import { execFileSync } from "node:child_process";
import {
	cpSync,
	mkdirSync,
	mkdtempSync,
	readdirSync,
	readFileSync,
	rmSync,
	symlinkSync,
	writeFileSync,
} from "node:fs";
import { tmpdir } from "node:os";
import path from "node:path";
import { fileURLToPath } from "node:url";
import {
	type BuildSystemPromptOptions,
	CONFIG_DIR_NAME,
	DefaultPackageManager,
	type ExtensionUIContext,
	getAgentDir,
	getDocsPath,
	getExamplesPath,
	getPackageDir,
	getReadmePath,
	SettingsManager,
	VERSION,
} from "@earendil-works/pi-coding-agent";
import { afterEach, describe, expect, it, vi } from "vitest";
import {
	createPiSession,
	type PiSession,
} from "../../../test/fixture/create-pi-session.ts";

const extensionRoot = path.resolve(import.meta.dirname, "..");
const repositoryRoot = path.resolve(extensionRoot, "../..");
const ENTRY = fileURLToPath(new URL("../index.ts", import.meta.url));
const PFUI_STATE_KEY = Symbol.for("@bugabinga/pi-ext-pfui/state");
const RENDERED_KEY = "__pfui_contract_rendered__";

const temporaryPaths: string[] = [];
let session: PiSession | undefined;

// The owned fixture inherits process.env, including any PI_CONTEXT_* the host
// shell exports when Pi runs this suite. Clear them so pfui starts from the same
// clean slate the fixture sandbox provides.
const CLEAN_CONTEXT: Record<string, string | undefined> = {
	PI_MANAGED_INSTALL_ROOT: undefined,
	PI_CONTEXT_PACKAGE_DIR: undefined,
	PI_CONTEXT_AGENT_DIR: undefined,
	PI_CONTEXT_README_PATH: undefined,
	PI_CONTEXT_DOCS_PATH: undefined,
	PI_CONTEXT_EXAMPLES_PATH: undefined,
	PI_CONTEXT_CHANGELOG_PATH: undefined,
	PI_CONTEXT_PACKAGE_JSON_PATH: undefined,
	PI_CONTEXT_VERSION: undefined,
	PI_CONTEXT_CONFIG_DIR_NAME: undefined,
};

function startSession(
	options: Parameters<typeof createPiSession>[0],
): Promise<PiSession> {
	return createPiSession({
		...options,
		env: { ...CLEAN_CONTEXT, ...options.env },
	});
}

// A later extension that captures the rendered system prompt through the public
// before_agent_start event. The owned fixture loads extensions by path only, so
// this replaces the original inline `observePrompt` factory.
const OBSERVE_PROMPT = `export default function (pi) {
	pi.on("before_agent_start", (event) => {
		globalThis["${RENDERED_KEY}"] = event.systemPrompt;
	});
}
`;

// A later extension that contributes general and tool guidelines, matching the
// original inline `contributeGuidelines` factory.
const CONTRIBUTE_GUIDELINES = `export default function (pi) {
	pi.on("before_agent_start", (event) => {
		event.systemPromptOptions.promptGuidelines.push("Late general guidance");
		event.systemPromptOptions.toolGuidelines.read = ["Late read guidance"];
	});
}
`;

// A later extension that appends to the prompt, matching the original inline
// `appendLater` factory.
const APPEND_LATER = `export default function (pi) {
	pi.on("before_agent_start", (event) => ({
		systemPrompt: \`\${event.systemPrompt}\\n\\nLATER EXTENSION\`,
	}));
}
`;

function tempDirectory(prefix: string): string {
	const directory = mkdtempSync(path.join(tmpdir(), prefix));
	temporaryPaths.push(directory);
	return directory;
}

function writeExtension(body: string): string {
	const directory = tempDirectory("pfui-ext-");
	const file = path.join(directory, "ext.ts");
	writeFileSync(file, body);
	return file;
}

function copyPfuiEntrypoint(directory: string): void {
	cpSync(
		path.join(extensionRoot, "index.ts"),
		path.join(directory, "index.ts"),
	);
	mkdirSync(path.join(directory, "src"), { recursive: true });
	cpSync(
		path.join(extensionRoot, "src", "pi-ext-debug.ts"),
		path.join(directory, "src", "pi-ext-debug.ts"),
	);
	cpSync(
		path.join(extensionRoot, "src", "debug.ts"),
		path.join(directory, "src", "debug.ts"),
	);
	symlinkSync(
		path.join(repositoryRoot, "node_modules"),
		path.join(directory, "node_modules"),
		"junction",
	);
}

