<?php

  // this is the local filesystem path to the webroot of composer.tiki.org - i.e. where the dist directory lives
  $composer_packages_path = '/path/to/composer/webroot';

  $base_url = 'https://composer.tiki.org/';
  $packages_url = $base_url .'packages.json';
  $packages = [];

  $content = parse_packages_url($packages_url);
  $packages = array_merge($packages, $content['packages']);
  if (!empty($content['includes'])) {
    foreach ($content['includes'] as $file => $sha1) {
      $include_url = $base_url . $file;
      $content = parse_packages_url($include_url);
      $packages = array_merge($packages, $content['packages']);
    }
  }

  $urls = [];
  foreach ($packages as $package => $versions) {
    foreach ($versions as $version) {
      if (! isset($version['dist'])) {
        continue;
      }
      $urls[] = str_replace($base_url, '', $version['dist']['url']);
    }
  }

  echo "Found ".count($packages)." packages with ".count($urls)." versions.\n";

  $directory = new \RecursiveDirectoryIterator($composer_packages_path.'/dist', \FilesystemIterator::FOLLOW_SYMLINKS);
  $filter = new \RecursiveCallbackFilterIterator($directory, function ($current, $key, $iterator) {
    // Skip hidden files and directories.
    if ($current->getFilename()[0] === '.') {
      return FALSE;
    }
    return true;
  });
  $iterator = new \RecursiveIteratorIterator($filter);
  foreach ($iterator as $info) {
    $file = preg_replace('/^\//', '', str_replace($composer_packages_path, '', $info->getPathname()));
    if (! in_array($file, $urls)) {
      echo "$file\n";
      if (isset($argv[1]) && $argv[1] == '--cleanup') {
        unlink($info->getPathname());
      }
    }
  }

  if (!isset($argv[1]) || $argv[1] != '--cleanup') {
    echo "Script run without --cleanup option - it only lists files to be deleted. If you want to actually remove the files, run the script with --cleanup option.\n";
  }

  function parse_packages_url($url) {
    echo "Processing $url\n";
    $content = file_get_contents($url);
    if (empty($content)) {
      die("Empty content in packages url: $url\n");
    }
    $parsed = json_decode($content, true);
    if (empty($parsed)) {
      die("Failed parsing $url\n");
    }
    return $parsed;
  }