content: /*
   * Copyright 2016, The Android Open Source Project
   *
   * 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 <%= appPackage %>.data.source.local;
  
  import android.content.ContentValues;
  import android.content.Context;
  import android.database.Cursor;
  import android.database.sqlite.SQLiteDatabase;
  import android.support.annotation.NonNull;
  
  import <%= appPackage %>.tasks.domain.model.Task;
  import <%= appPackage %>.data.source.TasksDataSource;
  import <%= appPackage %>.data.source.local.TasksPersistenceContract.TaskEntry;
  
  import java.util.ArrayList;
  import java.util.List;
  
  import static com.google.common.base.Preconditions.checkNotNull;
  
  /**
   * Concrete implementation of a data source as a db.
   */
  public class TasksLocalDataSource implements TasksDataSource {
  
      private static TasksLocalDataSource INSTANCE;
  
      private TasksDbHelper mDbHelper;
  
      // Prevent direct instantiation.
      private TasksLocalDataSource(@NonNull Context context) {
          checkNotNull(context);
          mDbHelper = new TasksDbHelper(context);
      }
  
      public static TasksLocalDataSource getInstance(@NonNull Context context) {
          if (INSTANCE == null) {
              INSTANCE = new TasksLocalDataSource(context);
          }
          return INSTANCE;
      }
  
      /**
       * Note: {@link LoadTasksCallback#onDataNotAvailable()} is fired if the database doesn't exist
       * or the table is empty.
       */
      @Override
      public void getTasks(@NonNull LoadTasksCallback callback) {
          List<Task> tasks = new ArrayList<Task>();
          SQLiteDatabase db = mDbHelper.getReadableDatabase();
  
          String[] projection = {
                  TaskEntry.COLUMN_NAME_ENTRY_ID,
                  TaskEntry.COLUMN_NAME_TITLE,
                  TaskEntry.COLUMN_NAME_DESCRIPTION,
                  TaskEntry.COLUMN_NAME_COMPLETED
          };
  
          Cursor c = db.query(
                  TaskEntry.TABLE_NAME, projection, null, null, null, null, null);
  
          if (c != null && c.getCount() > 0) {
              while (c.moveToNext()) {
                  String itemId = c.getString(c.getColumnIndexOrThrow(TaskEntry.COLUMN_NAME_ENTRY_ID));
                  String title = c.getString(c.getColumnIndexOrThrow(TaskEntry.COLUMN_NAME_TITLE));
                  String description =
                          c.getString(c.getColumnIndexOrThrow(TaskEntry.COLUMN_NAME_DESCRIPTION));
                  boolean completed =
                          c.getInt(c.getColumnIndexOrThrow(TaskEntry.COLUMN_NAME_COMPLETED)) == 1;
                  Task task = new Task(title, description, itemId, completed);
                  tasks.add(task);
              }
          }
          if (c != null) {
              c.close();
          }
  
          db.close();
  
          if (tasks.isEmpty()) {
              // This will be called if the table is new or just empty.
              callback.onDataNotAvailable();
          } else {
              callback.onTasksLoaded(tasks);
          }
  
      }
  
      /**
       * Note: {@link GetTaskCallback#onDataNotAvailable()} is fired if the {@link Task} isn't
       * found.
       */
      @Override
      public void getTask(@NonNull String taskId, @NonNull GetTaskCallback callback) {
          SQLiteDatabase db = mDbHelper.getReadableDatabase();
  
          String[] projection = {
                  TaskEntry.COLUMN_NAME_ENTRY_ID,
                  TaskEntry.COLUMN_NAME_TITLE,
                  TaskEntry.COLUMN_NAME_DESCRIPTION,
                  TaskEntry.COLUMN_NAME_COMPLETED
          };
  
          String selection = TaskEntry.COLUMN_NAME_ENTRY_ID + " LIKE ?";
          String[] selectionArgs = { taskId };
  
          Cursor c = db.query(
                  TaskEntry.TABLE_NAME, projection, selection, selectionArgs, null, null, null);
  
