/**
 * 广告数据迁移脚本 - Node.js
 * Feature: database-migration, Property 2: 数据记录数一致性
 * Validates: Requirements 9.4
 * 
 * 源表: MySQL advert (16 条记录)
 * 目标表: SQL Server adverts
 * 
 * 字段映射:
 * - id -> id
 * - imgurl -> img_url
 * - url -> url
 * - sort -> sort
 * - type -> type
 * - addtime (Unix时间戳) -> created_at (DATETIME2)
 * - update_time (Unix时间戳) -> updated_at (DATETIME2)
 * - ttype -> ttype
 * - coupon_id -> coupon_id
 * - goods_id -> goods_id
 */

const mysql = require('mysql2/promise');
const sql = require('mssql');

// MySQL 配置
const mysqlConfig = {
    host: '192.168.195.16',
    port: 1887,
    user: 'root',
    password: 'Dbt@com@123',
    database: 'youdas',
    charset: 'utf8mb4'
};

// SQL Server 配置
const sqlServerConfig = {
    server: '192.168.195.15',
    port: 1433,
    user: 'sa',
    password: 'Dbt@com@123',
    database: 'honey_box',
    options: {
        encrypt: false,
        trustServerCertificate: true
    }
};

// 转义SQL字符串
function escapeString(str) {
    if (str === null || str === undefined) return 'NULL';
    return "N'" + String(str).replace(/'/g, "''") + "'";
}

// Unix时间戳转换为SQL Server DATETIME2格式
function unixToDatetime(timestamp) {
    if (!timestamp || timestamp === 0) {
        return 'GETDATE()';
    }
    const date = new Date(timestamp * 1000);
    const year = date.getFullYear();
    const month = String(date.getMonth() + 1).padStart(2, '0');
    const day = String(date.getDate()).padStart(2, '0');
    const hours = String(date.getHours()).padStart(2, '0');
    const minutes = String(date.getMinutes()).padStart(2, '0');
    const seconds = String(date.getSeconds()).padStart(2, '0');
    return `'${year}-${month}-${day} ${hours}:${minutes}:${seconds}'`;
}

// 获取已迁移的广告ID列表
async function getMigratedIds(pool) {
    const result = await pool.request().query('SELECT id FROM adverts');
    return new Set(result.recordset.map(r => r.id));
}

// 批量插入广告数据
async function insertAdvertsBatch(pool, adverts) {
    if (adverts.length === 0) return 0;
    
    let insertedCount = 0;
    
    // 构建批量插入SQL
    let sqlBatch = 'SET IDENTITY_INSERT adverts ON;\n';
    
    for (const advert of adverts) {
        const ttypeValue = advert.ttype !== null && advert.ttype !== undefined ? advert.ttype : 'NULL';
        const couponIdValue = advert.coupon_id !== null && advert.coupon_id !== undefined ? advert.coupon_id : 'NULL';
        const goodsIdValue = advert.goods_id !== null && advert.goods_id !== undefined ? advert.goods_id : 'NULL';
        
        sqlBatch += `
INSERT INTO adverts (id, img_url, url, sort, type, created_at, updated_at, ttype, coupon_id, goods_id)
VALUES (${advert.id}, ${escapeString(advert.imgurl)}, ${escapeString(advert.url)}, ${advert.sort}, ${advert.type}, ${unixToDatetime(advert.addtime)}, ${unixToDatetime(advert.update_time)}, ${ttypeValue}, ${couponIdValue}, ${goodsIdValue});
`;
    }
    
    sqlBatch += 'SET IDENTITY_INSERT adverts OFF;';
    
    try {
        await pool.request().batch(sqlBatch);
        insertedCount = adverts.length;
        console.log(`  批量插入成功: ${adverts.length} 条记录`);
    } catch (err) {
        console.error('批量插入失败:', err.message);
        // 如果批量失败，尝试逐条插入
        for (const advert of adverts) {
            try {
                const ttypeValue = advert.ttype !== null && advert.ttype !== undefined ? advert.ttype : 'NULL';
                const couponIdValue = advert.coupon_id !== null && advert.coupon_id !== undefined ? advert.coupon_id : 'NULL';
                const goodsIdValue = advert.goods_id !== null && advert.goods_id !== undefined ? advert.goods_id : 'NULL';
                
