/**
 * Copyright (c) 2015, The CyanogenMod 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 org.cyanogenmod.cmsettings;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.os.Environment;
import android.os.UserHandle;
import android.util.Log;

import java.io.File;

/**
 * The CMDatabaseHelper allows creation of a database to store CM specific settings for a user
 * in System, Secure, and Global tables.
 */
public class CMDatabaseHelper extends SQLiteOpenHelper{
    private static final String TAG = "CMDatabaseHelper";
    private static final boolean LOCAL_LOGV = false;

    private static final String DATABASE_NAME = "cmsettings.db";
    private static final int DATABASE_VERSION = 1;

    static class CMTableNames {
        static final String TABLE_SYSTEM = "system";
        static final String TABLE_SECURE = "secure";
        static final String TABLE_GLOBAL = "global";
    }

    private static final String CREATE_TABLE_SQL_FORMAT = "CREATE TABLE %s (" +
            "_id INTEGER PRIMARY KEY AUTOINCREMENT," +
            "name TEXT UNIQUE ON CONFLICT REPLACE," +
            "value TEXT" +
            ");)";

    private static final String CREATE_INDEX_SQL_FORMAT = "CREATE INDEX %sIndex%d ON %s (name);";

    private int mUserHandle;

    /**
     * Gets the appropriate database path for a specific user
     * @param userId The database path for this user
     * @return The database path string
     */
    static String dbNameForUser(final int userId) {
        // The owner gets the unadorned db name;
        if (userId == UserHandle.USER_OWNER) {
            return DATABASE_NAME;
        } else {
            // Place the database in the user-specific data tree so that it's
            // cleaned up automatically when the user is deleted.
            File databaseFile = new File(
                    Environment.getUserSystemDirectory(userId), DATABASE_NAME);
            return databaseFile.getPath();
        }
    }

    /**
     * Creates an instance of {@link CMDatabaseHelper}
     * @param context
     * @param userId
     */
    public CMDatabaseHelper(Context context, int userId) {
        super(context, dbNameForUser(userId), null, DATABASE_VERSION);
        mUserHandle = userId;
    }

    /**
     * Creates System, Secure, and Global tables in the specified {@link SQLiteDatabase}
     * @param db The database.
     */
    @Override
    public void onCreate(SQLiteDatabase db) {
        db.beginTransaction();

        try {
            createDbTable(db, CMTableNames.TABLE_SYSTEM);
            createDbTable(db, CMTableNames.TABLE_SECURE);

            if (mUserHandle == UserHandle.USER_OWNER) {
                createDbTable(db, CMTableNames.TABLE_GLOBAL);
            }

            db.setTransactionSuccessful();

            if (LOCAL_LOGV) Log.v(TAG, "Successfully created tables for cm settings db");
        } finally {
            db.endTransaction();
        }
    }

    /**
     * Creates a table and index for the specified database and table name
     * @param db
     * @param tableName
     */
    private void createDbTable(SQLiteDatabase db, String tableName) {
        if (LOCAL_LOGV) Log.v(TAG, "Creating table and index for: " + tableName);

        String createTableSql = String.format(CREATE_TABLE_SQL_FORMAT, tableName);
        db.execSQL(createTableSql);

        String createIndexSql = String.format(CREATE_INDEX_SQL_FORMAT, tableName, 1, tableName);
        db.execSQL(createIndexSql);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

    }
}