<?php
# I think the point of this is to clean out vendor/ on fortrabbit automatically

/*
 * Generate a manifest:
 *
 *       php clean-dirs.php save vendor
 *       git add .present.vendor # optional, may be rsynced/uploaded to document root
 */

/** pretend to generate some assets */
function build(): array {
    if (!is_dir('dist')) mkdir('dist');
    $extensions = ['js', 'css', 'png'];
    $time = date('Ym-d_H:i:s');
    $new_files = [];
    foreach (range(1, 10) as $e) {
        $ix = rand(0, count($extensions)-1);
        $ext = $extensions[$ix];
        $current_file = "dist/$time.$e.$ext";
        $new_files[] = $current_file;
        touch($current_file);
    }
    return $new_files;
}

/** record present files */
function save(string $dir = 'dist/'): string {
    $dir = trim($dir, '/');
    $files = _find($dir, '/.*/', 'fl');
    $outFile = realpath(__DIR__) . "/.present.$dir";
    file_put_contents($outFile, implode(PHP_EOL, $files).PHP_EOL);
    return $outFile;
}

/**
 * remove files below DIR iff manifest file DIR/../.prerent.dir exists.
 * the manifest file enumerates files to keep.
 * everything below DIR is removed if the manifest file is empty.
 * nothing is removed if the manifest file is missing.
 */
function purge(string $dir = 'dist/'): void {
    $dir = trim($dir, '/');
    $rpath = dirname(realpath($dir));
    $keepFilesFrom = "$rpath/.present.$dir";
    if (! is_dir($dir)) return;
    if (! is_readable($keepFilesFrom)) return;

    $keep = [];
    $keeps = file_get_contents($keepFilesFrom);
    if (strlen($keeps)) {
        $keep = explode("\n", $keeps);
        unset($keeps);
    }

    $purgeList = _find($dir, '/.*/', 'fl');
    $purgeList = array_flip($purgeList);

    foreach ($keep as $keep1) {
        if (isset($purgeList[$keep1])) {
            unset($purgeList[$keep1]);
        }
    }
    foreach ($purgeList as $goner => $i) {
        $err = fopen('php://stderr', 'w');
        unlink($goner);
        fprintf($err, "gone: %s\n", $goner);
    }
    unlink($keepFilesFrom);
}

function _find($folder, $pattern = '/.*/', $filter = 'dfl'): array {
    $dir = new RecursiveDirectoryIterator($folder);
    $ite = new RecursiveIteratorIterator($dir);
    /** @var SplFileInfo[] $files */
    $files = new RegexIterator($ite, $pattern, RegexIterator::MATCH);
    $ff = [];
    foreach($files as $file) {
        $f = false !== strpos($filter, 'f') && $file->isFile();
        $d = false !== strpos($filter, 'd') && $file->isDir();
        $l = false !== strpos($filter, 'l') && $file->isLink();
        if ($f || $d || $l)
            $ff[] = $file->getPathname();
    }
    return $ff;
}

function _cat(array $stuff): string {
    return join(PHP_EOL, $stuff) . PHP_EOL;
}

function _help() {
    preg_match_all('/\nfunction ([a-z][^:]+)/s', file_get_contents(__FILE__), $functions, PREG_PATTERN_ORDER);
    printf("Usage:\n\tphp %s fn-name\n\t..where fn is one of:\n\n", basename(__FILE__));
    echo _cat($functions[1]);
}


function _main() {
    global $argc, $argv;
    if ($argc >= 2) {
        $path = $argv[2] ?? 'dist/';
        switch ($argv[1]) {
            case 'build': echo _cat(build()); break;
            case 'save': echo _cat([save($path)]); break;
            case 'purge':
                foreach (['dist/', 'vendor/'] as $purgeDir) {
                    purge($purgeDir);
                }
                break;
            default:
                _help();
        }
    }
    if ($argc == 1) {
        _help();
    }
    if ($_GET['build'] ?? false) {
        _cat(build());
    }
}

_main();