/**
 * <rstack-app-switcher> — Dropdown to switch between rSpace modules.
 *
 * Attributes:
 *   current — the active module ID (highlighted)
 *
 * Methods:
 *   setModules(list) — provide the list of available modules
 */

export interface AppSwitcherModule {
	id: string;
	name: string;
	icon: string;
	description: string;
}

export class RStackAppSwitcher extends HTMLElement {
	#shadow: ShadowRoot;
	#modules: AppSwitcherModule[] = [];

	constructor() {
		super();
		this.#shadow = this.attachShadow({ mode: "open" });
	}

	static get observedAttributes() {
		return ["current"];
	}

	get current(): string {
		return this.getAttribute("current") || "";
	}

	connectedCallback() {
		this.#render();
	}

	attributeChangedCallback() {
		this.#render();
	}

	setModules(modules: AppSwitcherModule[]) {
		this.#modules = modules;
		this.#render();
	}

	#render() {
		const current = this.current;
		const currentMod = this.#modules.find((m) => m.id === current);
		const label = currentMod ? `${currentMod.icon} ${currentMod.name}` : "🌌 rSpace";

		this.#shadow.innerHTML = `
			<style>${STYLES}</style>
			<div class="switcher">
				<button class="trigger" id="trigger">${label} <span class="caret">▾</span></button>
				<div class="menu" id="menu">
					${this.#modules
						.map(
							(m) => `
						<a class="item ${m.id === current ? "active" : ""}"
						   href="/${this.#getSpaceSlug()}/${m.id}"
						   data-id="${m.id}">
							<span class="item-icon">${m.icon}</span>
							<div class="item-text">
								<span class="item-name">${m.name}</span>
								<span class="item-desc">${m.description}</span>
							</div>
						</a>
					`
						)
						.join("")}
				</div>
			</div>
		`;

		const trigger = this.#shadow.getElementById("trigger")!;
		const menu = this.#shadow.getElementById("menu")!;

		trigger.addEventListener("click", (e) => {
			e.stopPropagation();
			menu.classList.toggle("open");
		});

		document.addEventListener("click", () => menu.classList.remove("open"));
	}

	#getSpaceSlug(): string {
		// Read from the space switcher or URL
		const spaceSwitcher = document.querySelector("rstack-space-switcher");
		if (spaceSwitcher) return spaceSwitcher.getAttribute("current") || "personal";
		// Fallback: parse from URL (/:space/:module)
		const parts = window.location.pathname.split("/").filter(Boolean);
		return parts[0] || "personal";
	}

	static define(tag = "rstack-app-switcher") {
		if (!customElements.get(tag)) customElements.define(tag, RStackAppSwitcher);
	}
}

const STYLES = `
:host { display: contents; }

.switcher { position: relative; }

.trigger {
  display: flex; align-items: center; gap: 6px;
  padding: 6px 14px; border-radius: 8px; border: none;
  font-size: 0.9rem; font-weight: 600; cursor: pointer;
  transition: background 0.15s;
  background: rgba(255,255,255,0.08); color: inherit;
}
:host-context([data-theme="light"]) .trigger {
  background: rgba(0,0,0,0.05); color: #0f172a;
}
:host-context([data-theme="dark"]) .trigger {
  background: rgba(255,255,255,0.08); color: #e2e8f0;
}
.trigger:hover { background: rgba(255,255,255,0.12); }
:host-context([data-theme="light"]) .trigger:hover { background: rgba(0,0,0,0.08); }

.caret { font-size: 0.7em; opacity: 0.6; }

.menu {
  position: absolute; top: 100%; left: 0; margin-top: 6px;
  min-width: 260px; border-radius: 12px; overflow: hidden;
  box-shadow: 0 8px 30px rgba(0,0,0,0.25); display: none; z-index: 200;
}
.menu.open { display: block; }
:host-context([data-theme="light"]) .menu {
  background: white; border: 1px solid rgba(0,0,0,0.1);
}
:host-context([data-theme="dark"]) .menu {
  background: #1e293b; border: 1px solid rgba(255,255,255,0.1);
}

.item {
  display: flex; align-items: center; gap: 12px;
  padding: 10px 14px; text-decoration: none;
  transition: background 0.12s; cursor: pointer;
}
:host-context([data-theme="light"]) .item { color: #374151; }
:host-context([data-theme="light"]) .item:hover { background: #f1f5f9; }
:host-context([data-theme="light"]) .item.active { background: #e0f2fe; }
:host-context([data-theme="dark"]) .item { color: #e2e8f0; }
:host-context([data-theme="dark"]) .item:hover { background: rgba(255,255,255,0.05); }
:host-context([data-theme="dark"]) .item.active { background: rgba(6,182,212,0.1); }

.item-icon { font-size: 1.3rem; width: 28px; text-align: center; flex-shrink: 0; }
.item-text { display: flex; flex-direction: column; min-width: 0; }
.item-name { font-size: 0.875rem; font-weight: 600; }
.item-desc { font-size: 0.75rem; opacity: 0.6; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
`;