/**
 * MorphGuard Notification Client
 * 
 * Provides client-side integration with the server's notification system,
 * including intelligent notification handling, priority management, 
 * context-aware display, and cognitive load management.
 */

class NotificationClient {
    /**
     * Initialize the notification client
     * @param {Object} options - Configuration options
     */
    constructor(options = {}) {
        // Default options
        this.options = {
            pollInterval: 10000, // 10 seconds
            maxNotifications: 5, // Maximum number of notifications to show at once
            autoHideDelay: 5000, // Auto-hide delay for toast notifications (ms)
            notificationContainer: '#notification-container',
            toastContainer: '#toast-container',
            modalContainer: '#modal-container',
            enablePolling: true,
            enableWebSocket: true,
            debug: false,
            onNotificationReceived: null, // Callback for new notifications
            onNotificationRead: null, // Callback for read notifications
            serverUrl: '/api/notifications',
            userPreferences: null, // User notification preferences
            ...options
        };

        // Notification state
        this.notifications = [];
        this.unreadCount = 0;
        this.activeNotifications = new Set();
        this.lastPollTime = 0;
        this.isPolling = false;
        this.webSocket = null;
        this.isWebSocketConnected = false;
        this.interactionHistory = [];
        this.cognitiveLoadEstimate = 0.0;
        this.attentionScore = 1.0;
        this.throttleTimers = {};

        // Session context
        this.sessionContext = {
            startTime: Date.now(),
            lastActivity: Date.now(),
            pageTransitions: 0,
            formInteractions: 0,
            scrollEvents: 0,
            clickEvents: 0,
            keyboardEvents: 0,
            errors: 0,
            activeModals: 0,
            isActive: true,
            timeOnPage: 0
        };

        // Initialize
        this.init();
    }

    /**
     * Initialize the notification client
     */
    init() {
        // Create notification containers if they don't exist
        this.createContainers();

        // Set up event listeners
        this.setupEventListeners();

        // Initialize WebSocket if enabled
        if (this.options.enableWebSocket) {
            this.connectWebSocket();
        }

        // Start polling for notifications
        if (this.options.enablePolling) {
            this.startPolling();
        }

        // Log initialization
        this.log('NotificationClient initialized');
    }

    /**
     * Create notification containers if they don't exist
     */
    createContainers() {
        const createContainer = (selector, className) => {
            if (!document.querySelector(selector)) {
                const container = document.createElement('div');
                container.id = selector.substring(1); // Remove the # from the selector
                container.className = className;
                document.body.appendChild(container);
            }
        };

        createContainer(this.options.notificationContainer, 'mg-notification-container');
        createContainer(this.options.toastContainer, 'mg-toast-container');
        createContainer(this.options.modalContainer, 'mg-modal-container');
    }

    /**
     * Set up event listeners
     */
    setupEventListeners() {
        // Track user activity
        document.addEventListener('click', e => this.trackActivity('click', e));
        document.addEventListener('keydown', e => this.trackActivity('keydown', e));
        document.addEventListener('scroll', e => this.trackActivity('scroll', e));
        document.addEventListener('mousemove', e => this.throttle('mousemove', () => this.trackActivity('mousemove'), 1000));
        
        // Track form interactions
        document.addEventListener('submit', e => this.trackActivity('form_submit', e));
        document.addEventListener('change', e => this.trackActivity('form_change', e));
        
        // Track page visibility
        document.addEventListener('visibilitychange', () => this.handleVisibilityChange());
        
        // Track page navigation
        window.addEventListener('popstate', () => this.trackActivity('navigation'));
        
        // Track errors
        window.addEventListener('error', e => this.trackActivity('error', e));

        // Set up periodic context updates
        setInterval(() => this.updateContext(), 5000);
    }

    /**
     * Throttle an event callback
     * @param {string} key - Throttle key
     * @param {Function} callback - Function to throttle
     * @param {number} limit - Throttle time in ms
     */
    throttle(key, callback, limit) {
        if (!this.throttleTimers[key]) {
            callback();
            this.throttleTimers[key] = setTimeout(() => {
                delete this.throttleTimers[key];
            }, limit);
        }
    }

    /**
     * Track user activity
     * @param {string} type - Activity type
     * @param {Event} event - Browser event
     */
    trackActivity(type, event) {
        const now = Date.now();
        this.sessionContext.lastActivity = now;
        this.sessionContext.isActive = true;
        
        // Update specific activity counters
        switch (type) {
            case 'click':
                this.sessionContext.clickEvents++;
                break;
            case 'keydown':
                this.sessionContext.keyboardEvents++;
                break;
            case 'scroll':
                this.sessionContext.scrollEvents++;
                break;
            case 'navigation':
                this.sessionContext.pageTransitions++;
                break;
            case 'form_submit':
            case 'form_change':
                this.sessionContext.formInteractions++;
                break;
            case 'error':
                this.sessionContext.errors++;
                break;
        }
        
