import assert from "node:assert/strict";
import { mkdir, mkdtemp, readFile, symlink, writeFile } from "node:fs/promises";
import { tmpdir } from "node:os";
import { join } from "node:path";
import test from "node:test";
import { createAgentRegistry } from "../src/bridge/agent-registry.js";

async function createWorktrees() {
	const root = await mkdtemp(join(tmpdir(), "pi-status-bridge-worktrees-"));
	const home = join(root, "home");
	const feature = join(root, "feature");
	await Promise.all([mkdir(home), mkdir(feature)]);
	return { root, home, feature, sessionRoot: join(root, "sessions") };
}

function createAdapterFactory() {
	const calls = [];
	return {
		calls,
		startAdapter: (options) => {
			const adapter = {
				sent: [],
				extensionResponses: [],
				stopped: false,
				send(command) {
					this.sent.push(command);
					return Promise.resolve({
						type: "response",
						command: command.type,
						success: true,
					});
				},
				respondToExtension(requestId, response) {
					this.extensionResponses.push({ requestId, response });
				},
				async stop() {
					this.stopped = true;
				},
			};
			calls.push({ options, adapter });
			return adapter;
		},
	};
}

test("starts only the home agent and creates other worktree agents on explicit selection", async () => {
	const worktrees = await createWorktrees();
	const fixture = createAdapterFactory();
	const registry = createAgentRegistry({
		homeWorktree: worktrees.home,
		sessionRoot: worktrees.sessionRoot,
		startAdapter: fixture.startAdapter,
	});

	const home = await registry.start();
	assert.equal(registry.listAgents().length, 1);
	assert.equal(home.worktreePath, worktrees.home);

	const feature = await registry.selectWorktree(worktrees.feature);
	const selectedAgain = await registry.selectWorktree(
		`${worktrees.feature}/../feature`,
	);
	assert.equal(feature.id, selectedAgain.id);
	assert.notEqual(home.id, feature.id);
	assert.deepEqual(
		fixture.calls.map(({ options }) => options.cwd),
		[worktrees.home, worktrees.feature],
	);
	assert.notEqual(home.sessionDir, feature.sessionDir);

	await registry.stop();
	assert.ok(fixture.calls.every(({ adapter }) => adapter.stopped));
});

test("stops agents created during shutdown and rejects new selections", async () => {
	const worktrees = await createWorktrees();
	const fixture = createAdapterFactory();
	let releaseFeatureCreation;
	const featureCreation = new Promise((resolve) => {
		releaseFeatureCreation = resolve;
	});
	let featureCreationStarted;
	const featureStarted = new Promise((resolve) => {
		featureCreationStarted = resolve;
	});
	const registry = createAgentRegistry({
		homeWorktree: worktrees.home,
		sessionRoot: worktrees.sessionRoot,
		startAdapter: (options) => {
			const adapter = fixture.startAdapter(options);
			if (options.cwd === worktrees.feature) {
				const send = adapter.send.bind(adapter);
				adapter.send = (command) => {
					if (command.type !== "get_state") return send(command);
					featureCreationStarted();
					return featureCreation.then(() => send(command));
				};
			}
			return adapter;
		},
	});
	await registry.start();
	const selecting = registry.selectWorktree(worktrees.feature);
	await featureStarted;

	const stopping = registry.stop();
	await assert.rejects(
		registry.selectWorktree(worktrees.feature),
		/registry is stopping/,
	);
	releaseFeatureCreation();
	await selecting;
	await stopping;
	assert.ok(fixture.calls.every(({ adapter }) => adapter.stopped));
});

test("drains a forget still resolving its canonical path during shutdown", async () => {
	const worktrees = await createWorktrees();
	const featureAlias = join(worktrees.root, "feature-alias");
	await symlink(worktrees.feature, featureAlias);
	const fixture = createAdapterFactory();
	const registry = createAgentRegistry({
		homeWorktree: worktrees.home,
		sessionRoot: worktrees.sessionRoot,
		startAdapter: fixture.startAdapter,
	});
	await registry.start();
	await registry.selectWorktree(worktrees.feature);
	const featureAdapter = fixture.calls[1].adapter;
	const stop = featureAdapter.stop.bind(featureAdapter);
	let stopCalls = 0;
	featureAdapter.stop = async () => {
		stopCalls += 1;
		await stop();
	};

