/**
 * Document display & preview helpers for edit pages.
 *
 * Extracted from pages/component/[id]/edit.vue, pieces/[id]/edit.vue,
 * product/[id]/edit.vue – each had an identical copy of these utilities.
 */

import { getFileIcon } from '~/utils/fileIcons'
import { isImageDocument, isPdfDocument } from '~/utils/documentPreview'

export const PDF_PREVIEW_MAX_BYTES = 5 * 1024 * 1024

export const formatSize = (size: number | null | undefined): string => {
  if (size === null || size === undefined) return '—'
  if (size === 0) return '0 B'
  const units = ['B', 'KB', 'MB', 'GB']
  const index = Math.min(units.length - 1, Math.floor(Math.log(size) / Math.log(1024)))
  const formatted = size / Math.pow(1024, index)
  return `${formatted.toFixed(1)} ${units[index]}`
}

const resolveUrl = (doc: any): string => doc?.fileUrl || doc?.path || ''

export const shouldInlinePdf = (doc: any): boolean => {
  if (!doc || !isPdfDocument(doc)) return false
  const url = resolveUrl(doc)
  if (!url) return false
  if (typeof doc.size === 'number' && doc.size > PDF_PREVIEW_MAX_BYTES) return false
  return true
}

export const appendPdfViewerParams = (src: string): string => {
  if (!src) return ''
  if (src.startsWith('data:')) return src
  if (src.includes('#')) return `${src}&toolbar=0&navpanes=0`
  return `${src}#toolbar=0&navpanes=0`
}

export const documentPreviewSrc = (doc: any): string => {
  const url = resolveUrl(doc)
  if (!url) return ''
  if (isPdfDocument(doc)) return appendPdfViewerParams(url)
  return url
}

export const documentThumbnailClass = (doc: any): string => {
  if (shouldInlinePdf(doc) || (isImageDocument(doc) && resolveUrl(doc))) return 'h-24 w-20'
  return 'h-16 w-16'
}

export interface FileIconResult {
  component: unknown
  colorClass: string
  label: string
}

export const documentIcon = (doc: any): FileIconResult =>
  getFileIcon({ name: doc?.filename || doc?.name, mime: doc?.mimeType })

export const downloadDocument = (doc: any): void => {
  // Prefer dedicated download endpoint
  if (doc?.downloadUrl) {
    window.open(doc.downloadUrl, '_blank')
    return
  }
  // Fallback for legacy data: URIs during migration
  const target = resolveUrl(doc)
  if (!target) return
  if (target.startsWith('data:')) {
    const link = document.createElement('a')
    link.href = target
    link.download = doc.filename || doc.name || 'document'
    link.click()
    return
  }
  window.open(target, '_blank')
}