        // Record in interaction history (limit to last 50 events)
        this.interactionHistory.push({
            type,
            timestamp: now,
            data: event ? this.sanitizeEventData(event) : null
        });
        
        if (this.interactionHistory.length > 50) {
            this.interactionHistory.shift();
        }
        
        // Update cognitive load estimate
        this.updateCognitiveLoadEstimate();
    }

    /**
     * Sanitize event data for storage
     * @param {Event} event - Browser event
     * @returns {Object} Sanitized event data
     */
    sanitizeEventData(event) {
        // Extract only needed data to avoid circular references
        if (!event) return null;
        
        const data = {};
        
        if (event.target) {
            data.target = {
                tagName: event.target.tagName,
                id: event.target.id,
                className: event.target.className,
                type: event.target.type
            };
        }
        
        if (event.key) {
            data.key = event.key;
        }
        
        return data;
    }

    /**
     * Handle visibility change events
     */
    handleVisibilityChange() {
        if (document.visibilityState === 'visible') {
            this.sessionContext.isActive = true;
            this.sessionContext.lastActivity = Date.now();
            // Refresh notifications when tab becomes visible
            this.fetchNotifications();
        } else {
            this.sessionContext.isActive = false;
        }
    }

    /**
     * Update the session context
     */
    updateContext() {
        const now = Date.now();
        
        // Update time on page
        this.sessionContext.timeOnPage = Math.floor((now - this.sessionContext.startTime) / 1000);
        
        // Check if user is still active (inactive after 60 seconds)
        if (now - this.sessionContext.lastActivity > 60000) {
            this.sessionContext.isActive = false;
        }
        
        // Calculate attention score based on recent activity
        this.updateAttentionScore();
    }

    /**
     * Update cognitive load estimate based on recent activity
     */
    updateCognitiveLoadEstimate() {
        // Simple cognitive load model based on:
        // 1. Number of active notifications
        // 2. Form interaction complexity
        // 3. Error rate
        // 4. Page transition frequency
        // 5. Input frequency
        
        const activeNotificationLoad = Math.min(this.activeNotifications.size / 5, 1) * 0.3;
        
        // Calculate input frequency (events in the last 30 seconds)
        const recentEvents = this.interactionHistory.filter(e => 
            Date.now() - e.timestamp < 30000
        ).length;
        const inputLoad = Math.min(recentEvents / 20, 1) * 0.2;
        
        // Calculate error impact
        const errorLoad = Math.min(this.sessionContext.errors / 5, 1) * 0.3;
        
        // Calculate form complexity
        const formLoad = Math.min(this.sessionContext.formInteractions / 10, 1) * 0.1;
        
        // Calculate page transition frequency
        const pageTransitionRate = this.sessionContext.pageTransitions / 
            (Math.max(this.sessionContext.timeOnPage, 1) / 60); // transitions per minute
        const navigationLoad = Math.min(pageTransitionRate / 3, 1) * 0.1;
        
        // Calculate combined load (0-1 scale)
        this.cognitiveLoadEstimate = Math.min(
            activeNotificationLoad + inputLoad + errorLoad + formLoad + navigationLoad,
            1.0
        );
        
        this.log(`Cognitive load estimate updated: ${this.cognitiveLoadEstimate.toFixed(2)}`);
    }

    /**
     * Update attention score based on recent activity
     */
    updateAttentionScore() {
        // Simple attention model based on:
        // 1. Time since last activity
        // 2. Recent input frequency
        // 3. Page visibility
        
        // Calculate time factor (attention decreases with inactivity)
        const timeSinceActivity = (Date.now() - this.sessionContext.lastActivity) / 1000; // seconds
        const timeFactor = Math.max(1 - (timeSinceActivity / 60), 0); // 0 after 60 seconds of inactivity
        
        // Calculate activity factor (recent events indicate attention)
        const recentEvents = this.interactionHistory.filter(e => 
            Date.now() - e.timestamp < 10000 // events in last 10 seconds
        ).length;
        const activityFactor = Math.min(recentEvents / 5, 1);
        
        // Page visibility factor
        const visibilityFactor = document.visibilityState === 'visible' ? 1 : 0;
        
        // Combined attention score (0-1 scale)
        this.attentionScore = Math.min(
            (timeFactor * 0.4) + (activityFactor * 0.3) + (visibilityFactor * 0.3),
            1.0
        );
        
        this.log(`Attention score updated: ${this.attentionScore.toFixed(2)}`);
    }

    /**
     * Connect to WebSocket for real-time notifications
     */
    connectWebSocket() {
        try {
            const protocol = window.location.protocol === 'https:' ? 'wss:' : 'ws:';
            const wsUrl = `${protocol}//${window.location.host}/ws/notifications`;
            
            this.webSocket = new WebSocket(wsUrl);
            
            this.webSocket.onopen = () => {
                this.isWebSocketConnected = true;
                this.log('WebSocket connected');
            };
            
            this.webSocket.onmessage = (event) => {
                try {
                    const data = JSON.parse(event.data);
                    
                    if (data.type === 'notification') {
                        this.handleNewNotification(data.notification);
                    } else if (data.type === 'read') {
                        this.handleNotificationRead(data.notificationId);
                    }
                } catch (err) {
                    this.log('Error processing WebSocket message:', err);
                }
            };
            
            this.webSocket.onclose = () => {
                this.isWebSocketConnected = false;
                this.log('WebSocket disconnected, reconnecting in 5 seconds...');
                
