import { readFileSync } from "node:fs";
import { dirname, join } from "node:path";
import { fileURLToPath } from "node:url";

export type CliOptions = {
  port: number;
  noAuth: boolean;
  help: boolean;
  version: boolean;
};

const DEFAULT_PORT = 8787;

function getPackageVersion(): string {
  try {
    const dir = dirname(fileURLToPath(import.meta.url));
    const packageJsonPath = join(dir, "..", "package.json");
    const packageJson = JSON.parse(readFileSync(packageJsonPath, "utf8")) as { version?: string };
    return packageJson.version ?? "0.0.0";
  } catch {
    return "0.0.0";
  }
}

export function parseCliArgs(argv: string[]): CliOptions {
  let port = Number(process.env.PORT);
  if (Number.isNaN(port)) {
    port = DEFAULT_PORT;
  }

  let noAuth = false;
  let help = false;
  let version = false;

  for (let index = 0; index < argv.length; index += 1) {
    const arg = argv[index];

    if (arg === "--help" || arg === "-h") {
      help = true;
      continue;
    }

    if (arg === "--version" || arg === "-v") {
      version = true;
      continue;
    }

    if (arg === "--no-auth") {
      noAuth = true;
      continue;
    }

    if (arg === "--port" || arg === "-p") {
      const value = Number(argv[index + 1]);
      if (!Number.isNaN(value)) {
        port = value;
        index += 1;
      }
      continue;
    }

    if (arg.startsWith("--port=")) {
      const value = Number(arg.slice("--port=".length));
      if (!Number.isNaN(value)) {
        port = value;
      }
    }
  }

  return { port, noAuth, help, version };
}

export function printHelp(): void {
  console.log(`pi-mobile-hub — Pi Mobile API hub

Usage:
  pi-mobile-hub [options]

Options:
  -p, --port <number>   Port to listen on (default: 8787)
      --no-auth         Disable pairing token requirement
  -h, --help            Show this help message
  -v, --version         Show version number

Examples:
  npx pi-mobile-hub
  npx pi-mobile-hub --port 9000
  npx pi-mobile-hub --no-auth
`);
}

export function printVersion(): void {
  console.log(getPackageVersion());
}