export interface Env {}
export interface ExecutionContext {}

function getMimeType(filename: string): string {
	const ext = filename.split('.').pop()?.toLowerCase();
	switch (ext) {
		case 'html': return 'text/html';
		case 'css': return 'text/css';
		case 'js': return 'application/javascript';
		case 'json': return 'application/json';
		case 'png': return 'image/png';
		case 'jpg':
		case 'jpeg': return 'image/jpeg';
		case 'gif': return 'image/gif';
		case 'svg': return 'image/svg+xml';
		case 'ico': return 'image/x-icon';
		case 'txt': return 'text/plain';
		case 'xml': return 'application/xml';
		case 'pdf': return 'application/pdf';
		case 'woff': return 'font/woff';
		case 'woff2': return 'font/woff2';
		case 'ttf': return 'font/ttf';
		case 'otf': return 'font/otf';
		case 'eot': return 'application/vnd.ms-fontobject';
		case 'md': return 'text/markdown';
		default: return 'application/octet-stream';
	}
}

export default {
	async fetch(request: Request, env: Env, ctx: ExecutionContext): Promise<Response> {
		const url = new URL(request.url);
		const userAgent = request.headers.get('User-Agent') || '';

		// 1. Check if request is coming from git
		if (userAgent.toLowerCase().includes('git')) {
            console.info("Redirecting to Chookspace, as useragent is Git");
			const redirectUrl = new URL(url.toString());
			redirectUrl.hostname = 'chookspace.com';
			return Response.redirect(redirectUrl.toString(), 302);
		}

		// Parse path: /(user)/(repo)/(file...)
		// Remove leading slash
		const path = url.pathname.slice(1);
		const parts = path.split('/');

		// Need at least user and repo
        // Otherwise, redirect to profile
		if (parts.length < 2) {
            console.info("Redirecting to Chookspace, not a long enough request");
			const redirectUrl = new URL(url.toString());
			redirectUrl.hostname = 'chookspace.com';
			return Response.redirect(redirectUrl.toString(), 302);
		}

		const user = parts[0];
		const repo = parts[1];
		let filePath = parts.slice(2).join('/');

		// 2. Handle index.html default
		if (!filePath || filePath === '') {
			filePath = 'index.html';
		} else if (filePath.endsWith('/')) {
			filePath += 'index.html';
		}

		// 3. Check if file exists at raw URL
		// URL structure: https://chookspace.com/(user)/(repo)/raw/branch/master/chookspace/(file)
		const rawBase = `https://chookspace.com/${user}/${repo}/raw/branch/master/chookspace`;
		const rawUrl = `${rawBase}/${filePath}`;

        console.log("Raw URL: ", rawUrl);

		try {
			// Prepare headers for the fetch request
			const fetchHeaders = new Headers(request.headers);
			fetchHeaders.set('User-Agent', 'Chsp-Worker-Proxy/1.0');

			const rawResponse = await fetch(rawUrl, {
				method: request.method,
				headers: fetchHeaders,
				redirect: 'follow'
			});
            console.info("Response from Chookspace was", rawResponse.status);

			// 4. If success (2xx), proxy it
			if (rawResponse.status >= 200 && rawResponse.status < 400) {
                console.info("Proxying page");
				const mimeType = getMimeType(filePath);
				
				// Create new headers to override Content-Type
				const newHeaders = new Headers(rawResponse.headers);
				newHeaders.set('Content-Type', mimeType);

				return new Response(rawResponse.body, {
					status: rawResponse.status,
					statusText: rawResponse.statusText,
					headers: newHeaders
				});
			}
		} catch (e) {
			// Fetch failed (network error etc), proceed to fallback
			console.error('Fetch error:', e);
		}

		// 5. If not found or error, redirect to chookspace site
        console.info("Redirecting to Chookspace normally...");
		const redirectUrl = new URL(url.toString());
		redirectUrl.hostname = 'chookspace.com';
		return Response.redirect(redirectUrl.toString(), 302);
	},
};