import { NextRequest, NextResponse } from 'next/server';
import { auth } from '@/auth';
import { getUserInfo, getEffectiveTier } from '@/lib/entitlements';
import { stripe } from '@/lib/stripe';
import type Stripe from 'stripe';
import { priceIdToTier, getDynamicPrices, isBillingEnabled } from '@/lib/billing/stripe-prices';

export const dynamic = 'force-dynamic';

export async function GET(req: NextRequest) {
  const session = await auth();
  if (!session?.user?.id) {
    return NextResponse.json({ error: 'Unauthorized' }, { status: 401 });
  }

  const userId = session.user.id;
  const { prisma } = await import('@/lib/prisma');
  
  const sessionId = req.nextUrl.searchParams.get('session_id');

  if (sessionId && sessionId.startsWith('cs_')) {
    try {
      const checkoutSession = await stripe.checkout.sessions.retrieve(sessionId);
      if (checkoutSession.subscription && checkoutSession.status === 'complete') {
        const subId = typeof checkoutSession.subscription === 'string' 
          ? checkoutSession.subscription 
          : (checkoutSession.subscription as any).id;
          
        const sub = await stripe.subscriptions.retrieve(subId) as any;
        const priceId = sub.items.data[0].price.id;
        const tier = (await priceIdToTier(priceId)) || (checkoutSession.metadata?.tier as any) || 'PRO';

        const currentPeriodStartTimestamp = 
          sub.current_period_start ?? 
          sub.items?.data?.[0]?.current_period_start ?? 
          sub.start_date ?? 
          Math.floor(Date.now() / 1000);

        const currentPeriodEndTimestamp = 
          sub.current_period_end ?? 
          sub.items?.data?.[0]?.current_period_end ?? 
          (currentPeriodStartTimestamp + 30 * 24 * 3600);
        
        await prisma.subscription.upsert({
          where: { userId },
          update: {
            tier,
            status: 'ACTIVE',
            stripeCustomerId: checkoutSession.customer as string,
            stripeSubscriptionId: sub.id,
            stripePriceId: priceId,
            currentPeriodStart: new Date(currentPeriodStartTimestamp * 1000),
            currentPeriodEnd: new Date(currentPeriodEndTimestamp * 1000),
            canceledAt: sub.canceled_at ? new Date(sub.canceled_at * 1000) : null,
            cancelAtPeriodEnd: sub.cancel_at_period_end,
          },
          create: {
            userId,
            tier,
            status: 'ACTIVE',
            stripeCustomerId: checkoutSession.customer as string,
            stripeSubscriptionId: sub.id,
            stripePriceId: priceId,
            currentPeriodStart: new Date(currentPeriodStartTimestamp * 1000),
            currentPeriodEnd: new Date(currentPeriodEndTimestamp * 1000),
          },
        });
      }
    } catch (err) {
      console.error('[billing/status] Failed to sync Stripe session:', err);
    }
  }
  try {
    const { tier, status, currentPeriodEnd } = await getUserInfo(userId);
    const effectiveTier = await getEffectiveTier(userId);
    const subscription = await prisma.subscription.findUnique({ where: { userId } });
    const prices = await getDynamicPrices();
    const billingEnabled = await isBillingEnabled();

    return NextResponse.json({
      tier,
      effectiveTier,
      status,
      currentPeriodEnd: currentPeriodEnd ?? null,
      currentPeriodStart: subscription?.currentPeriodStart ?? null,
      cancelAtPeriodEnd: subscription?.cancelAtPeriodEnd ?? false,
      hasStripeSubscription: !!subscription?.stripeSubscriptionId,
      prices,
      billingEnabled,
    });
  } catch (error) {
    console.error('[billing/status]', error);
    return NextResponse.json({ error: 'Failed to fetch billing status' }, { status: 500 });
  }
}