import { spawnSync } from "node:child_process";
import { copyFileSync, mkdtempSync, rmSync, writeFileSync } from "node:fs";
import { tmpdir } from "node:os";
import { join } from "node:path";
import { fileURLToPath } from "node:url";

let compiled: string | undefined;

/** A real Windows executable: execFile/spawn intentionally cannot run .cmd shims. */
export function writeWindowsExecutable(
	directory: string,
	name: string,
	stdout: string,
	delayMs = 0,
): string {
	if (!compiled) {
		const root = mkdtempSync(join(tmpdir(), "pi-ext-windows-executable-"));
		const output = join(root, "fake-cli.exe");
		const compiler = join(
			process.env["SystemRoot"] ?? "C:\\Windows",
			"Microsoft.NET",
			"Framework64",
			"v4.0.30319",
			"csc.exe",
		);
		const result = spawnSync(
			compiler,
			[
				"/nologo",
				"/target:exe",
				`/out:${output}`,
				fileURLToPath(new URL("../fixtures/fake-cli.cs", import.meta.url)),
			],
			{ encoding: "utf8", timeout: 15_000, windowsHide: true },
		);
		if (result.error || result.status !== 0) {
			rmSync(root, { recursive: true, force: true });
			throw new Error(
				`Windows executable fixture compilation failed: ${result.error?.message ?? result.stderr ?? result.stdout}`,
			);
		}
		compiled = output;
		process.once("exit", () => {
			rmSync(root, {
				recursive: true,
				force: true,
				maxRetries: 3,
				retryDelay: 100,
			});
		});
	}
	const output = join(directory, `${name}.exe`);
	copyFileSync(compiled, output);
	writeFileSync(
		`${output}.response`,
		`${delayMs}\n${Buffer.from(stdout).toString("base64")}\n`,
	);
	return output;
}