	const forgetting = registry.forgetDirectory(featureAlias);
	const stopping = registry.stop();
	await Promise.all([forgetting, stopping]);

	assert.equal(stopCalls, 1);
	assert.equal(
		registry
			.listAgents()
			.some((agent) => agent.worktreePath === worktrees.feature),
		false,
	);
});

test("forgets a directory without deleting its resumable session history", async () => {
	const worktrees = await createWorktrees();
	const fixture = createAdapterFactory();
	const registry = createAgentRegistry({
		homeWorktree: worktrees.home,
		sessionRoot: worktrees.sessionRoot,
		startAdapter: fixture.startAdapter,
	});
	const home = await registry.start();
	const feature = await registry.selectWorktree(worktrees.feature);
	const sessionPath = join(feature.sessionDir, "resumable.jsonl");
	const sessionContent = `${JSON.stringify({
		type: "session",
		id: "resumable",
		timestamp: "2025-01-01T00:00:00.000Z",
		cwd: worktrees.feature,
	})}\n`;
	await writeFile(sessionPath, sessionContent);
	await writeFile(
		join(feature.sessionDir, "bridge-agent.json"),
		`${JSON.stringify({ sessionPath, worktreePath: worktrees.feature })}\n`,
	);

	await registry.forgetDirectory(worktrees.feature);

	assert.equal(fixture.calls[1].adapter.stopped, true);
	assert.deepEqual(registry.listAgents(), [home]);
	assert.deepEqual(await registry.listDirectories(), [
		{
			worktreePath: worktrees.home,
			state: "idle",
			isHome: true,
			agentId: home.id,
		},
	]);
	assert.equal(await readFile(sessionPath, "utf8"), sessionContent);
	await assert.rejects(
		registry.forgetDirectory(worktrees.home),
		/cannot forget the home directory/,
	);

	const reopened = await registry.selectWorktree(worktrees.feature);
	assert.deepEqual(
		(await registry.listSessions(reopened.id)).map(({ id }) => id),
		["resumable"],
	);
	await registry.stop();
});

test("coordinates forgetting with directory creation and active commands", async () => {
	const worktrees = await createWorktrees();
	const fixture = createAdapterFactory();
	let releaseFeatureCreation;
	const featureCreation = new Promise((resolve) => {
		releaseFeatureCreation = resolve;
	});
	let featureCreationStarted;
	const featureStarted = new Promise((resolve) => {
		featureCreationStarted = resolve;
	});
	const registry = createAgentRegistry({
		homeWorktree: worktrees.home,
		sessionRoot: worktrees.sessionRoot,
		startAdapter: (options) => {
			const adapter = fixture.startAdapter(options);
			if (options.cwd === worktrees.feature) {
				const send = adapter.send.bind(adapter);
				adapter.send = (command) => {
					if (command.type !== "get_state") return send(command);
					featureCreationStarted();
					return featureCreation.then(() => send(command));
				};
			}
			return adapter;
		},
	});
	await registry.start();

	const selecting = registry.selectWorktree(worktrees.feature);
	await featureStarted;
	const forgettingDuringCreation = registry.forgetDirectory(worktrees.feature);
	releaseFeatureCreation();
	await selecting;
	await forgettingDuringCreation;
	assert.equal(fixture.calls[1].adapter.stopped, true);
	assert.equal(
		(await registry.listDirectories()).some(
			(directory) => directory.worktreePath === worktrees.feature,
		),
		false,
	);

