// Progressive Web App functionality with fixes for desktop and persistent prompts
// Handles service worker registration and PWA features

class PWAManager {
    constructor() {
        this.swRegistration = null;
        this.vapidPublicKey = null;
        this.pushSubscription = null;
        this.installPromptShown = false;
        this.pushPromptShown = false;
        this.init();
    }

    async init() {
        console.log('PWA: Initializing PWA Manager...');

        if ('serviceWorker' in navigator) {
            try {
                this.swRegistration = await navigator.serviceWorker.register('/sw.js');
                console.log('SW: Service Worker registered successfully');

                // Listen for updates
                this.swRegistration.addEventListener('updatefound', () => {
                    console.log('SW: New version available');
                    this.showUpdateNotification();
                });

            } catch (error) {
                console.log('SW: Service Worker registration failed:', error);
            }
        }

        // Setup PWA install prompt
        this.setupInstallPrompt();

        // Setup notifications (if enabled)
        this.setupNotifications();

        // Setup push notifications
        this.setupPushNotifications();

        // Loading screen is now managed by blazor-integration.js
        // Don't interfere with Blazor Server's loading lifecycle
        console.log('PWA: Initialization complete (loading screen managed by Blazor)');
    }

    setupInstallPrompt() {
        let deferredPrompt;

        // Check if already installed on init
        const isInstalled = this.isInstalled();
        if (isInstalled) {
            console.log('PWA: App is already installed');
            localStorage.setItem('pwaInstalled', 'true');
            this.installPromptShown = true; // Don't show prompt if already installed
            return;
        }

        window.addEventListener('beforeinstallprompt', (e) => {
            console.log('PWA: beforeinstallprompt event fired');
            e.preventDefault();
            deferredPrompt = e;

            // Only show if not already shown and not installed
            if (!this.installPromptShown && !this.isInstalled()) {
                this.showInstallButton(deferredPrompt);
                this.installPromptShown = true;
            }
        });

        window.addEventListener('appinstalled', () => {
            console.log('PWA: App was installed');
            localStorage.setItem('pwaInstalled', 'true');
            this.hideInstallButton();
            this.installPromptShown = true;
        });

        // Only show manual button if:
        // 1. Not installed
        // 2. Not already shown
        // 3. User hasn't dismissed it
        const installDismissed = localStorage.getItem('pwaInstallDismissed');
        if (!isInstalled && !this.installPromptShown && !installDismissed) {
            // Wait for browser prompt opportunity
            setTimeout(() => {
                if (!this.installPromptShown && !this.isInstalled()) {
                    console.log('PWA: Showing manual install option');
                    this.showManualInstallButton();
                    this.installPromptShown = true;
                }
            }, 5000);
        }
    }

    showInstallButton(deferredPrompt) {
        // Check again before showing
        if (this.isInstalled() || document.getElementById('pwa-install-btn')) {
            return;
        }

        const installBtn = document.createElement('button');
        installBtn.id = 'pwa-install-btn';
        installBtn.className = 'btn btn-primary btn-sm';
        installBtn.innerHTML = '<i class="fas fa-download"></i> Install App';
        // Detect if mobile bottom nav exists and adjust positioning
        const isMobileView = window.innerWidth < 768;
        const bottomPosition = isMobileView ? '80px' : '20px'; // 80px to clear mobile bottom nav

        installBtn.style.cssText = `
            position: fixed;
            bottom: ${bottomPosition};
            right: 20px;
            z-index: 1000;
            box-shadow: 0 4px 12px rgba(37, 99, 235, 0.3);
        `;

        // Add close button
        const closeBtn = document.createElement('button');
        closeBtn.className = 'btn-close btn-close-white';
        closeBtn.style.cssText = `
            position: absolute;
            top: -8px;
            right: -8px;
            background: red;
            border-radius: 50%;
            width: 20px;
            height: 20px;
            padding: 0;
        `;
        closeBtn.onclick = () => {
            localStorage.setItem('pwaInstallDismissed', 'true');
            this.hideInstallButton();
        };

        const wrapper = document.createElement('div');
        wrapper.id = 'pwa-install-wrapper';
        wrapper.style.cssText = `
            position: fixed;
            bottom: 20px;
            right: 20px;
            z-index: 1000;
        `;
        wrapper.appendChild(installBtn);
        wrapper.appendChild(closeBtn);

