// Maps a system-mail message (lifecycle hook) to its i18n title key.
// Kept as a typed helper so the thread-list and detail panes pick the
// same title even when the body templates evolve.

import type { TranslationKey } from "$lib/i18n/index.svelte";
import type { MailMessage } from "../../../api/diplomail";

const KEYWORDS: Array<{ test: RegExp; key: TranslationKey }> = [
	{ test: /game[._ ]paused/i, key: "game.mail.system.game_paused.title" },
	{ test: /game[._ ]cancelled|cancelled/i, key: "game.mail.system.game_cancelled.title" },
	{ test: /membership[._ ]removed|kicked/i, key: "game.mail.system.membership_removed.title" },
	{ test: /membership[._ ]blocked|blocked/i, key: "game.mail.system.membership_blocked.title" },
];

/**
 * systemTitleKey returns the localised title key for a system mail
 * row. The lobby renders these messages through templated subjects;
 * the UI matches on the subject to pick a canonical title regardless
 * of language. Falls back to a generic system-mail title when no
 * pattern matches.
 */
export function systemTitleKey(message: MailMessage): TranslationKey {
	const subject = message.subject ?? "";
	for (const { test, key } of KEYWORDS) {
		if (test.test(subject)) {
			return key;
		}
	}
	return "game.mail.system.generic.title";
}