/**
 * 검증게시판 첨부 — 이미지 + zip·hwp·hwpx
 */
import {
  pickImageFiles,
  prepareImagesForUpload,
} from './clipboardImageFiles';

export const VERIFICATION_ATTACHMENT_ACCEPT =
  'image/jpeg,image/png,image/gif,image/webp,image/bmp,.zip,.hwp,.hwpx,application/zip,application/x-hwp,application/vnd.hancom.hwpx';

const DOCUMENT_EXT = new Set(['.zip', '.hwp', '.hwpx']);

const DOCUMENT_MIME = new Set([
  'application/zip',
  'application/x-zip-compressed',
  'application/x-hwp',
  'application/haansoft-hwp',
  'application/vnd.hancom.hwp',
  'application/hwp+zip',
  'application/vnd.hancom.hwpx',
  'application/x-hwpx',
]);

function extOf(name: string): string {
  const i = name.lastIndexOf('.');
  return i >= 0 ? name.slice(i).toLowerCase() : '';
}

function mimeForDocumentExt(ext: string): string | null {
  switch (ext) {
    case '.zip': return 'application/zip';
    case '.hwp': return 'application/x-hwp';
    case '.hwpx': return 'application/vnd.hancom.hwpx';
    default: return null;
  }
}

export function isImageAttachment(contentType?: string | null, fileName?: string | null): boolean {
  const mime = (contentType ?? '').split(';')[0]?.trim().toLowerCase();
  if (mime.startsWith('image/')) return true;
  const ext = fileName ? extOf(fileName) : '';
  return ['.jpg', '.jpeg', '.png', '.gif', '.webp', '.bmp'].includes(ext);
}

export function isDocumentAttachmentFile(file: File): boolean {
  const ext = extOf(file.name);
  if (DOCUMENT_EXT.has(ext)) return true;
  const mime = file.type.split(';')[0]?.trim().toLowerCase();
  return DOCUMENT_MIME.has(mime);
}

function normalizeDocumentFile(file: File): File | null {
  if (file.size === 0) return null;
  const ext = extOf(file.name);
  if (!DOCUMENT_EXT.has(ext)) {
    const mime = file.type.split(';')[0]?.trim().toLowerCase();
    if (!DOCUMENT_MIME.has(mime)) return null;
  }
  const mime = mimeForDocumentExt(ext)
    ?? file.type.split(';')[0]?.trim().toLowerCase()
    ?? 'application/octet-stream';
  if (file.type === mime) return file;
  return new File([file], file.name, { type: mime, lastModified: file.lastModified });
}

/** FileList / File[] → 허용 첨부만 (이미지·zip·hwp·hwpx) */
export function pickAttachmentFiles(list: FileList | File[]): File[] {
  const out: File[] = [];
  for (const file of Array.from(list)) {
    if (isDocumentAttachmentFile(file)) {
      const doc = normalizeDocumentFile(file);
      if (doc) out.push(doc);
      continue;
    }
    const img = pickImageFiles([file])[0];
    if (img) out.push(img);
  }
  return out;
}

const MAX_BYTES = 5 * 1024 * 1024;

/** 이미지는 압축·문서는 그대로 업로드 */
export async function prepareAttachmentsForUpload(files: File[]): Promise<File[]> {
  const picked = pickAttachmentFiles(files);
  const out: File[] = [];
  for (const f of picked) {
    if (isDocumentAttachmentFile(f)) {
      if (f.size > MAX_BYTES) throw new Error('FILE_TOO_LARGE');
      out.push(f);
    } else {
      out.push(...await prepareImagesForUpload([f]));
    }
  }
  return out;
}

export const ATTACHMENT_TYPE_HINT =
  'jpeg, png, gif, webp, bmp, zip, hwp, hwpx (파일당 5MB)';