const TEN_MINUTES_MS = 10 * 60 * 1000;

/**
 * Build the data object expected by the stub module.
 *
 * @param {object}  metadata        Raw MPRIS Metadata dict
 * @param {string}  playbackStatus  "Playing" | "Paused" | "Stopped"
 * @param {number}  positionUs      Current position in microseconds
 * @param {string}  playedTime      ISO timestamp of when the track was first seen
 * @returns {object|null}           Formatted data, or null if metadata is missing
 */
export function formatTrackData(metadata, playbackStatus, positionUs, playedTime) {
	const title = metaString(metadata, "xesam:title");
	if (!title) return null;

	const artistList = metaStringArray(metadata, "xesam:artist");
	const album = metaString(metadata, "xesam:album") ?? "";
	const artUrl = metaString(metadata, "mpris:artUrl") ?? "";
	const lengthUs = metaInt(metadata, "mpris:length") ?? 0;

	const now = Date.now();
	const positionMs = Math.floor(positionUs / 1000);
	const lengthMs = Math.floor(lengthUs / 1000);

	let expiry;
	if (playbackStatus === "Paused") {
		expiry = new Date(now + TEN_MINUTES_MS).toISOString();
	} else {
		const remainingMs = Math.max(0, lengthMs - positionMs);
		expiry = new Date(now + remainingMs).toISOString();
	}

	return {
		artists: artistList.map((name) => ({ artistName: name })),
		trackName: title,
		playbackStatus,
		playedTime,
		releaseName: album,
		artUrl,
		duration: Math.round(lengthMs / 1000),
		expiry,
	};
}

// --- helpers for reading dbus-next Variant values ----

function metaString(metadata, key) {
	const v = metadata[key];
	if (!v) return undefined;
	return typeof v.value === "string" ? v.value : String(v.value);
}

function metaStringArray(metadata, key) {
	const v = metadata[key];
	if (!v) return [];
	const arr = v.value;
	return Array.isArray(arr) ? arr.map(String) : [String(arr)];
}

function metaInt(metadata, key) {
	const v = metadata[key];
	if (!v) return undefined;
	const n = Number(v.value);
	return Number.isFinite(n) ? n : undefined;
}