"use server";

import { revalidateTag } from "next/cache";
import { z } from "zod";
import { PERMS } from "@/lib/permission-slugs";
import { prisma } from "@/lib/prisma";
import { adminAction } from "@/lib/safe-action";
import { actionOk } from "@/lib/safe-action-shared";

const toggleWatchSchema = z.object({
	targetUserId: z.coerce.number().int().positive(),
	reason: z.string().max(255).optional(),
});

/**
 * Toggle a watch entry for the calling staff on the given target user.
 * If a row already exists it's removed; otherwise it's created with the
 * provided reason (defaulting to empty). Returns the resulting state so
 * the UI can flip the badge without re-fetching.
 */
export const toggleUserWatch = adminAction(
	{ permission: PERMS.USERS_VIEW, schema: toggleWatchSchema },
	async (ctx) => {
		const staffId = ctx.session.user.id;
		const { targetUserId, reason } = ctx.data;

		const existing = await prisma.userWatch.findUnique({
			where: { staffId_targetUserId: { staffId, targetUserId } },
		});

		if (existing) {
			await prisma.userWatch.delete({ where: { id: existing.id } });
			revalidateTag(`user-watch:${staffId}`, { expire: 0 });
			return actionOk({ watching: false });
		}

		await prisma.userWatch.create({
			data: { staffId, targetUserId, reason: reason ?? "" },
		});
		revalidateTag(`user-watch:${staffId}`, { expire: 0 });
		return actionOk({ watching: true });
	},
);