/*
 * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
 *
 * 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.
 */
// 包和类的导入
package net.micode.notes.data;

import android.content.ContentValues;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;

import net.micode.notes.data.Notes.DataColumns;
import net.micode.notes.data.Notes.DataConstants;
import net.micode.notes.data.Notes.NoteColumns;

// 数据库帮助类
public class NotesDatabaseHelper extends SQLiteOpenHelper {
    // 数据库名称
    private static final String DB_NAME = "note.db";
    // 数据库版本
    private static final int DB_VERSION = 4;

    // 表名常量接口
    public interface TABLE {
        public static final String NOTE = "note";
        public static final String DATA = "data";
    }

    // 标签常量，用于日志输出
    private static final String TAG = "NotesDatabaseHelper";
    // 单例实例
    private static NotesDatabaseHelper mInstance;

    // 创建笔记表的SQL语句
    private static final String CREATE_NOTE_TABLE_SQL =
        "CREATE TABLE " + TABLE.NOTE + "(" +
            NoteColumns.ID + " INTEGER PRIMARY KEY," +
            NoteColumns.PARENT_ID + " INTEGER NOT NULL DEFAULT 0," +
            NoteColumns.ALERTED_DATE + " INTEGER NOT NULL DEFAULT 0," +
            NoteColumns.BG_COLOR_ID + " INTEGER NOT NULL DEFAULT 0," +
            NoteColumns.CREATED_DATE + " INTEGER NOT NULL DEFAULT (strftime('%s','now') * 1000)," +
            NoteColumns.HAS_ATTACHMENT + " INTEGER NOT NULL DEFAULT 0," +
            NoteColumns.MODIFIED_DATE + " INTEGER NOT NULL DEFAULT (strftime('%s','now') * 1000)," +
            NoteColumns.NOTES_COUNT + " INTEGER NOT NULL DEFAULT 0," +
            NoteColumns.SNIPPET + " TEXT NOT NULL DEFAULT ''," +
            NoteColumns.TYPE + " INTEGER NOT NULL DEFAULT 0," +
            NoteColumns.WIDGET_ID + " INTEGER NOT NULL DEFAULT 0," +
            NoteColumns.WIDGET_TYPE + " INTEGER NOT NULL DEFAULT -1," +
            NoteColumns.SYNC_ID + " INTEGER NOT NULL DEFAULT 0," +
            NoteColumns.LOCAL_MODIFIED + " INTEGER NOT NULL DEFAULT 0," +
            NoteColumns.ORIGIN_PARENT_ID + " INTEGER NOT NULL DEFAULT 0," +
            NoteColumns.GTASK_ID + " TEXT NOT NULL DEFAULT ''," +
            NoteColumns.VERSION + " INTEGER NOT NULL DEFAULT 0" +
        ")";

    // 创建数据表的SQL语句
    private static final String CREATE_DATA_TABLE_SQL =
        "CREATE TABLE " + TABLE.DATA + "(" +
            DataColumns.ID + " INTEGER PRIMARY KEY," +
            DataColumns.MIME_TYPE + " TEXT NOT NULL," +
            DataColumns.NOTE_ID + " INTEGER NOT NULL DEFAULT 0," +
            NoteColumns.CREATED_DATE + " INTEGER NOT NULL DEFAULT (strftime('%s','now') * 1000)," +
            NoteColumns.MODIFIED_DATE + " INTEGER NOT NULL DEFAULT (strftime('%s','now') * 1000)," +
            DataColumns.CONTENT + " TEXT NOT NULL DEFAULT ''," +
            DataColumns.DATA1 + " INTEGER," +
            DataColumns.DATA2 + " INTEGER," +
            DataColumns.DATA3 + " TEXT NOT NULL DEFAULT ''," +
            DataColumns.DATA4 + " TEXT NOT NULL DEFAULT ''," +
            DataColumns.DATA5 + " TEXT NOT NULL DEFAULT ''" +
        ")";

    // 创建数据表中笔记ID索引的SQL语句
    private static final String CREATE_DATA_NOTE_ID_INDEX_SQL =
        "CREATE INDEX IF NOT EXISTS note_id_index ON " +
        TABLE.DATA + "(" + DataColumns.NOTE_ID + ");";

