/*
 * 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.data;


import android.app.SearchManager;
import android.content.ContentProvider;
import android.content.ContentUris;
import android.content.ContentValues;
import android.content.Intent;
import android.content.UriMatcher;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.net.Uri;
import android.text.TextUtils;
import android.util.Log;

import net.micode.notes.R;
import net.micode.notes.data.Notes.DataColumns;
import net.micode.notes.data.Notes.NoteColumns;
import net.micode.notes.data.NotesDatabaseHelper.TABLE;


/**
 * 便签应用内容提供者，继承自ContentProvider
 * 负责管理便签数据的增删改查操作，对外提供统一的数据访问接口
 * 通过UriMatcher匹配不同的URI请求，实现数据的分层访问控制
 */
public class NotesProvider extends ContentProvider {
    // UriMatcher实例，用于匹配不同的URI请求
    private static final UriMatcher mMatcher;
    // 数据库辅助类实例，用于操作数据库
    private NotesDatabaseHelper mHelper;
    // 日志标签
    private static final String TAG = "NotesProvider";

    // URI匹配常量（对应不同的访问路径）
    private static final int URI_NOTE            = 1;       // 便签列表URI
    private static final int URI_NOTE_ITEM       = 2;       // 单条便签URI
    private static final int URI_DATA            = 3;       // 便签数据列表URI
    private static final int URI_DATA_ITEM       = 4;       // 单条便签数据URI
    private static final int URI_SEARCH          = 5;       // 搜索URI
    private static final int URI_SEARCH_SUGGEST  = 6;       // 搜索建议URI

    static {
        // 初始化UriMatcher
        mMatcher = new UriMatcher(UriMatcher.NO_MATCH);
        // 注册便签相关URI
        mMatcher.addURI(Notes.AUTHORITY, "note", URI_NOTE);
        mMatcher.addURI(Notes.AUTHORITY, "note/#", URI_NOTE_ITEM);
        // 注册便签数据相关URI
        mMatcher.addURI(Notes.AUTHORITY, "data", URI_DATA);
        mMatcher.addURI(Notes.AUTHORITY, "data/#", URI_DATA_ITEM);
        // 注册搜索相关URI
        mMatcher.addURI(Notes.AUTHORITY, "search", URI_SEARCH);
        mMatcher.addURI(Notes.AUTHORITY, SearchManager.SUGGEST_URI_PATH_QUERY, URI_SEARCH_SUGGEST);
        mMatcher.addURI(Notes.AUTHORITY, SearchManager.SUGGEST_URI_PATH_QUERY + "/*", URI_SEARCH_SUGGEST);
    }

    /**
     * 搜索功能投影定义（用于搜索建议和结果）
     * 字段说明：
     * - ID: 便签ID
     * - SearchManager.SUGGEST_COLUMN_INTENT_EXTRA_DATA: 意图附加数据（便签ID）
     * - SearchManager.SUGGEST_COLUMN_TEXT_1: 搜索建议文本1（便签内容，去除换行符）
     * - SearchManager.SUGGEST_COLUMN_TEXT_2: 搜索建议文本2（便签内容，去除换行符）
     * - SearchManager.SUGGEST_COLUMN_ICON_1: 搜索建议图标（使用R.drawable.search_result）
     * - SearchManager.SUGGEST_COLUMN_INTENT_ACTION: 意图动作（ACTION_VIEW）
     * - SearchManager.SUGGEST_COLUMN_INTENT_DATA: 意图数据（文本便签MIME类型）
     */
    private static final String NOTES_SEARCH_PROJECTION = NoteColumns.ID + ","
            + NoteColumns.ID + " AS " + SearchManager.SUGGEST_COLUMN_INTENT_EXTRA_DATA + ","
            + "TRIM(REPLACE(" + NoteColumns.SNIPPET + ", x'0A','')) AS " + SearchManager.SUGGEST_COLUMN_TEXT_1 + ","
            + "TRIM(REPLACE(" + NoteColumns.SNIPPET + ", x'0A','')) AS " + SearchManager.SUGGEST_COLUMN_TEXT_2 + ","
            + R.drawable.search_result + " AS " + SearchManager.SUGGEST_COLUMN_ICON_1 + ","
            + "'" + Intent.ACTION_VIEW + "' AS " + SearchManager.SUGGEST_COLUMN_INTENT_ACTION + ","
            + "'" + Notes.TextNote.CONTENT_TYPE + "' AS " + SearchManager.SUGGEST_COLUMN_INTENT_DATA;

