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

// 資料庫配置
const dbConfig = {
  host: process.env.DB_HOST || 'localhost',
  user: process.env.DB_USER || 'root',
  password: process.env.DB_PASSWORD || '',
  database: process.env.DB_NAME || 'ai_scoring_app',
  timezone: '+08:00',
};

async function updateEvaluationTable() {
  let connection;
  
  try {
    console.log('🔗 連接到資料庫...');
    connection = await mysql.createConnection(dbConfig);
    console.log('✅ 資料庫連接成功');

    // 檢查欄位是否已存在
    console.log('🔍 檢查 evaluations 表結構...');
    const [columns] = await connection.execute(`
      SELECT COLUMN_NAME 
      FROM INFORMATION_SCHEMA.COLUMNS 
      WHERE TABLE_SCHEMA = ? AND TABLE_NAME = 'evaluations'
    `, [dbConfig.database]);
    
    const existingColumns = columns.map(col => col.COLUMN_NAME);
    console.log('📋 現有欄位:', existingColumns);

    // 添加新欄位
    const newColumns = [
      { name: 'performance_status', type: 'varchar(50) DEFAULT NULL COMMENT \'表現狀況\'' },
      { name: 'recommended_stars', type: 'int(11) DEFAULT NULL COMMENT \'推薦等級(星星數量)\'' },
      { name: 'excellent_items', type: 'int(11) DEFAULT NULL COMMENT \'優秀項目數量\'' },
      { name: 'improvement_items', type: 'int(11) DEFAULT NULL COMMENT \'待改進項目數量\'' }
    ];

    for (const column of newColumns) {
      if (!existingColumns.includes(column.name)) {
        console.log(`➕ 添加欄位: ${column.name}`);
        await connection.execute(`
          ALTER TABLE evaluations 
          ADD COLUMN \`${column.name}\` ${column.type} 
          AFTER \`grade\`
        `);
        console.log(`✅ 欄位 ${column.name} 添加成功`);
      } else {
        console.log(`⚠️ 欄位 ${column.name} 已存在，跳過`);
      }
    }

    // 驗證更新結果
    console.log('🔍 驗證更新結果...');
    const [updatedColumns] = await connection.execute(`
      SELECT COLUMN_NAME, DATA_TYPE, IS_NULLABLE, COLUMN_DEFAULT, COLUMN_COMMENT
      FROM INFORMATION_SCHEMA.COLUMNS 
      WHERE TABLE_SCHEMA = ? AND TABLE_NAME = 'evaluations'
      ORDER BY ORDINAL_POSITION
    `, [dbConfig.database]);
    
    console.log('📊 更新後的 evaluations 表結構:');
    updatedColumns.forEach(col => {
      console.log(`  - ${col.COLUMN_NAME}: ${col.DATA_TYPE} ${col.IS_NULLABLE === 'YES' ? 'NULL' : 'NOT NULL'} ${col.COLUMN_DEFAULT ? `DEFAULT ${col.COLUMN_DEFAULT}` : ''} ${col.COLUMN_COMMENT ? `(${col.COLUMN_COMMENT})` : ''}`);
    });

    console.log('\n🎉 evaluations 表更新完成！');
    console.log('📝 新增的欄位:');
    console.log('  - performance_status: 表現狀況');
    console.log('  - recommended_stars: 推薦等級(星星數量)');
    console.log('  - excellent_items: 優秀項目數量');
    console.log('  - improvement_items: 待改進項目數量');

  } catch (error) {
    console.error('❌ 更新過程中發生錯誤:', error);
    throw error;
  } finally {
    if (connection) {
      await connection.end();
      console.log('🔌 資料庫連接已關閉');
    }
  }
}

// 執行更新
if (require.main === module) {
  updateEvaluationTable()
    .then(() => {
      console.log('✅ 腳本執行完成');
      process.exit(0);
    })
    .catch((error) => {
      console.error('❌ 腳本執行失敗:', error);
      process.exit(1);
    });
}

module.exports = { updateEvaluationTable };