function copiedPfui(prefix: string): string {
	const directory = tempDirectory(prefix);
	copyPfuiEntrypoint(directory);
	return directory;
}

function baseOptions(): BuildSystemPromptOptions {
	return {
		cwd: "/work/project",
		selectedTools: ["read"],
		toolSnippets: { read: "Read files" },
		promptGuidelines: [],
	};
}

async function emittedOptions(
	options: BuildSystemPromptOptions,
): Promise<BuildSystemPromptOptions> {
	if (!session) throw new Error("Test session is not initialized");
	const result = await session.session.extensionRunner.emitBeforeAgentStart(
		{ messageType: "user", prompt: "user prompt" },
		options,
	);
	return result.systemPromptOptions;
}

function pfuiWarningState():
	| { warnings: Set<string>; deliveredWarnings: Set<string> }
	| undefined {
	return (
		globalThis as unknown as Record<
			symbol,
			{ warnings: Set<string>; deliveredWarnings: Set<string> } | undefined
		>
	)[PFUI_STATE_KEY];
}

function recordingUi(sink: unknown[][]): ExtensionUIContext {
	return {
		select: async () => undefined,
		confirm: async () => false,
		input: async () => undefined,
		notify: (...args: unknown[]) => {
			sink.push(args);
		},
		onTerminalInput: () => () => {},
		setStatus: () => {},
		setWorkingMessage: () => {},
		setWorkingVisible: () => {},
		setWorkingIndicator: () => {},
		setHiddenThinkingLabel: () => {},
		setWidget: () => {},
		setFooter: () => {},
		setHeader: () => {},
		setTitle: () => {},
		custom: async () => undefined,
		pasteToEditor: () => {},
		setEditorText: () => {},
		getEditorText: () => "",
		editor: async () => undefined,
		addAutocompleteProvider: () => {},
		setEditorComponent: () => {},
		getEditorComponent: () => undefined,
		getAllThemes: () => [],
		getTheme: () => undefined,
		setTheme: () => ({ success: false, error: "UI not available" }),
		getToolsExpanded: () => false,
		setToolsExpanded: () => {},
	} as unknown as ExtensionUIContext;
}

// The owned fixture binds in print mode with a no-op UI and delivers pfui's
// warnings to it during bind, which marks them delivered. Re-arm delivery and
// install a recording UI so a subsequent lifecycle emit re-delivers the same
// warnings for assertion, capturing the delivered notify calls.
function captureNotifications(active: PiSession): unknown[][] {
	const sink: unknown[][] = [];
	pfuiWarningState()?.deliveredWarnings.clear();
	active.session.extensionRunner.setUIContext(recordingUi(sink), "print");
	return sink;
}

function renderedPrompt(): string {
	return String((globalThis as Record<string, unknown>)[RENDERED_KEY] ?? "");
}

afterEach(async () => {
	await session?.dispose();
	session = undefined;
	vi.restoreAllMocks();
	delete (globalThis as Record<symbol, unknown>)[PFUI_STATE_KEY];
	delete (globalThis as Record<string, unknown>)[RENDERED_KEY];
	for (const directory of temporaryPaths.splice(0)) {
		rmSync(directory, { recursive: true, force: true });
	}
});

describe("pfui contract", () => {
	it("writes enabled lifecycle debug records in an isolated sandbox", async () => {
		const root = mkdtempSync(path.join(tmpdir(), "pi-ext-pfui-debug-"));
		try {
			session = await startSession({
				extensionPaths: [ENTRY],
				cwd: root,
				env: {
					PI_PFUI_DEBUG: "1",
					XDG_STATE_HOME: path.join(root, "state"),
				},
			});
			await session.session.extensionRunner.emit({
				type: "session_start",
				reason: "startup",
			});
			await emittedOptions({ ...baseOptions(), customPrompt: "CUSTOM" });
			await session.session.extensionRunner.emit({
				type: "session_shutdown",
				reason: "quit",
			});
			const events = readdirSync(
				path.join(root, "state", "pi-ext", "debug", "pfui"),
			).flatMap((file) =>
				readFileSync(
					path.join(root, "state", "pi-ext", "debug", "pfui", file),
					"utf8",
				)
					.trim()
					.split("\n")
					.map((line) => JSON.parse(line)),
			);
			expect(events).toEqual(
				expect.arrayContaining([
					expect.objectContaining({
						extension: "pfui",
						event: "session.start",
					}),
					expect.objectContaining({
						extension: "pfui",
						event: "session.shutdown",
					}),
					expect.objectContaining({
						event: "prompt.apply",
						outcome: "custom_prompt",
					}),
				]),
			);
		} finally {
			await session?.dispose();
			session = undefined;
			rmSync(root, { recursive: true, force: true });
		}
	});