          Task task = null;
  
          if (c != null && c.getCount() > 0) {
              c.moveToFirst();
              String itemId = c.getString(c.getColumnIndexOrThrow(TaskEntry.COLUMN_NAME_ENTRY_ID));
              String title = c.getString(c.getColumnIndexOrThrow(TaskEntry.COLUMN_NAME_TITLE));
              String description =
                      c.getString(c.getColumnIndexOrThrow(TaskEntry.COLUMN_NAME_DESCRIPTION));
              boolean completed =
                      c.getInt(c.getColumnIndexOrThrow(TaskEntry.COLUMN_NAME_COMPLETED)) == 1;
              task = new Task(title, description, itemId, completed);
          }
          if (c != null) {
              c.close();
          }
  
          db.close();
  
          if (task != null) {
              callback.onTaskLoaded(task);
          } else {
              callback.onDataNotAvailable();
          }
      }
  
      @Override
      public void saveTask(@NonNull Task task) {
          checkNotNull(task);
          SQLiteDatabase db = mDbHelper.getWritableDatabase();
  
          ContentValues values = new ContentValues();
          values.put(TaskEntry.COLUMN_NAME_ENTRY_ID, task.getId());
          values.put(TaskEntry.COLUMN_NAME_TITLE, task.getTitle());
          values.put(TaskEntry.COLUMN_NAME_DESCRIPTION, task.getDescription());
          values.put(TaskEntry.COLUMN_NAME_COMPLETED, task.isCompleted());
  
          db.insert(TaskEntry.TABLE_NAME, null, values);
  
          db.close();
      }
  
      @Override
      public void completeTask(@NonNull Task task) {
          SQLiteDatabase db = mDbHelper.getWritableDatabase();
  
          ContentValues values = new ContentValues();
          values.put(TaskEntry.COLUMN_NAME_COMPLETED, true);
  
          String selection = TaskEntry.COLUMN_NAME_ENTRY_ID + " LIKE ?";
          String[] selectionArgs = { task.getId() };
  
          db.update(TaskEntry.TABLE_NAME, values, selection, selectionArgs);
  
          db.close();
      }
  
      @Override
      public void completeTask(@NonNull String taskId) {
          // Not required for the local data source because the {@link TasksRepository} handles
          // converting from a {@code taskId} to a {@link task} using its cached data.
      }
  
      @Override
      public void activateTask(@NonNull Task task) {
          SQLiteDatabase db = mDbHelper.getWritableDatabase();
  
          ContentValues values = new ContentValues();
          values.put(TaskEntry.COLUMN_NAME_COMPLETED, false);
  
          String selection = TaskEntry.COLUMN_NAME_ENTRY_ID + " LIKE ?";
          String[] selectionArgs = { task.getId() };
  
          db.update(TaskEntry.TABLE_NAME, values, selection, selectionArgs);
  
          db.close();
      }
  
      @Override
      public void activateTask(@NonNull String taskId) {
          // Not required for the local data source because the {@link TasksRepository} handles
          // converting from a {@code taskId} to a {@link task} using its cached data.
      }
  
      @Override
      public void clearCompletedTasks() {
          SQLiteDatabase db = mDbHelper.getWritableDatabase();
  
          String selection = TaskEntry.COLUMN_NAME_COMPLETED + " LIKE ?";
          String[] selectionArgs = { "1" };
  
          db.delete(TaskEntry.TABLE_NAME, selection, selectionArgs);
  
          db.close();
      }
  
      @Override
      public void refreshTasks() {
          // Not required because the {@link TasksRepository} handles the logic of refreshing the
          // tasks from all the available data sources.
      }
  
      @Override
      public void deleteAllTasks() {
          SQLiteDatabase db = mDbHelper.getWritableDatabase();
  
          db.delete(TaskEntry.TABLE_NAME, null, null);
  
          db.close();
      }
  
      @Override
      public void deleteTask(@NonNull String taskId) {
          SQLiteDatabase db = mDbHelper.getWritableDatabase();
  
          String selection = TaskEntry.COLUMN_NAME_ENTRY_ID + " LIKE ?";
          String[] selectionArgs = { taskId };
  
          db.delete(TaskEntry.TABLE_NAME, selection, selectionArgs);
  
          db.close();
      }
  }
  