<?php
// LinkedIn Checker Backend (Cookie Fix + Debug Mode)
header("Access-Control-Allow-Origin: *");
header("Access-Control-Allow-Headers: Content-Type");
header("Content-Type: application/json");

// 1. ENABLE ERROR DISPLAY (Debug)
error_reporting(E_ALL);
ini_set('display_errors', 1);

// 2. CHECK IF cURL EXISTS
if (!function_exists('curl_init')) {
    echo json_encode(['status'=>'error', 'message'=>'CRITICAL: PHP cURL extension missing. Contact Hosting.']);
    exit();
}

if ($_SERVER['REQUEST_METHOD'] === 'OPTIONS') { http_response_code(200); exit(); }
if ($_SERVER['REQUEST_METHOD'] !== 'POST') { echo json_encode(['status'=>'error', 'message'=>'POST Only']); exit(); }

// Get Input
$input = json_decode(file_get_contents('php://input'), true);

if (json_last_error() !== JSON_ERROR_NONE) {
    echo json_encode(['status'=>'error', 'message'=>'Invalid JSON Input']); 
    exit();
}

$url = isset($input['url']) ? trim($input['url']) : '';
$proxyConfig = isset($input['proxy']) ? $input['proxy'] : null;
$rawCookie = isset($input['cookie']) ? $input['cookie'] : null;

// --- SMART COOKIE CLEANER ---
$cookie = '';
if (!empty($rawCookie)) {
    // 1. Ensure it's a string
    if (is_array($rawCookie)) {
        // If frontend accidentally sent an array, take the first value
        $rawCookie = isset($rawCookie[0]) ? $rawCookie[0] : '';
    }
    $cookie = trim((string)$rawCookie);
    
    // 2. Remove "li_at=" if user pasted it
    $cookie = str_ireplace('li_at=', '', $cookie);
    
    // 3. Remove surrounding quotes and spaces
    $cookie = trim($cookie, '"\' ');
    
    // 4. Force quote wrapping for safety (LinkedIn cookies often have special chars like &)
    // Only wrap if not empty
    if (!empty($cookie)) {
        $cookie = 'li_at="' . $cookie . '"';
    }
}

if (empty($url)) { echo json_encode(['status'=>'error', 'message'=>'No URL']); exit(); }

// --- TEST ENDPOINT ---
if ($url === 'https://linkedin.com/in/test') {
    $msg = 'PHP Connected';
    
    if (!empty($cookie)) {
        // Try to access Feed to verify cookie
        $testStatus = checkLinkedIn('https://www.linkedin.com/feed/', $proxyConfig, $cookie);
        
        if (strpos($testStatus['message'], 'Active') !== false || strpos($testStatus['message'], 'Feed') !== false) {
            $msg = 'Cookie Working (Session Active) ✅';
        } else {
            // Debug info: Show where it redirected
            $msg = 'Cookie Failed ❌ (' . $testStatus['message'] . ')';
        }
    } else {
        $msg .= ' (No Cookie Provided)';
    }
    
    echo json_encode(['status'=>'valid', 'message'=>$msg]);
    exit();
}

function checkLinkedIn($url, $proxyConfig, $cookie) {
    $ch = curl_init();
    
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
    curl_setopt($ch, CURLOPT_MAXREDIRS, 5); // Limit redirects
    curl_setopt($ch, CURLOPT_TIMEOUT, 30);
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
    
    // Enable Cookie Engine (Critical for session handling)
    curl_setopt($ch, CURLOPT_COOKIEFILE, ""); 
    
    // Accept Encoding (Gzip) - Makes it look more like a browser
    curl_setopt($ch, CURLOPT_ENCODING, "");

    // Real Browser Headers
    $headers = [
        'User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36',
        'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8',
        'Accept-Language: en-US,en;q=0.9',
        'Upgrade-Insecure-Requests: 1',
        'Sec-Ch-Ua: "Google Chrome";v="131", "Chromium";v="131", "Not_A Brand";v="24"',
        'Sec-Ch-Ua-Mobile: ?0',
        'Sec-Ch-Ua-Platform: "Windows"',
        'Sec-Fetch-Dest: document',
        'Sec-Fetch-Mode: navigate',
        'Sec-Fetch-Site: none',
        'Sec-Fetch-User: ?1',
        'Connection: keep-alive'
    ];
    curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
    
