import { realpathSync } from 'node:fs';
import { arch, platform } from 'node:os';
import { join, relative, resolve } from 'node:path';
import { pathToFileURL } from 'node:url';
import {
  PI_RUNTIME_PACKAGE,
  defaultPiBundleTarget,
  stagePiRuntimeBundle,
} from './lib/pi-runtime-bundle.mjs';

function parseTarget(value) {
  const separator = value.lastIndexOf('-');
  if (separator <= 0 || separator === value.length - 1) {
    throw new Error(`Invalid Pi runtime target: ${value}`);
  }
  const target = {
    platform: value.slice(0, separator),
    arch: value.slice(separator + 1),
  };
  if (!['win32', 'darwin', 'linux'].includes(target.platform)) {
    throw new Error(`Unsupported Pi runtime platform: ${target.platform}`);
  }
  if (!['x64', 'arm64'].includes(target.arch)) {
    throw new Error(`Unsupported Pi runtime architecture: ${target.arch}`);
  }
  return target.platform === 'linux' ? { ...target, libc: 'glibc' } : target;
}

export function parseBundleArgs(argv) {
  const options = { outputRoot: resolve('build/pi-runtime'), targets: [] };
  for (let index = 0; index < argv.length; index += 1) {
    const argument = argv[index];
    if (argument === '--output') {
      const value = argv[index + 1];
      if (!value || value.startsWith('--')) throw new Error('--output requires a value');
      options.outputRoot = resolve(value);
      index += 1;
    }
    else if (argument === '--target') {
      const value = argv[index + 1];
      if (!value || value.startsWith('--')) throw new Error('--target requires a value');
      options.targets.push(parseTarget(value));
      index += 1;
    }
    else if (argument === '--release-targets') {
      const currentPlatform = platform();
      const arches = currentPlatform === 'win32' ? ['x64'] : ['x64', 'arm64'];
      options.targets.push(...arches.map((targetArch) => parseTarget(`${currentPlatform}-${targetArch}`)));
    }
    else if (argument === '--help') options.help = true;
    else throw new Error(`Unknown argument: ${argument}`);
  }
  if (options.targets.length === 0) options.targets.push(defaultPiBundleTarget());

  const unique = new Map(options.targets.map((target) => [
    `${target.platform}-${target.arch}`,
    target,
  ]));
  options.targets = [...unique.values()];
  for (const target of options.targets) {
    if (target.platform !== platform()) {
      throw new Error(
        `Pi runtime ${target.platform}-${target.arch} must be staged on ${target.platform}, current host is ${platform()}-${arch()}`,
      );
    }
  }
  return options;
}

function printHelp() {
  process.stdout.write('Usage: node scripts/bundle-pi-runtime.mjs [options]\n\n');
  process.stdout.write('  --target <platform-arch>  Stage one runtime target (repeatable)\n');
  process.stdout.write('  --release-targets         Stage every configured architecture for the host OS\n');
  process.stdout.write('  --output <directory>      Output root (default: build/pi-runtime)\n');
}

export async function bundlePiRuntime(options, projectRoot = process.cwd()) {
  const resolvedProjectRoot = resolve(projectRoot);
  const sourcePackageRoot = realpathSync(join(
    resolvedProjectRoot,
    'node_modules',
    ...PI_RUNTIME_PACKAGE.split('/'),
  ));
  const results = [];
  for (const target of options.targets) {
    const destination = join(options.outputRoot, `${target.platform}-${target.arch}`);
    const destinationRelative = relative(options.outputRoot, destination);
    if (destinationRelative.startsWith('..') || destinationRelative === '') {
      throw new Error(`Unsafe Pi runtime destination: ${destination}`);
    }
    const manifest = await stagePiRuntimeBundle({
      projectRoot: resolvedProjectRoot,
      sourcePackageRoot,
      destination,
      target,
    });
    results.push({ destination, manifest });
  }
  return results;
}

async function main() {
  const options = parseBundleArgs(process.argv.slice(2));
  if (options.help) {
    printHelp();
    return;
  }
  const results = await bundlePiRuntime(options);
  process.stdout.write(`${JSON.stringify(results.map(({ destination, manifest }) => ({
    destination,
    target: manifest.target,
    packageCount: manifest.productionPackages.length,
    assetCount: manifest.runtimeAssets.length,
  })), null, 2)}\n`);
}

const isMain = process.argv[1] && pathToFileURL(resolve(process.argv[1])).href === import.meta.url;
if (isMain) {
  main().catch((error) => {
    process.stderr.write(`${error.stack ?? error.message}\n`);
    process.exitCode = 1;
  });
}