/**
 * 优惠券数据迁移脚本 - Node.js
 * Feature: database-migration, Property 2: 数据记录数一致性
 * Feature: database-migration, Property 7: 数据迁移往返一致性
 * Validates: Requirements 5.4
 * 
 * 源表: MySQL coupon (19 条记录)
 * 目标表: SQL Server coupons
 */

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
    }
};

// Unix时间戳转换为 SQL Server DATETIME2 格式
function unixToDatetime(timestamp) {
    if (!timestamp || timestamp === 0) {
        return null;
    }
    const date = new Date(timestamp * 1000);
    return date.toISOString().slice(0, 23).replace('T', ' ');
}

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

// 格式化日期时间
function formatDatetime(dt) {
    if (!dt) return 'NULL';
    return "'" + dt + "'";
}

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

// 批量插入优惠券数据
async function insertCouponsBatch(pool, coupons) {
    if (coupons.length === 0) return 0;
    
    let insertedCount = 0;
    
    // 构建批量插入SQL
    let sqlBatch = 'SET IDENTITY_INSERT coupons ON;\n';
    
    for (const coupon of coupons) {
        const createdAt = unixToDatetime(coupon.addtime) || new Date().toISOString().slice(0, 23).replace('T', ' ');
        
        sqlBatch += `
INSERT INTO coupons (
    id, type, title, sort, price, man_price, effective_day, status, ttype, created_at
) VALUES (
    ${coupon.id}, 
    ${coupon.type || 0}, 
    ${escapeString(coupon.title)}, 
    ${coupon.sort || 1}, 
    ${parseFloat(coupon.price) || 0}, 
    ${parseFloat(coupon.man_price) || 0}, 
    ${coupon.effective_day || 0}, 
    ${coupon.status || 0}, 
    ${coupon.ttype || 0}, 
    ${formatDatetime(createdAt)}
);
`;
    }
    
    sqlBatch += 'SET IDENTITY_INSERT coupons OFF;';
    
    try {
        await pool.request().batch(sqlBatch);
        insertedCount = coupons.length;
    } 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 coupon of coupons) {
            try {
                const createdAt = unixToDatetime(coupon.addtime) || new Date().toISOString().slice(0, 23).replace('T', ' ');
                
                const singleSql = `
SET IDENTITY_INSERT coupons ON;
INSERT INTO coupons (
    id, type, title, sort, price, man_price, effective_day, status, ttype, created_at
) VALUES (
    ${coupon.id}, 
    ${coupon.type || 0}, 
    ${escapeString(coupon.title)}, 
    ${coupon.sort || 1}, 
    ${parseFloat(coupon.price) || 0}, 
    ${parseFloat(coupon.man_price) || 0}, 
    ${coupon.effective_day || 0}, 
    ${coupon.status || 0}, 
    ${coupon.ttype || 0}, 
    ${formatDatetime(createdAt)}
);
SET IDENTITY_INSERT coupons OFF;`;
                
                await pool.request().batch(singleSql);
                insertedCount++;
            } catch (singleErr) {
                console.error(`插入优惠券 ${coupon.id} 失败:`, singleErr.message);
            }
        }
    }
    
    return insertedCount;
}

async function main() {
    console.log('========================================');
    console.log('优惠券数据迁移脚本 - 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('正在获取已迁移的优惠券ID...');
        const migratedIds = await getMigratedIds(sqlPool);
        console.log(`已迁移优惠券数: ${migratedIds.size}\n`);
        
        // 从 MySQL 获取所有优惠券数据
        console.log('正在从 MySQL 读取优惠券数据...');
        const [rows] = await mysqlConn.execute(`
            SELECT id, type, title, sort, price, man_price, effective_day, addtime, status, ttype
            FROM coupon
            ORDER BY id
        `);
        console.log(`MySQL 优惠券总数: ${rows.length}\n`);
        
        // 过滤出未迁移的优惠券
        const couponsToMigrate = rows.filter(coupon => !migratedIds.has(coupon.id));
        console.log(`待迁移优惠券数: ${couponsToMigrate.length}\n`);
        
        if (couponsToMigrate.length === 0) {
            console.log('所有优惠券数据已迁移完成！');
        } else {
            // 批量迁移（每批50条）
            const batchSize = 50;
            let totalInserted = 0;
            
            for (let i = 0; i < couponsToMigrate.length; i += batchSize) {
                const batch = couponsToMigrate.slice(i, i + batchSize);
                const inserted = await insertCouponsBatch(sqlPool, batch);
                totalInserted += inserted;
                console.log(`进度: ${Math.min(i + batchSize, couponsToMigrate.length)}/${couponsToMigrate.length} (本批插入: ${inserted})`);
            }
            
            console.log(`\n迁移完成！共插入 ${totalInserted} 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 coupon');
        const sqlResult = await sqlPool.request().query('SELECT COUNT(*) as count FROM coupons');
        
        console.log(`MySQL coupon 表记录数: ${mysqlCount[0].count}`);
        console.log(`SQL Server coupons 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}`);
        }
        
    } 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();