	it("loads through Pi once, first in the generated package list, while the workspace root exposes nothing", async () => {
		session = await startSession({ extensionPaths: [ENTRY] });

		expect(session.extensions).toHaveLength(1);
		const manifest = JSON.parse(
			readFileSync(path.join(repositoryRoot, "package.json"), "utf8"),
		) as { pi?: unknown };
		expect(manifest.pi).toEqual({});

		const packageManager = new DefaultPackageManager({
			cwd: session.cwd,
			agentDir: session.agentDir,
			settingsManager: SettingsManager.inMemory(),
		});
		const resolved = await packageManager.resolveExtensionSources(
			[repositoryRoot],
			{ temporary: true },
		);
		expect(resolved.extensions).toEqual([]);

		// Pi loads one generated package per extension; pfui must come first so it
		// owns the system prompt before other extensions contribute sections.
		const entries = JSON.parse(
			execFileSync(
				process.execPath,
				["--no-warnings", "scripts/build/settings-entries.ts"],
				{ cwd: repositoryRoot, encoding: "utf8" },
			),
		) as string[];
		const suffix = (entry: string) => entry.split(path.sep).slice(-2).join("/");
		expect(suffix(entries[0] ?? "")).toBe("dist/pfui");
		expect(suffix(entries[1] ?? "")).toBe("dist/footer");
		expect(
			entries.filter((entry) => suffix(entry) === "dist/pfui"),
		).toHaveLength(1);
		expect(new Set(entries).size).toBe(entries.length);
	});

	it("composes the fallback with dynamic tools and deduplicated guidelines", async () => {
		session = await startSession({ extensionPaths: [ENTRY] });
		const options = baseOptions();
		options.selectedTools = ["write", "read", "write"];
		options.toolSnippets = {
			read: "Read current files",
			write: "Write complete files",
			inactive: "Must stay hidden",
		};
		options.promptGuidelines = [
			"  Keep paths explicit.  ",
			"Keep paths explicit.",
			"",
			"Verify changes.",
		];

		const result = await emittedOptions(options);
		const identity = readFileSync(
			path.join(extensionRoot, "SYSTEM.md"),
			"utf8",
		).trim();

		expect(result.customPrompt).toBe(identity);
		expect(result.sections?.["tools"]).toContain(
			"- write: Write complete files\n- read: Read current files",
		);
		expect(result.sections?.["tools"]).not.toContain("inactive");
		expect(result.sections?.["general_guidelines"]).toBe(
			"Keep paths explicit.\nVerify changes.",
		);
		expect(result.sections?.["tool_guidelines"]).toBe("");
	});

	it.each([{ hiddenTools: [] }, { hiddenTools: ["read", "bash"] }])(
		"respects hiddenTools $hiddenTools without warning",
		async ({ hiddenTools }) => {
			session = await startSession({
				extensionPaths: [
					writeExtension(`export default function (pi) {
	pi.on("before_agent_start", (event) => {
		event.systemPromptOptions.hiddenTools = ${JSON.stringify(hiddenTools)};
	});
}`),
					ENTRY,
				],
			});
			const result = await emittedOptions({
				...baseOptions(),
				selectedTools: ["read", "bash", "codemode"],
				toolSnippets: {
					read: "Read files",
					bash: "Run shell",
					codemode: "Call tools indirectly",
				},
				toolGuidelines: {
					read: ["Read guidance"],
					bash: ["Shell guidance"],
					codemode: ["Codemode guidance"],
				},
			});
			const sections = result.sections;
			expect(sections?.["tools"]).toContain("- codemode:");
			expect(sections?.["tool_guidelines"]).toContain("Codemode guidance");
			if (hiddenTools.length) {
				expect(sections?.["tools"]).not.toContain("- read:");
				expect(sections?.["tools"]).not.toContain("- bash:");
				expect(sections?.["general_guidelines"]).toBe("");
				expect(sections?.["tool_guidelines"]).not.toContain("Read guidance");
				expect(sections?.["tool_guidelines"]).not.toContain("Shell guidance");
			} else {
				expect(sections?.["tools"]).toContain("- read:");
				expect(sections?.["tools"]).toContain("- bash:");
				expect(sections?.["general_guidelines"]).toContain("Use bash");
				expect(sections?.["tool_guidelines"]).toContain("Read guidance");
				expect(sections?.["tool_guidelines"]).toContain("Shell guidance");
			}
			expect([...(pfuiWarningState()?.warnings ?? [])]).not.toEqual(
				expect.arrayContaining([expect.stringContaining('"hiddenTools"')]),
			);
		},
	);

