/**
 * 检查数据库中所有表的主键ID分布情况
 * @file check-primary-keys.js
 * @description 分析各表的主键ID范围，为重新排序做准备
 */

const { sequelize } = require('./config/database-simple');
const { QueryTypes } = require('sequelize');

async function checkPrimaryKeys() {
  try {
    console.log('=== 检查数据库表主键ID分布情况 ===\n');
    
    // 获取所有表名
    const tables = await sequelize.query(
      "SELECT TABLE_NAME as table_name FROM information_schema.tables WHERE table_schema = DATABASE() AND table_type = 'BASE TABLE'",
      { type: QueryTypes.SELECT }
    );
    
    console.log(`发现 ${tables.length} 个表:\n`);
    
    const tableStats = [];
    
    for (const table of tables) {
      const tableName = table.table_name;
      
      try {
        // 检查表是否有id字段
        const columns = await sequelize.query(
          `SELECT COLUMN_NAME as column_name, DATA_TYPE as data_type, IS_NULLABLE as is_nullable, COLUMN_KEY as column_key 
           FROM information_schema.columns 
           WHERE table_schema = DATABASE() AND TABLE_NAME = '${tableName}' AND COLUMN_NAME = 'id'`,
          { type: QueryTypes.SELECT }
        );
        
        if (columns.length === 0) {
          console.log(`❌ ${tableName}: 没有id字段`);
          continue;
        }
        
        // 获取ID统计信息
        const stats = await sequelize.query(
          `SELECT 
             COUNT(*) as total_count,
             MIN(id) as min_id,
             MAX(id) as max_id,
             COUNT(DISTINCT id) as unique_count
           FROM ${tableName}`,
          { type: QueryTypes.SELECT }
        );
        
        const stat = stats[0];
        
        // 检查ID连续性
        const gapCheck = await sequelize.query(
          `SELECT COUNT(*) as gap_count
           FROM (
             SELECT id + 1 as next_id
             FROM ${tableName}
             WHERE id + 1 NOT IN (SELECT id FROM ${tableName})
             AND id < (SELECT MAX(id) FROM ${tableName})
           ) as gaps`,
          { type: QueryTypes.SELECT }
        );
        
        const hasGaps = gapCheck[0].gap_count > 0;
        
        const tableInfo = {
          tableName,
          totalCount: parseInt(stat.total_count),
          minId: stat.min_id,
          maxId: stat.max_id,
          uniqueCount: parseInt(stat.unique_count),
          hasGaps,
          needsReorder: stat.min_id !== 1 || hasGaps
        };
        
        tableStats.push(tableInfo);
        
        console.log(`✅ ${tableName}:`);
        console.log(`   - 记录数: ${tableInfo.totalCount}`);
        console.log(`   - ID范围: ${tableInfo.minId} - ${tableInfo.maxId}`);
        console.log(`   - 唯一ID数: ${tableInfo.uniqueCount}`);
        console.log(`   - 有间隙: ${hasGaps ? '是' : '否'}`);
        console.log(`   - 需要重排: ${tableInfo.needsReorder ? '是' : '否'}`);
        console.log('');
        
      } catch (error) {
        console.log(`❌ ${tableName}: 检查失败 - ${error.message}`);
      }
    }
    
    // 汇总统计
    console.log('\n=== 汇总统计 ===');
    const needReorderTables = tableStats.filter(t => t.needsReorder);
    console.log(`需要重新排序的表: ${needReorderTables.length}/${tableStats.length}`);
    
    if (needReorderTables.length > 0) {
      console.log('\n需要重新排序的表:');
      needReorderTables.forEach(table => {
        console.log(`- ${table.tableName} (${table.minId}-${table.maxId}, ${table.totalCount}条记录)`);
      });
    }
    
    return tableStats;
    
  } catch (error) {
    console.error('检查主键失败:', error);
    throw error;
  } finally {
    await sequelize.close();
  }
}

// 如果直接运行此脚本
if (require.main === module) {
  checkPrimaryKeys()
    .then(() => {
      console.log('\n检查完成!');
      process.exit(0);
    })
    .catch(error => {
      console.error('检查失败:', error);
      process.exit(1);
    });
}

module.exports = { checkPrimaryKeys };