);

    boolean success = !context.hasErrors();
    if (success) {
      ProjectViewSet projectViewSet = parser.getResult();
      File file = getCacheFile(project, importSettings);
      try {
        SerializationUtil.saveToDisk(file, projectViewSet);
      } catch (IOException e) {
        logger.error(e);
      }
      this.projectViewSet = projectViewSet;
    }
    return success ? projectViewSet : null;
  }

  private static File getCacheFile(Project project, BlazeImportSettings importSettings) {
    return new File(BlazeDataStorage.getProjectCacheDir(project, importSettings), CACHE_FILE_NAME);
  }
}