/*
 * 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.
 */

package net.micode.notes.gtask.data;

import android.content.ContentResolver;
import android.content.ContentUris;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.net.Uri;
import android.util.Log;

import net.micode.notes.data.Notes;
import net.micode.notes.data.Notes.DataColumns;
import net.micode.notes.data.Notes.DataConstants;
import net.micode.notes.data.Notes.NoteColumns;
import net.micode.notes.data.NotesDatabaseHelper.TABLE;
import net.micode.notes.gtask.exception.ActionFailureException;

import org.json.JSONException;
import org.json.JSONObject;


public class SqlData {//公开类， 数据库类
    private static final String TAG = SqlData.class.getSimpleName();
//调用getSimpleName ()函数来得到类的简写名称存入字符串TAG中
    private static final int INVALID_ID = -99999;

    public static final String[] PROJECTION_DATA = new String[] {//新建一个字符串数组，集合了 interface DataColumns 中所有SF常量
            DataColumns.ID, DataColumns.MIME_TYPE, DataColumns.CONTENT, DataColumns.DATA1,
            DataColumns.DATA3
    };
//代码块：与sqlNote中定义的常量是相类似的，是一些列的序号
    public static final int DATA_ID_COLUMN = 0;
//数据列的这一行表示的项的mime类型
    public static final int DATA_MIME_TYPE_COLUMN = 1;

    public static final int DATA_CONTENT_COLUMN = 2;

    public static final int DATA_CONTENT_DATA_1_COLUMN = 3;

    public static final int DATA_CONTENT_DATA_3_COLUMN = 4;

    private ContentResolver mContentResolver;
//定义以下8个内部变量
    private boolean mIsCreate;
//判断是否直接用Content生成，是为true，否则为false
    private long mDataId;

    private String mDataMimeType;
//数据mime类型
    private String mDataContent;
//数据内容
    private long mDataContentData1;

    private String mDataContentData3;

    private ContentValues mDiffDataValues;
//contenvalues只能存储基本类型的数据，像string，int之类的
    public SqlData(Context context) {//构造函数，初始化数据，参数类型为Context
        mContentResolver = context.getContentResolver();
        mIsCreate = true;//mIsCreate为TRUE是这种构造方式的标志
        mDataId = INVALID_ID;
        mDataMimeType = DataConstants.NOTE;
        mDataContent = "";
        mDataContentData1 = 0;
        mDataContentData3 = "";
        mDiffDataValues = new ContentValues();
    }
//第二种SqlData的构造方式，通过cursor来获取数据
    public SqlData(Context context, Cursor c) {
        mContentResolver = context.getContentResolver();
        mIsCreate = false;
        loadFromCursor(c);
        mDiffDataValues = new ContentValues();
    }

    private void loadFromCursor(Cursor c) {//构造函数，初始化数据，参数类型分别为 Context 和 Cursor
        mDataId = c.getLong(DATA_ID_COLUMN);
        mDataMimeType = c.getString(DATA_MIME_TYPE_COLUMN);
        mDataContent = c.getString(DATA_CONTENT_COLUMN);
        mDataContentData1 = c.getLong(DATA_CONTENT_DATA_1_COLUMN);
        mDataContentData3 = c.getString(DATA_CONTENT_DATA_3_COLUMN);
    }

    public void setContent(JSONObject js) throws JSONException {//设置用于共享的数据，并提供异常抛出与处理机制，其中很多if 条件语句的判断，某些条件下某些特定的操作
        long dataId = js.has(DataColumns.ID) ? js.getLong(DataColumns.ID) : INVALID_ID;
        if (mIsCreate || mDataId != dataId) {
            mDiffDataValues.put(DataColumns.ID, dataId);
        }
        mDataId = dataId;

        String dataMimeType = js.has(DataColumns.MIME_TYPE) ? js.getString(DataColumns.MIME_TYPE)//如果传入的JSONObject对象有DataColumns.MIME_TYPE一项，则设置dataMimeType为这个，否则设为SqlData.java
                : DataConstants.NOTE;
        if (mIsCreate || !mDataMimeType.equals(dataMimeType)) {
            mDiffDataValues.put(DataColumns.MIME_TYPE, dataMimeType);
        }
        mDataMimeType = dataMimeType;

