// API endpoint для получения статистики реферальной программы
// GET /api/referral/stats?username=xxx - возвращает статистику пользователя

import { NextRequest, NextResponse } from 'next/server';
import mysql from 'mysql2/promise';

// Database connection config from ENV
const dbConfig = {
  host: process.env.DB_HOST || '',
  user: process.env.DB_USER || '',
  password: process.env.DB_PASSWORD || '',
  database: process.env.DB_NAME || '',
  connectTimeout: 20000, // 20 seconds
  acquireTimeout: 20000,
};

// Check if DB is configured
const isDbConfigured = dbConfig.host && dbConfig.user && dbConfig.database;

export async function GET(request: NextRequest) {
  try {
    const { searchParams } = new URL(request.url);
    const username = searchParams.get('username');

    if (!username) {
      return NextResponse.json(
        { success: false, error: 'Username is required' },
        { status: 400 }
      );
    }

    // Return mock data if DB not configured (dev mode)
    if (!isDbConfigured) {
      console.log('⚠️ Referral stats skipped: DB not configured');
      return NextResponse.json({
        success: true,
        hasReferrals: false,
        dev_mode: true,
        stats: {
          referral_count: 0,
          bonus_days_earned: 0,
          total_referrals_used: 0,
        },
      });
    }

    // Connect to database
    const connection = await mysql.createConnection(dbConfig);

    try {
      // Get user's referral stats
      const [statsRows] = await connection.query(
        'SELECT * FROM referrals WHERE username = ?',
        [username]
      );

      if ((statsRows as any[]).length === 0) {
        return NextResponse.json({
          success: true,
          hasReferrals: false,
          stats: {
            referral_count: 0,
            bonus_days_earned: 0,
            total_referrals_used: 0,
          },
        });
      }

      const stats = (statsRows as any[])[0];

      // Get list of referred users
      const [referredRows] = await connection.query(
        `SELECT u.username, u.created_at, u.status
         FROM referrals r
         JOIN users u ON r.username = u.username
         WHERE r.referrer_username = ?
         ORDER BY r.created_at DESC`,
        [username]
      );

      return NextResponse.json({
        success: true,
        hasReferrals: true,
        stats: {
          referral_count: stats.referral_count || 0,
          bonus_days_earned: stats.bonus_days_earned || 0,
          total_referrals_used: stats.total_referrals_used || 0,
          created_at: stats.created_at,
          updated_at: stats.updated_at,
        },
        referred_users: (referredRows as any[]).map((user: any) => ({
          username: user.username,
          created_at: user.created_at,
          status: user.status,
        })),
      });
    } finally {
      await connection.end();
    }
  } catch (error) {
    console.error('Referral stats error:', error);
    return NextResponse.json(
      {
        success: false,
        error: error instanceof Error ? error.message : 'Unknown error',
      },
      { status: 500 }
    );
  }
}