import { SessionMiddleware } from "tabby-terminal";
import { Observable, Subject } from "rxjs";

const oscPrefix = Buffer.from("\x1b]");
const oscSuffix = Buffer.from("\x07");

function cleanTitle(raw: string): string {
	const t = (raw ?? "").trim();
	if (!t) return "Terminal";
	if (t.includes("/") || t.includes("\\")) {
		const segs = t.split(/[/\\]/).filter(s => s.length > 0);
		return segs.length ? segs[segs.length - 1] : t;
	}
	return t;
}

export default class OscNotifyMiddleware extends SessionMiddleware {
	getTitle: () => string;
	onClick: () => void;

	constructor(getTitle: () => string, onClick: () => void) {
		super();

		this.getTitle = getTitle;
		this.onClick = onClick;
	}

	get cwdReported$(): Observable<string> {
		return this.cwdReported;
	}
	get copyRequested$(): Observable<string> {
		return this.copyRequested;
	}

	private cwdReported = new Subject<string>();
	private copyRequested = new Subject<string>();
	private notifications: Notification[] = [];

	feedFromSession(data: Buffer): void {
		let startIndex = 0;

		while (data.includes(oscPrefix, startIndex) && data.includes(oscSuffix, startIndex)) {
			const params = data.subarray(data.indexOf(oscPrefix, startIndex) + oscPrefix.length);
			const oscString = params.subarray(0, params.indexOf(oscSuffix)).toString();

			startIndex = data.indexOf(oscSuffix, startIndex) + oscSuffix.length;

			const [ oscCodeString, ...oscParams ] = oscString.split(";");
			const oscCode = parseInt(oscCodeString);

			if (oscCode === 9) {
				this.showNotification(cleanTitle(this.getTitle()), oscParams[0] ?? "");
			} else if (oscCode === 777 && oscParams[0] === "notify") {
				const title = oscParams[1] || cleanTitle(this.getTitle());
				const body = oscParams.slice(2).join(";");
				this.showNotification(title, body);
			} else {
				continue;
			}
		}

		super.feedFromSession(data);
	}

	private showNotification(title: string, body: string): void {
		const notification = new Notification(title || "Terminal", { body });
		notification.onclick = () => this.onClick();
		this.notifications.push(notification);
	}

	close(): void {
		this.notifications.forEach((notification) => notification.close());
		this.notifications = [];
		this.cwdReported.complete();
		this.copyRequested.complete();
		super.close();
	}
}