import path from "node:path";

const WINDOWS_UNSAFE_CMD_CHARS_RE = /[&|<>%\r\n]/;

function isPnpmExecPath(value) {
  return /^pnpm(?:-cli)?(?:\.(?:c?js|cmd|exe))?$/.test(path.basename(value).toLowerCase());
}

function escapeForCmdExe(arg) {
  if (WINDOWS_UNSAFE_CMD_CHARS_RE.test(arg)) {
    throw new Error(`unsafe Windows cmd.exe argument detected: ${JSON.stringify(arg)}`);
  }
  const escaped = arg.replace(/\^/g, "^^");
  if (!escaped.includes(" ") && !escaped.includes('"')) {
    return escaped;
  }
  return `"${escaped.replace(/"/g, '""')}"`;
}

function buildCmdExeCommandLine(command, args) {
  return [escapeForCmdExe(command), ...args.map(escapeForCmdExe)].join(" ");
}

export function resolvePnpmRunner(params = {}) {
  const pnpmArgs = params.pnpmArgs ?? [];
  const npmExecPath = params.npmExecPath ?? process.env.npm_execpath;
  const nodeExecPath = params.nodeExecPath ?? process.execPath;
  const platform = params.platform ?? process.platform;
  const comSpec = params.comSpec ?? process.env.ComSpec ?? "cmd.exe";

  if (typeof npmExecPath === "string" && npmExecPath.length > 0 && isPnpmExecPath(npmExecPath)) {
    return {
      command: nodeExecPath,
      args: [npmExecPath, ...pnpmArgs],
      shell: false,
    };
  }

  if (platform === "win32") {
    return {
      command: comSpec,
      args: ["/d", "/s", "/c", buildCmdExeCommandLine("pnpm.cmd", pnpmArgs)],
      shell: false,
      windowsVerbatimArguments: true,
    };
  }

  return {
    command: "pnpm",
    args: pnpmArgs,
    shell: false,
  };
}