        String dataContent = js.has(DataColumns.CONTENT) ? js.getString(DataColumns.CONTENT) : "";
        if (mIsCreate || !mDataContent.equals(dataContent)) {
            mDiffDataValues.put(DataColumns.CONTENT, dataContent);
        }
        mDataContent = dataContent;
//以原有数据文本类型为基础，修改共享数据文本类型
        long dataContentData1 = js.has(DataColumns.DATA1) ? js.getLong(DataColumns.DATA1) : 0;
        if (mIsCreate || mDataContentData1 != dataContentData1) {
            mDiffDataValues.put(DataColumns.DATA1, dataContentData1);
        }
        mDataContentData1 = dataContentData1;//共享数据同步后，共享1类型数据等于该1类型数据

        String dataContentData3 = js.has(DataColumns.DATA3) ? js.getString(DataColumns.DATA3) : "";
        if (mIsCreate || !mDataContentData3.equals(dataContentData3)) {
            mDiffDataValues.put(DataColumns.DATA3, dataContentData3);
        }
        mDataContentData3 = dataContentData3;
    }
//获取共享数据内容及提供异常抛出与处理机制
    public JSONObject getContent() throws JSONException {
        if (mIsCreate) {
            Log.e(TAG, "it seems that we haven't created this in database yet");
            return null;
        }
        JSONObject js = new JSONObject();
        js.put(DataColumns.ID, mDataId);
        js.put(DataColumns.MIME_TYPE, mDataMimeType);
        js.put(DataColumns.CONTENT, mDataContent);
        js.put(DataColumns.DATA1, mDataContentData1);
        js.put(DataColumns.DATA3, mDataContentData3);
        return js;
    }
//将当前数据提交到数据库
    public void commit(long noteId, boolean validateVersion, long version) {
//commit 函数用于把当前所做的修改保存到数据库
        if (mIsCreate) {
            if (mDataId == INVALID_ID && mDiffDataValues.containsKey(DataColumns.ID)) {
                mDiffDataValues.remove(DataColumns.ID);//更新共享数据，键为NOTE_ID，值为noteId
            }

            mDiffDataValues.put(DataColumns.NOTE_ID, noteId);
            Uri uri = mContentResolver.insert(Notes.CONTENT_DATA_URI, mDiffDataValues);
            try {
                mDataId = Long.valueOf(uri.getPathSegments().get(1));
            } catch (NumberFormatException e) {
                Log.e(TAG, "Get note id error :" + e.toString());
                throw new ActionFailureException("create note failed");
            }
        } else {
            if (mDiffDataValues.size() > 0) {
                int result = 0;
                if (!validateVersion) {//如果版本还没确认，则结果记录下的只是data的ID，还有data内容
                    result = mContentResolver.update(ContentUris.withAppendedId(
                            Notes.CONTENT_DATA_URI, mDataId), mDiffDataValues, null, null);
                } else {
                    result = mContentResolver.update(ContentUris.withAppendedId(//若版本号确认，则对对应id进行更新，
                            Notes.CONTENT_DATA_URI, mDataId), mDiffDataValues,
                            " ? in (SELECT " + NoteColumns.ID + " FROM " + TABLE.NOTE
                                    + " WHERE " + NoteColumns.VERSION + "=?)", new String[] {
                                    String.valueOf(noteId), String.valueOf(version)
                            });//更新不存在，可能是用户在同步时已更新
                }
                if (result == 0) {
                    Log.w(TAG, "there is no update. maybe user updates note when syncing");
                }//如果更新不存在（或许用户在同步时已经完成更新），则报错c
            }
        }

        mDiffDataValues.clear();//回到初始化，清空，表示已经更新
        mIsCreate = false;
    }

    public long getId() {
        return mDataId;
    }//获取当前id
}