/*
 * 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.
 */

/**
 * 文件: Contact.java
 * 描述: 提供联系人相关功能的工具类，主要用于通过电话号码查询联系人姓名
 * 作用: 在便签应用中，当用户创建通话记录便签时，需要显示联系人姓名而不仅仅是电话号码
 */
package net.micode.notes.data;

import android.content.Context;
import android.database.Cursor;
import android.provider.ContactsContract.CommonDataKinds.Phone;
import android.provider.ContactsContract.Data;
import android.telephony.PhoneNumberUtils;
import android.util.Log;

import java.util.HashMap;

/**
 * 联系人工具类
 * 
 * 提供通过电话号码查询联系人姓名的功能，使用缓存机制提高查询效率
 */
public class Contact {
    /** 联系人缓存，键为电话号码，值为联系人姓名 */
    private static HashMap<String, String> sContactCache;
    
    /** 日志标签 */
    private static final String TAG = "Contact";

    /**
     * SQL查询条件，用于通过电话号码查询联系人
     * 使用PHONE_NUMBERS_EQUAL函数比较电话号码
     * 限制MIMETYPE为电话类型
     * 通过phone_lookup表的min_match字段进行匹配
     */
    private static final String CALLER_ID_SELECTION = "PHONE_NUMBERS_EQUAL(" + Phone.NUMBER
    + ",?) AND " + Data.MIMETYPE + "='" + Phone.CONTENT_ITEM_TYPE + "'"
    + " AND " + Data.RAW_CONTACT_ID + " IN "
            + "(SELECT raw_contact_id "
            + " FROM phone_lookup"
            + " WHERE min_match = '+')";

    /**
     * 通过电话号码获取联系人姓名
     * 
     * @param context 上下文环境，用于访问ContentResolver
     * @param phoneNumber 需要查询的电话号码
     * @return 联系人姓名，如果未找到则返回null
     */
    public static String getContact(Context context, String phoneNumber) {
        // 初始化缓存（如果需要）
        if(sContactCache == null) {
            sContactCache = new HashMap<String, String>();
        }

        // 检查缓存中是否已有该号码对应的联系人
        if(sContactCache.containsKey(phoneNumber)) {
            return sContactCache.get(phoneNumber);
        }

        // 替换SQL查询条件中的占位符，转换电话号码为标准格式
        String selection = CALLER_ID_SELECTION.replace("+",
                PhoneNumberUtils.toCallerIDMinMatch(phoneNumber));
                
        // 执行查询，获取联系人姓名
        Cursor cursor = context.getContentResolver().query(
                Data.CONTENT_URI,
                new String [] { Phone.DISPLAY_NAME },
                selection,
                new String[] { phoneNumber },
                null);

        // 处理查询结果
        if (cursor != null && cursor.moveToFirst()) {
            try {
                // 获取联系人姓名并存入缓存
                String name = cursor.getString(0);
                sContactCache.put(phoneNumber, name);
                return name;
            } catch (IndexOutOfBoundsException e) {
                // 处理索引越界异常
                Log.e(TAG, " Cursor get string error " + e.toString());
                return null;
            } finally {
                // 确保关闭游标，释放资源
                cursor.close();
            }
        } else {
            // 未找到匹配的联系人
            Log.d(TAG, "No contact matched with number:" + phoneNumber);
            return null;
        }
    }
}