export function formatFileSize(bytes) {
  if (bytes == null || bytes < 0) return '—'
  if (bytes === 0) return '0 B'
  const units = ['B', 'KB', 'MB', 'GB']
  const i = Math.min(Math.floor(Math.log(bytes) / Math.log(1024)), units.length - 1)
  const val = bytes / Math.pow(1024, i)
  return (i === 0 ? val.toFixed(0) : val.toFixed(1)) + ' ' + units[i]
}

const mimeLabels = {
  'image/jpeg': 'Изображение JPEG',
  'image/png': 'Изображение PNG',
  'image/gif': 'Изображение GIF',
  'image/webp': 'Изображение WebP',
  'image/svg+xml': 'Изображение SVG',
  'image/bmp': 'Изображение BMP',
  'image/tiff': 'Изображение TIFF',
  'image/avif': 'Изображение AVIF',
  'application/pdf': 'PDF документ',
  'application/msword': 'Документ Word',
  'application/vnd.openxmlformats-officedocument.wordprocessingml.document': 'Документ Word',
  'application/vnd.ms-excel': 'Таблица Excel',
  'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet': 'Таблица Excel',
  'application/vnd.ms-powerpoint': 'Презентация PowerPoint',
  'application/vnd.openxmlformats-officedocument.presentationml.presentation': 'Презентация PowerPoint',
  'application/zip': 'ZIP архив',
  'application/gzip': 'GZIP архив',
  'application/x-tar': 'TAR архив',
  'application/x-7z-compressed': '7z архив',
  'application/x-rar-compressed': 'RAR архив',
  'text/plain': 'Текстовый файл',
  'text/html': 'HTML файл',
  'text/css': 'CSS файл',
  'text/javascript': 'JavaScript файл',
  'application/json': 'JSON файл',
  'application/xml': 'XML файл',
  'application/x-yaml': 'YAML файл',
  'application/octet-stream': 'Бинарный файл',
  'application/x-msdos-program': 'Исполняемый файл',
  'inode/directory': 'Папка',
}

export function formatMimeType(mime) {
  if (!mime) return 'Неизвестно'
  return mimeLabels[mime] || mime
}

export function formatFileType(item) {
  if (item.type === 'folder') return 'Папка'
  const mime = (item.mime || '').toLowerCase()
  if (mimeLabels[mime]) return mimeLabels[mime]
  const name = (item.name || '').toLowerCase()
  const ext = name.split('.').pop()
  if (ext) return ext.toUpperCase()
  return 'Файл'
}

export function getFileKind(item) {
  if (item.type === 'folder') return 'folder'
  const mime = (item.mime || '').toLowerCase()
  if (mime.startsWith('image/')) return 'image'
  if (mime.startsWith('video/')) return 'video'
  if (mime.startsWith('audio/')) return 'audio'
  if (mime.startsWith('text/')) return 'text'
  if (mime.includes('pdf')) return 'pdf'
  if (mime.includes('word') || mime.includes('document')) return 'document'
  if (mime.includes('spreadsheet') || mime.includes('excel')) return 'spreadsheet'
  if (mime.includes('presentation') || mime.includes('powerpoint')) return 'presentation'
  if (mime.includes('zip') || mime.includes('tar') || mime.includes('gzip') || mime.includes('rar') || mime.includes('7z') || mime.includes('compress')) return 'archive'
  if (mime.includes('json') || mime.includes('xml') || mime.includes('yaml') || mime.includes('javascript') || mime.includes('css') || mime.includes('html')) return 'code'
  const name = (item.name || '').toLowerCase()
  const ext = name.split('.').pop()
  const codeExts = ['js','ts','jsx','tsx','vue','svelte','py','rs','go','c','cpp','h','hpp','java','kt','swift','rb','php','pl','sh','bash','zsh','fish','yml','yaml','json','xml','toml','ini','cfg','conf','md','markdown','css','scss','less','sass','sql','graphql','proto','gradle','cmake','makefile','dockerfile','env','gitignore']
  if (codeExts.includes(ext)) return 'code'
  return 'generic'
}

const imageMimes = ['image/jpeg','image/png','image/gif','image/webp','image/bmp','image/tiff','image/avif','image/svg+xml']
const textMimes = ['text/plain','text/html','text/css','text/javascript','application/json','application/xml','application/x-yaml','text/x-shellscript']
const codeNames = ['txt','log','conf','ini','yaml','yml','json','xml','csv','sh','py','js','ts','css','html','md','markdown','cfg']

const imageExts = ['jpg','jpeg','png','gif','webp','bmp','tiff','tif','avif','svg']

export function canPreviewFile(item) {
  if (item.type === 'folder') return false
  const mime = (item.mime || '').toLowerCase()
  const name = (item.name || '').toLowerCase()
  const ext = name.split('.').pop()
  if (imageMimes.includes(mime) || imageExts.includes(ext)) return true
  if (mime.includes('pdf')) return true
  if (textMimes.includes(mime) || codeNames.includes(ext)) return true
  return false
}

export function isImageFile(item) {
  const mime = (item.mime || '').toLowerCase()
  const name = (item.name || '').toLowerCase()
  const ext = name.split('.').pop()
  return imageMimes.includes(mime) || imageExts.includes(ext)
}

export function isTextFile(item) {
  const mime = (item.mime || '').toLowerCase()
  const name = (item.name || '').toLowerCase()
  const ext = name.split('.').pop()
  return textMimes.includes(mime) || (codeNames.includes(ext) && ext !== 'md' && ext !== 'markdown')
}

export function isPdfFile(item) {
  return (item.mime || '').toLowerCase().includes('pdf')
}

export function isMarkdownFile(item) {
  const name = (item.name || '').toLowerCase()
  return name.endsWith('.md') || name.endsWith('.markdown')
}

export function needsBase64Preview(item) {
  return isImageFile(item) || isPdfFile(item)
}

export function needsTextPreview(item) {
  return isTextFile(item) || isMarkdownFile(item)
}