        installBtn.addEventListener('click', async () => {
            if (deferredPrompt) {
                deferredPrompt.prompt();
                const { outcome } = await deferredPrompt.userChoice;
                console.log('PWA: User response to install prompt:', outcome);
                if (outcome === 'accepted') {
                    localStorage.setItem('pwaInstalled', 'true');
                }
                deferredPrompt = null;
                this.hideInstallButton();
            }
        });

        document.body.appendChild(wrapper);
    }

    hideInstallButton() {
        const wrapper = document.getElementById('pwa-install-wrapper');
        const btn = document.getElementById('pwa-install-btn');
        if (wrapper) wrapper.remove();
        if (btn) btn.remove();
    }

    showUpdateNotification() {
        const notification = document.createElement('div');
        notification.className = 'alert alert-info alert-dismissible';
        notification.style.cssText = `
            position: fixed;
            top: 20px;
            right: 20px;
            z-index: 1050;
            max-width: 300px;
        `;

        notification.innerHTML = `
            <strong>Update Available!</strong><br>
            A new version of the app is ready.
            <button type="button" class="btn btn-sm btn-outline-info ms-2" id="update-btn">
                Update Now
            </button>
            <button type="button" class="btn-close" data-bs-dismiss="alert"></button>
        `;

        document.body.appendChild(notification);

        document.getElementById('update-btn').addEventListener('click', () => {
            if (this.swRegistration && this.swRegistration.waiting) {
                this.swRegistration.waiting.postMessage({ type: 'SKIP_WAITING' });
                window.location.reload();
            }
        });
    }

    async setupNotifications() {
        if ('Notification' in window) {
            const permission = await this.requestNotificationPermission();
            console.log('Notifications permission:', permission);
        }
    }

    async requestNotificationPermission() {
        if (Notification.permission === 'default') {
            return Notification.permission;
        }
        return Notification.permission;
    }

    showNotification(title, options = {}) {
        if (Notification.permission === 'granted') {
            const notification = new Notification(title, {
                icon: '/icons/icon-192x192.png',
                badge: '/icons/icon-72x72.png',
                tag: 'littleshop-admin',
                ...options
            });

            setTimeout(() => {
                notification.close();
            }, 5000);

            return notification;
        }
    }

    showManualInstallButton() {
        // Don't show if PWA is not supported or already installed
        if (this.isInstalled() || document.getElementById('pwa-install-btn')) {
            return;
        }

        // Only show if browser supports PWA (has beforeinstallprompt event or is iOS)
        const isIOS = /iPad|iPhone|iPod/.test(navigator.userAgent) && !window.MSStream;
        const supportsPWA = 'serviceWorker' in navigator && ('BeforeInstallPromptEvent' in window || isIOS);

        if (!supportsPWA) {
            console.log('PWA: Browser does not support PWA installation');
            return;
        }

        const installBtn = document.createElement('button');
        installBtn.id = 'pwa-install-btn';
        installBtn.className = 'btn btn-primary btn-sm';
        installBtn.innerHTML = '<i class="fas fa-mobile-alt"></i> Install as App';
        // Detect if mobile bottom nav exists and adjust positioning
        const isMobileView = window.innerWidth < 768;
        const bottomPosition = isMobileView ? '80px' : '20px'; // 80px to clear mobile bottom nav

        installBtn.style.cssText = `
            position: fixed;
            bottom: ${bottomPosition};
            right: 20px;
            z-index: 1000;
            box-shadow: 0 4px 12px rgba(37, 99, 235, 0.3);
        `;

        // Add close button
        const closeBtn = document.createElement('button');
        closeBtn.className = 'btn-close btn-close-white';
        closeBtn.style.cssText = `
            position: absolute;
            top: -8px;
            right: -8px;
            background: red;
            border-radius: 50%;
            width: 20px;
            height: 20px;
            padding: 0;
        `;
        closeBtn.onclick = () => {
            localStorage.setItem('pwaInstallDismissed', 'true');
            this.hideInstallButton();
        };

        const wrapper = document.createElement('div');
        wrapper.id = 'pwa-install-wrapper';
        wrapper.style.cssText = `
            position: fixed;
            bottom: 20px;
            right: 20px;
            z-index: 1000;
        `;
        wrapper.appendChild(installBtn);
        wrapper.appendChild(closeBtn);

