import { readdirSync, readFileSync } from "node:fs";
import path from "node:path";
import { fileURLToPath } from "node:url";
import { afterEach, describe, expect, it, vi } from "vitest";
import {
	createPiSession,
	type PiSession,
} from "../../../test/fixture/create-pi-session.ts";

const extensionPath = fileURLToPath(new URL("../index.ts", import.meta.url));

describe("context-size debug", () => {
	let session: PiSession | undefined;

	afterEach(async () => {
		await session?.dispose();
		session = undefined;
	});

	it("writes its lifecycle JSONL through the standalone factory", async () => {
		// The fixture applies env BEFORE loading, so the debug module reads
		// PI_CONTEXT_SIZE_DEBUG at import; no withProcessEnv/vi.resetModules needed.
		session = await createPiSession({
			extensionPaths: [extensionPath],
			env: { PI_CONTEXT_SIZE_DEBUG: "1" },
		});
		const runner = session.session.extensionRunner;
		await runner.emit({ type: "session_start", reason: "startup" });
		await runner.emit({ type: "session_shutdown", reason: "quit" });

		const stateHome = session.env["XDG_STATE_HOME"];
		if (!stateHome) throw new Error("missing sandbox state home");
		const directory = path.join(stateHome, "pi-ext", "debug", "context-size");

		// Debug records flush asynchronously; poll until both events appear.
		const events = await vi.waitFor(() => {
			const [file] = readdirSync(directory);
			if (!file) throw new Error("no debug file yet");
			const parsed = readFileSync(path.join(directory, file), "utf8")
				.trim()
				.split("\n")
				.map((line) => JSON.parse(line).event);
			if (
				!parsed.includes("session.start") ||
				!parsed.includes("session.shutdown")
			)
				throw new Error("lifecycle events not flushed yet");
			return parsed;
		});
		expect(events).toEqual(
			expect.arrayContaining(["session.start", "session.shutdown"]),
		);
	});
});