import type { Email, EmailAttachment, EmailAttachmentKind } from "@/lib/email-data"

/** Pièce jointe calendrier (invitation) — masquée dans la liste des messages. */
export function isCalendarInvitationAttachment(name: string): boolean {
  return name.toLowerCase().endsWith(".ics")
}

/** PJ visibles dans la liste (hors fichiers .ics d’invitation). */
export function attachmentsForEmailList(
  email: Pick<Email, "attachments" | "hasAttachment" | "hasInvitation">
): EmailAttachment[] {
  if (email.attachments?.length) {
    return email.attachments.filter((a) => !isCalendarInvitationAttachment(a.name))
  }
  if (email.hasAttachment && email.hasInvitation !== true) {
    return [{ name: "Pièce jointe", kind: "other" }]
  }
  return []
}

/** Fichiers « riches » (cartes type Gmail) : PDF, images, vidéos, bureautique. */
const RICH_PREVIEW_EXT =
  /\.(mp4|mpe?g|webm|mov|avi|mkv|m4v|wmv|flv|xls|xlsx|xlsm|ods|numbers|ppt|pptx|key|odp|doc|docx|odt|rtf)$/i

/** Seuil « petit fichier » pour la rangée en pills (aperçu message uniquement). */
export const ATTACHMENT_PILL_MAX_BYTES = 2 * 1024 * 1024

export function resolveAttachmentKind(
  name: string,
  kind?: EmailAttachment["kind"]
): EmailAttachmentKind {
  if (kind) return kind
  const lower = name.toLowerCase()
  if (lower.endsWith(".pdf")) return "pdf"
  if (/\.(png|jpe?g|gif|webp|svg|avif|bmp|heic)$/.test(lower)) return "image"
  return "other"
}

export function isRichPreviewAttachment(name: string, kind?: EmailAttachment["kind"]): boolean {
  const resolved = resolveAttachmentKind(name, kind)
  if (resolved === "pdf" || resolved === "image") return true
  return RICH_PREVIEW_EXT.test(name.toLowerCase())
}

export function isSmallEnoughForPillRow(sizeBytes?: number): boolean {
  if (sizeBytes === undefined) return true
  return sizeBytes >= 0 && sizeBytes <= ATTACHMENT_PILL_MAX_BYTES
}

/** Tous les fichiers simples + petits → UI pills dans l’aperçu message. */
export function shouldUseAttachmentPillsInPreview(attachments: EmailAttachment[]): boolean {
  if (attachments.length === 0) return false
  return attachments.every(
    (a) => !isRichPreviewAttachment(a.name, a.kind) && isSmallEnoughForPillRow(a.sizeBytes)
  )
}

function decFr(n: number): string {
  return String(n).replace(".", ",")
}

export function formatAttachmentSize(sizeBytes: number): string {
  if (!Number.isFinite(sizeBytes) || sizeBytes < 0) return "—"
  if (sizeBytes < 1000) {
    return `${Math.round(sizeBytes)}\u00a0o`
  }
  const kb = sizeBytes / 1024
  if (kb < 1024) {
    const v = kb >= 10 ? Math.round(kb) : Math.round(kb * 10) / 10
    return `${decFr(v)}\u00a0Ko`
  }
  const mb = kb / 1024
  const v = mb >= 10 ? Math.round(mb) : Math.round(mb * 10) / 10
  return `${decFr(v)}\u00a0Mo`
}

export function attachmentPreviewTooltip(name: string, sizeBytes?: number): string {
  if (sizeBytes === undefined) return name
  return `${name}\n${formatAttachmentSize(sizeBytes)}`
}