        installBtn.addEventListener('click', () => {
            const isChrome = navigator.userAgent.includes('Chrome');
            const isEdge = navigator.userAgent.includes('Edge');
            const isFirefox = navigator.userAgent.includes('Firefox');
            const isIOS = /iPad|iPhone|iPod/.test(navigator.userAgent) && !window.MSStream;

            let instructions = 'To install this app:\n\n';

            if (isIOS) {
                instructions += '1. Tap the Share button (□↑) in Safari\n';
                instructions += '2. Scroll down and tap "Add to Home Screen"\n';
                instructions += '3. Tap "Add" to install';
            } else if (isChrome || isEdge) {
                instructions += '1. Look for the install icon (⬇️) in the address bar\n';
                instructions += '2. Or click the browser menu (⋮) → "Install TeleShop Admin"\n';
                instructions += '3. Or check if there\'s an "Install app" option in the browser menu';
            } else if (isFirefox) {
                instructions += '1. Firefox doesn\'t support PWA installation yet\n';
                instructions += '2. You can bookmark this page for easy access\n';
                instructions += '3. Or use Chrome/Edge for the full PWA experience';
            } else {
                instructions += '1. Look for an install or "Add to Home Screen" option\n';
                instructions += '2. Check your browser menu for app installation\n';
                instructions += '3. Or bookmark this page for quick access';
            }

            alert(instructions);
            localStorage.setItem('pwaInstallDismissed', 'true');
            this.hideInstallButton();
        });

        document.body.appendChild(wrapper);
    }

    isInstalled() {
        // Check multiple indicators
        const standalone = window.matchMedia('(display-mode: standalone)').matches;
        const iosStandalone = window.navigator.standalone === true;
        const localStorageFlag = localStorage.getItem('pwaInstalled') === 'true';

        return standalone || iosStandalone || localStorageFlag;
    }

    async setupPushNotifications() {
        if (!('serviceWorker' in navigator) || !('PushManager' in window)) {
            console.log('PWA: Push notifications not supported');
            return;
        }

        try {
            await this.getVapidPublicKey();
            await this.checkPushSubscription();

            // Only show prompt if:
            // 1. Not subscribed
            // 2. Not already shown
            // 3. User hasn't declined
            if (!this.pushSubscription && !this.pushPromptShown) {
                const userDeclined = localStorage.getItem('pushNotificationDeclined');

                if (!userDeclined) {
                    // Delay showing the prompt to avoid overwhelming user
                    setTimeout(() => {
                        if (!this.pushSubscription && !this.pushPromptShown) {
                            this.showPushNotificationSetup();
                            this.pushPromptShown = true;
                        }
                    }, 3000);
                }
            }

        } catch (error) {
            console.error('PWA: Failed to setup push notifications:', error);
        }
    }

    async getVapidPublicKey() {
        try {
            const response = await fetch('/api/push/vapid-key');
            if (response.ok) {
                const data = await response.json();
                this.vapidPublicKey = data.publicKey;
                console.log('PWA: VAPID public key retrieved');
            } else {
                throw new Error('Failed to get VAPID public key');
            }
        } catch (error) {
            console.error('PWA: Error getting VAPID public key:', error);
            throw error;
        }
    }

    async checkPushSubscription() {
        if (!this.swRegistration) {
            return;
        }

        try {
            this.pushSubscription = await this.swRegistration.pushManager.getSubscription();
            if (this.pushSubscription) {
                console.log('PWA: User has active push subscription');
                localStorage.setItem('pushSubscribed', 'true');
            } else {
                console.log('PWA: User is not subscribed to push notifications');
                localStorage.removeItem('pushSubscribed');
            }
        } catch (error) {
            console.error('PWA: Error checking push subscription:', error);
        }
    }

    async subscribeToPushNotifications() {
        if (!this.swRegistration || !this.vapidPublicKey) {
            throw new Error('Service worker or VAPID key not available');
        }

        try {
            // Check permission
            if (Notification.permission === 'denied') {
                throw new Error('Notification permission was denied. Please enable notifications in your browser settings.');
            }

            // Request permission if needed
            let permission = Notification.permission;
            if (permission === 'default') {
                permission = await Notification.requestPermission();
            }

            if (permission !== 'granted') {
                throw new Error('Notification permission is required for push notifications.');
            }

            console.log('PWA: Requesting push subscription...');

