tinker_tickets/api/check_duplicates.php

<?php

/**
 * Check for duplicate tickets API
 *
 * Searches for tickets with similar titles using LIKE and SOUNDEX
 */

require_once __DIR__ . '/bootstrap.php';
require_once dirname(__DIR__) . '/helpers/ResponseHelper.php';
require_once dirname(__DIR__) . '/models/TicketModel.php';

// Only accept GET requests
if ($_SERVER['REQUEST_METHOD'] !== 'GET') {
    ResponseHelper::error('Method not allowed', 405);
}

// Get title parameter
$title = isset($_GET['title']) ? trim($_GET['title']) : '';

if (strlen($title) < 5) {
    ResponseHelper::success(['duplicates' => []]);
}

// Search for similar titles
// Use both LIKE for substring matching and SOUNDEX for phonetic matching
$duplicates = [];

// Prepare search term for LIKE
$searchTerm = '%' . $title . '%';

// Get SOUNDEX of title
$soundexTitle = soundex($title);

// Build visibility filter so users only see titles they have access to
$ticketModel = new TicketModel($conn);
$visFilter = $ticketModel->getVisibilityFilter($currentUser);

// First, search for exact substring matches (case-insensitive)
$sql = "SELECT ticket_id, title, status, priority, created_at
        FROM tickets
        WHERE (
            title LIKE ?
            OR SOUNDEX(title) = ?
        )
        AND status != 'Closed'
        AND ({$visFilter['sql']})
        ORDER BY created_at DESC
        LIMIT 10";

$types = "ss" . $visFilter['types'];
$params = array_merge([$searchTerm, $soundexTitle], $visFilter['params']);

// Duplicate detection is advisory (it must not block ticket creation), so on any
// DB error degrade gracefully to "no duplicates" rather than fataling the request.
// mysqli may throw (default exception mode) or return false depending on config.
try {
    $stmt = $conn->prepare($sql);
    if (!$stmt) {
        throw new RuntimeException('prepare failed: ' . $conn->error);
    }
    if (!empty($params)) {
        $stmt->bind_param($types, ...$params);
    }
    $stmt->execute();
    $result = $stmt->get_result();
    if ($result === false) {
        // Non-exception mysqli mode: execute/get_result return false instead of
        // throwing. Treat as a query failure so we don't fatal on $result below.
        throw new RuntimeException('query failed: ' . $conn->error);
    }
} catch (Throwable $e) {
    error_log('check_duplicates: ' . $e->getMessage());
    ResponseHelper::success(['duplicates' => []]);
}

while ($row = $result->fetch_assoc()) {
    // Calculate similarity score
    $similarity = 0;

    // Check for exact substring match
    if (stripos($row['title'], $title) !== false) {
        $similarity = 90;
    // Check SOUNDEX match
    } elseif (soundex($row['title']) === $soundexTitle) {
        $similarity = 70;
    // Check word overlap
    } else {
        $titleWords = array_map('strtolower', preg_split('/\s+/', $title));
        $rowWords = array_map('strtolower', preg_split('/\s+/', $row['title']));
        $matchingWords = array_intersect($titleWords, $rowWords);
        $similarity = (count($matchingWords) / max(count($titleWords), 1)) * 60;
    }

    if ($similarity >= 30) {
        $duplicates[] = [
            'ticket_id' => $row['ticket_id'],
            'title' => $row['title'],
            'status' => $row['status'],
            'priority' => $row['priority'],
            'created_at' => $row['created_at'],
            'similarity' => round($similarity)
        ];
    }
}

$stmt->close();

// Sort by similarity descending
usort($duplicates, function ($a, $b) {
    return $b['similarity'] - $a['similarity'];
});

// Limit to top 5
$duplicates = array_slice($duplicates, 0, 5);

ResponseHelper::success(['duplicates' => $duplicates]);