    // 更新文件夹笔记数量的触发器SQL语句（当移动笔记时）
    private static final String NOTE_INCREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER =
        "CREATE TRIGGER increase_folder_count_on_update "+
        " AFTER UPDATE OF " + NoteColumns.PARENT_ID + " ON " + TABLE.NOTE +
        " BEGIN " +
        "  UPDATE " + TABLE.NOTE +
        "   SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + " + 1" +
        "  WHERE " + NoteColumns.ID + "=new." + NoteColumns.PARENT_ID + ";" +
        " END";

    // 减少文件夹笔记数量的触发器SQL语句（当从文件夹中移除笔记时）
    private static final String NOTE_DECREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER =
        "CREATE TRIGGER decrease_folder_count_on_update " +
        " AFTER UPDATE OF " + NoteColumns.PARENT_ID + " ON " + TABLE.NOTE +
        " BEGIN " +
        "  UPDATE " + TABLE.NOTE +
        "   SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + "-1" +
        "  WHERE " + NoteColumns.ID + "=old." + NoteColumns.PARENT_ID +
        "  AND " + NoteColumns.NOTES_COUNT + ">0" + ";" +
        " END";

    // 插入新笔记时增加文件夹笔记数量的触发器SQL语句
    private static final String NOTE_INCREASE_FOLDER_COUNT_ON_INSERT_TRIGGER =
        "CREATE TRIGGER increase_folder_count_on_insert " +
        " AFTER INSERT ON " + TABLE.NOTE +
        " BEGIN " +
        "  UPDATE " + TABLE.NOTE +
        "   SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + " + 1" +
        "  WHERE " + NoteColumns.ID + "=new." + NoteColumns.PARENT_ID + ";" +
        " END";

    // 从文件夹中删除笔记时减少文件夹笔记数量的触发器SQL语句
    private static final String NOTE_DECREASE_FOLDER_COUNT_ON_DELETE_TRIGGER =
        "CREATE TRIGGER decrease_folder_count_on_delete " +
        " AFTER DELETE ON " + TABLE.NOTE +
        " BEGIN " +
        "  UPDATE " + TABLE.NOTE +
        "   SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + "-1" +
        "  WHERE " + NoteColumns.ID + "=old." + NoteColumns.PARENT_ID +
        "  AND " + NoteColumns.NOTES_COUNT + ">0;" +
        " END";

    // 插入数据时更新笔记内容的触发器SQL语句
    private static final String DATA_UPDATE_NOTE_CONTENT_ON_INSERT_TRIGGER =
        "CREATE TRIGGER update_note_content_on_insert " +
        " AFTER INSERT ON " + TABLE.DATA +
        " WHEN new." + DataColumns.MIME_TYPE + "='" + DataConstants.NOTE + "'" +
        " BEGIN" +
        "  UPDATE " + TABLE.NOTE +
        "   SET " + NoteColumns.SNIPPET + "=new." + DataColumns.CONTENT +
        "  WHERE " + NoteColumns.ID + "=new." + DataColumns.NOTE_ID + ";" +
        " END";

    // 更新数据时更新笔记内容的触发器SQL语句
    private static final String DATA_UPDATE_NOTE_CONTENT_ON_UPDATE_TRIGGER =
        "CREATE TRIGGER update_note_content_on_update " +
        " AFTER UPDATE ON " + TABLE.DATA +
        " WHEN old." + DataColumns.MIME_TYPE + "='" + DataConstants.NOTE + "'" +
        " BEGIN" +
        "  UPDATE " + TABLE.NOTE +
        "   SET " + NoteColumns.SNIPPET + "=new." + DataColumns.CONTENT +
        "  WHERE " + NoteColumns.ID + "=new." + DataColumns.NOTE_ID + ";" +
        " END";

    // 删除数据时更新笔记内容的触发器SQL语句
    private static final String DATA_UPDATE_NOTE_CONTENT_ON_DELETE_TRIGGER =
        "CREATE TRIGGER update_note_content_on_delete " +
        " AFTER delete ON " + TABLE.DATA +
        " WHEN old." + DataColumns.MIME_TYPE + "='" + DataConstants.NOTE + "'" +
        " BEGIN" +
        "  UPDATE " + TABLE.NOTE +
        "   SET " + NoteColumns.SNIPPET + "=''" +
        "  WHERE " + NoteColumns.ID + "=old." + DataColumns.NOTE_ID + ";" +
        " END";

