import { randomUUID } from "node:crypto";
import { mkdtemp, realpath, writeFile } from "node:fs/promises";
import { tmpdir } from "node:os";
import path from "node:path";
import { afterEach, describe, expect, it } from "vitest";
import { checkToolAvailability, resolveCommand, spawnToText } from "../spawn";

const originalPath = process.env["PATH"];
const originalPathAlt = process.env["Path"];

afterEach(() => {
	if (originalPath === undefined) delete process.env["PATH"];
	else process.env["PATH"] = originalPath;
	if (originalPathAlt === undefined) delete process.env["Path"];
	else process.env["Path"] = originalPathAlt;
});

async function makeFakeTool(dir: string, name: string) {
	if (process.platform === "win32") {
		const toolPath = path.join(dir, `${name}.cmd`);
		await writeFile(toolPath, "@echo off\r\nexit /b 0\r\n");
		return toolPath;
	}

	const toolPath = path.join(dir, name);
	await writeFile(toolPath, "#!/bin/sh\nexit 0\n", { mode: 0o755 });
	return toolPath;
}

describe("checkToolAvailability", () => {
	it("finds executables on PATH without requiring Unix which", async () => {
		const dir = await mkdtemp(path.join(tmpdir(), "pi-web-path-"));
		const name = `fake-tool-${randomUUID()}`;
		await makeFakeTool(dir, name);
		process.env["PATH"] = dir;

		await expect(checkToolAvailability(name, "missing")).resolves.toBeNull();
	});

	it("does not keep stale negative cache entries after PATH changes", async () => {
		const dir = await mkdtemp(path.join(tmpdir(), "pi-web-path-"));
		const emptyDir = await mkdtemp(path.join(tmpdir(), "pi-web-empty-path-"));
		const name = `fake-tool-${randomUUID()}`;

		process.env["PATH"] = emptyDir;
		await expect(checkToolAvailability(name, "missing")).resolves.toBe(
			"missing",
		);

		await makeFakeTool(dir, name);
		process.env["PATH"] = dir;

		await expect(checkToolAvailability(name, "missing")).resolves.toBeNull();
	});

	it("resolves explicit command paths but rejects directories", async () => {
		const dir = await mkdtemp(path.join(tmpdir(), "pi-web-explicit-path-"));
		const name = `fake-tool-${randomUUID()}`;
		const executable = await makeFakeTool(dir, name);
		const resolved = await resolveCommand(path.join(dir, name));
		if (!resolved) throw new Error("Explicit command fixture was not resolved");
		// PATHEXT casing is not filesystem identity on Windows.
		expect(await realpath(resolved)).toBe(await realpath(executable));
		expect(await resolveCommand(dir)).toBeNull();
	});

	it("runs PATH-resolved tools without a shell-specific lookup utility", async () => {
		const dir = await mkdtemp(path.join(tmpdir(), "pi web path "));
		const name = `fake-tool-${randomUUID()}`;
		await makeFakeTool(dir, name);
		process.env["PATH"] = dir;

		await expect(spawnToText(name, ["arg with spaces"])).resolves.toBe("");
	});
});