import { type ClassValue, clsx } from 'clsx'
import { twMerge } from 'tailwind-merge'
import { useState, useEffect, useRef } from 'react'

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

export function formatBytes(bytes: number): string {
  if (bytes === 0) return '0 B'
  const k = 1024
  const sizes = ['B', 'KB', 'MB', 'GB']
  const i = Math.floor(Math.log(bytes) / Math.log(k))
  return `${parseFloat((bytes / Math.pow(k, i)).toFixed(1))} ${sizes[i]}`
}

export function formatDate(date: string | Date): string {
  return new Intl.DateTimeFormat('en-US', {
    month: 'short', day: 'numeric', year: 'numeric'
  }).format(new Date(date))
}

export function formatRelativeTime(date: string | Date): string {
  const now = new Date()
  const d = new Date(date)
  const diff = now.getTime() - d.getTime()
  const days = Math.floor(diff / 86400000)
  if (days === 0) return 'Today'
  if (days === 1) return 'Yesterday'
  if (days < 7) return `${days}d ago`
  if (days < 30) return `${Math.floor(days / 7)}w ago`
  return formatDate(date)
}

export function truncate(str: string, length: number): string {
  if (str.length <= length) return str
  return str.slice(0, length) + '...'
}

export function getFileIcon(type: string): string {
  const icons: Record<string, string> = {
    '.pdf': '📄',
    '.docx': '📝',
    '.csv': '📊',
    '.xlsx': '📊',
    '.txt': '📃',
    '.md': '📃',
  }
  return icons[type] || '📄'
}

export function getPlanColor(plan: string): string {
  const colors: Record<string, string> = {
    free: 'text-gray-600 bg-gray-100',
    starter: 'text-blue-600 bg-blue-100',
    pro: 'text-purple-600 bg-purple-100',
    enterprise: 'text-orange-600 bg-orange-100',
  }
  return colors[plan] || colors.free
}

// IMP-07: Debounce hook for search inputs (300ms default)
export function useDebounce<T>(value: T, delay: number = 300): T {
  const [debouncedValue, setDebouncedValue] = useState<T>(value)

  useEffect(() => {
    const timer = setTimeout(() => setDebouncedValue(value), delay)
    return () => clearTimeout(timer)
  }, [value, delay])

  return debouncedValue
}

export const AVAILABLE_MODELS = [
  {
    id: 'accounts/fireworks/models/llama-v3p1-70b-instruct',
    name: 'Llama 3.1 70B',
    provider: 'Fireworks AI',
    plans: ['starter', 'pro', 'enterprise'],
    badge: 'Fast',
  },
  {
    id: 'accounts/fireworks/models/mixtral-8x7b-instruct',
    name: 'Mixtral 8x7B',
    provider: 'Fireworks AI',
    plans: ['starter', 'pro', 'enterprise'],
    badge: 'Balanced',
  },
  {
    id: 'gpt-4o',
    name: 'GPT-4o',
    provider: 'OpenAI',
    plans: ['pro', 'enterprise'],
    badge: 'Powerful',
  },
  {
    id: 'gpt-4-turbo',
    name: 'GPT-4 Turbo',
    provider: 'OpenAI',
    plans: ['pro', 'enterprise'],
    badge: 'Smart',
  },
  {
    id: 'gpt-3.5-turbo',
    name: 'GPT-3.5 Turbo',
    provider: 'OpenAI',
    plans: ['pro', 'enterprise'],
    badge: 'Efficient',
  },
  {
    id: 'claude-3-5-sonnet-20241022',
    name: 'Claude 3.5 Sonnet',
    provider: 'Anthropic',
    plans: ['pro', 'enterprise'],
    badge: 'Reasoning',
  },
  {
    id: 'claude-3-opus-20240229',
    name: 'Claude 3 Opus',
    provider: 'Anthropic',
    plans: ['pro', 'enterprise'],
    badge: 'Advanced',
  },
  {
    id: 'gemini-1.5-pro',
    name: 'Gemini 1.5 Pro',
    provider: 'Google',
    plans: ['pro', 'enterprise'],
    badge: 'Long Context',
  },
]

export const CATEGORIES = [
  'Customer Support', 'Sales', 'FAQ', 'E-commerce',
  'Healthcare', 'Finance', 'Education', 'HR', 'Legal', 'Other'
]

export const INDUSTRIES = [
  'Technology', 'E-commerce', 'Healthcare', 'Finance',
  'Education', 'Legal', 'Real Estate', 'Hospitality', 'Retail', 'Other'
]

export const LANGUAGES = [
  { code: 'en', name: 'English' }, { code: 'fr', name: 'French' },
  { code: 'es', name: 'Spanish' }, { code: 'de', name: 'German' },
  { code: 'it', name: 'Italian' }, { code: 'pt', name: 'Portuguese' },
  { code: 'ja', name: 'Japanese' }, { code: 'ko', name: 'Korean' },
  { code: 'zh', name: 'Chinese' }, { code: 'ar', name: 'Arabic' },
]