/**
 * Subdomain-aware URL helpers for rSpace navigation.
 *
 * Canonical URL pattern: {space}.rspace.online/{moduleId}
 * Fallback (localhost):  /{space}/{moduleId}
 */

const RESERVED_SUBDOMAINS = ["www", "rspace", "create", "new", "start", "auth"];

/** Detect if the current page is on a {space}.rspace.online subdomain */
export function isSubdomain(): boolean {
	const parts = window.location.host.split(":")[0].split(".");
	return (
		parts.length >= 3 &&
		parts.slice(-2).join(".") === "rspace.online" &&
		!RESERVED_SUBDOMAINS.includes(parts[0])
	);
}

/** Get the current space from subdomain or path */
export function getCurrentSpace(): string {
	const hostParts = window.location.host.split(":")[0].split(".");
	if (
		hostParts.length >= 3 &&
		hostParts.slice(-2).join(".") === "rspace.online" &&
		!RESERVED_SUBDOMAINS.includes(hostParts[0])
	) {
		return hostParts[0];
	}
	const pathParts = window.location.pathname.split("/").filter(Boolean);
	return pathParts[0] || "demo";
}

/** Get the current module from the path (works for both subdomain and path routing) */
export function getCurrentModule(): string {
	const parts = window.location.pathname.split("/").filter(Boolean);
	if (isSubdomain()) {
		return parts[0] || "canvas";
	}
	return parts[1] || "canvas";
}

/**
 * Generate a navigation URL for a given space + module.
 *
 * On subdomains: same-space links use /{moduleId}, cross-space links
 * switch the subdomain to {newSpace}.rspace.online/{moduleId}.
 * On bare domain or localhost: uses /{space}/{moduleId}.
 */
export function rspaceNavUrl(space: string, moduleId: string): string {
	const hostParts = window.location.host.split(":")[0].split(".");
	const onSubdomain =
		hostParts.length >= 3 &&
		hostParts.slice(-2).join(".") === "rspace.online" &&
		!RESERVED_SUBDOMAINS.includes(hostParts[0]);

	if (onSubdomain) {
		// Same space → just change the path
		if (hostParts[0] === space) {
			return `/${moduleId}`;
		}
		// Different space → switch subdomain
		const baseDomain = hostParts.slice(-2).join(".");
		return `${window.location.protocol}//${space}.${baseDomain}/${moduleId}`;
	}

	// Bare domain (rspace.online) or localhost → use /{space}/{moduleId}
	const onRspace =
		window.location.host.includes("rspace.online") &&
		!window.location.host.startsWith("www");
	if (onRspace) {
		// Prefer subdomain routing
		return `${window.location.protocol}//${space}.rspace.online/${moduleId}`;
	}

	// Localhost/dev
	return `/${space}/${moduleId}`;
}