    // 便签内容搜索SQL查询语句
    private static String NOTES_SNIPPET_SEARCH_QUERY = "SELECT " + NOTES_SEARCH_PROJECTION
            + " FROM " + TABLE.NOTE
            + " WHERE " + NoteColumns.SNIPPET + " LIKE ?"
            + " AND " + NoteColumns.PARENT_ID + "<>" + Notes.ID_TRASH_FOLER
            + " AND " + NoteColumns.TYPE + "=" + Notes.TYPE_NOTE;

    /**
     * 内容提供者初始化方法（在创建时调用）
     * 初始化数据库辅助类实例
     * @return 初始化结果（始终返回true）
     */
    @Override
    public boolean onCreate() {
        mHelper = NotesDatabaseHelper.getInstance(getContext());
        return true;
    }

    /**
     * 处理数据查询请求
     * 根据URI匹配结果执行不同的查询逻辑
     * @param uri 查询请求URI
     * @param projection 查询字段投影
     * @param selection 查询条件
     * @param selectionArgs 查询条件参数
     * @param sortOrder 排序规则
     * @return 查询结果Cursor
     */
    @Override
    public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs,
                        String sortOrder) {
        Cursor c = null;
        SQLiteDatabase db = mHelper.getReadableDatabase();
        String id = null;
        // 根据URI匹配结果执行不同的查询逻辑
        switch (mMatcher.match(uri)) {
            case URI_NOTE:
                // 查询便签列表
                c = db.query(TABLE.NOTE, projection, selection, selectionArgs, null, null, sortOrder);
                break;
            case URI_NOTE_ITEM:
                // 查询单条便签（通过ID）
                id = uri.getPathSegments().get(1);
                c = db.query(TABLE.NOTE, projection, NoteColumns.ID + "=" + id
                        + parseSelection(selection), selectionArgs, null, null, sortOrder);
                break;
            case URI_DATA:
                // 查询便签数据列表
                c = db.query(TABLE.DATA, projection, selection, selectionArgs, null, null, sortOrder);
                break;
            case URI_DATA_ITEM:
                // 查询单条便签数据（通过ID）
                id = uri.getPathSegments().get(1);
                c = db.query(TABLE.DATA, projection, DataColumns.ID + "=" + id
                        + parseSelection(selection), selectionArgs, null, null, sortOrder);
                break;
            case URI_SEARCH:
            case URI_SEARCH_SUGGEST:
                // 处理搜索请求（搜索建议或搜索结果）
                if (sortOrder != null || projection != null) {
                    throw new IllegalArgumentException(
                            "do not specify sortOrder, selection, selectionArgs, or projection" + "with this query");
                }

                String searchString = null;
                if (mMatcher.match(uri) == URI_SEARCH_SUGGEST) {
                    // 从URI路径获取搜索字符串（搜索建议场景）
                    if (uri.getPathSegments().size() > 1) {
                        searchString = uri.getPathSegments().get(1);
                    }
                } else {
                    // 从查询参数获取搜索字符串（搜索结果场景）
                    searchString = uri.getQueryParameter("pattern");
                }

                if (TextUtils.isEmpty(searchString)) {
                    return null;
                }

                try {
                    // 构建模糊查询条件（前后添加通配符）
                    searchString = String.format("%%%s%%", searchString);
                    // 执行搜索SQL查询
                    c = db.rawQuery(NOTES_SNIPPET_SEARCH_QUERY,
                            new String[] { searchString });
                } catch (IllegalStateException ex) {
                    Log.e(TAG, "got exception: " + ex.toString());
                }
                break;
            default:
                throw new IllegalArgumentException("Unknown URI " + uri);
        }
        // 设置内容变更通知监听
        if (c != null) {
            c.setNotificationUri(getContext().getContentResolver(), uri);
        }
        return c;
    }

