import { clsx, type ClassValue } from 'clsx';
import { twMerge } from 'tailwind-merge';

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

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

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

export function formatRelativeTime(dateStr: string): string {
  const seconds = Math.floor((Date.now() - new Date(dateStr).getTime()) / 1000);
  if (seconds < 60) return 'just now';
  if (seconds < 3600) return `${Math.floor(seconds / 60)}m ago`;
  if (seconds < 86400) return `${Math.floor(seconds / 3600)}h ago`;
  return `${Math.floor(seconds / 86400)}d ago`;
}

export function getFileIcon(filename: string): string {
  const ext = filename.split('.').pop()?.toLowerCase();
  const icons: Record<string, string> = { js: '📄', ts: '📘', py: '🐍', cpp: '⚙️', java: '☕', html: '🌐', css: '🎨', json: '📋', md: '📝' };
  return icons[ext || ''] || '📄';
}

export async function copyToClipboard(text: string): Promise<boolean> {
  try { await navigator.clipboard.writeText(text); return true; } catch { return false; }
}

export function generateInviteLink(inviteCode: string): string {
  const baseUrl = typeof window !== 'undefined' ? window.location.origin : '';
  return `${baseUrl}/join/${inviteCode}`;
}

export function formatDuration(ms: number): string {
  if (ms < 1000) return `${ms}ms`;
  if (ms < 60000) return `${(ms / 1000).toFixed(1)}s`;
  return `${Math.floor(ms / 60000)}m ${Math.floor((ms % 60000) / 1000)}s`;
}