<?php
// Community-Bot: Discord- und Telegram-Anbindung. Alle Funktionen beginnen mit communitybot_.

const COMMUNITYBOT = 'community-bot';

function communitybot_config(): array
{
    $secret = static function (string $key): string {
        $v = (string) plugin_setting(COMMUNITYBOT, $key, '');
        if ($v === '') return '';
        try { return decrypt_secret($v); } catch (Throwable $e) { return ''; }
    };
    return [
        'discord_key' => strtolower(trim((string) plugin_setting(COMMUNITYBOT, 'discord_key', ''))),
        'discord_app' => trim((string) plugin_setting(COMMUNITYBOT, 'discord_app', '')),
        'discord_token' => $secret('discord_token'),
        'telegram_token' => $secret('telegram_token'),
        'telegram_secret' => $secret('telegram_secret'),
        'department_id' => (int) plugin_setting(COMMUNITYBOT, 'department_id', '0'),
        'priority_id' => (int) plugin_setting(COMMUNITYBOT, 'priority_id', '0'),
        'limit' => max(1, min(50, (int) plugin_setting(COMMUNITYBOT, 'limit', '3'))),
        'notify' => plugin_setting(COMMUNITYBOT, 'notify', '1') === '1',
    ];
}

function communitybot_set_secret(string $key, string $value): void
{
    plugin_set_setting(COMMUNITYBOT, $key, $value === '' ? '' : encrypt_secret($value));
}

/** HTTP-Aufruf (für Tests austauschbar über $GLOBALS['communitybot_http']). Liefert ['status' => int, 'body' => string]. */
function communitybot_http(string $method, string $url, array $headers = [], ?string $body = null): array
{
    if (isset($GLOBALS['communitybot_http']) && is_callable($GLOBALS['communitybot_http'])) {
        return ($GLOBALS['communitybot_http'])($method, $url, $headers, $body);
    }
    $ctx = stream_context_create(['http' => [
        'method' => $method,
        'header' => implode("\r\n", $headers),
        'content' => $body ?? '',
        'timeout' => 8,
        'ignore_errors' => true,
    ]]);
    $res = @file_get_contents($url, false, $ctx);
    $status = 0;
    foreach ($http_response_header ?? [] as $h) if (preg_match('#^HTTP/\S+\s+(\d+)#', $h, $m)) $status = (int) $m[1];
    return ['status' => $status, 'body' => $res === false ? '' : (string) $res];
}

function communitybot_json(string $method, string $url, array $headers, ?array $data): array
{
    $r = communitybot_http($method, $url, array_merge(['Content-Type: application/json', 'User-Agent: DeskHub-CommunityBot (https://deskhub.example, 1.0)'], $headers), $data === null ? null : json_encode($data, JSON_UNESCAPED_UNICODE));
    return ['status' => $r['status'], 'json' => json_decode($r['body'], true) ?: [], 'body' => $r['body']];
}

function communitybot_clip(string $text, int $max): string
{
    $text = trim(preg_replace('/\s+/u', ' ', strip_tags(html_entity_decode($text, ENT_QUOTES | ENT_HTML5, 'UTF-8'))));
    return mb_strlen($text) > $max ? mb_substr($text, 0, $max - 1) . '…' : $text;
}

// ── Gemeinsame Befehle ─────────────────────────────────────────────────────

/** Platzhalter-Adresse; Mails an ".invalid" werden vom Kern nie verschickt. */
function communitybot_email(string $platform, string $user): string
{
    return $platform . '-' . preg_replace('/[^a-z0-9]/i', '', $user) . '@' . $platform . '.invalid';
}

function communitybot_find_link(PDO $pdo, string $platform, string $user, string $number): ?array
{
    $number = ltrim(trim($number), '#');
    if ($number === '') return null;
    $s = $pdo->prepare('SELECT t.*, l.ext_chat FROM plugin_communitybot_links l JOIN tickets t ON t.id = l.ticket_id WHERE l.platform = ? AND l.ext_user = ? AND t.ticket_number = ? ORDER BY l.id DESC LIMIT 1');
    $s->execute([$platform, $user, $number]);
    return $s->fetch() ?: null;
}