                // Reconnect after 5 seconds
                setTimeout(() => this.connectWebSocket(), 5000);
            };
            
            this.webSocket.onerror = (error) => {
                this.log('WebSocket error:', error);
                this.isWebSocketConnected = false;
            };
        } catch (err) {
            this.log('Error connecting to WebSocket:', err);
        }
    }

    /**
     * Start polling for notifications
     */
    startPolling() {
        if (this.isPolling) return;
        
        this.isPolling = true;
        this.pollForNotifications();
    }

    /**
     * Poll for notifications
     */
    pollForNotifications() {
        if (!this.isPolling) return;
        
        // Only poll if the page is visible and we're not using WebSockets
        if (document.visibilityState === 'visible' && !this.isWebSocketConnected) {
            this.fetchNotifications();
        }
        
        // Schedule next poll
        setTimeout(() => this.pollForNotifications(), this.options.pollInterval);
    }

    /**
     * Fetch notifications from the server
     */
    async fetchNotifications() {
        try {
            this.lastPollTime = Date.now();
            
            const response = await fetch(`${this.options.serverUrl}?since=${this.lastPollTime - this.options.pollInterval}`);
            
            if (!response.ok) {
                throw new Error(`HTTP error! Status: ${response.status}`);
            }
            
            const data = await response.json();
            
            // Process new notifications
            if (data.notifications && Array.isArray(data.notifications)) {
                data.notifications.forEach(notification => {
                    this.handleNewNotification(notification);
                });
            }
            
            // Update unread count
            if (data.unreadCount !== undefined) {
                this.unreadCount = data.unreadCount;
                this.updateUnreadBadge();
            }
        } catch (err) {
            this.log('Error fetching notifications:', err);
        }
    }

    /**
     * Handle a new notification
     * @param {Object} notification - Notification data
     */
    handleNewNotification(notification) {
        // Add to notifications list
        this.notifications.unshift(notification);
        
        // Limit the number of notifications we keep in memory
        if (this.notifications.length > 100) {
            this.notifications = this.notifications.slice(0, 100);
        }
        
        // Update unread count
        if (notification.state !== 'read') {
            this.unreadCount++;
            this.updateUnreadBadge();
        }
        
        // Determine if we should show the notification based on:
        // 1. Priority
        // 2. Current cognitive load
        // 3. Current attention score
        // 4. User preferences
        const shouldShow = this.shouldShowNotification(notification);
        
        if (shouldShow) {
            // Display the notification based on channel
            this.displayNotification(notification);
        } else {
            // Queue for later if not showing now
            this.queueNotificationForLater(notification);
        }
        
        // Call notification received callback
        if (this.options.onNotificationReceived) {
            this.options.onNotificationReceived(notification);
        }
    }

    /**
     * Determine if a notification should be shown immediately
     * @param {Object} notification - Notification data
     * @returns {boolean} Whether to show the notification
     */
    shouldShowNotification(notification) {
        // Always show critical notifications
        if (notification.priority === 'CRITICAL') {
            return true;
        }
        
        // Check user preferences
        const userPrefs = this.options.userPreferences || {};
        const categoryPref = userPrefs[notification.category] || 'normal';
        
        if (categoryPref === 'none') {
            return false;
        }
        
        // Check cognitive load threshold based on priority
        const loadThresholds = {
            'HIGH': 0.8,    // Show high priority unless cognitive load is very high
            'MEDIUM': 0.6,  // Show medium priority unless cognitive load is high
            'LOW': 0.4,     // Show low priority only when cognitive load is low
            'BACKGROUND': 0.3 // Show background notifications only when cognitive load is very low
        };
        
        const loadThreshold = loadThresholds[notification.priority] || 0.6;
        if (this.cognitiveLoadEstimate > loadThreshold) {
            return false;
        }
        
        // Check attention threshold based on priority
        const attentionThresholds = {
            'HIGH': 0.3,     // Show high priority even with low attention
            'MEDIUM': 0.5,   // Show medium priority with moderate attention
            'LOW': 0.7,      // Show low priority only with high attention
            'BACKGROUND': 0.8 // Show background notifications only with very high attention
        };
        
        const attentionThreshold = attentionThresholds[notification.priority] || 0.5;
        if (this.attentionScore < attentionThreshold) {
            return false;
        }
        
