<?php
/**
 * UserPreferencesModel
 * Handles user-specific preferences and settings with caching
 */
require_once dirname(__DIR__) . '/helpers/CacheHelper.php';

class UserPreferencesModel {
    private mysqli $conn;
    private static string $CACHE_PREFIX = 'user_prefs';
    private static int $CACHE_TTL = 300; // 5 minutes

    public function __construct(mysqli $conn) {
        $this->conn = $conn;
    }

    /**
     * Get all preferences for a user (with caching)
     * @param int $userId User ID
     * @return array Associative array of preference_key => preference_value
     */
    public function getUserPreferences(int $userId): array {
        return CacheHelper::remember(self::$CACHE_PREFIX, $userId, function() use ($userId) {
            $sql = "SELECT preference_key, preference_value
                    FROM user_preferences
                    WHERE user_id = ?";
            $stmt = $this->conn->prepare($sql);
            $stmt->bind_param("i", $userId);
            $stmt->execute();
            $result = $stmt->get_result();

            $prefs = [];
            while ($row = $result->fetch_assoc()) {
                $prefs[$row['preference_key']] = $row['preference_value'];
            }
            $stmt->close();
            return $prefs;
        }, self::$CACHE_TTL);
    }

    /**
     * Set or update a preference for a user
     * @param int $userId User ID
     * @param string $key Preference key
     * @param string $value Preference value
     * @return bool Success status
     */
    public function setPreference(int $userId, string $key, string $value): bool {
        $sql = "INSERT INTO user_preferences (user_id, preference_key, preference_value)
                VALUES (?, ?, ?)
                ON DUPLICATE KEY UPDATE preference_value = VALUES(preference_value)";
        $stmt = $this->conn->prepare($sql);
        $stmt->bind_param("iss", $userId, $key, $value);
        $result = $stmt->execute();
        $stmt->close();

        // Invalidate cache for this user
        if ($result) {
            CacheHelper::delete(self::$CACHE_PREFIX, $userId);
        }

        return $result;
    }

    /**
     * Get a single preference value for a user
     * @param int $userId User ID
     * @param string $key Preference key
     * @param mixed $default Default value if preference doesn't exist
     * @return mixed Preference value or default
     */
    public function getPreference(int $userId, string $key, $default = null) {
        $prefs = $this->getUserPreferences($userId);
        return $prefs[$key] ?? $default;
    }

    /**
     * Delete a preference for a user
     * @param int $userId User ID
     * @param string $key Preference key
     * @return bool Success status
     */
    public function deletePreference(int $userId, string $key): bool {
        $sql = "DELETE FROM user_preferences
                WHERE user_id = ? AND preference_key = ?";
        $stmt = $this->conn->prepare($sql);
        $stmt->bind_param("is", $userId, $key);
        $result = $stmt->execute();
        $stmt->close();

        // Invalidate cache for this user
        if ($result) {
            CacheHelper::delete(self::$CACHE_PREFIX, $userId);
        }

        return $result;
    }

    /**
     * Delete all preferences for a user
     * @param int $userId User ID
     * @return bool Success status
     */
    public function deleteAllPreferences(int $userId): bool {
        $sql = "DELETE FROM user_preferences WHERE user_id = ?";
        $stmt = $this->conn->prepare($sql);
        $stmt->bind_param("i", $userId);
        $result = $stmt->execute();
        $stmt->close();

        // Invalidate cache for this user
        if ($result) {
            CacheHelper::delete(self::$CACHE_PREFIX, $userId);
        }

        return $result;
    }

    /**
     * Clear all user preferences cache
     */
    public static function clearCache(): void {
        CacheHelper::delete(self::$CACHE_PREFIX);
    }
}