    /**
     * 处理数据插入请求
     * 根据URI匹配结果插入不同类型的数据
     * @param uri 插入请求URI
     * @param values 要插入的ContentValues
     * @return 插入成功的URI（包含ID）
     */
    @Override
    public Uri insert(Uri uri, ContentValues values) {
        SQLiteDatabase db = mHelper.getWritableDatabase();
        long dataId = 0, noteId = 0, insertedId = 0;
        // 根据URI匹配结果执行不同的插入逻辑
        switch (mMatcher.match(uri)) {
            case URI_NOTE:
                // 插入便签记录
                insertedId = noteId = db.insert(TABLE.NOTE, null, values);
                break;
            case URI_DATA:
                // 插入便签数据记录（需关联便签ID）
                if (values.containsKey(DataColumns.NOTE_ID)) {
                    noteId = values.getAsLong(DataColumns.NOTE_ID);
                } else {
                    Log.d(TAG, "Wrong data format without note id:" + values.toString());
                }
                insertedId = dataId = db.insert(TABLE.DATA, null, values);
                break;
            default:
                throw new IllegalArgumentException("Unknown URI " + uri);
        }
        // 通知便签URI内容变更（若插入便签记录）
        if (noteId > 0) {
            getContext().getContentResolver().notifyChange(
                    ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, noteId), null);
        }

        // 通知便签数据URI内容变更（若插入便签数据记录）
        if (dataId > 0) {
            getContext().getContentResolver().notifyChange(
                    ContentUris.withAppendedId(Notes.CONTENT_DATA_URI, dataId), null);
        }

        return ContentUris.withAppendedId(uri, insertedId);
    }

    /**
     * 处理数据删除请求
     * 根据URI匹配结果删除不同类型的数据
     * @param uri 删除请求URI
     * @param selection 删除条件
     * @param selectionArgs 删除条件参数
     * @return 删除的记录数
     */
    @Override
    public int delete(Uri uri, String selection, String[] selectionArgs) {
        int count = 0;
        String id = null;
        SQLiteDatabase db = mHelper.getWritableDatabase();
        boolean deleteData = false;
        // 根据URI匹配结果执行不同的删除逻辑
        switch (mMatcher.match(uri)) {
            case URI_NOTE:
                // 删除便签记录（过滤系统文件夹）
                selection = "(" + selection + ") AND " + NoteColumns.ID + ">0 ";
                count = db.delete(TABLE.NOTE, selection, selectionArgs);
                break;
            case URI_NOTE_ITEM:
                // 删除单条便签记录（通过ID，过滤系统文件夹）
                id = uri.getPathSegments().get(1);
                long noteId = Long.valueOf(id);
                if (noteId <= 0) {
                    break;
                }
                count = db.delete(TABLE.NOTE,
                        NoteColumns.ID + "=" + id + parseSelection(selection), selectionArgs);
                break;
            case URI_DATA:
                // 删除便签数据记录
                count = db.delete(TABLE.DATA, selection, selectionArgs);
                deleteData = true;
                break;
            case URI_DATA_ITEM:
                // 删除单条便签数据记录（通过ID）
                id = uri.getPathSegments().get(1);
                count = db.delete(TABLE.DATA,
                        DataColumns.ID + "=" + id + parseSelection(selection), selectionArgs);
                deleteData = true;
                break;
            default:
                throw new IllegalArgumentException("Unknown URI " + uri);
        }
        // 通知内容变更（若删除成功）
        if (count > 0) {
            if (deleteData) {
                getContext().getContentResolver().notifyChange(Notes.CONTENT_NOTE_URI, null);
            }
            getContext().getContentResolver().notifyChange(uri, null);
        }
        return count;
    }

