)

function checkAchievements($userId) {
    global $pdo;
    
    // Get user stats
    $stmt = $pdo->prepare("SELECT * FROM users WHERE id = ?");
    $stmt->execute([$userId]);
    $user = $stmt->fetch();
    
    if (!$user) return;
    
    // Get user's earned achievements
    $stmt = $pdo->prepare("SELECT achievement_id FROM user_achievements WHERE user_id = ?");
    $stmt->execute([$userId]);
    $earnedIds = array_column($stmt->fetchAll(), 'achievement_id');
    
    // Get all achievements
    $stmt = $pdo->query("SELECT * FROM achievements");
    $achievements = $stmt->fetchAll();
    
    // Check each achievement
    foreach ($achievements as $achievement) {
        // Skip if already earned
        if (in_array($achievement['id'], $earnedIds)) {
            continue;
        }
        
        $earned = false;
        $current = 0;
        
        switch ($achievement['requirement_type']) {
            case 'surfs_completed':
                $stmt = $pdo->prepare("SELECT COUNT(*) as total FROM surf_sessions WHERE user_id = ? AND completed = 1");
                $stmt->execute([$userId]);
                $current = $stmt->fetch()['total'];
                $earned = ($current >= $achievement['requirement_value']);
                break;
                
            case 'level':
                $current = $user['level'];
                $earned = ($current >= $achievement['requirement_value']);
                break;
                
            case 'sites_added':
                $stmt = $pdo->prepare("SELECT COUNT(*) as total FROM sites WHERE user_id = ?");
                $stmt->execute([$userId]);
                $current = $stmt->fetch()['total'];
                $earned = ($current >= $achievement['requirement_value']);
                break;
                
            case 'credits_earned':
                $stmt = $pdo->prepare("SELECT SUM(amount) as total FROM transactions WHERE user_id = ? AND type = 'earn'");
                $stmt->execute([$userId]);
                $current = $stmt->fetch()['total'] ?? 0;
                $earned = ($current >= $achievement['requirement_value']);
                break;
                
            case 'login_streak':
                $current = $user['login_streak'];
                $earned = ($current >= $achievement['requirement_value']);
                break;
        }
        
        // Award achievement if earned
        if ($earned) {
            try {
                // Insert achievement
                $stmt = $pdo->prepare("INSERT INTO user_achievements (user_id, achievement_id) VALUES (?, ?)");
                $stmt->execute([$userId, $achievement['id']]);
                
                // Award credits
                if ($achievement['credits_reward'] > 0) {
                    addCredits($userId, $achievement['credits_reward'], 'bonus', 'Achievement: ' . $achievement['name']);
                }
                
                // Store in session for notification
                if (!isset($_SESSION['new_achievements'])) {
                    $_SESSION['new_achievements'] = [];
                }
                $_SESSION['new_achievements'][] = $achievement;
                
            } catch (Exception $e) {
                // Achievement already exists (race condition), ignore
            }
        }
    }
}

function updateLoginStreak($userId) {
    global $pdo;
    
    $stmt = $pdo->prepare("SELECT login_streak, last_streak_date FROM users WHERE id = ?");
    $stmt->execute([$userId]);
    $user = $stmt->fetch();
    
    $today = date('Y-m-d');
    $lastDate = $user['last_streak_date'];
    
    if (!$lastDate) {
        // First login
        $stmt = $pdo->prepare("UPDATE users SET login_streak = 1, last_streak_date = ? WHERE id = ?");
        $stmt->execute([$today, $userId]);
    } elseif ($lastDate == $today) {
        // Already logged in today, do nothing
        return;
    } elseif ($lastDate == date('Y-m-d', strtotime('-1 day'))) {
        // Consecutive day - increment streak
        $newStreak = $user['login_streak'] + 1;
        $stmt = $pdo->prepare("UPDATE users SET login_streak = ?, last_streak_date = ? WHERE id = ?");
        $stmt->execute([$newStreak, $today, $userId]);
        
        // Check streak achievements
        checkAchievements($userId);
    } else {
        // Streak broken - reset to 1
        $stmt = $pdo->prepare("UPDATE users SET login_streak = 1, last_streak_date = ? WHERE id = ?");
        $stmt->execute([$today, $userId]);
    }
}

function getNewAchievementNotifications() {
    if (isset($_SESSION['new_achievements'])) {
        $achievements = $_SESSION['new_achievements'];
        unset($_SESSION['new_achievements']);
        return $achievements;
    }
    return [];
}

function trackAnalyticsEvent($siteId, $userId, $eventType, $duration = 0) {
    global $pdo;
    
    try {
        $stmt = $pdo->prepare("INSERT INTO analytics_events (site_id, user_id, event_type, duration) VALUES (?, ?, ?, ?)");
        $stmt->execute([$siteId, $userId, $eventType, $duration]);
        