            // Desktop Chrome workaround: Sometimes needs a small delay
            if (!navigator.userAgent.includes('Mobile')) {
                await new Promise(resolve => setTimeout(resolve, 100));
            }

            let subscription;
            try {
                // Subscribe with shorter timeout for desktop
                const timeoutMs = navigator.userAgent.includes('Mobile') ? 15000 : 10000;

                subscription = await Promise.race([
                    this.swRegistration.pushManager.subscribe({
                        userVisibleOnly: true,
                        applicationServerKey: this.urlBase64ToUint8Array(this.vapidPublicKey)
                    }),
                    new Promise((_, reject) =>
                        setTimeout(() => reject(new Error(`Push subscription timed out after ${timeoutMs/1000} seconds.`)), timeoutMs)
                    )
                ]);

                console.log('PWA: Subscription successful:', subscription.endpoint);

            } catch (subscriptionError) {
                console.error('PWA: Subscription error:', subscriptionError);

                // Desktop-specific error handling
                if (!navigator.userAgent.includes('Mobile')) {
                    if (subscriptionError.message.includes('timeout')) {
                        throw new Error('Push subscription timed out. This can happen with VPNs or corporate firewalls. The app will work without push notifications.');
                    }
                }
                throw subscriptionError;
            }

            // Send to server
            console.log('PWA: Sending subscription to server...');
            const response = await fetch('/api/push/subscribe', {
                method: 'POST',
                headers: {
                    'Content-Type': 'application/json',
                },
                body: JSON.stringify({
                    endpoint: subscription.endpoint,
                    p256dh: btoa(String.fromCharCode(...new Uint8Array(subscription.getKey('p256dh')))),
                    auth: btoa(String.fromCharCode(...new Uint8Array(subscription.getKey('auth'))))
                }),
                credentials: 'same-origin'
            });

            if (response.ok) {
                this.pushSubscription = subscription;
                localStorage.setItem('pushSubscribed', 'true');
                console.log('PWA: Successfully subscribed to push notifications');
                this.hidePushNotificationSetup();
                return true;
            } else {
                throw new Error('Failed to save push subscription to server');
            }
        } catch (error) {
            console.error('PWA: Failed to subscribe:', error);
            throw error;
        }
    }

    async unsubscribeFromPushNotifications() {
        if (!this.pushSubscription) {
            return true;
        }

        try {
            await this.pushSubscription.unsubscribe();

            await fetch('/api/push/unsubscribe', {
                method: 'POST',
                headers: {
                    'Content-Type': 'application/json',
                },
                body: JSON.stringify({
                    endpoint: this.pushSubscription.endpoint
                }),
                credentials: 'same-origin'
            });

            this.pushSubscription = null;
            localStorage.removeItem('pushSubscribed');
            console.log('PWA: Successfully unsubscribed from push notifications');
            return true;
        } catch (error) {
            console.error('PWA: Failed to unsubscribe:', error);
            throw error;
        }
    }

    showPushNotificationSetup() {
        if (document.getElementById('push-notification-setup')) {
            return;
        }

        const setupDiv = document.createElement('div');
        setupDiv.id = 'push-notification-setup';
        setupDiv.className = 'alert alert-info';
        setupDiv.style.cssText = `
            position: fixed;
            top: 80px;
            right: 20px;
            z-index: 1050;
            max-width: 350px;
        `;

        setupDiv.innerHTML = `
            <div class="d-flex align-items-center">
                <i class="fas fa-bell me-2"></i>
                <div class="flex-grow-1">
                    <strong>Push Notifications</strong><br>
                    <small>Get notified of new orders and updates</small>
                </div>
                <button type="button" class="btn-close ms-2" id="close-push-btn" aria-label="Close"></button>
            </div>
            <div class="mt-2">
                <button type="button" class="btn btn-sm btn-primary" id="subscribe-push-btn">Enable</button>
                <button type="button" class="btn btn-sm btn-outline-secondary ms-1" id="skip-push-btn">Not Now</button>
            </div>
        `;

        document.body.appendChild(setupDiv);

