// PATCH /api/profile/:userId — applies a partial update to a user profile.

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

import { db } from "./db";

export interface ProfilePatch {

  displayName?: string;

  bio?: string;

}

/**

 * Applies a partial update to the specified user profile.

 * Only fields explicitly included in the request body should be updated.

 * Fields absent from the request must retain their current stored values.

 */

export async function patchProfile(

  req: Request,

  res: Response,

): Promise<void> {

  const { userId } = req.params;

  const { displayName, bio } = req.body as ProfilePatch;

  const profile = await db.profiles.findById(userId);

  if (!profile) {

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

    return;

  }

  await db.profiles.update(userId, { displayName, bio });

  res.status(200).json({ updated: true });

}