// POST /api/billing/upgrade — promotes an account to a higher-tier plan.

import type { Request, Response } from "express";

import { db } from "./db";

import { billing } from "./billing";

export const PLAN_TIERS: Record<string, number> = {

  free: 0,

  starter: 1,

  pro: 2,

  enterprise: 3,

};

export async function handlePlanUpgrade(

  req: Request,

  res: Response,

): Promise<void> {

  const { userId, targetPlan } = req.body as {

    userId: string;

    targetPlan: string;

  };

  if (!userId || !targetPlan) {

    res.status(400).json({ error: "userId and targetPlan are required" });

    return;

  }

  if (!(targetPlan in PLAN_TIERS)) {

    res.status(400).json({ error: "Unknown plan" });

    return;

  }

  const account = await db.accounts.findById(userId);

  if (!account) {

    res.status(404).json({ error: "Account not found" });

    return;

  }

  await db.accounts.updatePlan(userId, targetPlan);

  const charge = await billing.chargeUpgrade(userId, account.plan, targetPlan);

  if (!charge.success) {

    res.status(402).json({ error: "Payment failed — please update your payment method" });

    return;

  }

  res.status(200).json({ plan: targetPlan, chargeId: charge.id });

}