	await registry.selectWorktree(worktrees.feature);
	const concurrentAdapter = fixture.calls[2].adapter;
	const stop = concurrentAdapter.stop.bind(concurrentAdapter);
	let releaseStop;
	const stopGate = new Promise((resolve) => {
		releaseStop = resolve;
	});
	let stopCalls = 0;
	concurrentAdapter.stop = async () => {
		stopCalls += 1;
		await stopGate;
		await stop();
	};
	const firstForget = registry.forgetDirectory(worktrees.feature);
	const secondForget = registry.forgetDirectory(worktrees.feature);
	await new Promise((resolve) => setImmediate(resolve));
	await assert.rejects(
		registry.selectWorktree(worktrees.feature),
		/being forgotten/,
	);
	releaseStop();
	await Promise.all([firstForget, secondForget]);
	assert.equal(stopCalls, 1);
	assert.equal(registry.listAgents().length, 1);

	const feature = await registry.selectWorktree(worktrees.feature);
	const { adapter, options } = fixture.calls[3];
	const send = adapter.send.bind(adapter);
	let releasePrompt;
	const promptResponse = new Promise((resolve) => {
		releasePrompt = resolve;
	});
	adapter.send = (command) =>
		command.type === "prompt" ? promptResponse : send(command);
	const prompt = registry.route(feature.id, "prompt", {
		message: "Keep working",
	});
	const forgettingDuringPrompt = registry.forgetDirectory(worktrees.feature);
	await new Promise((resolve) => setImmediate(resolve));
	assert.equal(adapter.stopped, false);
	releasePrompt({ type: "response", success: true });
	await prompt;
	await assert.rejects(forgettingDuringPrompt, /while Pi is working/);
	assert.equal(adapter.stopped, false);

	options.onEvent({ type: "agent_state", data: { state: "idle" } });
	await registry.forgetDirectory(worktrees.feature);
	assert.equal(adapter.stopped, true);

	const failedFeature = await registry.selectWorktree(worktrees.feature);
	const failedFixture = fixture.calls[4];
	let rejectPrompt;
	const failedPromptResponse = new Promise((_resolve, reject) => {
		rejectPrompt = reject;
	});
	const failedSend = failedFixture.adapter.send.bind(failedFixture.adapter);
	failedFixture.adapter.send = (command) =>
		command.type === "prompt" ? failedPromptResponse : failedSend(command);
	const failedPrompt = registry.route(failedFeature.id, "prompt", {
		message: "Start before the response fails",
	});
	const failedPromptAssertion = assert.rejects(failedPrompt, /send failed/);
	failedFixture.options.onEvent({
		type: "agent_state",
		data: { state: "streaming" },
	});
	rejectPrompt(new Error("send failed"));
	await failedPromptAssertion;
	await assert.rejects(
		registry.forgetDirectory(worktrees.feature),
		/while Pi is working/,
	);
	failedFixture.options.onEvent({
		type: "agent_state",
		data: { state: "idle" },
	});
	await registry.forgetDirectory(worktrees.feature);
	await registry.stop();
});

test("catalogues managed directories and exposes only their sessions", async () => {
	const worktrees = await createWorktrees();
	const fixture = createAdapterFactory();
	const registry = createAgentRegistry({
		homeWorktree: worktrees.home,
		sessionRoot: worktrees.sessionRoot,
		startAdapter: fixture.startAdapter,
	});
	await registry.start();
	const feature = await registry.selectWorktree(worktrees.feature);
	const olderSession = join(feature.sessionDir, "older.jsonl");
	const newestSession = join(feature.sessionDir, "newest.jsonl");
	await writeFile(
		olderSession,
		[
			JSON.stringify({
				type: "session",
				id: "older",
				timestamp: "2025-01-01T00:00:00.000Z",
				cwd: worktrees.feature,
			}),
			JSON.stringify({
				type: "message",
				message: { role: "user", content: "Older task" },
			}),
		].join("\n"),
	);
	await writeFile(
		newestSession,
		[
			JSON.stringify({
				type: "session",
				id: "newest",
				timestamp: "2025-01-02T00:00:00.000Z",
				cwd: worktrees.feature,
			}),
			JSON.stringify({ type: "session_info", name: "Newest work" }),
			JSON.stringify({
				type: "message",
				message: { role: "user", content: "Newest task" },
			}),
		].join("\n"),
	);
	await writeFile(
		join(feature.sessionDir, "bridge-agent.json"),
		`${JSON.stringify({ sessionPath: newestSession, worktreePath: worktrees.feature })}\n`,
	);