function communitybot_help(string $platform): string
{
    $p = $platform === 'telegram' ? '/ticket Betreff | Nachricht' : '/ticket betreff:… nachricht:…';
    return "So geht's:\n{$p} – neues Ticket anlegen\n/status Nummer – Stand eines Tickets\n/antwort Nummer Text – Ihrem Ticket etwas hinzufügen";
}

function communitybot_cmd_ticket(PDO $pdo, string $platform, string $user, string $chat, string $name, string $subject, string $message): string
{
    $cfg = communitybot_config();
    $subject = trim($subject);
    $message = trim($message);
    if ($message === '' && $subject !== '') { $message = $subject; $subject = ''; }
    if ($message === '') return 'Bitte beschreiben Sie Ihr Anliegen: ' . ($platform === 'telegram' ? '/ticket Betreff | Nachricht' : '/ticket mit Betreff und Nachricht');
    if ($subject === '') $subject = communitybot_clip($message, 60);
    $subject = mb_substr($subject, 0, 200);
    $message = mb_substr($message, 0, 4000);

    $c = $pdo->prepare('SELECT COUNT(*) FROM plugin_communitybot_links WHERE platform = ? AND ext_user = ? AND created_at >= ?');
    $c->execute([$platform, $user, date('Y-m-d H:i:s', time() - 3600)]);
    if ((int) $c->fetchColumn() >= $cfg['limit']) return 'Sie haben in der letzten Stunde schon ' . $cfg['limit'] . ' Tickets angelegt. Bitte versuchen Sie es später noch einmal oder ergänzen Sie ein bestehendes Ticket mit /antwort.';

    $label = $platform === 'discord' ? 'Discord' : 'Telegram';
    $name = trim(preg_replace('/[\x00-\x1F]+/u', ' ', $name));
    if ($name === '') $name = $label . '-Nutzer';
    try {
        $r = public_ticket_create($pdo, [
            'name' => mb_substr($name, 0, 120),
            'email' => communitybot_email($platform, $user),
            'subject' => $subject,
            'message' => $message,
            'departmentId' => $cfg['department_id'] ?: null,
            'priorityId' => $cfg['priority_id'] ?: null,
        ], '0.0.0.0', ['activity' => 'Ticket über ' . $label . ' erstellt', 'tag' => $label]);
    } catch (AdminModelException $e) {
        return 'Das Ticket konnte nicht angelegt werden: ' . $e->getMessage();
    } catch (Throwable $e) {
        error_log('communitybot ticket: ' . $e->getMessage());
        return 'Das Ticket konnte gerade nicht angelegt werden. Bitte versuchen Sie es später noch einmal.';
    }
    $pdo->prepare('INSERT INTO plugin_communitybot_links (ticket_id, platform, ext_user, ext_chat, ext_name, created_at) VALUES (?,?,?,?,?,?)')
        ->execute([$r['id'], $platform, $user, $chat, mb_substr($name, 0, 120), db_now()]);
    $hint = $cfg['notify'] ? ' Wir melden uns hier, sobald es eine Antwort gibt.' : '';
    return 'Ihr Ticket #' . $r['number'] . ' wurde angelegt.' . $hint . ' Stand abfragen mit /status ' . $r['number'] . '.';
}

function communitybot_cmd_status(PDO $pdo, string $platform, string $user, string $number): string
{
    if (trim($number) === '') {
        $s = $pdo->prepare('SELECT t.ticket_number, t.subject, t.status FROM plugin_communitybot_links l JOIN tickets t ON t.id = l.ticket_id WHERE l.platform = ? AND l.ext_user = ? ORDER BY l.id DESC LIMIT 5');
        $s->execute([$platform, $user]);
        $rows = $s->fetchAll();
        if (!$rows) return 'Sie haben über diesen Kanal noch kein Ticket angelegt.';
        return "Ihre letzten Tickets:\n" . implode("\n", array_map(fn($t) => '#' . $t['ticket_number'] . ' – ' . status_label((string) $t['status'])[0] . ' – ' . communitybot_clip((string) $t['subject'], 50), $rows));
    }
    $t = communitybot_find_link($pdo, $platform, $user, $number);
    if (!$t) return 'Dieses Ticket gibt es nicht oder es gehört nicht zu Ihnen.';
    return 'Ticket #' . $t['ticket_number'] . ' „' . communitybot_clip((string) $t['subject'], 60) . '“: ' . status_label((string) $t['status'])[0] . ' (zuletzt geändert ' . format_dt((string) $t['updated_at']) . ').';
}

