// Formatiert Sekunden als m:ss. Bei ungültigem Wert wird ein Platzhalter angezeigt.
function formatTime(seconds) {
	if (typeof seconds !== "number" || Number.isNaN(seconds)) {
		return "-";
	}

	const minutes = Math.floor(seconds / 60);
	const remainingSeconds = Math.floor(seconds % 60);
	return `${minutes}:${String(remainingSeconds).padStart(2, "0")}`;
}

// Liefert den aktuellen Login-Kontext, falls Auth global verfügbar ist.
function getLoggedInAuth() {
	if (!window.AppAuth || typeof window.AppAuth.getAuth !== "function") {
		return null;
	}

	const auth = window.AppAuth.getAuth();
	if (!auth || !auth.username) {
		return null;
	}

	return auth;
}

// Vereinheitlicht Benutzernamen für robuste Vergleiche (z. B. Groß-/Kleinschreibung).
function normalizeUsername(username) {
	return String(username ?? "").trim().toLowerCase();
}

function getLoggedInUsername() {
	const auth = getLoggedInAuth();
	if (!auth) {
		return null;
	}

	return normalizeUsername(auth.username);
}

// Nutzt den vom Backend gelieferten Rang, fallback auf die aktuelle Listenposition.
function getDisplayedRank(entry, index) {
	const place = Number(entry?.place);
	if (!Number.isNaN(place) && place > 0) {
		return place;
	}

	return index + 1;
}

// Bestes Ergebnis: höchste Punktzahl, bei Gleichstand die geringere Zeit.
function getBestScoreEntry(entries) {
	return entries
		.slice()
		.sort((a, b) => {
			const scoreA = Number(a.score ?? 0);
			const scoreB = Number(b.score ?? 0);
			if (scoreB !== scoreA) {
				return scoreB - scoreA;
			}

			const timeA = Number(a.time ?? Number.MAX_SAFE_INTEGER);
			const timeB = Number(b.time ?? Number.MAX_SAFE_INTEGER);
			return timeA - timeB;
		})[0] ?? null;
}

async function getCurrentUserLeaderboardEntry(username) {
	if (!window.ScoreService || !username) {
		return null;
	}

	const scoreService = new window.ScoreService(window.config);
	const result = await scoreService.getScoreByName(username);

	if (!result.ok || !Array.isArray(result.body) || result.body.length === 0) {
		return null;
	}

	return getBestScoreEntry(result.body);
}

// Rendert die Top-Liste und markiert den eingeloggten Nutzer visuell.
function renderLeaderboard(entries, extraUserEntry = null) {
	const tableBody = document.getElementById("leaderboard-body");
	if (!tableBody) {
		return;
	}

	const loggedInUsername = getLoggedInUsername();

	tableBody.innerHTML = "";

	entries.forEach((entry, index) => {
		const row = document.createElement("tr");
		const rowUsername = normalizeUsername(entry.username);

		if (loggedInUsername && rowUsername === loggedInUsername) {
			row.classList.add("leaderboard-row-current-user");
		}

		row.innerHTML = `
			<td>${getDisplayedRank(entry, index)}</td>
			<td>${entry.username ?? "-"}</td>
			<td>${formatTime(entry.time)} min</td>
			<td>${entry.score ?? "-"}</td>
		`;

		tableBody.appendChild(row);
	});

	if (extraUserEntry) {
		// Trennt Top-10 und eigenen Eintrag optisch, wenn der Nutzer nicht in den Top-10 ist.
		const spacerRow = document.createElement("tr");
		spacerRow.classList.add("leaderboard-row-gap");
		spacerRow.innerHTML = '<td colspan="4"></td>';
		tableBody.appendChild(spacerRow);

		const userRow = document.createElement("tr");
		userRow.classList.add("leaderboard-row-current-user");
		userRow.classList.add("leaderboard-row-current-user-extra");
		userRow.innerHTML = `
			<td>${getDisplayedRank(extraUserEntry, 0)}</td>
			<td>${extraUserEntry.username ?? "-"}</td>
			<td>${formatTime(extraUserEntry.time)} min</td>
			<td>${extraUserEntry.score ?? "-"}</td>
		`;

		tableBody.appendChild(userRow);
	}
}

async function loadTopTenLeaderboard() {
	const leaderboardService = new window.LeaderboardService(window.config);
	const result = await leaderboardService.getLeaderboard(0, 10);

	if (!result.ok || !Array.isArray(result.body)) {
		renderLeaderboard([]);
		return;
	}

	const auth = getLoggedInAuth();
	let extraUserEntry = null;

	if (auth && auth.username) {
		const loggedInUsername = normalizeUsername(auth.username);
		// Falls der Nutzer nicht in den Top-10 erscheint, wird sein bestes Ergebnis separat gezeigt.
		const isInTopTen = result.body.some(
			(entry) => normalizeUsername(entry.username) === loggedInUsername,
		);

		if (!isInTopTen) {
			extraUserEntry = await getCurrentUserLeaderboardEntry(auth.username);
		}
	}

	renderLeaderboard(result.body, extraUserEntry);
}

window.initLeaderboardPage = function initLeaderboardPage() {
	loadTopTenLeaderboard().catch((error) => {
		console.error("Fehler beim Laden des Leaderboards:", error);
		renderLeaderboard([]);
	});
};