    // 删除笔记时删除属于该笔记的数据的触发器SQL语句
    private static final String NOTE_DELETE_DATA_ON_DELETE_TRIGGER =
        "CREATE TRIGGER delete_data_on_delete " +
        " AFTER DELETE ON " + TABLE.NOTE +
        " BEGIN" +
        "  DELETE FROM " + TABLE.DATA +    "   WHERE " + DataColumns.NOTE_ID + "=old." + NoteColumns.ID + ";" +
    " END";

// 删除文件夹时删除属于该文件夹的笔记的触发器SQL语句
private static final String FOLDER_DELETE_NOTES_ON_DELETE_TRIGGER =
    "CREATE TRIGGER folder_delete_notes_on_delete " +
    " AFTER DELETE ON " + TABLE.NOTE +
    " BEGIN" +
    "  DELETE FROM " + TABLE.NOTE +
    "   WHERE " + NoteColumns.PARENT_ID + "=old." + NoteColumns.ID + ";" +
    " END";

// 将笔记移动到回收站文件夹时移动属于该文件夹的笔记的触发器SQL语句
private static final String FOLDER_MOVE_NOTES_ON_TRASH_TRIGGER =
    "CREATE TRIGGER folder_move_notes_on_trash " +
    " AFTER UPDATE ON " + TABLE.NOTE +
    " WHEN new." + NoteColumns.PARENT_ID + "=" + Notes.ID_TRASH_FOLER +
    " BEGIN" +
    "  UPDATE " + TABLE.NOTE +
    "   SET " + NoteColumns.PARENT_ID + "=" + Notes.ID_TRASH_FOLER +
    "  WHERE " + NoteColumns.PARENT_ID + "=old." + NoteColumns.ID + ";" +
    " END";

// 构造函数
public NotesDatabaseHelper(Context context) {
    super(context, DB_NAME, null, DB_VERSION);
}

// 创建笔记表的方法
public void createNoteTable(SQLiteDatabase db) {
    db.execSQL(CREATE_NOTE_TABLE_SQL);
    reCreateNoteTableTriggers(db);
    createSystemFolder(db);
    Log.d(TAG, "note table has been created");
}

// 重新创建笔记表触发器的方法
private void reCreateNoteTableTriggers(SQLiteDatabase db) {
    db.execSQL("DROP TRIGGER IF EXISTS increase_folder_count_on_update");
    db.execSQL("DROP TRIGGER IF EXISTS decrease_folder_count_on_update");
    db.execSQL("DROP TRIGGER IF EXISTS decrease_folder_count_on_delete");
    db.execSQL("DROP TRIGGER IF EXISTS delete_data_on_delete");
    db.execSQL("DROP TRIGGER IF EXISTS increase_folder_count_on_insert");
    db.execSQL("DROP TRIGGER IF EXISTS folder_delete_notes_on_delete");
    db.execSQL("DROP TRIGGER IF EXISTS folder_move_notes_on_trash");

    db.execSQL(NOTE_INCREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER);
    db.execSQL(NOTE_DECREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER);
    db.execSQL(NOTE_DECREASE_FOLDER_COUNT_ON_DELETE_TRIGGER);
    db.execSQL(NOTE_DELETE_DATA_ON_DELETE_TRIGGER);
    db.execSQL(NOTE_INCREASE_FOLDER_COUNT_ON_INSERT_TRIGGER);
    db.execSQL(FOLDER_DELETE_NOTES_ON_DELETE_TRIGGER);
    db.execSQL(FOLDER_MOVE_NOTES_ON_TRASH_TRIGGER);
}

// 创建系统文件夹的方法
private void createSystemFolder(SQLiteDatabase db) {
    ContentValues values = new ContentValues();

    // 创建通话记录文件夹
    values.put(NoteColumns.ID, Notes.ID_CALL_RECORD_FOLDER);
    values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
    db.insert(TABLE.NOTE, null, values);

