import { html } from "./html";

export interface Route {
	path: string;
	component: () => Promise<string> | string;
	title?: string;
	showInNavigation?: boolean;
}

export class Router {
	private currentRoute: Route | null = null;
	private loadedRoutes: Set<string> = new Set();
	isLoading: boolean = false;
	routes: Route[] = [];

	constructor(private container: HTMLElement) {
		window.addEventListener("popstate", () => this.handleRoute());
		document.addEventListener("click", (e) => this.handleClick(e));
	}

	private async render() {
		if (!this.currentRoute) return;

		this.isLoading = true;
		const preloaded = this.loadedRoutes.has(this.currentRoute.path);
		if (!preloaded) {
			this.container.style.opacity = "0.5";
			this.container.style.pointerEvents = "none";
		}

		try {
			const result = this.currentRoute.component();
			const content = result instanceof Promise ? await result : result;
			this.loadedRoutes.add(this.currentRoute.path);

			if (!preloaded) await new Promise((resolve) => setTimeout(resolve, 150));
			this.container.innerHTML = content;

			if (!preloaded) {
				this.container.style.opacity = "1";
				this.container.style.pointerEvents = "auto";
			}
		} catch (error) {
			console.error("failed to load page:", error);
			this.container.innerHTML = this.getErrorContent();
			this.container.style.opacity = "1";
			this.container.style.pointerEvents = "auto";
		} finally {
			this.isLoading = false;
		}
	}

	addRoute(route: Route) {
		this.routes.push(route);
		return this;
	}

	private handleClick(e: Event) {
		const target = e.target as HTMLElement;
		const link = target.closest("a[data-link]");

		if (link) {
			e.preventDefault();
			const href = link.getAttribute("href");
			if (href) {
				this.navigate(href);
			}
		}
	}

	private handleRoute() {
		const path = window.location.pathname;
		const route =
			this.routes.find((r) => r.path === path) ||
			this.routes.find((r) => r.path === "*");

		if (route) {
			this.currentRoute = route;
			this.render();
			if (route.title) {
				document.title = `${route.title} - willow!`;
			}
			this.updateNavigation(path);
		}
	}

	updateNavigation = (currentPath: string) => {
		const navLinks = document.querySelectorAll(
			".navigation-bar__nav a[data-link]",
		);
		navLinks.forEach((link) => {
			const href = link.getAttribute("href");
			if (href === currentPath) {
				link.classList.add("active");
			} else {
				link.classList.remove("active");
			}
		});
	};

	navigate(path: string) {
		window.history.pushState({}, "", path);
		this.handleRoute();
	}

	private getErrorContent() {
		return html`
      <div class="error">
        <h1>error</h1>
        <p>failed to load page. please try again.</p>
        <div class="error__actions">
          <a href="/" class="button__pill" data-link>go home</a>
          <button class="button__pill reload" onclick="location.reload()">
            reload
          </button>
        </div>
      </div>
    `;
	}

	start() {
		this.handleRoute();
	}
}