import { spawn } from "node:child_process";

const MAX_OUTPUT_BYTES = 10 * 1024 * 1024;

export interface RunCliOptions {
  stdin?: string;
  windowsCmdShim?: boolean;
}

function isCmdShim(bin: string, force = false): boolean {
  return process.platform === "win32" && (force || /(?:\.cmd|\.bat)$/i.test(bin));
}

export function runCli(
  bin: string,
  args: string[],
  timeoutMs = 120_000,
  options: RunCliOptions = {},
): Promise<string> {
  return new Promise((resolve) => {
    // ponytail: only Windows command shims need cmd.exe; real .exe paths keep argv semantics.
    const command = isCmdShim(bin, options.windowsCmdShim) ? process.env.ComSpec ?? "cmd.exe" : bin;
    const commandArgs = isCmdShim(bin, options.windowsCmdShim) ? ["/d", "/s", "/c", bin, ...args] : args;
    const child = spawn(command, commandArgs, {
      shell: false,
      timeout: timeoutMs,
      windowsHide: true,
    });

    let stdout = "";
    let stderr = "";
    let killedForOutput = false;
    const append = (target: "stdout" | "stderr", chunk: Buffer) => {
      if (stdout.length + stderr.length + chunk.length > MAX_OUTPUT_BYTES) {
        killedForOutput = true;
        child.kill();
        return;
      }
      if (target === "stdout") stdout += chunk.toString();
      else stderr += chunk.toString();
    };

    child.stdout.on("data", (d) => append("stdout", d));
    child.stderr.on("data", (d) => append("stderr", d));
    child.on("error", (err) => resolve(`[CLI error: ${err.message.slice(0, 200)}]`));
    child.on("close", (code) => {
      if (killedForOutput) {
        resolve(`[CLI error: output exceeded ${MAX_OUTPUT_BYTES} bytes]`);
        return;
      }
      if (code === 0) {
        resolve(stdout.trim());
        return;
      }
      resolve(`[CLI exited ${code ?? "unknown"}: ${(stderr || stdout).slice(0, 400) || "no output"}]`);
    });

    if (options.stdin !== undefined) child.stdin.end(options.stdin);
  });
}