	it("renders guidelines contributed by later extensions", async () => {
		session = await startSession({
			extensionPaths: [
				ENTRY,
				writeExtension(CONTRIBUTE_GUIDELINES),
				writeExtension(OBSERVE_PROMPT),
			],
		});

		await emittedOptions(baseOptions());

		expect(renderedPrompt()).toContain(`<general_guidelines>
Late general guidance
</general_guidelines>`);
		expect(renderedPrompt()).toContain(`<tool_guidelines>
<tool name="read">
Late read guidance
</tool>
</tool_guidelines>`);
	});

	it("passes a configured custom prompt through unchanged", async () => {
		session = await startSession({ extensionPaths: [ENTRY] });
		const options = { ...baseOptions(), customPrompt: "CUSTOM" };

		const result = await emittedOptions(options);
		expect(result.customPrompt).toBe("CUSTOM");
		expect(result.sections?.["tools"]).toBeUndefined();
		expect(result.sections?.["general_guidelines"]).toBeUndefined();
		expect(result.sections?.["tool_guidelines"]).toBeUndefined();
	});

	it("leaves the fallback available for later extension composition", async () => {
		session = await startSession({
			extensionPaths: [ENTRY, writeExtension(APPEND_LATER)],
		});

		const result = await emittedOptions(baseOptions());
		expect(result.forceSystemPrompt).toContain(
			"You are the spirit in the machine.\nBound inside Pi, give the user's will form.",
		);
		expect(result.forceSystemPrompt).toContain("<tools>");
		expect(result.forceSystemPrompt).not.toContain("<rules>");
		expect(result.forceSystemPrompt).toMatch(/<\/tools>\n\nLATER EXTENSION$/);
	});

	it("preserves Pi prompt section formatting and normalizes cwd", async () => {
		session = await startSession({
			extensionPaths: [ENTRY, writeExtension(OBSERVE_PROMPT)],
		});
		const skill = session.session.resourceLoader
			.getSkills()
			.skills.find(
				(candidate: { name: string }) => candidate.name === "pi-knowledge",
			);
		expect(skill).toBeDefined();
		const options: BuildSystemPromptOptions = {
			...baseOptions(),
			cwd: "C:\\work\\project",
			appendSystemPrompt: "APPENDED",
			contextFiles: [{ path: "/repo/AGENTS.md", content: "PROJECT RULE" }],
			skills: [skill!],
		};

		const result = await emittedOptions(options);
		const identity = readFileSync(
			path.join(extensionRoot, "SYSTEM.md"),
			"utf8",
		).trim();
		expect(result.customPrompt).toBe(identity);
		expect(result.appendSystemPrompt).toBe("APPENDED");
		expect(result.contextFiles).toEqual([
			{ path: "/repo/AGENTS.md", content: "PROJECT RULE" },
		]);
		expect(result.skills).toEqual([skill]);
		expect(result.sections?.["tools"]).toContain("- read: Read files");
		expect(result.sections?.["general_guidelines"]).toBe("");
		expect(result.sections?.["tool_guidelines"]).toBe("");
		expect(renderedPrompt()).not.toContain("<general_guidelines>");
		expect(renderedPrompt()).not.toContain("<tool_guidelines>");
		expect(result.sections?.["cwd"]).toBeUndefined();
		expect(result.sections?.["docs"]).toBeUndefined();
	});

