import { prisma } from '@/lib/prisma';
import { stripe } from '@/lib/stripe';

export interface CancelSubscriptionResult {
  success: boolean;
  error?: string;
}

/**
 * Cancels an active user subscription by setting its auto-renew (cancel_at_period_end) status to true
 * in Stripe and synchronizing the status back into the local Prisma database.
 * 
 * @param userId - Unique identifier of the user
 * @returns An object indicating the success or failure of the operation
 */
export async function cancelSubscription(userId: string): Promise<CancelSubscriptionResult> {
  if (!userId) {
    return { success: false, error: 'User ID is required' };
  }

  try {
    const subscription = await prisma.subscription.findUnique({
      where: { userId },
    });

    if (!subscription) {
      return { success: false, error: 'No active subscription found' };
    }

    if (subscription.stripeSubscriptionId) {
      // Direct call to Stripe API with period end cancellation set to true
      const updatedSub = await stripe.subscriptions.update(subscription.stripeSubscriptionId, {
        cancel_at_period_end: true,
      }) as any;

      // Local database synchronization
      await prisma.subscription.update({
        where: { userId },
        data: {
          cancelAtPeriodEnd: true,
          canceledAt: updatedSub.canceled_at ? new Date(updatedSub.canceled_at * 1000) : new Date(),
          currentPeriodEnd: updatedSub.current_period_end ? new Date(updatedSub.current_period_end * 1000) : subscription.currentPeriodEnd,
          updatedAt: new Date(),
        },
      });
    } else {
      // Mock mode cancel (e.g. for development / local bypass testing)
      await prisma.subscription.update({
        where: { userId },
        data: {
          cancelAtPeriodEnd: true,
          canceledAt: new Date(),
          updatedAt: new Date(),
        },
      });
    }

    return { success: true };
  } catch (error: any) {
    console.error('[cancelSubscription] Error processing cancellation:', error);
    return {
      success: false,
      error: error.message || 'Failed to cancel subscription',
    };
  }
}