import { NextRequest, NextResponse } from "next/server";
import { stripe } from "@/lib/stripe";
import { formatAmountForStripe } from "@/lib/stripe";
import { getPool } from "@/lib/database";

// Define pricing tiers
const PRICING_TIERS = {
  basic: {
    name: "Basic",
    amount: 9.99,
    storageLimit: 5,
  },
  standard: {
    name: "Standard",
    amount: 19.99,
    storageLimit: 20,
  },
  premium: {
    name: "Premium",
    amount: 39.99,
    storageLimit: 100,
  },
};

export async function POST(request: NextRequest) {
  try {
    // Check if Stripe is configured
    if (!process.env.STRIPE_SECRET_KEY) {
      console.error("Stripe secret key is not configured");
      return NextResponse.json(
        {
          error:
            "Stripe is not configured. Please add STRIPE_SECRET_KEY to your environment variables.",
        },
        { status: 500 }
      );
    }

    const { tier, userId } = await request.json();

    // Validate tier
    const selectedTier = PRICING_TIERS[tier as keyof typeof PRICING_TIERS];
    if (!selectedTier) {
      return NextResponse.json(
        { error: "Invalid tier selected" },
        { status: 400 }
      );
    }

    // Validate user
    if (!userId) {
      return NextResponse.json(
        { error: "User ID is required" },
        { status: 400 }
      );
    }

    // Check if user already has an active subscription
    const pool = getPool();
    const client = await pool.connect();

    try {
      const existingSub = await client.query(
        `SELECT id, status FROM subscriptions WHERE user_id = $1 AND status = 'ACTIVE'`,
        [userId]
      );

      if (existingSub.rows.length > 0) {
        return NextResponse.json(
          {
            error:
              "You already have an active subscription. Please cancel your current subscription before purchasing a new one.",
          },
          { status: 400 }
        );
      }
    } catch (dbError) {
      console.error("Database error checking existing subscription:", dbError);
      // Continue with payment creation even if check fails
    } finally {
      client.release();
    }

    // Get the base URL
    const origin = request.headers.get("origin") || "http://localhost:3000";

    // Create checkout session
    const session = await stripe.checkout.sessions.create({
      mode: "subscription",
      payment_method_types: ["card"],
      line_items: [
        {
          price_data: {
            currency: "usd",
            product_data: {
              name: selectedTier.name,
              description: `${selectedTier.storageLimit}GB storage limit`,
            },
            unit_amount: formatAmountForStripe(selectedTier.amount),
            recurring: {
              interval: "month",
            },
          },
          quantity: 1,
        },
      ],
      success_url: `${origin}/?success=true&session_id={CHECKOUT_SESSION_ID}`,
      cancel_url: `${origin}/?canceled=true`,
      metadata: {
        userId: userId,
        tier: tier,
      },
    });

    return NextResponse.json({ sessionId: session.id, url: session.url });
  } catch (error: any) {
    console.error("Error creating checkout session:", error);
    return NextResponse.json(
      { error: error.message || "Failed to create checkout session" },
      { status: 500 }
    );
  }
}