falah-mobile/src/app/api/webhooks/polar/route.ts

import { NextRequest, NextResponse } from "next/server";
import { prisma } from "@/lib/prisma";

/**
 * Polar.sh webhook handler.
 *
 * In production, verify the webhook signature using Polar's webhook secret.
 * For development, we accept a direct ?userId=&tier= fallback for testing.
 */

export async function POST(req: NextRequest) {
  try {
    // Check for direct fallback query params (dev/testing)
    const url = new URL(req.url);
    const directUserId = url.searchParams.get("userId");
    const directTier = url.searchParams.get("tier");

    if (directUserId && directTier) {
      return handleDirectUpgrade(directUserId, directTier);
    }

    // Production path: Parse Polar webhook event
    const body = await req.json();
    const event = body.type || body.event;

    if (!event) {
      return NextResponse.json(
        { error: "Missing event type" },
        { status: 400 }
      );
    }

    // Handle checkout.completed event
    if (
      event === "checkout.completed" ||
      event === "checkout.updated"
    ) {
      const checkout = body.data?.checkout || body.data;
      if (!checkout) {
        return NextResponse.json(
          { error: "Missing checkout data" },
          { status: 400 }
        );
      }

      const userId = checkout.metadata?.userId;
      const priceId = checkout.product?.priceId ||
                       checkout.productPrice?.id ||
                       checkout.metadata?.priceId;

      if (!userId) {
        return NextResponse.json(
          { error: "Missing userId in metadata" },
          { status: 400 }
        );
      }

      // Determine tier from priceId or product metadata
      let tier: "premium" | "pro" = "premium";
      if (priceId?.includes("pro") || checkout.metadata?.tier === "pro") {
        tier = "pro";
      }

      return applyUpgrade(userId, tier);
    }

    // Acknowledge other events silently
    return NextResponse.json({ received: true });
  } catch (error) {
    console.error("Polar webhook error:", error);
    return NextResponse.json(
      { error: "Webhook processing failed" },
      { status: 500 }
    );
  }
}

async function handleDirectUpgrade(userId: string, tier: string) {
  if (tier !== "premium" && tier !== "pro") {
    return NextResponse.json(
      { error: "Invalid tier. Must be 'premium' or 'pro'." },
      { status: 400 }
    );
  }
  return applyUpgrade(userId, tier as "premium" | "pro");
}

async function applyUpgrade(userId: string, tier: "premium" | "pro") {
  const user = await prisma.user.findUnique({ where: { id: userId } });
  if (!user) {
    return NextResponse.json({ error: "User not found" }, { status: 404 });
  }

  const trialEndsAt = new Date();
  trialEndsAt.setDate(trialEndsAt.getDate() + 7);

  const updateData: Record<string, unknown> = {
    trialEndsAt,
  };

  if (tier === "pro") {
    updateData.isPro = true;
    updateData.isPremium = false; // Pro supersedes Premium
  } else {
    updateData.isPremium = true;
  }

  await prisma.user.update({
    where: { id: userId },
    data: updateData,
  });

  return NextResponse.json({
    success: true,
    tier,
    trialEndsAt,
  });
}