function communitybot_cmd_reply(PDO $pdo, string $platform, string $user, string $number, string $text): string
{
    $text = trim($text);
    if (trim($number) === '' || $text === '') return 'So geht es: /antwort Ticketnummer Ihre Nachricht';
    $t = communitybot_find_link($pdo, $platform, $user, $number);
    if (!$t) return 'Dieses Ticket gibt es nicht oder es gehört nicht zu Ihnen.';
    if ($t['status'] === 'closed') return 'Das Ticket #' . $t['ticket_number'] . ' ist geschlossen. Bitte legen Sie mit /ticket ein neues an.';
    $now = db_now();
    $pdo->prepare('INSERT INTO ticket_threads (ticket_id, author_type, message, is_internal_note, created_at) VALUES (?,?,?,0,?)')->execute([$t['id'], 'customer', mb_substr($text, 0, 4000), $now]);
    $reopen = in_array($t['status'], ['answered', 'resolved'], true);
    $new = $reopen ? 'open' : $t['status'];
    $pdo->prepare('UPDATE tickets SET status = ?, updated_at = ? WHERE id = ?')->execute([$new, $now, $t['id']]);
    log_activity($pdo, (int) $t['id'], null, 'Kunde hat geantwortet (' . ($platform === 'discord' ? 'Discord' : 'Telegram') . ')');
    if ($reopen) log_activity($pdo, (int) $t['id'], null, 'Ticket wieder geöffnet');
    webhook_dispatch($pdo, 'ticket.replied', (int) $t['id'], ['author' => 'customer']);
    if ($new !== $t['status']) webhook_dispatch($pdo, 'ticket.status_changed', (int) $t['id'], ['previousStatus' => $t['status']]);
    return 'Ihre Nachricht wurde zu Ticket #' . $t['ticket_number'] . ' hinzugefügt.';
}

// ── Discord ────────────────────────────────────────────────────────────────

function communitybot_discord_verify(array $req, string $publicKeyHex): bool
{
    $sig = (string) ($req['headers']['x-signature-ed25519'] ?? '');
    $ts = (string) ($req['headers']['x-signature-timestamp'] ?? '');
    if ($publicKeyHex === '' || !ctype_xdigit($publicKeyHex) || strlen($publicKeyHex) !== 64 || !ctype_xdigit($sig) || strlen($sig) !== 128 || !ctype_digit($ts)) return false;
    if (abs(time() - (int) $ts) > 600) return false;
    if (!function_exists('sodium_crypto_sign_verify_detached')) return false;
    try {
        return sodium_crypto_sign_verify_detached(hex2bin($sig), $ts . $req['body'], hex2bin($publicKeyHex));
    } catch (Throwable $e) {
        return false;
    }
}

function communitybot_discord(array $req): array
{
    $cfg = communitybot_config();
    if (!communitybot_discord_verify($req, $cfg['discord_key'])) return ['status' => 401, 'json' => ['error' => 'Ungültige Signatur.']];
    $in = json_decode($req['body'], true);
    if (!is_array($in)) return ['status' => 400, 'json' => ['error' => 'Ungültige Anfrage.']];
    if (($in['type'] ?? 0) === 1) return ['status' => 200, 'json' => ['type' => 1]];
    if (($in['type'] ?? 0) !== 2) return ['status' => 200, 'json' => ['type' => 4, 'data' => ['content' => 'Das wird nicht unterstützt.', 'flags' => 64]]];

