import { NextRequest, NextResponse } from 'next/server';
import { auth } from '@/auth';
import { getUserInfo, getEffectiveTier } from '@/lib/entitlements';
import { stripe } from '@/lib/stripe';
import { getDynamicPrices, isBillingEnabled } from '@/lib/billing/stripe-prices';
import { syncSubscriptionFromStripe } from '@/lib/billing/sync-subscription-from-stripe';
import { shouldOfferSubscriptionTrial, SUBSCRIPTION_TRIAL_DAYS } from '@/lib/billing/trial';

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 { id: string }).id;
          
        const sub = await stripe.subscriptions.retrieve(subId);
        const syncUserId =
          (checkoutSession.metadata?.userId as string | undefined) ??
          (sub.metadata?.userId as string | undefined) ??
          userId;
        if (syncUserId === userId) {
          await syncSubscriptionFromStripe(sub, userId);
        }
      }
    } 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();
    const { getPackPublicPrices } = await import('@/lib/billing/credit-packs');
    const creditPacks = await getPackPublicPrices();

    // Si retour checkout pack : créditer au cas où le webhook n'a pas encore tourné
    if (sessionId && sessionId.startsWith('cs_')) {
      try {
        const checkoutSession = await stripe.checkout.sessions.retrieve(sessionId);
        if (
          checkoutSession.mode === 'payment' &&
          checkoutSession.status === 'complete' &&
          (checkoutSession.metadata?.type === 'credit_pack' || checkoutSession.metadata?.packId) &&
          checkoutSession.metadata?.userId === userId
        ) {
          const { addPurchasedCredits } = await import('@/lib/credits');
          const {
            getCreditPack,
            isCreditPackId,
          } = await import('@/lib/billing/credit-packs');
          const packId = checkoutSession.metadata?.packId;
          let credits = Number(checkoutSession.metadata?.credits ?? 0);
          if (packId && isCreditPackId(packId) && (!Number.isFinite(credits) || credits <= 0)) {
            credits = getCreditPack(packId).credits;
          }
          if (Number.isFinite(credits) && credits > 0) {
            await addPurchasedCredits(userId, credits, {
              stripeSessionId: checkoutSession.id,
              packId: packId ?? null,
              type: 'credit_pack',
              source: 'billing_status_sync',
            });
          }
        }
      } catch (packSyncErr) {
        console.error('[billing/status] pack sync failed:', packSyncErr);
      }
    }

    const trialEligible = await shouldOfferSubscriptionTrial(userId);

    return NextResponse.json({
      tier,
      effectiveTier,
      status,
      currentPeriodEnd: currentPeriodEnd ?? null,
      currentPeriodStart: subscription?.currentPeriodStart ?? null,
      cancelAtPeriodEnd: subscription?.cancelAtPeriodEnd ?? false,
      hasStripeSubscription: !!subscription?.stripeSubscriptionId,
      trialEndsAt: subscription?.trialEndsAt?.toISOString() ?? null,
      trialEligible,
      trialDays: trialEligible ? SUBSCRIPTION_TRIAL_DAYS : 0,
      prices,
      creditPacks,
      billingEnabled,
    });
  } catch (error) {
    console.error('[billing/status]', error);
    return NextResponse.json({ error: 'Failed to fetch billing status' }, { status: 500 });
  }
}