/**
 * <rstack-space-switcher> — Dropdown to switch between user's spaces.
 *
 * Attributes:
 *   current — the active space slug
 *   name    — the display name of the active space
 *
 * Fetches the user's spaces from /api/spaces on click.
 */

import { isAuthenticated } from "./rstack-identity";

interface SpaceInfo {
	slug: string;
	name: string;
	icon?: string;
}

export class RStackSpaceSwitcher extends HTMLElement {
	#shadow: ShadowRoot;
	#spaces: SpaceInfo[] = [];
	#loaded = false;

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

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

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

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

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

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

	async #loadSpaces() {
		if (this.#loaded) return;
		try {
			const res = await fetch("/api/spaces");
			if (res.ok) {
				const data = await res.json();
				this.#spaces = data.spaces || [];
			}
		} catch {
			// Offline or API not available — just show current
		}
		this.#loaded = true;
	}

	#render() {
		const current = this.current;
		const name = this.spaceName;

		this.#shadow.innerHTML = `
			<style>${STYLES}</style>
			<div class="switcher">
				<button class="trigger" id="trigger">
					<span class="slash">/</span>
					<span class="space-name">${name || "Select space"}</span>
					<span class="caret">▾</span>
				</button>
				<div class="menu" id="menu">
					<div class="menu-loading">Loading spaces...</div>
				</div>
			</div>
		`;

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

		trigger.addEventListener("click", async (e) => {
			e.stopPropagation();
			const isOpen = menu.classList.toggle("open");
			if (isOpen && !this.#loaded) {
				await this.#loadSpaces();
				this.#renderMenu(menu, current);
			}
		});

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

	#renderMenu(menu: HTMLElement, current: string) {
		if (this.#spaces.length === 0) {
			menu.innerHTML = `
				<div class="menu-empty">
					${isAuthenticated() ? "No spaces yet" : "Sign in to see your spaces"}
				</div>
				<a class="item item--create" href="/new">+ Create new space</a>
			`;
			return;
		}

		const moduleId = this.#getCurrentModule();

		menu.innerHTML = `
			${this.#spaces
				.map(
					(s) => `
				<a class="item ${s.slug === current ? "active" : ""}"
				   href="/${s.slug}/${moduleId}">
					<span class="item-icon">${s.icon || "🌐"}</span>
					<span class="item-name">${s.name}</span>
				</a>
			`
				)
				.join("")}
			<div class="divider"></div>
			<a class="item item--create" href="/new">+ Create new space</a>
		`;
	}

	#getCurrentModule(): string {
		const parts = window.location.pathname.split("/").filter(Boolean);
		return parts[1] || "canvas";
	}

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

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

.switcher { position: relative; }

.trigger {
  display: flex; align-items: center; gap: 4px;
  padding: 6px 12px; border-radius: 8px; border: none;
  font-size: 0.875rem; font-weight: 500; cursor: pointer;
  transition: background 0.15s; background: transparent; color: inherit;
}
:host-context([data-theme="light"]) .trigger { color: #374151; }
:host-context([data-theme="dark"]) .trigger { color: #94a3b8; }
.trigger:hover { background: rgba(0,0,0,0.05); }
:host-context([data-theme="dark"]) .trigger:hover { background: rgba(255,255,255,0.05); }

.slash { opacity: 0.4; font-weight: 300; margin-right: 2px; }
.space-name { max-width: 160px; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.caret { font-size: 0.7em; opacity: 0.5; }

.menu {
  position: absolute; top: 100%; left: 0; margin-top: 6px;
  min-width: 220px; max-height: 320px; overflow-y: auto;
  border-radius: 12px; 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: 10px;
  padding: 10px 14px; text-decoration: none; cursor: pointer;
  transition: background 0.12s;
}
: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: 1.1rem; flex-shrink: 0; }
.item-name { font-size: 0.875rem; font-weight: 500; }

.item--create {
  font-size: 0.85rem; font-weight: 600; color: #06b6d4 !important;
}
.item--create:hover { background: rgba(6,182,212,0.08) !important; }

.divider { height: 1px; margin: 4px 0; }
:host-context([data-theme="light"]) .divider { background: rgba(0,0,0,0.08); }
:host-context([data-theme="dark"]) .divider { background: rgba(255,255,255,0.08); }

.menu-loading, .menu-empty {
  padding: 16px; text-align: center; font-size: 0.85rem; color: #94a3b8;
}
`;