#!/usr/bin/env php
<?php
/**
 * This script monitors a folder for changes and forces a change in the inode or file-modification time
 * if it detects a change or deletion.
 *
 * Basically it's a PHP re-implementation of https://github.com/sillypog/inotify-proxy
 *
 * I do this because docker-sync was not copying changes from my MacOS folder to volume that was used by
 * my docker container. And docker-sync is the only way to get a FAST filesystem if you're using Docker
 * on Mac.
 *
 * Unfortunately, Virtual Box does not trigger inotify events within the container when a file is modified
 * on the OSX host. This issue is described here: https://www.virtualbox.org/ticket/10660
 * https://www.virtualbox.org/ticket/14234 and marked as WONT-FIX.
 *
 * Also see https://github.com/EugenMayer/docker-sync/issues/410
 *
 * @author E. Akerboom
 * @date 2020
 */

class Watcher
{
    protected $folder;
    protected $timestamps;
    protected $exclude = [];

    public function __construct($folder, $exclude = ["node_modules", "vendor", "storage", "resources", "public"])
    {
        $this->folder = $folder;
        $this->exclude = $exclude;

        echo "\nFiles in " . realpath($folder) . ":\n\n";
        foreach ($this->files() as $f) {
            echo "- " . $f->getRealPath() . "\n";
            $this->timestamps[$f->getRealPath()] = $f->getMTime();
        }

        $this->watch();
    }

    protected function watch() {
        do {
            sleep(1);
            $this->process();
        } while (true);
    }

    protected function process() {
        $seen = [];
        foreach ($this->files() as $f) {
            $path = $f->getRealPath();
            $seen[$path] = 1;

            try {
                $modified = $f->getMTime();
            } catch (RuntimeException $e) {
                $this->deleted($path);
                continue;
            }

            if (!array_key_exists($path, $this->timestamps)) {
                $this->changed($path);
            } else {
                if ($this->timestamps[$path] !== $modified) {
                    $this->changed($path);
                }
            }
        }

        $deleted = array_diff_key($this->timestamps, $seen);
        foreach ($deleted as $path=>$file) {
            $this->deleted($path);
        }
    }

    protected function changed($path) {
        // make sure to trigger filesystem event
        echo "\nChanged: $path";
        if (abs(filemtime($path) - $this->timestamps[$path]) > 1) {
            touch($path);
        }
        $this->timestamps[$path] = filemtime($path);
    }

    protected function deleted($path) {
        // make sure to trigger filesystem event
        echo "\nDeleted: $path";

        // the original deletion of the file didn't trigger an inotify event

        // therefore, we re-create the file that was deleted ...
        touch($path);

        // ... and give unison chance to catch up ...
        sleep(5);

        // ... after which we delete it with a 'native' delete event
        // that IS picked up by unison
        unlink($path);

        // and we forget about the file completely
        unset($this->timestamps[$path]);
    }

    /**
     * @return SplFileInfo[] A list of files
     */
    protected function files()
    {
        $exclude = $this->exclude;
        $directory = new \RecursiveDirectoryIterator($this->folder, \FilesystemIterator::FOLLOW_SYMLINKS);
        $filter = new \RecursiveCallbackFilterIterator($directory, function ($current, $key, $iterator) use ($exclude) {
            // Skip hidden files and directories.
            if ($current->getFilename()[0] === '.') {
                return FALSE;
            }
            if ($current->isDir()) {
                return !in_array($current->getFilename(), $exclude);
            }
            // Only recurse into intended subdirectories.
            return !in_array($current->getRealPath(), $exclude);
        });

        $iterator = new \RecursiveIteratorIterator($filter);
        foreach ($iterator as $info) {
            yield $info;
        }
    }
}

if ($argc !== 2) {
    echo "SYNTAX: ./watcher.php <folder>\n";
    die;
}

$folder = $argv[1];
if (!file_exists($folder)) {
    echo "Folder {$folder} does not exist\n";
    die;
}

new Watcher($argv[1]);