import type Stripe from 'stripe';
import { prisma } from '@/lib/prisma';
import { priceIdToTier } from '@/lib/billing/stripe-prices';
import { SubscriptionStatus, SubscriptionTier } from '@prisma/client';

function mapStripeStatus(stripeStatus: Stripe.Subscription.Status): SubscriptionStatus {
  switch (stripeStatus) {
    case 'active':
      return SubscriptionStatus.ACTIVE;
    case 'trialing':
      return SubscriptionStatus.TRIALING;
    case 'past_due':
      return SubscriptionStatus.PAST_DUE;
    case 'canceled':
    case 'unpaid':
      return SubscriptionStatus.CANCELED;
    case 'incomplete':
    case 'incomplete_expired':
      return SubscriptionStatus.INACTIVE;
    default:
      return SubscriptionStatus.INACTIVE;
  }
}

export async function syncSubscriptionFromStripe(
  subscription: Stripe.Subscription,
  userId: string,
): Promise<void> {
  const priceId = subscription.items.data[0]?.price?.id ?? null;
  const resolvedTier = priceId ? await priceIdToTier(priceId) : null;

  const tierFromMetadata =
    (subscription.metadata?.tier as string | undefined) ??
    (subscription.metadata?.tier as string | undefined);

  let tier: SubscriptionTier;
  if (resolvedTier) {
    tier = resolvedTier as SubscriptionTier;
  } else if (tierFromMetadata === 'PRO' || tierFromMetadata === 'BUSINESS' || tierFromMetadata === 'ENTERPRISE') {
    tier = tierFromMetadata as SubscriptionTier;
  } else {
    tier = SubscriptionTier.BASIC;
  }

  const status = mapStripeStatus(subscription.status);

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

  const currentPeriodEndTimestamp = 
    (subscription as any).current_period_end ?? 
    (subscription as any).items?.data?.[0]?.current_period_end ?? 
    (currentPeriodStartTimestamp + 30 * 24 * 3600);

  const currentPeriodStart = new Date(currentPeriodStartTimestamp * 1000);
  const currentPeriodEnd = new Date(currentPeriodEndTimestamp * 1000);

  await prisma.subscription.upsert({
    where: { stripeSubscriptionId: subscription.id },
    update: {
      tier,
      status,
      stripeCustomerId: typeof subscription.customer === 'string' ? subscription.customer : subscription.customer.id,
      stripePriceId: priceId,
      currentPeriodStart,
      currentPeriodEnd,
      cancelAtPeriodEnd: subscription.cancel_at_period_end,
      canceledAt: subscription.canceled_at ? new Date(subscription.canceled_at * 1000) : null,
      trialEndsAt: subscription.trial_end ? new Date(subscription.trial_end * 1000) : null,
      updatedAt: new Date(),
    },
    create: {
      userId,
      tier,
      status,
      stripeCustomerId: typeof subscription.customer === 'string' ? subscription.customer : subscription.customer.id,
      stripeSubscriptionId: subscription.id,
      stripePriceId: priceId,
      currentPeriodStart,
      currentPeriodEnd,
      cancelAtPeriodEnd: subscription.cancel_at_period_end,
      canceledAt: subscription.canceled_at ? new Date(subscription.canceled_at * 1000) : null,
      trialEndsAt: subscription.trial_end ? new Date(subscription.trial_end * 1000) : null,
    },
  });
}

export async function handleSubscriptionDeleted(subscription: Stripe.Subscription): Promise<void> {
  const existing = await prisma.subscription.findUnique({
    where: { stripeSubscriptionId: subscription.id },
  });
  if (!existing) return;

  await prisma.subscription.update({
    where: { stripeSubscriptionId: subscription.id },
    data: {
      status: SubscriptionStatus.CANCELED,
      cancelAtPeriodEnd: false,
      canceledAt: subscription.canceled_at ? new Date(subscription.canceled_at * 1000) : new Date(),
      updatedAt: new Date(),
    },
  });
}

export async function resolveUserIdFromStripeEvent(
  subscription: Stripe.Subscription,
): Promise<string | null> {
  const metaUserId = subscription.metadata?.userId as string | undefined;
  if (metaUserId) return metaUserId;

  const customerId = typeof subscription.customer === 'string'
    ? subscription.customer
    : subscription.customer.id;

  const existing = await prisma.subscription.findFirst({
    where: { stripeCustomerId: customerId },
    select: { userId: true },
  });

  return existing?.userId ?? null;
}