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

// Apply rate limiting
require_once dirname(__DIR__) . '/middleware/RateLimitMiddleware.php';
RateLimitMiddleware::apply('api');

session_start();
require_once dirname(__DIR__) . '/config/config.php';
require_once dirname(__DIR__) . '/helpers/ResponseHelper.php';

header('Content-Type: application/json');

// Check authentication
if (!isset($_SESSION['user']) || !isset($_SESSION['user']['user_id'])) {
    ResponseHelper::unauthorized();
}

// 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' => []]);
}

// Create database connection
$conn = new mysqli(
    $GLOBALS['config']['DB_HOST'],
    $GLOBALS['config']['DB_USER'],
    $GLOBALS['config']['DB_PASS'],
    $GLOBALS['config']['DB_NAME']
);

if ($conn->connect_error) {
    ResponseHelper::serverError('Database connection failed');
}

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

// Prepare search term for LIKE
$searchTerm = '%' . $conn->real_escape_string($title) . '%';

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

// 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'
        ORDER BY created_at DESC
        LIMIT 10";

$stmt = $conn->prepare($sql);
$stmt->bind_param("ss", $searchTerm, $soundexTitle);
$stmt->execute();
$result = $stmt->get_result();

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);

$conn->close();

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