        // Event listeners
        const subscribeBtn = document.getElementById('subscribe-push-btn');
        const skipBtn = document.getElementById('skip-push-btn');
        const closeBtn = document.getElementById('close-push-btn');

        const hideSetup = () => {
            localStorage.setItem('pushNotificationDeclined', 'true');
            this.hidePushNotificationSetup();
        };

        if (subscribeBtn) {
            subscribeBtn.addEventListener('click', async () => {
                subscribeBtn.disabled = true;
                skipBtn.disabled = true;
                subscribeBtn.innerHTML = '<i class="fas fa-spinner fa-spin me-1"></i>Enabling...';

                try {
                    await this.subscribeToPushNotifications();

                    this.showNotification('Push notifications enabled!', {
                        body: 'You will now receive notifications for new orders and updates.'
                    });
                } catch (error) {
                    console.error('PWA: Subscription failed:', error);

                    let userMessage = 'Failed to enable push notifications.';
                    if (error.message.includes('permission')) {
                        userMessage = 'Please allow notifications when prompted.';
                    } else if (error.message.includes('timeout') || error.message.includes('VPN')) {
                        userMessage = 'Connection timeout. This may be due to network restrictions. The app will work without push notifications.';
                        // Auto-dismiss on timeout
                        hideSetup();
                        alert(userMessage);
                        return;
                    }

                    alert(userMessage);
                    subscribeBtn.disabled = false;
                    skipBtn.disabled = false;
                    subscribeBtn.innerHTML = 'Enable';
                }
            });
        }

        if (skipBtn) {
            skipBtn.addEventListener('click', hideSetup);
        }

        if (closeBtn) {
            closeBtn.addEventListener('click', hideSetup);
        }
    }

    hidePushNotificationSetup() {
        const setupDiv = document.getElementById('push-notification-setup');
        if (setupDiv) {
            setupDiv.remove();
        }
    }

    async sendTestNotification() {
        try {
            const response = await fetch('/api/push/test', {
                method: 'POST',
                headers: {
                    'Content-Type': 'application/json',
                },
                body: JSON.stringify({
                    title: 'Test Notification',
                    body: 'This is a test push notification from LittleShop Admin!'
                }),
                credentials: 'same-origin'
            });

            const result = await response.json();
            if (response.ok) {
                console.log('PWA: Test notification sent successfully');
                return true;
            } else {
                throw new Error(result.error || 'Failed to send test notification');
            }
        } catch (error) {
            console.error('PWA: Failed to send test notification:', error);
            throw error;
        }
    }

    urlBase64ToUint8Array(base64String) {
        const padding = '='.repeat((4 - base64String.length % 4) % 4);
        const base64 = (base64String + padding)
            .replace(/\-/g, '+')
            .replace(/_/g, '/');

        const rawData = window.atob(base64);
        const outputArray = new Uint8Array(rawData.length);

        for (let i = 0; i < rawData.length; ++i) {
            outputArray[i] = rawData.charCodeAt(i);
        }
        return outputArray;
    }
}

// Initialize PWA Manager
const pwaManager = new PWAManager();
window.pwaManager = pwaManager;

// Expose functions globally
window.showNotification = (title, options) => pwaManager.showNotification(title, options);
window.sendTestPushNotification = () => pwaManager.sendTestNotification();
window.subscribeToPushNotifications = () => pwaManager.subscribeToPushNotifications();
window.unsubscribeFromPushNotifications = () => pwaManager.unsubscribeFromPushNotifications();

// Handle 401 errors globally - redirect to login
if (window.fetch) {
    const originalFetch = window.fetch;
    window.fetch = async function(...args) {
        const response = await originalFetch.apply(this, args);

        // Check if it's an admin area request and got 401
        if (response.status === 401 && window.location.pathname.startsWith('/Admin')) {
            // Don't redirect if already on login page
            if (!window.location.pathname.includes('/Account/Login')) {
                window.location.href = '/Admin/Account/Login?ReturnUrl=' + encodeURIComponent(window.location.pathname);
            }
        }

        return response;
    };
}

// Also handle 401 from direct navigation
window.addEventListener('load', () => {
    // Check if we got redirected to /Admin instead of /Admin/Account/Login
    if (window.location.pathname === '/Admin' || window.location.pathname === '/Admin/') {
        // Check if user is authenticated by trying to fetch a protected resource
        fetch('/Admin/Dashboard', {
            method: 'HEAD',
            credentials: 'same-origin'
        }).then(response => {
            if (response.status === 401 || response.status === 302) {
                window.location.href = '/Admin/Account/Login';
            }
        }).catch(() => {
            // Network error, do nothing
        });
    }
});

// Loading screen fallback timeout removed - now managed by blazor-integration.js
// Blazor Server controls loading screen lifecycle based on SignalR connection state