/**
 * Format bytes to human readable string
 */
export const formatBytes = (bytes: number, decimals = 2): string => {
    if (bytes === 0) return '0 B';
    
    const k = 1024;
    const dm = decimals < 0 ? 0 : decimals;
    const sizes = ['B', 'KB', 'MB', 'GB', 'TB'];
    
    const i = Math.floor(Math.log(bytes) / Math.log(k));
    
    return parseFloat((bytes / Math.pow(k, i)).toFixed(dm)) + ' ' + sizes[i];
};

/**
 * Format duration in milliseconds to human readable string
 */
export const formatDuration = (ms: number): string => {
    if (ms < 1000) return `${ms}ms`;
    if (ms < 60000) return `${(ms / 1000).toFixed(1)}s`;
    if (ms < 3600000) {
        const minutes = Math.floor(ms / 60000);
        const seconds = Math.floor((ms % 60000) / 1000);
        return `${minutes}m ${seconds}s`;
    }
    const hours = Math.floor(ms / 3600000);
    const minutes = Math.floor((ms % 3600000) / 60000);
    return `${hours}h ${minutes}m`;
};

/**
 * Format number with commas
 */
export const formatNumber = (num: number): string => {
    return num.toLocaleString();
};

/**
 * Format currency
 */
export const formatCurrency = (amount: number, currency = 'USD', locale = 'en-US'): string => {
    return new Intl.NumberFormat(locale, {
        style: 'currency',
        currency,
    }).format(amount);
};

/**
 * Format percentage
 */
export const formatPercentage = (value: number, decimals = 1): string => {
    return `${(value * 100).toFixed(decimals)}%`;
};

/**
 * Format timestamp to relative time
 */
export const formatRelativeTime = (timestamp: number): string => {
    const now = Date.now();
    const diff = now - timestamp;
    
    if (diff < 60000) return 'just now';
    if (diff < 3600000) return `${Math.floor(diff / 60000)}m ago`;
    if (diff < 86400000) return `${Math.floor(diff / 3600000)}h ago`;
    if (diff < 604800000) return `${Math.floor(diff / 86400000)}d ago`;
    
    return new Date(timestamp).toLocaleDateString();
};

/**
 * Truncate text with ellipsis
 */
export const truncateText = (text: string, maxLength: number, suffix = '...'): string => {
    if (text.length <= maxLength) return text;
    return text.substring(0, maxLength - suffix.length) + suffix;
};

/**
 * Format model name for display
 */
export const formatModelName = (model: string): string => {
    // Remove common prefixes
    const cleaned = model
        .replace(/^(openai\/)/, '')
        .replace(/^(anthropic\/)/, '')
        .replace(/^(google\/)/, '')
        .replace(/^(deepseek\/)/, '');
    
    // Capitalize words
    return cleaned
        .split('-')
        .map(word => word.charAt(0).toUpperCase() + word.slice(1))
        .join(' ');
};

/**
 * Format file size with appropriate unit
 */
export const formatFileSize = (bytes: number): string => {
    if (bytes === 0) return '0 Bytes';
    
    const k = 1000; // Use 1000 for file sizes (not 1024)
    const sizes = ['Bytes', 'KB', 'MB', 'GB', 'TB'];
    const i = Math.floor(Math.log(bytes) / Math.log(k));
    
    return `${parseFloat((bytes / Math.pow(k, i)).toFixed(2))} ${sizes[i]}`;
};

/**
 * Format date to ISO string for display
 */
export const formatISODate = (date: Date | string | number): string => {
    const d = new Date(date);
    return d.toISOString().split('T')[0];
};