/**
 * Subdomain-aware URL helpers for rSpace navigation.
 *
 * Canonical URL pattern: {space}.rspace.online/{moduleId}
 * Bare domain pattern:   rspace.online/{moduleId}  (implicitly demo space)
 * 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])
	);
}

/** Detect if the current page is on the bare rspace.online domain (no subdomain) */
export function isBareDomain(): boolean {
	const host = window.location.host.split(":")[0];
	return host === "rspace.online" || host === "www.rspace.online";
}

/** Get the current space from subdomain or path */
export function getCurrentSpace(): string {
	if (isSubdomain()) {
		return window.location.host.split(":")[0].split(".")[0];
	}
	// Bare domain: space is implicit (demo by default, until auto-provision)
	if (isBareDomain()) {
		return "demo";
	}
	// Path-based (localhost): /{space}/{moduleId}
	const pathParts = window.location.pathname.split("/").filter(Boolean);
	return pathParts[0] || "demo";
}

/** Get the current module from the path (works for subdomain, bare domain, and path routing) */
export function getCurrentModule(): string {
	const parts = window.location.pathname.split("/").filter(Boolean);
	if (isSubdomain()) {
		return parts[0] || "rspace";
	}
	// Bare domain: path is /{moduleId}
	if (isBareDomain()) {
		return parts[0] || "rspace";
	}
	// Path-based (localhost): /{space}/{moduleId}
	return parts[1] || "rspace";
}

/**
 * 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 (rspace.online): stays on bare domain as /{moduleId}
 * for default (demo) space, subdomain for explicit spaces.
 * On 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)
	if (isBareDomain()) {
		// Default space → stay on bare domain: /{moduleId}
		if (space === "demo") {
			return `/${moduleId}`;
		}
		// Explicit space → switch to subdomain
		return `${window.location.protocol}//${space}.rspace.online/${moduleId}`;
	}

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