    $user = $in['member']['user'] ?? $in['user'] ?? [];
    $uid = (string) ($user['id'] ?? '');
    if (!preg_match('/^\d{5,25}$/', $uid)) return ['status' => 400, 'json' => ['error' => 'Kein Nutzer.']];
    $name = (string) ($user['global_name'] ?? $user['username'] ?? '');
    $opt = [];
    foreach ((array) ($in['data']['options'] ?? []) as $o) if (isset($o['name'])) $opt[(string) $o['name']] = (string) ($o['value'] ?? '');
    $pdo = get_db();
    $chat = (string) ($in['channel_id'] ?? '');
    switch ((string) ($in['data']['name'] ?? '')) {
        case 'ticket': $text = communitybot_cmd_ticket($pdo, 'discord', $uid, $chat, $name, $opt['betreff'] ?? '', $opt['nachricht'] ?? ''); break;
        case 'status': $text = communitybot_cmd_status($pdo, 'discord', $uid, $opt['nummer'] ?? ''); break;
        case 'antwort': $text = communitybot_cmd_reply($pdo, 'discord', $uid, $opt['nummer'] ?? '', $opt['text'] ?? ''); break;
        default: $text = communitybot_help('discord');
    }
    // flags 64: nur der Absender sieht die Antwort; keine Erwähnungen aus Nutzertext
    return ['status' => 200, 'json' => ['type' => 4, 'data' => ['content' => mb_substr($text, 0, 1900), 'flags' => 64, 'allowed_mentions' => ['parse' => []]]]];
}

function communitybot_discord_commands(): array
{
    $str = fn(string $n, string $d, bool $req, int $max = 1000) => ['type' => 3, 'name' => $n, 'description' => $d, 'required' => $req, 'max_length' => $max];
    return [
        ['name' => 'ticket', 'description' => 'Ein Support-Ticket anlegen', 'options' => [$str('betreff', 'Worum geht es?', true, 100), $str('nachricht', 'Bitte beschreiben Sie Ihr Anliegen', true, 1000)]],
        ['name' => 'status', 'description' => 'Stand eines Tickets abfragen', 'options' => [$str('nummer', 'Ticketnummer (leer lassen für Ihre letzten)', false, 40)]],
        ['name' => 'antwort', 'description' => 'Zu einem Ihrer Tickets etwas hinzufügen', 'options' => [$str('nummer', 'Ticketnummer', true, 40), $str('text', 'Ihre Nachricht', true, 1000)]],
    ];
}

function communitybot_discord_register(): array
{
    $cfg = communitybot_config();
    if ($cfg['discord_app'] === '' || $cfg['discord_token'] === '') return ['ok' => false, 'message' => 'Bitte Anwendungs-ID und Bot-Token eintragen.'];
    $r = communitybot_json('PUT', 'https://discord.com/api/v10/applications/' . rawurlencode($cfg['discord_app']) . '/commands', ['Authorization: Bot ' . $cfg['discord_token']], communitybot_discord_commands());
    if ($r['status'] >= 200 && $r['status'] < 300) return ['ok' => true, 'message' => 'Die Befehle /ticket, /status und /antwort sind bei Discord eingetragen (es kann bis zu einer Stunde dauern, bis sie überall erscheinen).'];
    return ['ok' => false, 'message' => 'Discord hat abgelehnt (Status ' . $r['status'] . '): ' . communitybot_clip((string) ($r['json']['message'] ?? $r['body']), 200)];
}

function communitybot_discord_dm(string $userId, string $text): bool
{
    $cfg = communitybot_config();
    if ($cfg['discord_token'] === '') return false;
    $h = ['Authorization: Bot ' . $cfg['discord_token']];
    $ch = communitybot_json('POST', 'https://discord.com/api/v10/users/@me/channels', $h, ['recipient_id' => $userId]);
    $id = (string) ($ch['json']['id'] ?? '');
    if ($id === '') return false;
    $m = communitybot_json('POST', 'https://discord.com/api/v10/channels/' . rawurlencode($id) . '/messages', $h, ['content' => mb_substr($text, 0, 1900), 'allowed_mentions' => ['parse' => []]]);
    return $m['status'] >= 200 && $m['status'] < 300;
}

