import { clsx, type ClassValue } from 'clsx';

export function cn(...inputs: ClassValue[]) {
  return clsx(inputs);
}

export function formatDate(date: string | Date): string {
  const d = new Date(date);
  const now = new Date();
  const diffInHours = (now.getTime() - d.getTime()) / (1000 * 60 * 60);
  
  if (diffInHours < 1) {
    return 'Just now';
  } else if (diffInHours < 24) {
    return `${Math.floor(diffInHours)}h ago`;
  } else if (diffInHours < 24 * 7) {
    return `${Math.floor(diffInHours / 24)}d ago`;
  } else {
    return d.toLocaleDateString();
  }
}

export function generateId(): string {
  return Math.random().toString(36).substr(2, 9);
}

export function truncateText(text: string, maxLength: number): string {
  if (text.length <= maxLength) return text;
  return text.substr(0, maxLength) + '...';
}

export function extractTitle(content: string): string {
  // Extract first line or first 50 characters as title
  const firstLine = content.split('\n')[0];
  return truncateText(firstLine || 'New Conversation', 50);
}

export function isValidEmail(email: string): boolean {
  const emailRegex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
  return emailRegex.test(email);
}

export function debounce<T extends (...args: any[]) => any>(
  func: T,
  wait: number
): (...args: Parameters<T>) => void {
  let timeout: NodeJS.Timeout;
  return (...args) => {
    clearTimeout(timeout);
    timeout = setTimeout(() => func(...args), wait);
  };
}

export function throttle<T extends (...args: any[]) => any>(
  func: T,
  limit: number
): (...args: Parameters<T>) => void {
  let inThrottle: boolean;
  return (...args) => {
    if (!inThrottle) {
      func(...args);
      inThrottle = true;
      setTimeout(() => (inThrottle = false), limit);
    }
  };
}

export function copyToClipboard(text: string): Promise<void> {
  if (navigator.clipboard) {
    return navigator.clipboard.writeText(text);
  } else {
    // Fallback for older browsers
    const textArea = document.createElement('textarea');
    textArea.value = text;
    document.body.appendChild(textArea);
    textArea.focus();
    textArea.select();
    try {
      document.execCommand('copy');
      document.body.removeChild(textArea);
      return Promise.resolve();
    } catch (err) {
      document.body.removeChild(textArea);
      return Promise.reject(err);
    }
  }
}

export function downloadText(content: string, filename: string): void {
  const element = document.createElement('a');
  const file = new Blob([content], { type: 'text/plain' });
  element.href = URL.createObjectURL(file);
  element.download = filename;
  document.body.appendChild(element);
  element.click();
  document.body.removeChild(element);
}

export function parseJsonSafely<T>(json: string): T | null {
  try {
    return JSON.parse(json);
  } catch {
    return null;
  }
}

export function getStorageItem<T>(key: string, defaultValue: T): T {
  try {
    const item = localStorage.getItem(key);
    return item ? JSON.parse(item) : defaultValue;
  } catch {
    return defaultValue;
  }
}

export function setStorageItem<T>(key: string, value: T): void {
  try {
    localStorage.setItem(key, JSON.stringify(value));
  } catch (error) {
    console.error('Failed to save to localStorage:', error);
  }
}