/**
 * models-config.ts — extension entry for the visual config panel.
 *
 * /providers  →  start local HTTP server (if not running) + open browser.
 * session_shutdown  →  stop server.
 *
 * On-demand: server only runs while pi is running AND user opened the panel.
 */

import { spawn } from "node:child_process";
import type { ExtensionAPI } from "@earendil-works/pi-coding-agent";
import {
	startServer,
	PANEL_PORT,
	getOrCreatePanelToken,
	isPortUp,
	type ServerHandle,
} from "./server.js";

let handle: ServerHandle | null = null;

/** 关掉其他进程开的旧 server (POST /api/shutdown), 等端口释放。 */
async function shutdownRemoteServer(port: number, token: string): Promise<void> {
	try {
		await fetch(`http://127.0.0.1:${port}/api/shutdown`, {
			method: "POST",
			headers: { "Content-Type": "application/json" },
			body: JSON.stringify({ token }),
		});
	} catch {
		// server 可能已关闭, 忽略
	}
	// 等端口释放 (最多 2s)
	for (let i = 0; i < 20; i++) {
		if (!(await isPortUp(port))) return;
		await new Promise((r) => setTimeout(r, 100));
	}
}

function openBrowser(url: string) {
	// best-effort, never throws, detached so it survives pi exit
	try {
		const cmd =
			process.platform === "darwin"
				? "open"
				: process.platform === "win32"
					? "cmd"
					: "xdg-open";
		const args =
			process.platform === "win32" ? ["/c", "start", "", url] : [url];
		const child = spawn(cmd, args, { detached: true, stdio: "ignore" });
		child.unref();
	} catch {
		// ignore — user can copy the URL manually
	}
}

export default function (pi: ExtensionAPI) {
	pi.registerCommand("providers", {
		description: "可视化配置 models.json (本地网页)",
		handler: async (_args, ctx) => {
			if (ctx.hasUI === false) {
				ctx.ui.notify("/providers 需要交互模式", "error");
				return;
			}
			if (handle) {
				ctx.ui.notify(`配置面板已在运行: ${handle.url}`, "info");
				openBrowser(handle.url);
				return;
			}
			// 其他 pi CLI 可能已开了面板 server。关掉旧的, 用本进程代码起新的,
			// 确保面板始终跑在当前 CLI 进程加载的最新扩展代码上。
			if (await isPortUp(PANEL_PORT)) {
				await shutdownRemoteServer(PANEL_PORT, getOrCreatePanelToken());
			}
			try {
				handle = await startServer(() => { handle = null; }, () => pi.events.emit("roundrobin:config-changed", undefined));
				ctx.ui.notify(`配置面板已启动 → ${handle.url}`, "info");
				openBrowser(handle.url);
			} catch (e) {
				ctx.ui.notify(`启动失败: ${e instanceof Error ? e.message : e}`, "error");
				handle = null;
			}
		},
	});

	pi.on("session_shutdown", async () => {
		if (handle) {
			try {
				await handle.close();
			} catch {
				// ignore
			}
			handle = null;
		}
	});
}