willy.club/routes/willychat.php

<?php

use WillySoft\Http\Route;

abstract class WillyChat {
    static string $data_path;
    static array $messages;
}

Route::middleware(function() {
    WillyChat::$data_path = '/dev/shm/database.json';

    if (!file_exists(WillyChat::$data_path)) {
        file_put_contents(
            WillyChat::$data_path, 
            json_encode([])
        );
    }

    WillyChat::$messages = json_decode(
        file_get_contents(WillyChat::$data_path),
        true
    );
});

Route::match('get|post','/willychat/', function() {
    $default_nick = 'Willy';
    $nick = $default_nick; 
    $just_sent_message = false;
    $errmsg = false;

    if (!empty($_POST)) {
        $nick = filter_input(INPUT_POST, 'nick');
        $text = filter_input(INPUT_POST, 'text');

        $errmsg = (function() use (&$text, &$nick): string|false {

            if (empty(trim($nick, ' '))) {
                return 'You must choose a nickname.';
            }

            $nick_max_chars = 128;
            if (strlen($nick) > $nick_max_chars) {
                return 'Your nickname is too long.';
            }

            $text_max_chars = 4096;
            if (strlen($text) > $text_max_chars) {
                return 'Your message is too long. ' . strlen($text) . ' out of ' . $text_max_chars . ' characters.';
            }

            if (empty(trim($text, ' '))) {
                return 'Message body cannot be empty.';
            }

            return false;
        })();

        if (!$errmsg) {
            if (count(WillyChat::$messages) > 100) {
                array_pop(WillyChat::$messages);
            }

            array_unshift(WillyChat::$messages, [
                'nick' => $nick,
                'date' => time(),
                'text' => $text
            ]);

            file_put_contents(WillyChat::$data_path,
                json_encode(
                    WillyChat::$messages
                )
            );
        }
        $just_sent_message = true;
    }
    
    view('pages/willychat/index', [
        'nick' => $nick,
        'just_sent_message' => $just_sent_message,
        'errmsg' => $errmsg
    ]);
});

Route::get('/willychat/messages', function() {
    view('pages/willychat/messages', [
        'messages' => WillyChat::$messages
    ]); 
});

Route::get('/willychat/sync', function() {
    json_response(
        hash('crc32', serialize(WillyChat::$messages))
    );
});