import fs from "fs";
import path from "path";

export interface ResolvedCliTool {
  command: string;
  argsPrefix: string[];
}

export interface ResolveCliToolOptions {
  root: string;
  binary: string;
  platform?: NodeJS.Platform;
}

export const resolveCliTool = (
  options: ResolveCliToolOptions,
): ResolvedCliTool => {
  if (!/^[A-Za-z0-9][A-Za-z0-9_-]*$/.test(options.binary)) {
    throw new Error("CLI binary name is invalid");
  }
  const platform = options.platform || process.platform;
  const executable = platform === "win32" ? `${options.binary}.cmd` : options.binary;
  const localBinary = path.join(options.root, "node_modules", ".bin", executable);
  if (fs.existsSync(localBinary) && fs.statSync(localBinary).isFile()) {
    return { command: localBinary, argsPrefix: [] };
  }
  return {
    command: platform === "win32" ? "npx.cmd" : "npx",
    argsPrefix: ["--no-install", options.binary],
  };
};