// ── Telegram ───────────────────────────────────────────────────────────────

function communitybot_telegram(array $req): array
{
    $cfg = communitybot_config();
    $given = (string) ($req['headers']['x-telegram-bot-api-secret-token'] ?? '');
    if ($cfg['telegram_secret'] === '' || !hash_equals($cfg['telegram_secret'], $given)) return ['status' => 401, 'json' => ['error' => 'Ungültiges Token.']];
    $in = json_decode($req['body'], true);
    $msg = is_array($in) ? ($in['message'] ?? null) : null;
    if (!is_array($msg) || !isset($msg['chat']['id'], $msg['from']['id']) || !is_string($msg['text'] ?? null)) return ['status' => 200, 'json' => new stdClass()];
    if (!empty($msg['from']['is_bot'])) return ['status' => 200, 'json' => new stdClass()];
    if (!preg_match('/^\/([a-z_]+)(?:@\w+)?(?:\s+(.*))?$/isu', trim($msg['text']), $m)) return ['status' => 200, 'json' => new stdClass()];

    $uid = (string) $msg['from']['id'];
    $chat = (string) $msg['chat']['id'];
    $name = trim(((string) ($msg['from']['first_name'] ?? '')) . ' ' . ((string) ($msg['from']['last_name'] ?? '')));
    if ($name === '') $name = (string) ($msg['from']['username'] ?? '');
    $arg = trim((string) ($m[2] ?? ''));
    $pdo = get_db();
    switch (strtolower($m[1])) {
        case 'ticket':
            $parts = array_map('trim', explode('|', $arg, 2));
            $text = communitybot_cmd_ticket($pdo, 'telegram', $uid, $chat, $name, count($parts) === 2 ? $parts[0] : '', count($parts) === 2 ? $parts[1] : $parts[0]);
            break;
        case 'status': $text = communitybot_cmd_status($pdo, 'telegram', $uid, $arg); break;
        case 'antwort':
            $p = preg_split('/\s+/u', $arg, 2) ?: [''];
            $text = communitybot_cmd_reply($pdo, 'telegram', $uid, $p[0] ?? '', $p[1] ?? '');
            break;
        case 'start': case 'hilfe': case 'help': $text = "Hallo! Ich nehme Ihre Support-Anfragen entgegen.\n" . communitybot_help('telegram'); break;
        default: return ['status' => 200, 'json' => new stdClass()];
    }
    // Antwort direkt im Webhook-Ergebnis: kein zusätzlicher Aufruf nötig
    $out = ['method' => 'sendMessage', 'chat_id' => $msg['chat']['id'], 'text' => mb_substr($text, 0, 3900)];
    if (isset($msg['message_id'])) $out['reply_to_message_id'] = $msg['message_id'];
    return ['status' => 200, 'json' => $out];
}

function communitybot_telegram_send(string $chatId, string $text): bool
{
    $cfg = communitybot_config();
    if ($cfg['telegram_token'] === '') return false;
    $r = communitybot_json('POST', 'https://api.telegram.org/bot' . $cfg['telegram_token'] . '/sendMessage', [], ['chat_id' => $chatId, 'text' => mb_substr($text, 0, 3900)]);
    return $r['status'] >= 200 && $r['status'] < 300;
}