    /**
     * 处理数据更新请求
     * 根据URI匹配结果更新不同类型的数据
     * @param uri 更新请求URI
     * @param values 要更新的ContentValues
     * @param selection 更新条件
     * @param selectionArgs 更新条件参数
     * @return 更新的记录数
     */
    @Override
    public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
        int count = 0;
        String id = null;
        SQLiteDatabase db = mHelper.getWritableDatabase();
        boolean updateData = false;
        // 根据URI匹配结果执行不同的更新逻辑
        switch (mMatcher.match(uri)) {
            case URI_NOTE:
                // 更新便签记录（增加版本号）
                increaseNoteVersion(-1, selection, selectionArgs);
                count = db.update(TABLE.NOTE, values, selection, selectionArgs);
                break;
            case URI_NOTE_ITEM:
                // 更新单条便签记录（通过ID，增加版本号）
                id = uri.getPathSegments().get(1);
                increaseNoteVersion(Long.valueOf(id), selection, selectionArgs);
                count = db.update(TABLE.NOTE, values, NoteColumns.ID + "=" + id
                        + parseSelection(selection), selectionArgs);
                break;
            case URI_DATA:
                // 更新便签数据记录
                count = db.update(TABLE.DATA, values, selection, selectionArgs);
                updateData = true;
                break;
            case URI_DATA_ITEM:
                // 更新单条便签数据记录（通过ID）
                id = uri.getPathSegments().get(1);
                count = db.update(TABLE.DATA, values, DataColumns.ID + "=" + id
                        + parseSelection(selection), selectionArgs);
                updateData = true;
                break;
            default:
                throw new IllegalArgumentException("Unknown URI " + uri);
        }

        // 通知内容变更（若更新成功）
        if (count > 0) {
            if (updateData) {
                getContext().getContentResolver().notifyChange(Notes.CONTENT_NOTE_URI, null);
            }
            getContext().getContentResolver().notifyChange(uri, null);
        }
        return count;
    }

    /**
     * 解析查询条件（添加AND连接符）
     * @param selection 原始查询条件
     * @return 解析后的查询条件
     */
    private String parseSelection(String selection) {
        return (!TextUtils.isEmpty(selection) ? " AND (" + selection + ')' : "");
    }

    /**
     * 增加便签版本号（用于冲突检测）
     * @param id 便签ID（-1表示批量更新）
     * @param selection 更新条件
     * @param selectionArgs 更新条件参数
     */
    private void increaseNoteVersion(long id, String selection, String[] selectionArgs) {
        StringBuilder sql = new StringBuilder(120);
        sql.append("UPDATE ");
        sql.append(TABLE.NOTE);
        sql.append(" SET ");
        sql.append(NoteColumns.VERSION);
        sql.append("=" + NoteColumns.VERSION + "+1 ");

        // 构建更新条件
        if (id > 0 || !TextUtils.isEmpty(selection)) {
            sql.append(" WHERE ");
        }
        if (id > 0) {
            sql.append(NoteColumns.ID + "=" + String.valueOf(id));
        }
        if (!TextUtils.isEmpty(selection)) {
            String selectString = id > 0 ? parseSelection(selection) : selection;
            for (String args : selectionArgs) {
                selectString = selectString.replaceFirst("\\?", args);
            }
            sql.append(selectString);
        }

        // 执行SQL更新语句
        mHelper.getWritableDatabase().execSQL(sql.toString());
    }

    /**
     * 获取URI对应的MIME类型（未实现）
     * @param uri 目标URI
     * @return MIME类型字符串
     */
    @Override
    public String getType(Uri uri) {
        // TODO Auto-generated method stub
        return null;
    }

}