import {
	createAgentSession,
	createCodemodeExtension,
	createMcpExtension,
	createToolSearchExtension,
	DefaultResourceLoader,
	getAgentDir,
	SessionManager,
	SettingsManager,
} from "@earendil-works/pi-coding-agent";

const cwd = process.cwd();

// 资源加载器：SDK 不会替你把内置扩展塞进来，必须显式传 extensionFactories
const resourceLoader = new DefaultResourceLoader({
	cwd,
	agentDir: getAgentDir(),
	extensionFactories: [
		createCodemodeExtension({ mode: "on" }),
		createToolSearchExtension(),
		createMcpExtension(),
	],
});

// 必须自己 reload：SDK 只有在内部创建加载器时才会替你 reload
await resourceLoader.reload();

// 扩展加载失败不会抛异常，结果收集在这里
const { errors, warnings } = resourceLoader.getExtensions();
if (errors.length > 0) {
	console.error("扩展加载失败:", errors);
}
if (warnings?.length) {
	console.warn("扩展告警:", warnings);
}

const settingsManager = SettingsManager.create(cwd);
// "+name" 是在原有默认工具上追加，不是替换
settingsManager.applyOverrides({ defaultTools: ["+codemode", "+tool_search"] });

// 反例：以为扩展会自己加载
import { createAgentSession } from "@earendil-works/pi-coding-agent";

const { session } = await createAgentSession();

// 这个列表永远是空的
console.log(session.getAllTools().filter((tool) => tool.name.startsWith("mcp__")));

// sdk-mcp-assembly.ts
import {
	createAgentSession,
	createCodemodeExtension,
	createMcpExtension,
	createToolSearchExtension,
	DefaultResourceLoader,
	getAgentDir,
	SessionManager,
	SettingsManager,
} from "@earendil-works/pi-coding-agent";

const cwd = process.cwd();

// 第一步：显式装配三个内置扩展，SDK 不会替你做
const resourceLoader = new DefaultResourceLoader({
	cwd,
	agentDir: getAgentDir(),
	extensionFactories: [
		createCodemodeExtension({ mode: "on" }),
		createToolSearchExtension(),
		createMcpExtension(),
	],
});
await resourceLoader.reload();

const loadErrors = resourceLoader.getExtensions().errors;
if (loadErrors.length > 0) {
	throw new Error(`扩展加载失败: ${loadErrors.map((e) => `${e.path}: ${e.error}`).join("; ")}`);
}

// 第二步：在创建会话之前追加激活项，"+" 是追加语义
const settingsManager = SettingsManager.create(cwd);
settingsManager.applyOverrides({ defaultTools: ["+codemode", "+tool_search"] });

const { session } = await createAgentSession({
	resourceLoader,
	settingsManager,
	sessionManager: SessionManager.inMemory(),
});

try {
	// 第三步：绑定扩展。session_start 在这里发出，MCP 扩展此时开始后台连接
	await session.bindExtensions({});

	// 第四步：断言工具表。服务器在后台连接，需要等工具注册进来
	const mcpTools = await waitForMcpTools(session, 10_000);
	console.log("MCP 工具:", mcpTools.length > 0 ? mcpTools.join(", ") : "(无)");
	console.log("声明给模型的工具:", session.getActiveToolNames().join(", "));

	const unsubscribe = session.subscribe((event) => {
		if (event.type === "message_update" && event.assistantMessageEvent.type === "text_delta") {
			process.stdout.write(event.assistantMessageEvent.delta);
		}
	});
	try {
		await session.prompt("List the files in the current directory.");
	} finally {
		unsubscribe();
	}
	console.log();
} finally {
	session.dispose();
}

/**
 * 轮询等待 MCP 工具注册。官方没有提供"等待 MCP 连接完成"的接口，
 * 这是教学用的辅助函数，不是官方 API。
 */
async function waitForMcpTools(
	session: { getAllTools(): Array<{ name: string; exposure: string }> },
	timeoutMs: number,
): Promise<string[]> {
	const deadline = Date.now() + timeoutMs;
	for (;;) {
		const names = session
			.getAllTools()
			.filter((tool) => tool.name.startsWith("mcp__"))
			.map((tool) => `${tool.name}(${tool.exposure})`);
		if (names.length > 0) return names;
		if (Date.now() >= deadline) return [];
		await new Promise((resolve) => setTimeout(resolve, 200));
	}
}

import {
	type CreateAgentSessionRuntimeFactory,
	createAgentSessionFromServices,
	createAgentSessionRuntime,
	createAgentSessionServices,
	createCodemodeExtension,
	createMcpExtension,
	createToolSearchExtension,
	getAgentDir,
	SessionManager,
} from "@earendil-works/pi-coding-agent";

// 用运行时的原因：只有 runtime.dispose() 会发 session_shutdown，MCP 的连接清理挂在这个事件上
// session.dispose() 不发这个事件，stdio 服务器的子进程会残留
const createRuntime: CreateAgentSessionRuntimeFactory = async ({ cwd, sessionManager, sessionStartEvent }) => {
	const services = await createAgentSessionServices({
		cwd,
		// 运行时重建服务时，扩展工厂要一起传，否则新会话里又没有 MCP 了
		resourceLoaderOptions: {
			extensionFactories: [
				createCodemodeExtension({ mode: "on" }),
				createToolSearchExtension(),
				createMcpExtension(),
			],
		},
	});
	return {
		...(await createAgentSessionFromServices({ services, sessionManager, sessionStartEvent })),
		services,
		diagnostics: services.diagnostics,
	};
};

const runtime = await createAgentSessionRuntime(createRuntime, {
	cwd: process.cwd(),
	agentDir: getAgentDir(),
	sessionManager: SessionManager.create(process.cwd()),
});

try {
	// 绑定扩展发出 session_start，MCP 扩展在这时开始后台连接
	await runtime.session.bindExtensions({});
	await runtime.session.prompt("List the files in the current directory.");
} finally {
	// dispose() 先发 session_shutdown（MCP 在此关闭连接），再 dispose 会话
	await runtime.dispose();
}