<?php
/** Problem records group related tickets and retain root-cause documentation. */

function ticket_resolution_reasons(): array
{
    return [
        'fixed' => 'Fehler behoben',
        'guidance' => 'Anleitung oder Beratung',
        'duplicate' => 'Doppelt / zusammengeführt',
        'not_reproducible' => 'Nicht reproduzierbar',
        'no_action' => 'Keine Maßnahme erforderlich',
        'spam' => 'Spam oder Sperre',
        'automated' => 'Automatisch geschlossen',
        'other' => 'Sonstiges',
    ];
}

function ticket_problem_statuses(): array
{
    return [
        'investigating' => 'Wird untersucht',
        'workaround' => 'Workaround verfügbar',
        'monitoring' => 'Wird beobachtet',
        'resolved' => 'Behoben',
    ];
}

function ticket_problem_number(int $id): string
{
    return 'PRB-' . str_pad((string) $id, 6, '0', STR_PAD_LEFT);
}

function ticket_problems(PDO $pdo, bool $activeOnly = false): array
{
    $where = $activeOnly ? "WHERE p.status <> 'resolved'" : '';
    return $pdo->query("SELECT p.*, s.name AS creator_name, (SELECT COUNT(*) FROM problem_tickets pt WHERE pt.problem_id = p.id) AS ticket_count FROM problems p LEFT JOIN staff s ON s.id = p.created_by $where ORDER BY CASE WHEN p.status = 'resolved' THEN 1 ELSE 0 END, p.updated_at DESC, p.id DESC LIMIT 300")->fetchAll();
}

function ticket_problem_get(PDO $pdo, int $id): ?array
{
    $stmt = $pdo->prepare('SELECT p.*, s.name AS creator_name FROM problems p LEFT JOIN staff s ON s.id = p.created_by WHERE p.id = ?');
    $stmt->execute([$id]);
    return $stmt->fetch() ?: null;
}

function ticket_problem_create(PDO $pdo, array $input, int $staffId): int
{
    $title = trim(mb_substr((string) ($input['title'] ?? ''), 0, 200));
    if ($title === '') throw new InvalidArgumentException('Bitte einen Titel für das Problem angeben.');
    $status = (string) ($input['status'] ?? 'investigating');
    if (!isset(ticket_problem_statuses()[$status])) $status = 'investigating';
    $resolution = trim((string) ($input['resolution'] ?? ''));
    if ($status === 'resolved' && $resolution === '') throw new InvalidArgumentException('Bitte dokumentieren Sie die dauerhafte Lösung, bevor Sie das Problem als behoben markieren.');
    $now = db_now();
    $stmt = $pdo->prepare('INSERT INTO problems (title, description, root_cause, workaround, resolution, status, created_by, updated_by, created_at, updated_at, resolved_at) VALUES (?,?,?,?,?,?,?,?,?,?,?)');
    $stmt->execute([
        $title,
        trim((string) ($input['description'] ?? '')) ?: null,
        trim((string) ($input['root_cause'] ?? '')) ?: null,
        trim((string) ($input['workaround'] ?? '')) ?: null,
        $resolution ?: null,
        $status, $staffId, $staffId, $now, $now, $status === 'resolved' ? $now : null,
    ]);
    return (int) $pdo->lastInsertId();
}

function ticket_problem_update(PDO $pdo, int $id, array $input, int $staffId): bool
{
    $title = trim(mb_substr((string) ($input['title'] ?? ''), 0, 200));
    $status = (string) ($input['status'] ?? 'investigating');
    if ($title === '') throw new InvalidArgumentException('Bitte einen Titel für das Problem angeben.');
    if (!isset(ticket_problem_statuses()[$status])) throw new InvalidArgumentException('Der Problemstatus ist ungültig.');
    $resolution = trim((string) ($input['resolution'] ?? ''));
    if ($status === 'resolved' && $resolution === '') throw new InvalidArgumentException('Bitte dokumentieren Sie die dauerhafte Lösung, bevor Sie das Problem als behoben markieren.');
    $current = ticket_problem_get($pdo, $id);
    if (!$current) return false;
    $resolvedAt = $status === 'resolved' ? ($current['resolved_at'] ?: db_now()) : null;
    $stmt = $pdo->prepare('UPDATE problems SET title = ?, description = ?, root_cause = ?, workaround = ?, resolution = ?, status = ?, updated_by = ?, updated_at = ?, resolved_at = ? WHERE id = ?');
    $stmt->execute([
        $title,
        trim((string) ($input['description'] ?? '')) ?: null,
        trim((string) ($input['root_cause'] ?? '')) ?: null,
        trim((string) ($input['workaround'] ?? '')) ?: null,
        $resolution ?: null,
        $status, $staffId, db_now(), $resolvedAt, $id,
    ]);
    return true;
}

function ticket_problem_tickets(PDO $pdo, int $problemId): array
{
    $stmt = $pdo->prepare('SELECT t.id, t.ticket_number, t.subject, t.status, t.requester_name, t.created_at, s.name AS linked_by_name FROM problem_tickets pt JOIN tickets t ON t.id = pt.ticket_id LEFT JOIN staff s ON s.id = pt.linked_by WHERE pt.problem_id = ? ORDER BY pt.linked_at DESC, t.id DESC');
    $stmt->execute([$problemId]);
    return $stmt->fetchAll();
}

function ticket_problem_link(PDO $pdo, int $problemId, int $ticketId, int $staffId): bool
{
    if (!ticket_problem_get($pdo, $problemId)) return false;
    $ticket = $pdo->prepare('SELECT id FROM tickets WHERE id = ?');
    $ticket->execute([$ticketId]);
    if (!$ticket->fetchColumn()) return false;
    $insertIgnore = $pdo->getAttribute(PDO::ATTR_DRIVER_NAME) === 'sqlite' ? 'INSERT OR IGNORE' : 'INSERT IGNORE';
    $stmt = $pdo->prepare("$insertIgnore INTO problem_tickets (problem_id, ticket_id, linked_by, linked_at) VALUES (?,?,?,?)");
    $stmt->execute([$problemId, $ticketId, $staffId, db_now()]);
    return true;
}

/** Löst die Verknüpfung. Liefert false, wenn es sie nicht gab. */
function ticket_problem_unlink(PDO $pdo, int $problemId, int $ticketId): bool
{
    $stmt = $pdo->prepare('DELETE FROM problem_tickets WHERE problem_id = ? AND ticket_id = ?');
    $stmt->execute([$problemId, $ticketId]);
    return $stmt->rowCount() > 0;
}

function ticket_problems_for_ticket(PDO $pdo, int $ticketId): array
{
    $stmt = $pdo->prepare('SELECT p.* FROM problems p JOIN problem_tickets pt ON pt.problem_id = p.id WHERE pt.ticket_id = ? ORDER BY p.updated_at DESC, p.id DESC');
    $stmt->execute([$ticketId]);
    return $stmt->fetchAll();
}

function ticket_record_resolution(PDO $pdo, int $ticketId, string $reason, string $note = ''): bool
{
    if (!isset(ticket_resolution_reasons()[$reason])) return false;
    $pdo->prepare('UPDATE tickets SET resolution_code = ?, resolution_note = ? WHERE id = ?')
        ->execute([$reason, trim(mb_substr($note, 0, 2000)) ?: null, $ticketId]);
    return true;
}