        // Check active notification limit
        if (this.activeNotifications.size >= this.options.maxNotifications) {
            // Only show if higher priority than existing notifications
            const lowestPriorityActive = this.getLowestPriorityActiveNotification();
            const priorityValues = {
                'CRITICAL': 0,
                'HIGH': 1,
                'MEDIUM': 2,
                'LOW': 3,
                'BACKGROUND': 4
            };
            
            if (priorityValues[notification.priority] >= priorityValues[lowestPriorityActive]) {
                return false;
            }
        }
        
        return true;
    }

    /**
     * Get the lowest priority active notification
     * @returns {string} Notification priority
     */
    getLowestPriorityActiveNotification() {
        let lowestPriority = 'CRITICAL';
        const priorityValues = {
            'CRITICAL': 0,
            'HIGH': 1,
            'MEDIUM': 2,
            'LOW': 3,
            'BACKGROUND': 4
        };
        
        for (const id of this.activeNotifications) {
            const notification = this.notifications.find(n => n.id === id);
            if (notification && priorityValues[notification.priority] > priorityValues[lowestPriority]) {
                lowestPriority = notification.priority;
            }
        }
        
        return lowestPriority;
    }

    /**
     * Queue a notification for later display
     * @param {Object} notification - Notification data
     */
    queueNotificationForLater(notification) {
        // For now, we just log that we're queueing it
        this.log(`Queueing notification for later: ${notification.id}`);
        
        // In a full implementation, we would store this and periodically check if conditions are right to show it
    }

    /**
     * Display a notification
     * @param {Object} notification - Notification data
     */
    displayNotification(notification) {
        // Add to active notifications
        this.activeNotifications.add(notification.id);
        
        // Display based on channel
        if (notification.channels.includes('MODAL')) {
            this.showModalNotification(notification);
        } else if (notification.channels.includes('TOAST')) {
            this.showToastNotification(notification);
        } else if (notification.channels.includes('UI')) {
            this.showUINotification(notification);
        }
        
        // Update cognitive load estimate
        this.updateCognitiveLoadEstimate();
    }

    /**
     * Show a modal notification
     * @param {Object} notification - Notification data
     */
    showModalNotification(notification) {
        const modalContainer = document.querySelector(this.options.modalContainer);
        if (!modalContainer) return;
        
        // Create modal element
        const modal = document.createElement('div');
        modal.className = `mg-modal mg-priority-${notification.priority.toLowerCase()}`;
        modal.dataset.notificationId = notification.id;
        
        // Add modal content
        modal.innerHTML = `
            <div class="mg-modal-content">
                <div class="mg-modal-header">
                    <h3>${notification.title}</h3>
                    <button class="mg-modal-close">&times;</button>
                </div>
                <div class="mg-modal-body">
                    <p>${notification.content}</p>
                </div>
                <div class="mg-modal-footer">
                    ${this.renderNotificationActions(notification)}
                </div>
            </div>
        `;
        
        // Add event listeners
        modal.querySelector('.mg-modal-close').addEventListener('click', () => {
            this.dismissNotification(notification.id);
            modal.remove();
        });
        
        // Add action event listeners
        const actionButtons = modal.querySelectorAll('.mg-action-button');
        actionButtons.forEach(button => {
            button.addEventListener('click', (e) => {
                const actionId = e.target.dataset.actionId;
                this.handleNotificationAction(notification.id, actionId);
                
                // Close modal if the action should dismiss
                if (e.target.dataset.dismiss === 'true') {
                    this.dismissNotification(notification.id);
                    modal.remove();
                }
            });
        });
        
        // Add to DOM
        modalContainer.appendChild(modal);
        
        // Update session context
        this.sessionContext.activeModals++;
    }

    /**
     * Show a toast notification
     * @param {Object} notification - Notification data
     */
    showToastNotification(notification) {
        const toastContainer = document.querySelector(this.options.toastContainer);
        if (!toastContainer) return;
        
        // Create toast element
        const toast = document.createElement('div');
        toast.className = `mg-toast mg-priority-${notification.priority.toLowerCase()}`;
        toast.dataset.notificationId = notification.id;
        
        // Add icon if available
        const iconHtml = notification.icon ? 
            `<div class="mg-toast-icon"><i class="fa fa-${notification.icon}"></i></div>` : '';
        
        // Add toast content
        toast.innerHTML = `
            ${iconHtml}
            <div class="mg-toast-content">
                <div class="mg-toast-header">
                    <h4>${notification.title}</h4>
                    <button class="mg-toast-close">&times;</button>
                </div>
                <div class="mg-toast-body">
                    <p>${notification.content}</p>
                </div>
                <div class="mg-toast-actions">
                    ${this.renderNotificationActions(notification)}
                </div>
            </div>
        `;
        
        // Add event listeners
        toast.querySelector('.mg-toast-close').addEventListener('click', () => {
            this.dismissNotification(notification.id);
            this.removeToast(toast);
        });
        
