#!/usr/bin/env node

/**
 * pi-mono WebUI Server
 *
 * 被 webui 扩展启动，作为独立子进程运行。
 * 内嵌 HTTP 服务 + pi RPC 子进程，提供浏览器聊天界面。
 *
 * 用法（由扩展自动调用）：
 *   tsx backend/main.ts --port 19133
 *
 * 前端静态文件位于 frontend/dist/ 下（Vite 构建产物）。
 */

import { existsSync, unlinkSync, writeFileSync } from "node:fs";
import { arch, hostname, platform, release, type } from "node:os";
import { parsePort } from "./config/cli.ts";
import { createWebUiPaths } from "./config/paths.ts";
import { closeWebuiDatabase, initWebuiDatabase } from "./db/index.ts";
import { createWebUiServer } from "./http/server.ts";
import { createPiClient } from "./rpc/pi-client.ts";
import type { WebUiContext } from "./types/context.ts";

const paths = createWebUiPaths();
const port = parsePort();

function writePidFile(): void {
	try {
		writeFileSync(paths.pidFile, String(process.pid), "utf8");
	} catch {
		/* ignore */
	}
}

function clearPidFile(): void {
	try {
		if (existsSync(paths.pidFile)) unlinkSync(paths.pidFile);
	} catch {
		/* ignore */
	}
}

function shutdown(exitCode = 0): never {
	closeWebuiDatabase();
	clearPidFile();
	process.exit(exitCode);
}

const webuiDb = initWebuiDatabase(paths.extensionRoot);
console.log(`[webui] 配置数据库: ${webuiDb.dbPath}`);
console.log(`[webui] 运行环境: Node.js ${process.version} | ${type()} ${release()} (${platform()}/${arch()}) | 主机: ${hostname()}`);

process.on("SIGTERM", () => shutdown(0));
process.on("SIGINT", () => shutdown(0));
writePidFile();

const piClient = createPiClient(paths, (code) => {
	if (code !== 0 && code !== null) {
		console.error(`[webui] pi RPC 进程异常退出 (code=${code})，WebUI 即将关闭`);
		setTimeout(() => shutdown(1), 500);
		return;
	}
	shutdown(1);
});

const ctx: WebUiContext = {
	config: { paths, port },
	rpc: {
		sendCmd: piClient.sendCmd,
		submitPrompt: piClient.submitPrompt,
		sendExtensionUiResponse: piClient.sendExtensionUiResponse,
		getRunSnapshot: piClient.getRunSnapshot,
		connectSseClient: piClient.connectSseClient,
		removeSseClient: piClient.removeSseClient,
	},
	db: webuiDb,
};

const server = createWebUiServer(ctx);

server.on("error", (err: NodeJS.ErrnoException) => {
	if (err.code === "EADDRINUSE") {
		console.error(`[webui] 端口 ${port} 已被占用`);
	} else {
		console.error(`[webui] HTTP 服务启动失败: ${err.message}`);
	}
	process.exit(1);
});

server.listen(port, "0.0.0.0", () => {
	console.log(`[webui] HTTP 服务已启动: http://localhost:${port}`);
	console.log(`[webui] 局域网访问: http://${hostname()}:${port}`);
});