export function humanFileSize(size: number) {
	if (size < 1024) return `${size} B`;
	const i = Math.min(4, Math.floor(Math.log(size) / Math.log(1024)));
	return `${(size / 1024 ** i).toFixed(2)} ${["B", "KiB", "MiB", "GiB", "TiB"][i]}`;
}

// TextDecoder-based UTF-8 check that works in both Bun and the browser.
export function isValidUTF8(buf: ArrayBuffer | ArrayBufferView): boolean {
	try {
		new TextDecoder("utf-8", { fatal: true }).decode(buf);
		return true;
	} catch (_e) {
		return false;
	}
}

const MODE_STORAGE_KEY = "zbin-mode";

// Enables the (HTML-disabled) client-side radio now that JS is running, applies
// the saved client/server preference (defaulting to client since JS is here),
// and persists changes. Shared by the index (encrypt_mode) and show (decrypt_mode) pages.
export function setupModeRadios(name: string) {
	const radios = document.querySelectorAll<HTMLInputElement>(
		`input[name="${name}"]`,
	);
	if (radios.length === 0) return;
	const saved = localStorage.getItem(MODE_STORAGE_KEY) ?? "client";
	for (const radio of radios) {
		radio.disabled = false;
		radio.checked = radio.value === saved;
		radio.addEventListener("change", () => {
			if (radio.checked) localStorage.setItem(MODE_STORAGE_KEY, radio.value);
		});
	}
}

export function getMode(name: string): string {
	const checked = document.querySelector<HTMLInputElement>(
		`input[name="${name}"]:checked`,
	);
	return checked?.value ?? "server";
}