        // Add action event listeners
        const actionButtons = toast.querySelectorAll('.mg-action-button');
        actionButtons.forEach(button => {
            button.addEventListener('click', (e) => {
                const actionId = e.target.dataset.actionId;
                this.handleNotificationAction(notification.id, actionId);
                
                // Close toast if the action should dismiss
                if (e.target.dataset.dismiss === 'true') {
                    this.dismissNotification(notification.id);
                    this.removeToast(toast);
                }
            });
        });
        
        // Add to DOM
        toastContainer.appendChild(toast);
        
        // Auto-hide after delay (for non-critical notifications)
        if (notification.priority !== 'CRITICAL' && !notification.requires_acknowledgment) {
            setTimeout(() => {
                this.removeToast(toast);
            }, this.options.autoHideDelay);
        }
        
        // Animate in
        setTimeout(() => {
            toast.classList.add('mg-toast-visible');
        }, 10);
    }

    /**
     * Remove a toast notification with animation
     * @param {HTMLElement} toast - Toast element
     */
    removeToast(toast) {
        toast.classList.remove('mg-toast-visible');
        toast.classList.add('mg-toast-hiding');
        
        // Remove from DOM after animation
        setTimeout(() => {
            if (toast.parentNode) {
                toast.parentNode.removeChild(toast);
            }
            
            // Remove from active notifications
            const notificationId = toast.dataset.notificationId;
            if (notificationId) {
                this.activeNotifications.delete(notificationId);
            }
            
            // Update cognitive load estimate
            this.updateCognitiveLoadEstimate();
        }, 300);
    }

    /**
     * Show a UI notification
     * @param {Object} notification - Notification data
     */
    showUINotification(notification) {
        const notificationContainer = document.querySelector(this.options.notificationContainer);
        if (!notificationContainer) return;
        
        // Create notification element
        const notificationEl = document.createElement('div');
        notificationEl.className = `mg-notification mg-priority-${notification.priority.toLowerCase()}`;
        notificationEl.dataset.notificationId = notification.id;
        
        // Add icon if available
        const iconHtml = notification.icon ? 
            `<div class="mg-notification-icon"><i class="fa fa-${notification.icon}"></i></div>` : '';
        
        // Add notification content
        notificationEl.innerHTML = `
            ${iconHtml}
            <div class="mg-notification-content">
                <div class="mg-notification-header">
                    <h4>${notification.title}</h4>
                    <span class="mg-notification-time">${this.formatTime(notification.created_at)}</span>
                </div>
                <div class="mg-notification-body">
                    <p>${notification.content}</p>
                </div>
                <div class="mg-notification-actions">
                    ${this.renderNotificationActions(notification)}
                </div>
            </div>
        `;
        
        // Add click event to mark as read
        notificationEl.addEventListener('click', (e) => {
            // Don't mark as read if clicking an action button
            if (e.target.closest('.mg-action-button')) {
                return;
            }
            
            this.markAsRead(notification.id);
        });
        
        // Add action event listeners
        const actionButtons = notificationEl.querySelectorAll('.mg-action-button');
        actionButtons.forEach(button => {
            button.addEventListener('click', (e) => {
                const actionId = e.target.dataset.actionId;
                this.handleNotificationAction(notification.id, actionId);
            });
        });
        
        // Add to DOM at the top of the container
        if (notificationContainer.firstChild) {
            notificationContainer.insertBefore(notificationEl, notificationContainer.firstChild);
        } else {
            notificationContainer.appendChild(notificationEl);
        }
    }

    /**
     * Render notification action buttons
     * @param {Object} notification - Notification data
     * @returns {string} HTML for action buttons
     */
    renderNotificationActions(notification) {
        if (!notification.actions || !notification.actions.length) {
            return '';
        }
        
        return notification.actions.map(action => {
            const btnClass = action.style || 'primary';
            const dismiss = action.dismiss ? 'true' : 'false';
            return `<button class="mg-action-button mg-btn-${btnClass}" data-action-id="${action.id}" data-dismiss="${dismiss}">${action.label}</button>`;
        }).join('');
    }

    /**
     * Format a timestamp into a human-readable string
     * @param {string} timestamp - ISO timestamp
     * @returns {string} Formatted time
     */
    formatTime(timestamp) {
        const date = new Date(timestamp);
        const now = new Date();
        const diff = now - date;
        
        // Show relative time for recent notifications
        if (diff < 60000) {
            return 'Just now';
        } else if (diff < 3600000) {
            const minutes = Math.floor(diff / 60000);
            return `${minutes}m ago`;
        } else if (diff < 86400000) {
            const hours = Math.floor(diff / 3600000);
            return `${hours}h ago`;
        } else {
            // For older notifications, show the date
            return date.toLocaleDateString();
        }
    }

    /**
     * Handle a notification action
     * @param {string} notificationId - Notification ID
     * @param {string} actionId - Action ID
     */
    async handleNotificationAction(notificationId, actionId) {
        try {
            // Find the notification
            const notification = this.notifications.find(n => n.id === notificationId);
            if (!notification) return;
            
