<?php
require_once __DIR__ . '/bootstrap.php';
require_once dirname(__DIR__) . '/models/TicketModel.php';
require_once dirname(__DIR__) . '/models/AuditLogModel.php';
require_once dirname(__DIR__) . '/models/UserModel.php';

// Get request data
$data = json_decode(file_get_contents('php://input'), true);
if (!is_array($data)) {
    http_response_code(400);
    echo json_encode(['success' => false, 'error' => 'Invalid JSON body']);
    exit;
}

$ticketId = isset($data['ticket_id']) ? (int)$data['ticket_id'] : null;
$assignedTo = $data['assigned_to'] ?? null;

if (!$ticketId) {
    http_response_code(400);
    echo json_encode(['success' => false, 'error' => 'Ticket ID required']);
    exit;
}

$ticketModel = new TicketModel($conn);
$auditLogModel = new AuditLogModel($conn);
$userModel = new UserModel($conn);

// Verify ticket exists
$ticket = $ticketModel->getTicketById($ticketId);
if (!$ticket) {
    http_response_code(404);
    echo json_encode(['success' => false, 'error' => 'Ticket not found']);
    exit;
}

// Authorization: only admins or the ticket creator/assignee can reassign
if (!$isAdmin && $ticket['created_by'] !== $userId && $ticket['assigned_to'] !== $userId) {
    http_response_code(403);
    echo json_encode(['success' => false, 'error' => 'Permission denied']);
    exit;
}

if ($assignedTo === null || $assignedTo === '') {
    // Unassign ticket
    $success = $ticketModel->unassignTicket($ticketId, $userId);
    if ($success) {
        $auditLogModel->log($userId, 'unassign', 'ticket', $ticketId);
    }
} else {
    // Validate assigned_to is a valid user ID
    $assignedTo = (int)$assignedTo;
    $targetUser = $userModel->getUserById($assignedTo);
    if (!$targetUser) {
        echo json_encode(['success' => false, 'error' => 'Invalid user ID']);
        exit;
    }

    // Assign ticket
    $success = $ticketModel->assignTicket($ticketId, $assignedTo, $userId);
    if ($success) {
        $auditLogModel->log($userId, 'assign', 'ticket', $ticketId, ['assigned_to' => $assignedTo]);
    }
}

if (!$success) {
    http_response_code(500);
    echo json_encode(['success' => false, 'error' => 'Failed to update ticket assignment']);
} else {
    echo json_encode(['success' => true]);
}