import { NextRequest, NextResponse } from 'next/server';
import { cookies } from 'next/headers';
import { db } from '@/lib/db';

export const dynamic = 'force-dynamic';

export async function GET(request: NextRequest) {
  try {
    // Check newsletter-admin cookie authentication
    const cookieStore = cookies();
    const adminCookie = cookieStore.get('newsletter-admin');

    if (!adminCookie || adminCookie.value !== 'authenticated') {
      return NextResponse.json(
        { error: 'Unauthorized - Admin login required' },
        { status: 401 }
      );
    }

    // Get 30 days ago date
    const thirtyDaysAgo = new Date();
    thirtyDaysAgo.setDate(thirtyDaysAgo.getDate() - 30);

    // Get 7 days ago date
    const sevenDaysAgo = new Date();
    sevenDaysAgo.setDate(sevenDaysAgo.getDate() - 7);

    // Get start of current month
    const startOfMonth = new Date();
    startOfMonth.setDate(1);
    startOfMonth.setHours(0, 0, 0, 0);

    // Fetch all statistics in parallel
    const [
      totalUsers,
      premiumUsers,
      newUsersThisWeek,
      newUsersThisMonth,
      totalQRCodes,
      dynamicQRCodes,
      staticQRCodes,
      totalScans,
      dynamicQRCodesWithScans,
      activeQRCodes,
      newsletterSubscribers,
    ] = await Promise.all([
      // Total users
      db.user.count(),

      // Premium users (PRO or BUSINESS)
      db.user.count({
        where: {
          plan: {
            in: ['PRO', 'BUSINESS'],
          },
        },
      }),

      // New users this week
      db.user.count({
        where: {
          createdAt: {
            gte: sevenDaysAgo,
          },
        },
      }),

      // New users this month
      db.user.count({
        where: {
          createdAt: {
            gte: startOfMonth,
          },
        },
      }),

      // Total QR codes
      db.qRCode.count(),

      // Dynamic QR codes
      db.qRCode.count({
        where: {
          type: 'DYNAMIC',
        },
      }),

      // Static QR codes
      db.qRCode.count({
        where: {
          type: 'STATIC',
        },
      }),

      // Total scans
      db.qRScan.count(),

      // Get all dynamic QR codes with their scan counts
      db.qRCode.findMany({
        where: {
          type: 'DYNAMIC',
        },
        include: {
          _count: {
            select: {
              scans: true,
            },
          },
        },
      }),

      // Active QR codes (scanned in last 30 days)
      db.qRCode.findMany({
        where: {
          scans: {
            some: {
              ts: {
                gte: thirtyDaysAgo,
              },
            },
          },
        },
        distinct: ['id'],
      }),

      // Newsletter subscribers
      db.newsletterSubscription.count({
        where: {
          status: 'subscribed',
        },
      }),
    ]);

    // Calculate dynamic QR scans
    const dynamicQRScans = dynamicQRCodesWithScans.reduce(
      (total, qr) => total + qr._count.scans,
      0
    );

    // Calculate average scans per dynamic QR
    const avgScansPerDynamicQR =
      dynamicQRCodes > 0 ? (dynamicQRScans / dynamicQRCodes).toFixed(1) : '0';

    // Get top 5 most scanned QR codes
    const topQRCodes = await db.qRCode.findMany({
      take: 5,
      include: {
        _count: {
          select: {
            scans: true,
          },
        },
        user: {
          select: {
            email: true,
            name: true,
          },
        },
      },
      orderBy: {
        scans: {
          _count: 'desc',
        },
      },
    });

    // Get recent users
    const recentUsers = await db.user.findMany({
      take: 5,
      orderBy: {
        createdAt: 'desc',
      },
      select: {
        email: true,
        name: true,
        plan: true,
        createdAt: true,
      },
    });

    return NextResponse.json({
      users: {
        total: totalUsers,
        premium: premiumUsers,
        newThisWeek: newUsersThisWeek,
        newThisMonth: newUsersThisMonth,
        recent: recentUsers,
      },
      qrCodes: {
        total: totalQRCodes,
        dynamic: dynamicQRCodes,
        static: staticQRCodes,
        active: activeQRCodes.length,
      },
      scans: {
        total: totalScans,
        dynamicOnly: dynamicQRScans,
        avgPerDynamicQR: avgScansPerDynamicQR,
      },
      newsletter: {
        subscribers: newsletterSubscribers,
      },
      topQRCodes: topQRCodes.map((qr) => ({
        id: qr.id,
        title: qr.title,
        type: qr.type,
        scans: qr._count.scans,
        owner: qr.user.name || qr.user.email,
        createdAt: qr.createdAt,
      })),
    });
  } catch (error) {
    console.error('Error fetching admin stats:', error);
    return NextResponse.json(
      { error: 'Failed to fetch statistics' },
      { status: 500 }
    );
  }
}