        // Update site aggregate stats
        updateSiteAnalytics($siteId);
    } catch (Exception $e) {
        // Log error but don't break the flow
        error_log("Analytics tracking error: " . $e->getMessage());
    }
}

function updateSiteAnalytics($siteId) {
    global $pdo;
    
    // Calculate average duration
    $stmt = $pdo->prepare("SELECT AVG(duration) as avg_duration FROM surf_sessions WHERE site_id = ? AND completed = 1");
    $stmt->execute([$siteId]);
    $avgDuration = $stmt->fetch()['avg_duration'] ?? 0;
    
    // Update site
    $stmt = $pdo->prepare("UPDATE sites SET avg_duration = ? WHERE id = ?");
    $stmt->execute([$avgDuration, $siteId]);
}



// Achievement Helper Functions
// ADD THESE FUNCTIONS TO THE END OF config.php (before the closing ?>)

function checkAchievements($userId) {
    global $pdo;
    
    // Get user stats
    $stmt = $pdo->prepare("SELECT * FROM users WHERE id = ?");
    $stmt->execute([$userId]);
    $user = $stmt->fetch();
    
    if (!$user) return;
    
    // Get user's earned achievements
    $stmt = $pdo->prepare("SELECT achievement_id FROM user_achievements WHERE user_id = ?");
    $stmt->execute([$userId]);
    $earnedIds = array_column($stmt->fetchAll(), 'achievement_id');
    
    // Get all achievements
    $stmt = $pdo->query("SELECT * FROM achievements");
    $achievements = $stmt->fetchAll();
    
    // Check each achievement
    foreach ($achievements as $achievement) {
        // Skip if already earned
        if (in_array($achievement['id'], $earnedIds)) {
            continue;
        }
        
        $earned = false;
        $current = 0;
        
        switch ($achievement['requirement_type']) {
            case 'surfs_completed':
                $stmt = $pdo->prepare("SELECT COUNT(*) as total FROM surf_sessions WHERE user_id = ? AND completed = 1");
                $stmt->execute([$userId]);
                $current = $stmt->fetch()['total'];
                $earned = ($current >= $achievement['requirement_value']);
                break;
                
            case 'level':
                $current = $user['level'];
                $earned = ($current >= $achievement['requirement_value']);
                break;
                
            case 'sites_added':
                $stmt = $pdo->prepare("SELECT COUNT(*) as total FROM sites WHERE user_id = ?");
                $stmt->execute([$userId]);
                $current = $stmt->fetch()['total'];
                $earned = ($current >= $achievement['requirement_value']);
                break;
                
            case 'credits_earned':
                $stmt = $pdo->prepare("SELECT SUM(amount) as total FROM transactions WHERE user_id = ? AND type = 'earn'");
                $stmt->execute([$userId]);
                $current = $stmt->fetch()['total'] ?? 0;
                $earned = ($current >= $achievement['requirement_value']);
                break;
                
            case 'login_streak':
                $current = $user['login_streak'];
                $earned = ($current >= $achievement['requirement_value']);
                break;
        }
        
        // Award achievement if earned
        if ($earned) {
            try {
                // Insert achievement
                $stmt = $pdo->prepare("INSERT INTO user_achievements (user_id, achievement_id) VALUES (?, ?)");
                $stmt->execute([$userId, $achievement['id']]);
                
                // Award credits
                if ($achievement['credits_reward'] > 0) {
                    addCredits($userId, $achievement['credits_reward'], 'bonus', 'Achievement: ' . $achievement['name']);
                }
                
                // Store in session for notification
                if (!isset($_SESSION['new_achievements'])) {
                    $_SESSION['new_achievements'] = [];
                }
                $_SESSION['new_achievements'][] = $achievement;
                
            } catch (Exception $e) {
                // Achievement already exists (race condition), ignore
            }
        }
    }
}

function updateLoginStreak($userId) {
    global $pdo;
    
    $stmt = $pdo->prepare("SELECT login_streak, last_streak_date FROM users WHERE id = ?");
    $stmt->execute([$userId]);
    $user = $stmt->fetch();
    
    $today = date('Y-m-d');
    $lastDate = $user['last_streak_date'];
    
    if (!$lastDate) {
        // First login
        $stmt = $pdo->prepare("UPDATE users SET login_streak = 1, last_streak_date = ? WHERE id = ?");
        $stmt->execute([$today, $userId]);
    } elseif ($lastDate == $today) {
        // Already logged in today, do nothing
        return;
    } elseif ($lastDate == date('Y-m-d', strtotime('-1 day'))) {
        // Consecutive day - increment streak
        $newStreak = $user['login_streak'] + 1;
        $stmt = $pdo->prepare("UPDATE users SET login_streak = ?, last_streak_date = ? WHERE id = ?");
        $stmt->execute([$newStreak, $today, $userId]);
        