	it("omits skills when neither read nor bash is active", async () => {
		session = await startSession({ extensionPaths: [ENTRY] });
		const skill = session.session.resourceLoader
			.getSkills()
			.skills.find(
				(candidate: { name: string }) => candidate.name === "pi-knowledge",
			);
		const result = await emittedOptions({
			...baseOptions(),
			selectedTools: ["powershell"],
			toolSnippets: { powershell: "Run PowerShell" },
			skills: [skill!],
		});

		expect(result.skills).toEqual([skill]);
		expect(result.sections?.["tools"]).not.toContain("pi-knowledge");
		expect(result.sections?.["general_guidelines"]).toBe(
			"Use PowerShell for file operations like listing, searching, and finding files",
		);
		expect(result.sections?.["tool_guidelines"]).toBe("");
	});

	it("separates general and tool guidelines without escaping their text", async () => {
		session = await startSession({ extensionPaths: [ENTRY] });
		const result = await emittedOptions({
			...baseOptions(),
			selectedTools: ["edit", "angel"],
			toolSnippets: { edit: "Edit files", angel: "Consult Angel" },
			toolGuidelines: {
				edit: ["Edit carefully", "Shared <rule> & text", "Edit carefully"],
				angel: ["Shared <rule> & text", "Ask a focused question"],
			},
			promptGuidelines: ["Global guidance", "Global guidance"],
		});

		expect(result.sections?.["general_guidelines"]).toBe("Global guidance");
		expect(result.sections?.["tool_guidelines"]).toBe(`<tool name="edit">
Edit carefully
Shared <rule> & text
</tool>

<tool name="angel">
Shared <rule> & text
Ask a focused question
</tool>`);
	});

	it("discovers the bundled pi-knowledge skill with its contract", async () => {
		session = await startSession({ extensionPaths: [ENTRY] });
		const skill = session.session.resourceLoader
			.getSkills()
			.skills.find(
				(candidate: { name: string }) => candidate.name === "pi-knowledge",
			);

		expect(skill?.filePath).toBe(
			path.join(extensionRoot, "skills", "pi-knowledge", "SKILL.md"),
		);
		const source = readFileSync(skill!.filePath, "utf8");
		expect(source).toContain("Requires Pi.");
		expect(source).toContain(
			"questions about Pi and for implementing or changing Pi",
		);
		expect(source).toContain(
			"Resolve only the needed variables using available tools",
		);
		expect(source).toContain("Never dump the complete environment");
		expect(source).toContain("If required variables are missing");
		expect(source).not.toMatch(/Bash|PowerShell|active shell/);
		expect(source).toContain("Read every selected Markdown file completely");
		expect(source).toContain("If a mapped file moved or is absent");
	});

	it("keeps a valid bundled skill when Pi reports only warnings", async () => {
		const warned = copiedPfui("pfui-warned-");
		cpSync(
			path.join(extensionRoot, "SYSTEM.md"),
			path.join(warned, "SYSTEM.md"),
		);
		mkdirSync(path.join(warned, "skills", "pi-knowledge"), {
			recursive: true,
		});
		writeFileSync(
			path.join(warned, "skills", "pi-knowledge", "SKILL.md"),
			`---\nname: pi-knowledge\ndescription: "${"x".repeat(1025)}"\n---\n\n# Pi knowledge\n`,
		);
		session = await startSession({
			cwd: tempDirectory("pfui-warned-cwd-"),
			extensionPaths: [path.join(warned, "index.ts")],
		});

		expect(
			session.session.resourceLoader
				.getSkills()
				.skills.some(
					(candidate: { name: string }) => candidate.name === "pi-knowledge",
				),
		).toBe(true);
	});

	it("preserves Pi 0.86 tool guidelines and custom sections", async () => {
		session = await startSession({ extensionPaths: [ENTRY] });
		const options: BuildSystemPromptOptions = {
			...baseOptions(),
			toolGuidelines: {
				read: ["Read before editing."],
			},
			sections: {
				custom_context: "Keep the change focused.",
			},
		};

		const notifications = captureNotifications(session);
		const result = await emittedOptions(options);

		expect(notifications).toHaveLength(0);
		expect(result.sections?.["general_guidelines"]).toBe("");
		expect(result.sections?.["tool_guidelines"]).toBe(`<tool name="read">
Read before editing.
</tool>`);
		expect(result.sections?.["custom_context"]).toBe(
			"Keep the change focused.",
		);
	});

