// Toast notification system for backend errors
// Displays toast notifications at the top of the page

type ToastType = 'error' | 'success' | 'info';

const TOAST_DEFAULT_DURATION = 5000;

// Create toast container
const createToastContainer = (): HTMLElement => {
    let container = document.getElementById('toast-container');
    if (!container) {
        container = document.createElement('div');
        container.id = 'toast-container';
        container.className = 'fixed top-5 right-5 z-[9999] flex flex-col gap-2.5 pointer-events-none';
        document.body.appendChild(container);
    }
    return container;
};

// Escape HTML to prevent XSS
const escapeHtml = (text: string): string => {
    const div = document.createElement('div');
    div.textContent = text;
    return div.innerHTML;
};

// Get toast configuration by type
const getToastConfig = (type: ToastType) => {
    const configs = {
        error: {
            bgClass: 'bg-red-500/90',
            icon: '❌'
        },
        success: {
            bgClass: 'bg-green-500/90',
            icon: '✅'
        },
        info: {
            bgClass: 'bg-blue-500/90',
            icon: 'ℹ️'
        }
    };
    return configs[type];
};

// Create a toast element
const createToastElement = (message: string, type: ToastType): HTMLElement => {
    const toast = document.createElement('div');
    const config = getToastConfig(type);
    
    toast.className = `${config.bgClass} text-white p-4 rounded-lg shadow-lg flex items-center gap-3 min-w-[300px] max-w-[500px] text-sm leading-relaxed pointer-events-auto opacity-0 -translate-y-5 transition-all duration-300 border border-white/10`;
    
    toast.innerHTML = `
        <span class="text-xl flex-shrink-0">${config.icon}</span>
        <span class="flex-1 break-words">${escapeHtml(message)}</span>
        <button class="toast-close bg-transparent border-0 text-white cursor-pointer text-lg p-0 w-5 h-5 flex items-center justify-center opacity-70 hover:opacity-100 flex-shrink-0 transition-opacity">
            ×
        </button>
    `;
    
    // Add close button handler
    const closeBtn = toast.querySelector('.toast-close') as HTMLElement;
    if (closeBtn) {
        closeBtn.onclick = () => removeToast(toast);
    }
    
    return toast;
};

// Trigger toast animation
const animateToastIn = (toast: HTMLElement): void => {
    setTimeout(() => {
        toast.style.opacity = '1';
        toast.style.transform = 'translateY(0)';
    }, 10);
};

// Remove toast with animation
const removeToast = (toast: HTMLElement): void => {
    toast.style.opacity = '0';
    toast.style.transform = 'translateY(-20px)';
    setTimeout(() => {
        if (toast.parentElement) {
            toast.parentElement.removeChild(toast);
        }
    }, 300);
};

// Show toast notification
const showToast = (message: string, type: ToastType, duration: number = TOAST_DEFAULT_DURATION): void => {
    const container = createToastContainer();
    const toast = createToastElement(message, type);
    container.appendChild(toast);
    animateToastIn(toast);
    
    // Auto-remove after duration
    setTimeout(() => {
        removeToast(toast);
    }, duration);
};

// Parse error from XHR response
const parseXHRError = (xhr: XMLHttpRequest): string => {
    let errorMessage = 'An error occurred';
    try {
        const response = JSON.parse(xhr.responseText);
        errorMessage = response.error || response.message || errorMessage;
    } catch (e) {
        errorMessage = xhr.responseText || errorMessage;
    }
    return errorMessage;
};

// Parse error from fetch response
const parseFetchError = async (response: Response): Promise<string> => {
    const contentType = response.headers.get('content-type');
    if (contentType && contentType.includes('application/json')) {
        const data = await response.json();
        return data.error || data.message || `Error ${response.status}`;
    }
    return `Error ${response.status}: ${response.statusText}`;
};

// Setup HTMX error listeners
const setupHTMXListeners = (): void => {
    // Listen for HTMX afterSwap event to detect errors in swapped content
    document.body.addEventListener('htmx:afterSwap', (evt: Event) => {
        interface HTMXEventDetail {
            xhr: XMLHttpRequest;
            succeeded: boolean;
            target: Element;
        }
        
        const customEvent = evt as CustomEvent<HTMXEventDetail>;
        
        // Check if request failed
        if (customEvent.detail.succeeded === false && customEvent.detail.xhr) {
            const xhr = customEvent.detail.xhr;
            
            // Show toast for HTTP errors
            if (xhr.status >= 400 && xhr.status < 600) {
                const errorMessage = parseXHRError(xhr);
                showToast(errorMessage, 'error');
            }
        }
    });
    
    // Also listen for response errors (network issues, invalid responses)
    document.body.addEventListener('htmx:responseError', (evt: Event) => {
        const customEvent = evt as CustomEvent<{ xhr: XMLHttpRequest }>;
        const xhr = customEvent.detail.xhr;
        const errorMessage = parseXHRError(xhr);
        showToast(errorMessage, 'error');
    });
};

// Setup fetch interceptor
const setupFetchInterceptor = (): void => {
    const originalFetch = window.fetch;
    window.fetch = async (...args: Parameters<typeof fetch>): Promise<Response> => {
        try {
            const response = await originalFetch(...args);
            
            if (!response.ok) {
                const errorMessage = await parseFetchError(response);
                showToast(errorMessage, 'error');
            }
            
            return response;
        } catch (error) {
            showToast('Network error: Unable to connect to server', 'error');
            throw error;
        }
    };
};

// Initialize toast system
const initializeToastSystem = (): void => {
    setupHTMXListeners();
    setupFetchInterceptor();
};

// Auto-initialize when DOM is ready
if (typeof document !== 'undefined') {
    if (document.readyState === 'loading') {
        document.addEventListener('DOMContentLoaded', initializeToastSystem);
    } else {
        initializeToastSystem();
    }
}

// Export toast API for manual use
(window as any).showToast = {
    error: (message: string, duration?: number) => showToast(message, 'error', duration),
    success: (message: string, duration?: number) => showToast(message, 'success', duration),
    info: (message: string, duration?: number) => showToast(message, 'info', duration)
};