        // Check streak achievements
        checkAchievements($userId);
    } else {
        // Streak broken - reset to 1
        $stmt = $pdo->prepare("UPDATE users SET login_streak = 1, last_streak_date = ? WHERE id = ?");
        $stmt->execute([$today, $userId]);
    }
}

function getNewAchievementNotifications() {
    if (isset($_SESSION['new_achievements'])) {
        $achievements = $_SESSION['new_achievements'];
        unset($_SESSION['new_achievements']);
        return $achievements;
    }
    return [];
}

function trackAnalyticsEvent($siteId, $userId, $eventType, $duration = 0) {
    global $pdo;
    
    try {
        $stmt = $pdo->prepare("INSERT INTO analytics_events (site_id, user_id, event_type, duration) VALUES (?, ?, ?, ?)");
        $stmt->execute([$siteId, $userId, $eventType, $duration]);
        
        // Update site aggregate stats
        updateSiteAnalytics($siteId);
    } catch (Exception $e) {
        // Log error but don't break the flow
        error_log("Analytics tracking error: " . $e->getMessage());
    }
}

function updateSiteAnalytics($siteId) {
    global $pdo;
    
    // Calculate average duration
    $stmt = $pdo->prepare("SELECT AVG(duration) as avg_duration FROM surf_sessions WHERE site_id = ? AND completed = 1");
    $stmt->execute([$siteId]);
    $avgDuration = $stmt->fetch()['avg_duration'] ?? 0;
    
    // Update site
    $stmt = $pdo->prepare("UPDATE sites SET avg_duration = ? WHERE id = ?");
    $stmt->execute([$avgDuration, $siteId]);
}
?><!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Register - TrafficQuest</title>
    <style>
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
        
        body {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            min-height: 100vh;
            display: flex;
            align-items: center;
            justify-content: center;
            padding: 20px;
        }
        
        .container {
            background: white;
            padding: 40px;
            border-radius: 10px;
            box-shadow: 0 10px 40px rgba(0,0,0,0.2);
            width: 100%;
            max-width: 450px;
        }
        
        .logo {
            text-align: center;
            margin-bottom: 30px;
        }
        
        .logo h1 {
            color: #667eea;
            font-size: 32px;
            margin-bottom: 5px;
        }
        
        .logo p {
            color: #666;
            font-size: 14px;
        }
        
        .alert {
            padding: 12px;
            border-radius: 5px;
            margin-bottom: 20px;
            font-size: 14px;
        }
        
        .alert-error {
            background: #fee;
            color: #c33;
            border: 1px solid #fcc;
        }
        
        .alert-success {
            background: #efe;
            color: #3c3;
            border: 1px solid #cfc;
        }
        
        .form-group {
            margin-bottom: 20px;
        }
        
        label {
            display: block;
            margin-bottom: 5px;
            color: #333;
            font-weight: 500;
        }
        
        input[type="text"],
        input[type="email"],
        input[type="password"] {
            width: 100%;
            padding: 12px;
            border: 2px solid #e0e0e0;
            border-radius: 5px;
            font-size: 14px;
            transition: border-color 0.3s;
        }
        
        input:focus {
            outline: none;
            border-color: #667eea;
        }
        
        button {
            width: 100%;
            padding: 14px;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            color: white;
            border: none;
            border-radius: 5px;
            font-size: 16px;
            font-weight: 600;
            cursor: pointer;
            transition: transform 0.2s;
        }
        
        button:hover {
            transform: translateY(-2px);
        }
        
        button:active {
            transform: translateY(0);
        }
        
        .links {
            text-align: center;
            margin-top: 20px;
            font-size: 14px;
        }
        
        .links a {
            color: #667eea;
            text-decoration: none;
        }
        
        .links a:hover {
            text-decoration: underline;
        }
    </style>
</head>
<body>
    <div class="container">
        <div class="logo">
            <h1>🎯 TrafficQuest</h1>
            <p>Start Your Traffic Adventure</p>
        </div>
        
                
                
        <form method="POST" action="">
            <div class="form-group">
                <label>Username</label>
                <input type="text" name="username" required value="">
            </div>
            
            <div class="form-group">
                <label>Email Address</label>
                <input type="email" name="email" required value="">
            </div>
            
            <div class="form-group">
                <label>Password (min 6 characters)</label>
                <input type="password" name="password" required>
            </div>
            
            <div class="form-group">
                <label>Confirm Password</label>
                <input type="password" name="confirm_password" required>
            </div>
            
            <button type="submit">Create Account</button>
        </form>
        
        <div class="links">
            Already have an account? <a href="login.php">Login here</a>
        </div>
    </div>
</body>
</html>