/**
 * 奖品等级数据迁移脚本 - Node.js
 * Feature: database-migration, Property 2: 数据记录数一致性
 * Validates: Requirements 2.6
 * 
 * 源表: MySQL shang (106 条记录)
 * 目标表: SQL Server prize_levels
 * 
 * 字段映射:
 * - imgurl -> img_url
 * - special_imgurl -> special_img_url
 * - update_time -> updated_at (Unix时间戳转DATETIME2)
 */

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 || str === 'None') return 'NULL';
    return "N'" + String(str).replace(/'/g, "''") + "'";
}

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

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

// 批量插入奖品等级数据
async function insertPrizeLevelsBatch(pool, items) {
    if (items.length === 0) return 0;
    
    let insertedCount = 0;
    
    for (const item of items) {
        try {
            // 时间戳转换
            const updatedAt = unixToDatetime(item.update_time);
            
            const insertSql = `
SET IDENTITY_INSERT prize_levels ON;
INSERT INTO prize_levels (
    id, title, pro, img_url, color, goods_id, special_img_url, sort, updated_at
) VALUES (
    ${item.id},
    ${escapeString(item.title)},
    ${parseFloat(item.pro) || 0},
    ${escapeString(item.imgurl)},
    ${escapeString(item.color)},
    ${item.goods_id || 0},
    ${escapeString(item.special_imgurl)},
    ${item.sort || 0},
    ${formatDatetime(updatedAt)}
);
SET IDENTITY_INSERT prize_levels OFF;`;
            
            await pool.request().batch(insertSql);
            insertedCount++;
        } catch (err) {
            console.error(`插入奖品等级 ${item.id} (${item.title}) 失败:`, err.message);
        }
    }
    
    return insertedCount;
}

async function main() {
    console.log('========================================');
    console.log('奖品等级数据迁移脚本 - 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('正在获取已迁移的奖品等级ID...');
        const migratedIds = await getMigratedIds(sqlPool);
        console.log(`已迁移奖品等级数: ${migratedIds.size}\n`);
        
        // 从 MySQL 获取所有奖品等级数据
        console.log('正在从 MySQL 读取奖品等级数据...');
        const [rows] = await mysqlConn.execute(`
            SELECT id, title, pro, imgurl, color, goods_id, special_imgurl, sort, update_time
            FROM shang
            ORDER BY id
        `);
        console.log(`MySQL 奖品等级总数: ${rows.length}\n`);
        
        // 过滤出未迁移的奖品等级
        const itemsToMigrate = rows.filter(item => !migratedIds.has(item.id));
        console.log(`待迁移奖品等级数: ${itemsToMigrate.length}\n`);
        
        if (itemsToMigrate.length === 0) {
            console.log('所有奖品等级数据已迁移完成！');
        } else {
            // 批量迁移（每批50条）
            const batchSize = 50;
            let totalInserted = 0;
            
            for (let i = 0; i < itemsToMigrate.length; i += batchSize) {
                const batch = itemsToMigrate.slice(i, i + batchSize);
                const inserted = await insertPrizeLevelsBatch(sqlPool, batch);
                totalInserted += inserted;
                console.log(`进度: ${Math.min(i + batchSize, itemsToMigrate.length)}/${itemsToMigrate.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 shang');
        const sqlResult = await sqlPool.request().query('SELECT COUNT(*) as count FROM prize_levels');
        
        console.log(`MySQL shang 表记录数: ${mysqlCount[0].count}`);
        console.log(`SQL Server prize_levels 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}`);
        }
        
        // 验证奖品等级分布
        console.log('\n========================================');
        console.log('奖品等级分布验证');
        console.log('========================================');
        
        const [mysqlLevels] = await mysqlConn.execute('SELECT title, COUNT(*) as count FROM shang GROUP BY title ORDER BY count DESC LIMIT 10');
        const sqlLevelsResult = await sqlPool.request().query('SELECT TOP 10 title, COUNT(*) as count FROM prize_levels GROUP BY title ORDER BY count DESC');
        
        console.log('MySQL 奖品等级分布 (前10):');
        for (const row of mysqlLevels) {
            console.log(`  ${row.title}: ${row.count} 条`);
        }
        
        console.log('SQL Server 奖品等级分布 (前10):');
        for (const row of sqlLevelsResult.recordset) {
            console.log(`  ${row.title}: ${row.count} 条`);
        }
        
    } 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();