// Opens sub3's hosted /login and /checkout pages. Copy this file into any web app (React, Vue, Svelte, plain
// JS). Importing it does not touch `window`, so it is safe in server-side rendering.

// The checkout path for one item of a product: /checkout?product=acme/app&item=pro&units=12&user=0x…
// units: months for a tier (12 = a year, billed as 10), packs for a pack; ignored for lifetime items.
export function checkoutPath(product, item, { units, user } = {}) {
	const params = new URLSearchParams({ product, item });
	if (units) params.set('units', String(units));
	if (user) params.set('user', user); // who receives it; default is the paying wallet
	return `/checkout?${params}`;
}

// Opens `path` on the sub3 site and resolves with its result. Call it from a click handler (popup blockers).
// With { redirect: true } the page navigates instead and the result comes back in the URL fragment.
export function openSub3(path, { site, redirect = false } = {}) {
	const origin = new URL(site).origin;
	const url = new URL(path, origin);
	if (redirect) {
		url.searchParams.set('return', location.origin + location.pathname + location.search);
		location.assign(url.href);
		return new Promise(() => {}); // the page is leaving
	}
	return new Promise((resolve, reject) => {
		const popup = window.open(url.href, 'sub3', 'popup,width=440,height=760');
		if (!popup) return reject(new Error('The popup was blocked. Allow popups or use redirects.'));
		const timer = setInterval(() => popup.closed && stop(new Error('The window was closed')), 500);
		function stop(error, result) {
			clearInterval(timer);
			window.removeEventListener('message', receive);
			if (error) reject(error);
			else resolve(result);
		}
		function receive(event) {
			if (event.origin !== origin || event.source !== popup) return;
			const message = event.data ?? {};
			if (message.type === 'sub3:ready') popup.postMessage({ type: 'sub3:hello' }, origin);
			if (message.type === 'sub3:result') stop(null, message.result);
			if (message.type === 'sub3:cancel') stop(new Error(message.reason || 'Cancelled'));
		}
		window.addEventListener('message', receive);
	});
}

// After a redirect: the result from the URL fragment (#sub3=… or #sub3_error=…), or null. Clears the fragment.
export function readSub3Result() {
	const hash = new URLSearchParams(location.hash.slice(1));
	if (!hash.has('sub3') && !hash.has('sub3_error')) return null;
	history.replaceState(null, '', location.pathname + location.search);
	if (hash.has('sub3_error')) throw new Error(hash.get('sub3_error') || 'Cancelled');
	const base64 = hash.get('sub3').replace(/-/g, '+').replace(/_/g, '/');
	const bytes = Uint8Array.from(atob(base64), (c) => c.charCodeAt(0));
	return JSON.parse(new TextDecoder().decode(bytes));
}