    // 创建根文件夹（默认文件夹）
    values.clear();
    values.put(NoteColumns.ID, Notes.ID_ROOT_FOLDER);
    values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
    db.insert(TABLE.NOTE, null, values);

    // 创建临时文件夹（用于移动笔记）
    values.clear();
    values.put(NoteColumns.ID, Notes.ID_TEMPARAY_FOLDER);
    values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
    db.insert(TABLE.NOTE, null, values);

    // 创建回收站文件夹
    values.clear();
    values.put(NoteColumns.ID, Notes.ID_TRASH_FOLER);
    values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
    db.insert(TABLE.NOTE, null, values);
}

// 创建数据表的方法
public void createDataTable(SQLiteDatabase db) {
    db.execSQL(CREATE_DATA_TABLE_SQL);
    reCreateDataTableTriggers(db);
    db.execSQL(CREATE_DATA_NOTE_ID_INDEX_SQL);
    Log.d(TAG, "data table has been created");
}

// 重新创建数据表触发器的方法
private void reCreateDataTableTriggers(SQLiteDatabase db) {
    db.execSQL("DROP TRIGGER IF EXISTS update_note_content_on_insert");
    db.execSQL("DROP TRIGGER IF EXISTS update_note_content_on_update");
    db.execSQL("DROP TRIGGER IF EXISTS update_note_content_on_delete");

    db.execSQL(DATA_UPDATE_NOTE_CONTENT_ON_INSERT_TRIGGER);
    db.execSQL(DATA_UPDATE_NOTE_CONTENT_ON_UPDATE_TRIGGER);
    db.execSQL(DATA_UPDATE_NOTE_CONTENT_ON_DELETE_TRIGGER);
}

// 获取单例实例的方法
static synchronized NotesDatabaseHelper getInstance(Context context) {
    if (mInstance == null) {
        mInstance = new NotesDatabaseHelper(context);
    }
    return mInstance;
}

// 当创建数据库时调用的方法
@Override
public void onCreate(SQLiteDatabase db) {
    createNoteTable(db);
    createDataTable(db);
}

// 当数据库升级时调用的方法
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    boolean reCreateTriggers = false;
    boolean skipV2 = false;

    if (oldVersion == 1) {
        upgradeToV2(db);
        skipV2 = true; // this upgrade including the upgrade from v2 to v3
        oldVersion++;
    }

    if (oldVersion == 2 && !skipV2) {
        upgradeToV3(db);
        reCreateTriggers = true;
        oldVersion++;
    }

    if (oldVersion == 3) {
        upgradeToV4(db);
        oldVersion++;
    }

    if (reCreateTriggers) {
        reCreateNoteTableTriggers(db);
        reCreateDataTableTriggers(db);
    }

    if (oldVersion != newVersion) {
        throw new IllegalStateException("Upgrade notes database to version " + newVersion
                + "fails");
    }
}

// 升级到版本2的方法
private void upgradeToV2(SQLiteDatabase db) {
    db.execSQL("DROP TABLE IF EXISTS " + TABLE.NOTE);
    db.execSQL("DROP TABLE IF EXISTS " + TABLE.DATA);
    createNoteTable(db);
    createDataTable(db);
}

// 升级到版本3的方法
private void upgradeToV3(SQLiteDatabase db) {
    // 删除未使用的触发器
    db.execSQL("DROP TRIGGER IF EXISTS update_note_modified_date_on_insert");
    db.execSQL("DROP TRIGGER IF EXISTS update_note_modified_date_on_delete");
    db.execSQL("DROP TRIGGER IF EXISTS update_note_modified_date_on_update");
    // 添加gtask id列
    db.execSQL("ALTER TABLE " + TABLE.NOTE + " ADD COLUMN " + NoteColumns.GTASK_ID
            + " TEXT NOT NULL DEFAULT ''");
    // 添加回收站系统文件夹
    ContentValues values = new ContentValues();
    values.put(NoteColumns.ID, Notes.ID_TRASH_FOLER);
    values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
    db.insert(TABLE.NOTE, null, values);
}

// 升级到版本4的方法
private void upgradeToV4(SQLiteDatabase db) {
    db.execSQL("ALTER TABLE " + TABLE.NOTE + " ADD COLUMN " + NoteColumns.VERSION
            + " INTEGER NOT NULL DEFAULT 0");
}