	const sessions = await registry.listSessions(feature.id);
	assert.deepEqual(
		sessions.map(({ id, name, isCurrent }) => ({ id, name, isCurrent })),
		[
			{ id: "newest", name: "Newest work", isCurrent: false },
			{ id: "older", name: undefined, isCurrent: false },
		],
	);
	await registry.route(feature.id, "switch_session", {
		sessionPath: newestSession,
	});
	await registry.route(feature.id, "new_session");
	assert.deepEqual(
		fixture.calls[1].adapter.sent.map((command) => command.type),
		["get_state", "switch_session", "get_state", "new_session", "get_state"],
	);
	await assert.rejects(
		registry.route(feature.id, "switch_session", {
			sessionPath: olderSession.replace("older", "../outside"),
		}),
		/ENOENT|belong/,
	);
	await registry.stop();

	const restored = createAgentRegistry({
		homeWorktree: worktrees.home,
		sessionRoot: worktrees.sessionRoot,
		startAdapter: createAdapterFactory().startAdapter,
	});
	await restored.start();
	assert.deepEqual(await restored.listDirectories(), [
		{
			worktreePath: worktrees.feature,
			state: "inactive",
			isHome: false,
		},
		{
			worktreePath: worktrees.home,
			state: "idle",
			isHome: true,
			agentId: restored.listAgents()[0].id,
		},
	]);
	await restored.stop();
});

test("routes commands by explicit agent ID and replays only events after the cursor", async () => {
	const worktrees = await createWorktrees();
	const fixture = createAdapterFactory();
	const registry = createAgentRegistry({
		homeWorktree: worktrees.home,
		sessionRoot: worktrees.sessionRoot,
		startAdapter: fixture.startAdapter,
	});
	const agent = await registry.start();
	const [{ options, adapter }] = fixture.calls;

	const response = await registry.route(agent.id, "prompt", {
		message: "Stay in this worktree",
	});
	assert.deepEqual(response, {
		type: "response",
		command: "prompt",
		success: true,
	});
	const stats = await registry.route(agent.id, "get_session_stats");
	assert.deepEqual(stats, {
		type: "response",
		command: "get_session_stats",
		success: true,
	});
	const commands = await registry.route(agent.id, "get_commands");
	assert.deepEqual(commands, {
		type: "response",
		command: "get_commands",
		success: true,
	});
	assert.deepEqual(adapter.sent, [
		{ type: "get_state" },
		{ type: "prompt", message: "Stay in this worktree" },
		{ type: "get_session_stats" },
		{ type: "get_commands" },
	]);

	options.onEvent({
		type: "agent_state",
		data: { state: "streaming" },
	});
	await registry.route(agent.id, "submit_prompt", {
		message: "After this turn",
	});
	assert.deepEqual(adapter.sent.at(-1), {
		type: "follow_up",
		message: "After this turn",
	});

	options.onEvent({
		type: "stream",
		data: { event: { type: "message_update" } },
	});
	options.onEvent({ type: "queue", data: { event: { type: "queue_update" } } });
	assert.deepEqual(
		registry.eventsAfter(agent.id, 0).map(({ seq, type }) => ({ seq, type })),
		[
			{ seq: 1, type: "agent_state" },
			{ seq: 2, type: "stream" },
			{ seq: 3, type: "queue" },
		],
	);
	assert.deepEqual(
		registry.eventsAfter(agent.id, 1).map(({ seq, type }) => ({ seq, type })),
		[
			{ seq: 2, type: "stream" },
			{ seq: 3, type: "queue" },
		],
	);

	await assert.rejects(
		registry.route("missing-agent", "abort"),
		/unknown agent/,
	);
	await registry.stop();
});