            // Find the action
            const action = notification.actions.find(a => a.id === actionId);
            if (!action) return;
            
            // Log the action
            this.log(`Notification action ${actionId} for notification ${notificationId}`);
            
            // Send to server
            await fetch(`${this.options.serverUrl}/${notificationId}/action`, {
                method: 'POST',
                headers: {
                    'Content-Type': 'application/json'
                },
                body: JSON.stringify({
                    actionId,
                    timestamp: new Date().toISOString()
                })
            });
            
            // If the action should dismiss the notification
            if (action.dismiss) {
                this.dismissNotification(notificationId);
            }
            
            // Execute client-side action handler if available
            if (action.clientHandler && typeof window[action.clientHandler] === 'function') {
                window[action.clientHandler](notification, action);
            }
        } catch (err) {
            this.log('Error handling notification action:', err);
        }
    }

    /**
     * Mark a notification as read
     * @param {string} notificationId - Notification ID
     */
    async markAsRead(notificationId) {
        try {
            // Find the notification
            const notification = this.notifications.find(n => n.id === notificationId);
            if (!notification) return;
            
            // Skip if already read
            if (notification.state === 'read') return;
            
            // Update state locally
            notification.state = 'read';
            notification.read_at = new Date().toISOString();
            
            // Update unread count
            this.unreadCount = Math.max(0, this.unreadCount - 1);
            this.updateUnreadBadge();
            
            // Send to server
            await fetch(`${this.options.serverUrl}/${notificationId}/read`, {
                method: 'POST',
                headers: {
                    'Content-Type': 'application/json'
                },
                body: JSON.stringify({
                    timestamp: notification.read_at
                })
            });
            
            // Update UI
            const notificationEl = document.querySelector(`[data-notification-id="${notificationId}"]`);
            if (notificationEl) {
                notificationEl.classList.add('mg-notification-read');
            }
            
            // Call notification read callback
            if (this.options.onNotificationRead) {
                this.options.onNotificationRead(notification);
            }
        } catch (err) {
            this.log('Error marking notification as read:', err);
        }
    }

    /**
     * Dismiss a notification
     * @param {string} notificationId - Notification ID
     */
    dismissNotification(notificationId) {
        // Remove from active notifications
        this.activeNotifications.delete(notificationId);
        
        // Mark as read
        this.markAsRead(notificationId);
        
        // Update cognitive load estimate
        this.updateCognitiveLoadEstimate();
    }

    /**
     * Acknowledge a notification (for notifications that require acknowledgment)
     * @param {string} notificationId - Notification ID
     * @param {Object} data - Acknowledgment data
     */
    async acknowledgeNotification(notificationId, data = {}) {
        try {
            // Find the notification
            const notification = this.notifications.find(n => n.id === notificationId);
            if (!notification) return;
            
            // Skip if already acknowledged or doesn't require acknowledgment
            if (notification.state === 'read' || !notification.requires_acknowledgment) return;
            
            // Update state locally
            notification.state = 'read';
            notification.read_at = new Date().toISOString();
            notification.acknowledgment_data = {
                ...data,
                timestamp: notification.read_at
            };
            
            // Update unread count
            this.unreadCount = Math.max(0, this.unreadCount - 1);
            this.updateUnreadBadge();
            
            // Send to server
            await fetch(`${this.options.serverUrl}/${notificationId}/acknowledge`, {
                method: 'POST',
                headers: {
                    'Content-Type': 'application/json'
                },
                body: JSON.stringify(notification.acknowledgment_data)
            });
            
            // Update UI
            const notificationEl = document.querySelector(`[data-notification-id="${notificationId}"]`);
            if (notificationEl) {
                notificationEl.classList.add('mg-notification-read');
            }
            
            // Call notification read callback
            if (this.options.onNotificationRead) {
                this.options.onNotificationRead(notification);
            }
        } catch (err) {
            this.log('Error acknowledging notification:', err);
        }
    }

    /**
     * Handle notification read event
     * @param {string} notificationId - Notification ID
     */
    handleNotificationRead(notificationId) {
        // Find the notification
        const notification = this.notifications.find(n => n.id === notificationId);
        if (!notification) return;
        
        // Skip if already read
        if (notification.state === 'read') return;
        
        // Update state locally
        notification.state = 'read';
        notification.read_at = new Date().toISOString();
        
        // Update unread count
        this.unreadCount = Math.max(0, this.unreadCount - 1);
        this.updateUnreadBadge();
        
        // Update UI
        const notificationEl = document.querySelector(`[data-notification-id="${notificationId}"]`);
        if (notificationEl) {
            notificationEl.classList.add('mg-notification-read');
        }
        
        // Call notification read callback
        if (this.options.onNotificationRead) {
            this.options.onNotificationRead(notification);
        }
    }

