import { NextRequest, NextResponse } from "next/server";
import Stripe from "stripe";
import { eq } from "drizzle-orm";

import { getStripe } from "@/lib/stripe/service";
import { getUserFromSession } from "@/lib/auth/get-user";
import { db } from "@/lib/db";
import { subscriptions } from "@/lib/schema";

const stripe = getStripe();

const SUBSCRIPTION_PRICE_ID = process.env.STRIPE_SUBSCRIPTION_PRICE_ID!;
const ORIGIN = process.env.NEXT_PUBLIC_APP_URL || "http://localhost:3000";

export async function POST(req: NextRequest) {
  try {
    console.log("💳 [SUBSCRIPTION CHECKOUT] Request received");

    // --------------------------------------------------
    // 1️⃣ Get authenticated user
    // --------------------------------------------------
    const user = await getUserFromSession();
    if (!user) {
      console.error("❌ [SUBSCRIPTION CHECKOUT] Unauthorized");
      return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
    }

    console.log("✅ [SUBSCRIPTION CHECKOUT] User authenticated:", user.id);

    // --------------------------------------------------
    // 2️⃣ Check if user already has an active subscription
    // --------------------------------------------------
    const [existingSubscription] = await db
      .select()
      .from(subscriptions)
      .where(eq(subscriptions.userId, user.id))
      .limit(1);

    if (existingSubscription?.status === "active") {
      console.log("⚠️  [SUBSCRIPTION CHECKOUT] User already has active subscription");
      return NextResponse.json(
        { error: "User already has an active subscription" },
        { status: 400 }
      );
    }

    console.log("✅ [SUBSCRIPTION CHECKOUT] No active subscription found");

    // --------------------------------------------------
    // 3️⃣ Create or get Stripe customer
    // --------------------------------------------------
    let stripeCustomerId = existingSubscription?.stripeCustomerId;

    if (!stripeCustomerId) {
      console.log("➕ [SUBSCRIPTION CHECKOUT] Creating Stripe customer");
      const customer = await stripe.customers.create({
        email: user.email,
        metadata: {
          userId: user.id,
        },
      });
      stripeCustomerId = customer.id;
      console.log("✅ [SUBSCRIPTION CHECKOUT] Stripe customer created:", stripeCustomerId);
    } else {
      console.log("✅ [SUBSCRIPTION CHECKOUT] Using existing Stripe customer:", stripeCustomerId);
    }

    // --------------------------------------------------
    // 4️⃣ Create checkout session
    // --------------------------------------------------
    console.log("📝 [SUBSCRIPTION CHECKOUT] Creating checkout session");

    const session = await stripe.checkout.sessions.create({
      customer: stripeCustomerId,
      mode: "subscription",
      line_items: [
        {
          price: SUBSCRIPTION_PRICE_ID,
          quantity: 1,
        },
      ],
      success_url: `${ORIGIN}/billing?success=true`,
      cancel_url: `${ORIGIN}/billing?canceled=true`,
      metadata: {
        userId: user.id,
      },
    });

    console.log("✅ [SUBSCRIPTION CHECKOUT] Checkout session created:", session.id);

    // --------------------------------------------------
    // 5️⃣ Store Stripe customer ID if this is first time
    // --------------------------------------------------
    if (!existingSubscription) {
      await db.insert(subscriptions).values({
        userId: user.id,
        stripeCustomerId,
        status: "trialing",
      });
      console.log("✅ [SUBSCRIPTION CHECKOUT] Subscription record created");
    }

    return NextResponse.json({ url: session.url });
  } catch (error: any) {
    console.error("❌ [SUBSCRIPTION CHECKOUT] Error:", error.message);
    return NextResponse.json(
      { error: error.message },
      { status: 500 }
    );
  }
}