import { NextRequest, NextResponse } from 'next/server';
import { appendExpiredCookies, getAuthCookieName } from '@/lib/cookieConfig';
import { getSessionUserId } from '@/lib/session';
import { db } from '@/lib/db';
import { stripe } from '@/lib/stripe';
import { csrfProtection } from '@/lib/csrf';
import { rateLimit, getClientIdentifier, RateLimits } from '@/lib/rateLimit';

export async function DELETE(request: NextRequest) {
  try {
    // CSRF Protection
    const csrfCheck = csrfProtection(request);
    if (!csrfCheck.valid) {
      return NextResponse.json(
        { error: csrfCheck.error },
        { status: 403 }
      );
    }

    const userId = getSessionUserId();

    // Rate Limiting (user-based)
    const clientId = userId || getClientIdentifier(request);
    const rateLimitResult = rateLimit(clientId, RateLimits.ACCOUNT_DELETE);

    if (!rateLimitResult.success) {
      return NextResponse.json(
        {
          error: 'Too many requests. Please try again later.',
          retryAfter: Math.ceil((rateLimitResult.reset - Date.now()) / 1000)
        },
        {
          status: 429,
          headers: {
            'X-RateLimit-Limit': rateLimitResult.limit.toString(),
            'X-RateLimit-Remaining': rateLimitResult.remaining.toString(),
            'X-RateLimit-Reset': rateLimitResult.reset.toString(),
          }
        }
      );
    }
    if (!userId) {
      return NextResponse.json({ error: 'Unauthorized' }, { status: 401 });
    }

    // Get user data including Stripe information
    const user = await db.user.findUnique({
      where: { id: userId },
      select: {
        id: true,
        stripeSubscriptionId: true,
        stripeCustomerId: true,
        plan: true,
      },
    });

    if (!user) {
      return NextResponse.json({ error: 'User not found' }, { status: 404 });
    }

    // Cancel Stripe subscription if user has one
    if (user.stripeSubscriptionId && user.plan !== 'FREE') {
      try {
        await stripe.subscriptions.cancel(user.stripeSubscriptionId);
      } catch (stripeError) {
        console.error('Error canceling Stripe subscription:', stripeError);
        // Continue with deletion even if Stripe cancellation fails
      }
    }

    // Delete user and all related data (cascading deletes should handle QR codes, scans, etc.)
    await db.user.delete({
      where: { id: userId },
    });

    // Clear auth cookie. Same reasoning as the logout route: both the host-only and the
    // domain-scoped variant have to be expired, otherwise the survivor keeps a session
    // pointing at a user row that no longer exists.
    const response = NextResponse.json({ success: true });
    appendExpiredCookies(response.headers, [{ name: getAuthCookieName(), httpOnly: true }]);

    return response;
  } catch (error) {
    console.error('Error deleting account:', error);
    return NextResponse.json(
      { error: 'Internal server error' },
      { status: 500 }
    );
  }
}