    /**
     * Update the unread notification badge
     */
    updateUnreadBadge() {
        // Find all elements with the notification badge class
        const badges = document.querySelectorAll('.mg-notification-badge');
        
        badges.forEach(badge => {
            if (this.unreadCount > 0) {
                badge.textContent = this.unreadCount > 99 ? '99+' : this.unreadCount;
                badge.classList.add('mg-notification-badge-visible');
            } else {
                badge.classList.remove('mg-notification-badge-visible');
            }
        });
    }

    /**
     * Get all notifications
     * @returns {Array} Notifications
     */
    getNotifications() {
        return [...this.notifications];
    }

    /**
     * Get unread notifications
     * @returns {Array} Unread notifications
     */
    getUnreadNotifications() {
        return this.notifications.filter(n => n.state !== 'read');
    }

    /**
     * Get notifications by category
     * @param {string} category - Notification category
     * @returns {Array} Notifications in the category
     */
    getNotificationsByCategory(category) {
        return this.notifications.filter(n => n.category === category);
    }

    /**
     * Clear all notifications
     */
    async clearAllNotifications() {
        try {
            // Clear on server
            await fetch(`${this.options.serverUrl}/clear`, {
                method: 'POST'
            });
            
            // Clear locally
            this.notifications = [];
            this.unreadCount = 0;
            this.activeNotifications.clear();
            
            // Update UI
            this.updateUnreadBadge();
            
            // Clear notification containers
            document.querySelector(this.options.notificationContainer).innerHTML = '';
            document.querySelector(this.options.toastContainer).innerHTML = '';
            
            // Update cognitive load estimate
            this.updateCognitiveLoadEstimate();
        } catch (err) {
            this.log('Error clearing notifications:', err);
        }
    }

    /**
     * Get session context for the server
     * @returns {Object} Session context
     */
    getContextForServer() {
        return {
            session_data: {
                is_active: this.sessionContext.isActive,
                last_activity: this.sessionContext.lastActivity,
                time_on_page: this.sessionContext.timeOnPage,
                page_transitions: this.sessionContext.pageTransitions,
                form_interactions: this.sessionContext.formInteractions
            },
            cognitive_load: this.cognitiveLoadEstimate,
            attention_score: this.attentionScore,
            device_info: {
                viewport_width: window.innerWidth,
                viewport_height: window.innerHeight,
                user_agent: navigator.userAgent,
                is_mobile: /Mobi|Android/i.test(navigator.userAgent)
            }
        };
    }

    /**
     * Set user preferences for notifications
     * @param {Object} preferences - User preferences
     */
    setUserPreferences(preferences) {
        this.options.userPreferences = preferences;
    }

    /**
     * Log debug messages
     * @param  {...any} args - Log arguments
     */
    log(...args) {
        if (this.options.debug) {
            console.log('[NotificationClient]', ...args);
        }
    }
}

// CSS Styles for notifications
const addNotificationStyles = () => {
    const style = document.createElement('style');
    style.textContent = `
        /* Notification containers */
        .mg-notification-container {
            max-height: 600px;
            overflow-y: auto;
            width: 320px;
        }
        
        .mg-toast-container {
            position: fixed;
            top: 20px;
            right: 20px;
            z-index: 9999;
            max-width: 350px;
        }
        
        .mg-modal-container {
            position: fixed;
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
            z-index: 10000;
            background-color: rgba(0, 0, 0, 0.5);
            display: flex;
            align-items: center;
            justify-content: center;
        }
        
        /* Notification badge */
        .mg-notification-badge {
            display: none;
            min-width: 20px;
            height: 20px;
            border-radius: 10px;
            background-color: #e74c3c;
            color: white;
            font-size: 12px;
            text-align: center;
            line-height: 20px;
            padding: 0 4px;
        }
        
        .mg-notification-badge-visible {
            display: inline-block;
        }
        
        /* UI Notification */
        .mg-notification {
            display: flex;
            padding: 12px;
            margin-bottom: 8px;
            border-radius: 4px;
            background-color: #fff;
            box-shadow: 0 1px 3px rgba(0, 0, 0, 0.12);
            border-left: 4px solid #3498db;
            transition: all 0.2s ease;
        }
        
        .mg-notification:hover {
            box-shadow: 0 3px 6px rgba(0, 0, 0, 0.16);
        }
        
        .mg-notification-read {
            opacity: 0.7;
            border-left-color: #bdc3c7;
        }
        
        .mg-notification-content {
            flex: 1;
        }
        
        .mg-notification-header {
            display: flex;
            justify-content: space-between;
            align-items: center;
            margin-bottom: 4px;
        }
        
        .mg-notification-header h4 {
            margin: 0;
            font-size: 14px;
            font-weight: bold;
        }
        
        .mg-notification-time {
            font-size: 12px;
            color: #7f8c8d;
        }
        
