import type { FastifyInstance, FastifyRequest, FastifyReply } from 'fastify';
import fp from 'fastify-plugin';
import { eq } from 'drizzle-orm';
import { subscriptions } from '../db/schema/subscriptions.js';
import { forbidden } from '../utils/errors.js';

export type SubscriptionInfo = {
  plan: 'free' | 'pro';
  status: 'active' | 'trialing' | 'cancelled' | 'expired';
  isPro: boolean;
  expiresAt: Date | null;
};

declare module 'fastify' {
  interface FastifyRequest {
    subscription?: SubscriptionInfo | null;
  }
  interface FastifyInstance {
    withSubscription: (req: FastifyRequest, reply: FastifyReply) => Promise<void>;
    requirePro: (req: FastifyRequest, reply: FastifyReply) => Promise<void>;
  }
}

async function loadSubscription(db: FastifyInstance['db'], userId: string): Promise<SubscriptionInfo | null> {
  const [sub] = await db
    .select()
    .from(subscriptions)
    .where(eq(subscriptions.userId, userId))
    .limit(1);

  if (!sub) return null;

  const now = new Date();
  const isExpired = sub.expiresAt && sub.expiresAt < now;
  const isPro =
    sub.plan === 'pro' &&
    (sub.status === 'active' || sub.status === 'trialing') &&
    !isExpired;

  return {
    plan: sub.plan as 'free' | 'pro',
    status: sub.status as SubscriptionInfo['status'],
    isPro,
    expiresAt: sub.expiresAt,
  };
}

export async function requirePro(req: FastifyRequest, _reply: FastifyReply): Promise<void> {
  const sub = req.subscription;

  if (!sub?.isPro) {
    throw forbidden('Pro subscription required');
  }
}

const subscriptionPlugin = async (app: FastifyInstance) => {
  app.decorateRequest('subscription', undefined);

  app.decorate('withSubscription', async (req: FastifyRequest, _reply: FastifyReply) => {
    if (!req.user?.id) return;
    const sub = await loadSubscription(app.db, req.user.id);
    req.subscription = sub;
  });

  app.decorate('requirePro', requirePro);
};

export default fp(subscriptionPlugin, {
  name: 'subscription',
  dependencies: ['database', 'auth'],
});