                const singleSql = `
SET IDENTITY_INSERT adverts ON;
INSERT INTO adverts (id, img_url, url, sort, type, created_at, updated_at, ttype, coupon_id, goods_id)
VALUES (${advert.id}, ${escapeString(advert.imgurl)}, ${escapeString(advert.url)}, ${advert.sort}, ${advert.type}, ${unixToDatetime(advert.addtime)}, ${unixToDatetime(advert.update_time)}, ${ttypeValue}, ${couponIdValue}, ${goodsIdValue});
SET IDENTITY_INSERT adverts OFF;`;
                
                await pool.request().batch(singleSql);
                insertedCount++;
                console.log(`  ✓ 插入广告 ${advert.id}`);
            } catch (singleErr) {
                console.error(`  ✗ 插入广告 ${advert.id} 失败:`, singleErr.message);
            }
        }
    }
    
    return insertedCount;
}

async function main() {
    console.log('========================================');
    console.log('广告数据迁移脚本 - Node.js');
    console.log('========================================\n');
    
    let mysqlConn = null;
    let sqlPool = null;
    
    try {
        // 连接 MySQL
        console.log('正在连接 MySQL...');
        mysqlConn = await mysql.createConnection(mysqlConfig);
        console.log('MySQL 连接成功\n');
        
        // 连接 SQL Server
        console.log('正在连接 SQL Server...');
        sqlPool = await sql.connect(sqlServerConfig);
        console.log('SQL Server 连接成功\n');
        
        // 获取已迁移的ID
        console.log('正在获取已迁移的广告ID...');
        const migratedIds = await getMigratedIds(sqlPool);
        console.log(`已迁移广告数: ${migratedIds.size}\n`);
        
        // 从 MySQL 获取所有广告数据
        console.log('正在从 MySQL 读取广告数据...');
        const [rows] = await mysqlConn.execute(`
            SELECT id, imgurl, url, sort, type, addtime, update_time, ttype, coupon_id, goods_id
            FROM advert
            ORDER BY id
        `);
        console.log(`MySQL 广告总数: ${rows.length}\n`);
        
        // 显示广告列表
        console.log('广告列表:');
        for (const row of rows) {
            const status = migratedIds.has(row.id) ? '已迁移' : '待迁移';
            console.log(`  ${row.id}. type=${row.type}, sort=${row.sort} [${status}]`);
        }
        console.log('');
        
        // 过滤出未迁移的广告
        const advertsToMigrate = rows.filter(advert => !migratedIds.has(advert.id));
        console.log(`待迁移广告数: ${advertsToMigrate.length}\n`);
        
        if (advertsToMigrate.length === 0) {
            console.log('所有广告数据已迁移完成！');
        } else {
            // 批量迁移
            console.log('开始迁移广告数据...');
            const inserted = await insertAdvertsBatch(sqlPool, advertsToMigrate);
            console.log(`\n迁移完成！共插入 ${inserted} 条记录`);
        }
        
        // 验证迁移结果
        console.log('\n========================================');
        console.log('迁移结果验证');
        console.log('========================================');
        
        const [mysqlCount] = await mysqlConn.execute('SELECT COUNT(*) as count FROM advert');
        const sqlResult = await sqlPool.request().query('SELECT COUNT(*) as count FROM adverts');
        
        console.log(`MySQL advert 表记录数: ${mysqlCount[0].count}`);
        console.log(`SQL Server adverts 表记录数: ${sqlResult.recordset[0].count}`);
        
        if (mysqlCount[0].count === sqlResult.recordset[0].count) {
            console.log('\n✅ 数据迁移完成，记录数一致！');
        } else {
            console.log(`\n⚠️ 记录数不一致，差异: ${mysqlCount[0].count - sqlResult.recordset[0].count}`);
        }
        
        // 显示迁移统计
        console.log('\n迁移统计:');
        const stats = await sqlPool.request().query(`
            SELECT 
                COUNT(*) as total,
                COUNT(DISTINCT type) as type_count,
                COUNT(CASE WHEN goods_id > 0 THEN 1 END) as with_goods,
                COUNT(CASE WHEN coupon_id > 0 THEN 1 END) as with_coupon
            FROM adverts
        `);
        console.log(`  总记录数: ${stats.recordset[0].total}`);
        console.log(`  广告类型数: ${stats.recordset[0].type_count}`);
        console.log(`  关联商品: ${stats.recordset[0].with_goods}`);
        console.log(`  关联优惠券: ${stats.recordset[0].with_coupon}`);
        
    } catch (err) {
        console.error('迁移过程中发生错误:', err);
        process.exit(1);
    } finally {
        // 关闭连接
        if (mysqlConn) await mysqlConn.end();
        if (sqlPool) await sqlPool.close();
    }
}

main();