	it("exports public Pi context and cleans only unchanged owned values", async () => {
		session = await startSession({
			extensionPaths: [ENTRY],
			env: { PI_CONTEXT_VERSION: VERSION },
		});
		const packageDir = getPackageDir();
		const expected = {
			PI_CONTEXT_PACKAGE_DIR: packageDir,
			PI_CONTEXT_AGENT_DIR: getAgentDir(),
			PI_CONTEXT_README_PATH: getReadmePath(),
			PI_CONTEXT_DOCS_PATH: getDocsPath(),
			PI_CONTEXT_EXAMPLES_PATH: getExamplesPath(),
			PI_CONTEXT_CHANGELOG_PATH: path.join(packageDir, "CHANGELOG.md"),
			PI_CONTEXT_PACKAGE_JSON_PATH: path.join(packageDir, "package.json"),
			PI_CONTEXT_VERSION: VERSION,
			PI_CONTEXT_CONFIG_DIR_NAME: CONFIG_DIR_NAME,
		};
		for (const [name, value] of Object.entries(expected)) {
			expect(process.env[name]).toBe(value);
		}

		// The original observed these values inside a later extension's
		// session_shutdown handler, which runs after pfui's cleanup. Reading
		// process.env immediately after the shutdown emit observes the same state.
		process.env["PI_CONTEXT_DOCS_PATH"] = "kept-after-shutdown";
		await session.session.extensionRunner.emit({
			type: "session_shutdown",
			reason: "quit",
		});

		expect(process.env["PI_CONTEXT_PACKAGE_DIR"]).toBeUndefined();
		expect(process.env["PI_CONTEXT_DOCS_PATH"]).toBe("kept-after-shutdown");
		expect(process.env["PI_CONTEXT_VERSION"]).toBe(VERSION);
	});

	it("keeps running Pi context when the managed pointer selects a different release", async () => {
		const installRoot = tempDirectory("pfui-managed-");
		const packageDir = path.join(
			installRoot,
			"releases",
			"9.8.7",
			"node_modules",
			"@earendil-works",
			"pi-coding-agent",
		);
		mkdirSync(path.join(packageDir, "docs"), { recursive: true });
		mkdirSync(path.join(packageDir, "examples"));
		writeFileSync(path.join(installRoot, "current-version"), "9.8.7\n");
		writeFileSync(
			path.join(packageDir, "package.json"),
			JSON.stringify({
				name: "@earendil-works/pi-coding-agent",
				version: "9.8.7",
			}),
		);
		writeFileSync(path.join(packageDir, "README.md"), "# Pi");
		writeFileSync(path.join(packageDir, "CHANGELOG.md"), "# Changelog");
		session = await startSession({
			extensionPaths: [ENTRY],
			env: { PI_MANAGED_INSTALL_ROOT: installRoot },
		});
		const runningPackage = getPackageDir();
		const expected = {
			PI_CONTEXT_PACKAGE_DIR: runningPackage,
			PI_CONTEXT_README_PATH: getReadmePath(),
			PI_CONTEXT_DOCS_PATH: getDocsPath(),
			PI_CONTEXT_EXAMPLES_PATH: getExamplesPath(),
			PI_CONTEXT_CHANGELOG_PATH: path.join(runningPackage, "CHANGELOG.md"),
			PI_CONTEXT_PACKAGE_JSON_PATH: path.join(runningPackage, "package.json"),
			PI_CONTEXT_VERSION: VERSION,
		};
		for (const [name, value] of Object.entries(expected))
			expect(process.env[name]).toBe(value);
	});

	it.each(["missing", "traversal", "metadata"])(
		"keeps running Pi context despite %s managed pointer errors",
		async (failure) => {
			const installRoot = tempDirectory("pfui-managed-invalid-");
			if (failure === "traversal")
				writeFileSync(path.join(installRoot, "current-version"), "../outside");
			if (failure === "metadata") {
				writeFileSync(path.join(installRoot, "current-version"), "9.8.7");
				const packageDir = path.join(
					installRoot,
					"releases",
					"9.8.7",
					"node_modules",
					"@earendil-works",
					"pi-coding-agent",
				);
				mkdirSync(packageDir, { recursive: true });
				writeFileSync(
					path.join(packageDir, "package.json"),
					JSON.stringify({ name: "other", version: "9.8.7" }),
				);
			}
			session = await startSession({
				extensionPaths: [ENTRY],
				env: { PI_MANAGED_INSTALL_ROOT: installRoot },
			});
			expect(process.env["PI_CONTEXT_PACKAGE_DIR"]).toBe(getPackageDir());
			expect(process.env["PI_CONTEXT_VERSION"]).toBe(VERSION);
			expect(process.env["PI_CONTEXT_DOCS_PATH"]).toBe(getDocsPath());
			const notifications = captureNotifications(session);
			await session.session.extensionRunner.emit({
				type: "session_start",
				reason: "startup",
			});
			expect(notifications).toEqual([]);
		},
	);

