export async function checkToolExists(toolName: string): Promise<boolean> {
  try {
    const command = new Deno.Command("which", {
      args: [toolName],
      stdout: "piped",
      stderr: "piped",
    });
    const { code } = await command.output();
    return code === 0;
  } catch {
    return false;
  }
}

export async function requireTool(
  toolName: string,
  installationInstructions: string,
): Promise<boolean> {
  const exists = await checkToolExists(toolName);
  if (!exists) {
    console.warn(`\n⚠️  [Pre-flight Check] Tool '${toolName}' is missing.`);
    console.warn(`   Please install it: ${installationInstructions}`);
    console.warn(`   Skipping execution that depends on this tool.\n`);
    return false;
  }
  return true;
}

export async function execTool(
  toolName: string,
  args: string[],
  options?: { stdin?: string },
): Promise<{ code: number; stdout: string; stderr: string }> {
  const commandOpts: Deno.CommandOptions = {
    args,
    stdout: "piped",
    stderr: "piped",
  };

  if (options?.stdin) {
    commandOpts.stdin = "piped";
  }

  const command = new Deno.Command(toolName, commandOpts);

  if (options?.stdin) {
    const process = command.spawn();
    const writer = process.stdin.getWriter();
    await writer.write(new TextEncoder().encode(options.stdin));
    await writer.close();

    const { code, stdout, stderr } = await process.output();
    return {
      code,
      stdout: new TextDecoder().decode(stdout),
      stderr: new TextDecoder().decode(stderr),
    };
  }

  const { code, stdout, stderr } = await command.output();
  return {
    code,
    stdout: new TextDecoder().decode(stdout),
    stderr: new TextDecoder().decode(stderr),
  };
}