/**
 * 任务数据迁移脚本 - Node.js
 * Feature: database-migration, Property 2: 数据记录数一致性
 * Validates: Requirements 7.1
 * 
 * 源表: MySQL task_list (9 条记录)
 * 目标表: SQL Server tasks
 */

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 + "'";
}

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

// 批量插入任务数据
async function insertTasksBatch(pool, tasks) {
    if (tasks.length === 0) return 0;
    
    let insertedCount = 0;
    
    // 构建批量插入SQL
    let sqlBatch = 'SET IDENTITY_INSERT tasks ON;\n';
    
    for (const task of tasks) {
        const createdAt = unixToDatetime(task.addtime) || new Date().toISOString().slice(0, 23).replace('T', ' ');
        const updatedAt = unixToDatetime(task.updatetime) || createdAt;
        const deletedAt = unixToDatetime(task.deltime);
        
        sqlBatch += `
INSERT INTO tasks (
    id, title, type, cate, is_important, number, z_number, sort,
    created_at, updated_at, deleted_at
) VALUES (
    ${task.id}, 
    ${escapeString(task.title)}, 
    ${task.type || 0}, 
    ${task.cate || 0}, 
    ${task.is_important || 0}, 
    ${task.number || 0}, 
    ${task.z_number || 0}, 
    ${task.sort || 0},
    ${formatDatetime(createdAt)}, 
    ${formatDatetime(updatedAt)}, 
    ${formatDatetime(deletedAt)}
);
`;
    }
    
    sqlBatch += 'SET IDENTITY_INSERT tasks OFF;';
    
    try {
        await pool.request().batch(sqlBatch);
        insertedCount = tasks.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 task of tasks) {
            try {
                const createdAt = unixToDatetime(task.addtime) || new Date().toISOString().slice(0, 23).replace('T', ' ');
                const updatedAt = unixToDatetime(task.updatetime) || createdAt;
                const deletedAt = unixToDatetime(task.deltime);
                
                const singleSql = `
SET IDENTITY_INSERT tasks ON;
INSERT INTO tasks (
    id, title, type, cate, is_important, number, z_number, sort,
    created_at, updated_at, deleted_at
) VALUES (
    ${task.id}, 
    ${escapeString(task.title)}, 
    ${task.type || 0}, 
    ${task.cate || 0}, 
    ${task.is_important || 0}, 
    ${task.number || 0}, 
    ${task.z_number || 0}, 
    ${task.sort || 0},
    ${formatDatetime(createdAt)}, 
    ${formatDatetime(updatedAt)}, 
    ${formatDatetime(deletedAt)}
);
SET IDENTITY_INSERT tasks OFF;`;
                
                await pool.request().batch(singleSql);
                insertedCount++;
            } catch (singleErr) {
                console.error(`插入任务 ${task.id} 失败:`, singleErr.message);
            }
        }
    }
    
    return insertedCount;
}

async function main() {
    console.log('========================================');
    console.log('任务数据迁移脚本 - 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('正在获取已迁移的任务ID...');
        const migratedIds = await getMigratedIds(sqlPool);
        console.log(`已迁移任务数: ${migratedIds.size}\n`);
        
        // 从 MySQL 获取所有任务数据
        console.log('正在从 MySQL 读取任务数据...');
        const [rows] = await mysqlConn.execute(`
            SELECT id, title, type, cate, is_important, number, z_number, sort,
                   addtime, updatetime, deltime
            FROM task_list
            ORDER BY id
        `);
        console.log(`MySQL 任务总数: ${rows.length}\n`);
        
        // 过滤出未迁移的任务
        const tasksToMigrate = rows.filter(task => !migratedIds.has(task.id));
        console.log(`待迁移任务数: ${tasksToMigrate.length}\n`);
        
        if (tasksToMigrate.length === 0) {
            console.log('所有任务数据已迁移完成！');
        } else {
            // 批量迁移
            const inserted = await insertTasksBatch(sqlPool, tasksToMigrate);
            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 task_list');
        const sqlResult = await sqlPool.request().query('SELECT COUNT(*) as count FROM tasks');
        
        console.log(`MySQL task_list 表记录数: ${mysqlCount[0].count}`);
        console.log(`SQL Server tasks 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();