    // --- SET COOKIE ---
    if (!empty($cookie)) {
        curl_setopt($ch, CURLOPT_COOKIE, $cookie);
    }

    // --- PROXY SETUP ---
    if ($proxyConfig && !empty($proxyConfig['host'])) {
        $proxy = $proxyConfig['host'] . ':' . $proxyConfig['port'];
        curl_setopt($ch, CURLOPT_PROXY, $proxy);
        curl_setopt($ch, CURLOPT_PROXYTYPE, CURLPROXY_SOCKS5_HOSTNAME);
        if (!empty($proxyConfig['user'])) {
            curl_setopt($ch, CURLOPT_PROXYUSERPWD, $proxyConfig['user'] . ':' . $proxyConfig['pass']);
        }
    }

    $html = curl_exec($ch);
    $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
    $finalUrl = curl_getinfo($ch, CURLINFO_EFFECTIVE_URL);
    $curlError = curl_error($ch);
    curl_close($ch);

    if ($curlError) {
        return ['status' => 'error', 'message' => 'cURL Error: ' . $curlError];
    }

    // --- ANALYSIS ---
    
    // 1. Check for Feed (Test Mode / Self Check)
    if ($url === 'https://www.linkedin.com/feed/') {
         // Check for feed specific indicators
         if ($httpCode == 200 && (
             strpos($finalUrl, '/feed') !== false || 
             strpos($html, 'feed-identity-module') !== false ||
             strpos($html, 'share-box-feed-entry') !== false
         )) {
             return ['status' => 'valid', 'message' => 'Active (Feed Access)'];
         }
         
         // If redirected to login
         if (strpos($finalUrl, 'login') !== false || strpos($finalUrl, 'uas/auth') !== false) {
             return ['status' => 'invalid', 'message' => 'Login Redirect'];
         }
         
         return ['status' => 'invalid', 'message' => 'Login Failed (Code: '.$httpCode.')'];
    }

    // 2. LOGGED IN MODE (Checking Profiles with Cookie)
    if (!empty($cookie)) {
        if ($httpCode == 200) {
            // Check Title
            if (preg_match('/<title>(.*?)<\/title>/i', $html, $matches)) {
                $title = strtolower($matches[1]);
                
                // Active Pattern
                if (strpos($title, '| linkedin') !== false && strpos($title, 'unavailable') === false && strpos($title, 'not found') === false) {
                    return ['status' => 'valid', 'message' => 'Active (Verified)'];
                }
                
                // Banned Pattern
                if (strpos($title, 'unavailable') !== false || strpos($title, 'not found') !== false) {
                    return ['status' => 'invalid', 'message' => 'Banned (Not Found)'];
                }
            }
            
            // Check Body Text
            if (stripos($html, 'profile not found') !== false) return ['status' => 'invalid', 'message' => 'Banned (Content)'];
            
            // Redirected to Feed = Profile likely Banned/Does not exist (if searching specific profile)
            // Or if we are just checking session, it's valid. But here we assume $url is a profile.
            if (strpos($finalUrl, '/feed') !== false) return ['status' => 'invalid', 'message' => 'Banned (Redirected)'];

            // Default Valid
            return ['status' => 'valid', 'message' => 'Active (Logged In)'];
        }
        
        if ($httpCode == 999) return ['status' => 'valid', 'message' => 'Active (Secured/999)']; 
    }

    // 3. PUBLIC MODE (No Cookie)
    if ($httpCode == 404) return ['status' => 'invalid', 'message' => 'Banned (404)'];
    if ($httpCode == 999 || $httpCode == 429) return ['status' => 'valid', 'message' => 'Active (Secured)'];
    
    if ($httpCode == 200) {
        if (strpos($finalUrl, 'authwall') !== false || strpos($finalUrl, 'login') !== false || strpos($finalUrl, 'checkpoint') !== false) {
            return ['status' => 'valid', 'message' => 'Active (Authwall)'];
        }
        if (stripos($html, 'profile not found') !== false) return ['status' => 'invalid', 'message' => 'Banned (Content)'];
        
        return ['status' => 'valid', 'message' => 'Active (Public)'];
    }

    return ['status' => 'invalid', 'message' => "Code: $httpCode"];
}

echo json_encode(checkLinkedIn($url, $proxyConfig, $cookie));
?>