	it("preserves a conflicting context variable and warns", async () => {
		session = await startSession({
			extensionPaths: [ENTRY],
			env: { PI_CONTEXT_VERSION: "external-version" },
		});

		expect(process.env["PI_CONTEXT_VERSION"]).toBe("external-version");
		const notifications = captureNotifications(session);
		await session.session.extensionRunner.emit({
			type: "session_start",
			reason: "startup",
		});
		expect(notifications).toHaveLength(1);
		expect(String(notifications[0]?.[0])).toContain(
			"PI_CONTEXT_VERSION already has a different value",
		);

		await session.session.extensionRunner.emit({
			type: "session_shutdown",
			reason: "quit",
		});
		expect(process.env["PI_CONTEXT_VERSION"]).toBe("external-version");
	});

	it("omits a missing resolved resource path and warns", async () => {
		const cwd = tempDirectory("pfui-missing-path-cwd-");
		session = await startSession({
			extensionPaths: [ENTRY],
			cwd,
			// The fixture always creates its agent dir, so point the extension's
			// resolved agent dir at a missing path to reproduce the omitted resource.
			env: { PI_CODING_AGENT_DIR: path.join(cwd, "absent-agent") },
		});

		expect(process.env["PI_CONTEXT_AGENT_DIR"]).toBeUndefined();
		const notifications = captureNotifications(session);
		await session.session.extensionRunner.emit({
			type: "session_start",
			reason: "startup",
		});
		expect(notifications).toHaveLength(1);
		expect(String(notifications[0]?.[0])).toContain(
			"PI_CONTEXT_AGENT_DIR was omitted",
		);
	});

	it("preserves Pi's prompt when the bundled fallback is missing", async () => {
		const broken = copiedPfui("pfui-missing-fallback-");
		cpSync(path.join(extensionRoot, "skills"), path.join(broken, "skills"), {
			recursive: true,
		});
		session = await startSession({
			cwd: tempDirectory("pfui-missing-fallback-cwd-"),
			extensionPaths: [path.join(broken, "index.ts")],
		});

		const notifications = captureNotifications(session);
		const result = await emittedOptions(baseOptions());
		expect(result.customPrompt).toBeUndefined();
		const warnings = notifications
			.map((notification) => String(notification[0]))
			.join("\n");
		expect(warnings).toContain("Bundled SYSTEM.md is unavailable");
	});

	it.each([
		["missing", undefined, "is missing"],
		["invalid", "---\nname: pi-knowledge\n---\ninvalid\n", "is invalid"],
	])("omits a %s bundled skill and warns", async (_case, source, message) => {
		const broken = copiedPfui(`pfui-${_case}-skill-`);
		cpSync(
			path.join(extensionRoot, "SYSTEM.md"),
			path.join(broken, "SYSTEM.md"),
		);
		if (source) {
			mkdirSync(path.join(broken, "skills", "pi-knowledge"), {
				recursive: true,
			});
			writeFileSync(
				path.join(broken, "skills", "pi-knowledge", "SKILL.md"),
				source,
			);
		}
		session = await startSession({
			cwd: tempDirectory(`pfui-${_case}-skill-cwd-`),
			extensionPaths: [path.join(broken, "index.ts")],
		});

		expect(
			session.session.resourceLoader
				.getSkills()
				.skills.some(
					(candidate: { name: string }) => candidate.name === "pi-knowledge",
				),
		).toBe(false);
		const notifications = captureNotifications(session);
		await session.session.extensionRunner.emit({
			type: "session_start",
			reason: "startup",
		});
		const warnings = notifications
			.map((notification) => String(notification[0]))
			.join("\n");
		expect(warnings).toContain(`Bundled pi-knowledge skill ${message}`);
	});
});