function communitybot_telegram_register(): array
{
    $cfg = communitybot_config();
    if ($cfg['telegram_token'] === '') return ['ok' => false, 'message' => 'Bitte das Bot-Token von @BotFather eintragen.'];
    if ($cfg['telegram_secret'] === '') {
        $cfg['telegram_secret'] = bin2hex(random_bytes(24));
        communitybot_set_secret('telegram_secret', $cfg['telegram_secret']);
    }
    $r = communitybot_json('POST', 'https://api.telegram.org/bot' . $cfg['telegram_token'] . '/setWebhook', [], [
        'url' => communitybot_url('telegram'), 'secret_token' => $cfg['telegram_secret'], 'allowed_updates' => ['message'], 'drop_pending_updates' => true,
    ]);
    if (!empty($r['json']['ok'])) {
        communitybot_json('POST', 'https://api.telegram.org/bot' . $cfg['telegram_token'] . '/setMyCommands', [], ['commands' => [
            ['command' => 'ticket', 'description' => 'Ticket anlegen: /ticket Betreff | Nachricht'],
            ['command' => 'status', 'description' => 'Stand eines Tickets'],
            ['command' => 'antwort', 'description' => 'Zu einem Ticket antworten'],
            ['command' => 'hilfe', 'description' => 'Hilfe'],
        ]]);
        return ['ok' => true, 'message' => 'Der Telegram-Bot ist verbunden.'];
    }
    return ['ok' => false, 'message' => 'Telegram hat abgelehnt: ' . communitybot_clip((string) ($r['json']['description'] ?? $r['body']), 200)];
}

function communitybot_url(string $endpoint): string
{
    return rtrim(base_url(), '/') . '/api/public/v1/plugin_webhook.php?p=' . COMMUNITYBOT . '&e=' . $endpoint;
}

// ── Benachrichtigungen ─────────────────────────────────────────────────────

function communitybot_send_to(array $link, string $text): bool
{
    return $link['platform'] === 'discord'
        ? communitybot_discord_dm((string) $link['ext_user'], $text)
        : communitybot_telegram_send((string) $link['ext_chat'], $text);
}

function communitybot_links(PDO $pdo, int $ticketId): array
{
    // pro Nutzer nur einmal, auch wenn mehrere Verknüpfungen bestehen
    $s = $pdo->prepare('SELECT platform, ext_user, MAX(ext_chat) AS ext_chat FROM plugin_communitybot_links WHERE ticket_id = ? GROUP BY platform, ext_user');
    $s->execute([$ticketId]);
    return $s->fetchAll();
}

function communitybot_notify_reply(PDO $pdo, int $ticketId): void
{
    if (!communitybot_config()['notify']) return;
    $links = communitybot_links($pdo, $ticketId);
    if (!$links) return;
    $t = $pdo->prepare('SELECT ticket_number, is_spam FROM tickets WHERE id = ?');
    $t->execute([$ticketId]);
    $ticket = $t->fetch();
    if (!$ticket || !empty($ticket['is_spam'])) return;
    $m = $pdo->prepare("SELECT message FROM ticket_threads WHERE ticket_id = ? AND author_type = 'staff' AND is_internal_note = 0 ORDER BY id DESC LIMIT 1");
    $m->execute([$ticketId]);
    $msg = (string) $m->fetchColumn();
    if ($msg === '') return;
    $text = 'Neue Antwort zu Ticket #' . $ticket['ticket_number'] . ":\n\n" . communitybot_clip($msg, 1200) . "\n\nAntworten: /antwort " . $ticket['ticket_number'] . ' Ihre Nachricht';
    foreach ($links as $l) {
        try { communitybot_send_to($l, $text); } catch (Throwable $e) { error_log('communitybot notify: ' . $e->getMessage()); }
    }
}

function communitybot_notify_status(PDO $pdo, int $ticketId): void
{
    if (!communitybot_config()['notify']) return;
    $links = communitybot_links($pdo, $ticketId);
    if (!$links) return;
    $t = $pdo->prepare('SELECT ticket_number, status, is_spam FROM tickets WHERE id = ?');
    $t->execute([$ticketId]);
    $ticket = $t->fetch();
    if (!$ticket || !empty($ticket['is_spam']) || !in_array($ticket['status'], ['resolved', 'closed'], true)) return;
    $text = 'Ihr Ticket #' . $ticket['ticket_number'] . ' ist jetzt „' . status_label((string) $ticket['status'])[0] . '“. Wenn noch etwas offen ist, antworten Sie mit /antwort ' . $ticket['ticket_number'] . ' Ihre Nachricht.';
    foreach ($links as $l) {
        try { communitybot_send_to($l, $text); } catch (Throwable $e) { error_log('communitybot notify: ' . $e->getMessage()); }
    }
}