        .mg-notification-body p {
            margin: 0;
            font-size: 13px;
            color: #2c3e50;
        }
        
        .mg-notification-actions {
            margin-top: 8px;
            display: flex;
            gap: 8px;
        }
        
        /* Toast notification */
        .mg-toast {
            display: flex;
            padding: 12px;
            margin-bottom: 10px;
            border-radius: 4px;
            background-color: #fff;
            box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
            max-width: 100%;
            opacity: 0;
            transform: translateY(-20px);
            transition: all 0.3s ease;
        }
        
        .mg-toast-visible {
            opacity: 1;
            transform: translateY(0);
        }
        
        .mg-toast-hiding {
            opacity: 0;
            transform: translateY(-20px);
        }
        
        .mg-toast-icon {
            margin-right: 12px;
            font-size: 20px;
            display: flex;
            align-items: center;
            justify-content: center;
        }
        
        .mg-toast-content {
            flex: 1;
        }
        
        .mg-toast-header {
            display: flex;
            justify-content: space-between;
            align-items: center;
            margin-bottom: 4px;
        }
        
        .mg-toast-header h4 {
            margin: 0;
            font-size: 14px;
            font-weight: bold;
        }
        
        .mg-toast-close {
            background: none;
            border: none;
            font-size: 16px;
            cursor: pointer;
            padding: 0;
            color: #7f8c8d;
        }
        
        .mg-toast-body p {
            margin: 0;
            font-size: 13px;
            color: #2c3e50;
        }
        
        .mg-toast-actions {
            margin-top: 8px;
            display: flex;
            gap: 8px;
        }
        
        /* Modal notification */
        .mg-modal {
            width: 90%;
            max-width: 500px;
            background-color: #fff;
            border-radius: 4px;
            box-shadow: 0 10px 25px rgba(0, 0, 0, 0.2);
            overflow: hidden;
        }
        
        .mg-modal-content {
            padding: 0;
        }
        
        .mg-modal-header {
            padding: 16px;
            display: flex;
            justify-content: space-between;
            align-items: center;
            background-color: #f8f9fa;
            border-bottom: 1px solid #e9ecef;
        }
        
        .mg-modal-header h3 {
            margin: 0;
            font-size: 18px;
            font-weight: 600;
        }
        
        .mg-modal-close {
            background: none;
            border: none;
            font-size: 20px;
            cursor: pointer;
            padding: 0;
            color: #7f8c8d;
        }
        
        .mg-modal-body {
            padding: 16px;
        }
        
        .mg-modal-body p {
            margin: 0 0 12px 0;
            font-size: 14px;
            color: #2c3e50;
            line-height: 1.5;
        }
        
        .mg-modal-footer {
            padding: 12px 16px;
            border-top: 1px solid #e9ecef;
            display: flex;
            justify-content: flex-end;
            gap: 8px;
        }
        
        /* Priority colors */
        .mg-priority-critical {
            border-left-color: #e74c3c;
        }
        
        .mg-priority-high {
            border-left-color: #e67e22;
        }
        
        .mg-priority-medium {
            border-left-color: #3498db;
        }
        
        .mg-priority-low {
            border-left-color: #2ecc71;
        }
        
        .mg-priority-background {
            border-left-color: #95a5a6;
        }
        
        /* Action buttons */
        .mg-action-button {
            background: none;
            border: 1px solid #3498db;
            border-radius: 4px;
            padding: 6px 12px;
            font-size: 12px;
            cursor: pointer;
            transition: all 0.2s ease;
        }
        
        .mg-btn-primary {
            background-color: #3498db;
            color: white;
        }
        
        .mg-btn-primary:hover {
            background-color: #2980b9;
        }
        
        .mg-btn-secondary {
            background-color: transparent;
            color: #3498db;
        }
        
        .mg-btn-secondary:hover {
            background-color: #eef8ff;
        }
        
        .mg-btn-danger {
            background-color: #e74c3c;
            border-color: #e74c3c;
            color: white;
        }
        
        .mg-btn-danger:hover {
            background-color: #c0392b;
        }
        
        .mg-btn-success {
            background-color: #2ecc71;
            border-color: #2ecc71;
            color: white;
        }
        
        .mg-btn-success:hover {
            background-color: #27ae60;
        }
    `;
    
    document.head.appendChild(style);
};

// Add styles when the DOM is loaded
if (document.readyState === 'loading') {
    document.addEventListener('DOMContentLoaded', addNotificationStyles);
} else {
    addNotificationStyles();
}

// Create a global reference to the notification client
window.notificationClient = null;

// Initialize the notification client
window.initNotificationClient = (options = {}) => {
    window.notificationClient = new NotificationClient(options);
    return window.notificationClient;
};

// Export for module usage
if (typeof module !== 'undefined' && module.exports) {
    module.exports = {
        NotificationClient,
        initNotificationClient: (options) => {
            window.notificationClient = new NotificationClient(options);
            return window.notificationClient;
        }
    };
}