import { NextRequest, NextResponse } from "next/server";
import { db, eq, waitlist } from "@opencut/db";
import { checkBotId } from "botid/server";
import { nanoid } from "nanoid";
import { waitlistRateLimit } from "@/lib/rate-limit";
import { z } from "zod";
import { env } from "@/env";
import { cookies } from "next/headers";
import crypto from "crypto";

const waitlistSchema = z.object({
	email: z.string().email("Invalid email format").min(1, "Email is required"),
});

const CSRF_TOKEN_NAME = "waitlist-csrf";
const TOKEN_EXPIRY = 60 * 60 * 1000;

async function validateCSRFToken(request: NextRequest): Promise<boolean> {
	const clientToken = request.headers.get("x-csrf-token");
	if (!clientToken) return false;

	const cookieStore = await cookies();
	const cookieValue = cookieStore.get(CSRF_TOKEN_NAME)?.value;
	if (!cookieValue) return false;

	const [token, timestamp, signature] = cookieValue.split(":");
	if (!token || !timestamp || !signature) return false;

	if (clientToken !== token) return false;

	const now = Date.now();
	const tokenTime = parseInt(timestamp);
	if (now - tokenTime > TOKEN_EXPIRY) return false;

	const expectedSignature = crypto
		.createHmac("sha256", env.BETTER_AUTH_SECRET)
		.update(`${token}:${timestamp}`)
		.digest("hex");

	return signature === expectedSignature;
}

export async function POST(request: NextRequest) {
	const verification = await checkBotId();

	if (verification.isBot) {
		return NextResponse.json({ error: "Access denied" }, { status: 403 });
	}

	const identifier = request.headers.get("x-forwarded-for") ?? "127.0.0.1";
	const { success } = await waitlistRateLimit.limit(identifier);

	if (!success) {
		return NextResponse.json(
			{ error: "Too many requests. Please try again later." },
			{ status: 429 },
		);
	}
	const isValidToken = await validateCSRFToken(request);
	if (!isValidToken) {
		return NextResponse.json(
			{ error: "Invalid security token" },
			{ status: 403 },
		);
	}

	try {
		const body = await request.json();
		const { email } = waitlistSchema.parse(body);

		const existingEmail = await db
			.select()
			.from(waitlist)
			.where(eq(waitlist.email, email.toLowerCase()))
			.limit(1);

		if (existingEmail.length > 0) {
			return NextResponse.json(
				{ error: "Email already registered" },
				{ status: 409 },
			);
		}

		await db.insert(waitlist).values({
			id: nanoid(),
			email: email.toLowerCase(),
		});

		return NextResponse.json(
			{ message: "Successfully joined waitlist!" },
			{ status: 201 },
		);
	} catch (error) {
		if (error instanceof z.ZodError) {
			const firstError = error.errors[0];
			return NextResponse.json({ error: firstError.message }, { status: 400 });
		}

		console.error("Waitlist signup error:", error);
		return NextResponse.json(
			{ error: "Internal server error" },
			{ status: 500 },
		);
	}
}