import { ref, type Ref } from 'vue';
import { uploadDmsAttachment, buildDmsFileDisplayUrl } from '@/network/api/dms/file-upload';
import {
  BusinessAssistantUploadedFile,
  BusinessAssistantInputFileTransmission,
  createBusinessAssistantId,
  MAX_FILE_SIZE,
  MAX_IMAGE_SIZE,
  SUPPORTED_ATTACHMENT_EXTENSIONS,
  SUPPORTED_IMAGE_EXTENSIONS,
  SUPPORTED_IMAGE_LABEL,
  SUPPORTED_ATTACHMENT_LABEL,
} from './shared';

const DRAFT_HOME_KEY = '__business_assistant_home_draft__';

export function useBusinessAssistantUpload(options?: {
  imageInputRef?: Ref<HTMLInputElement | null>;
  fileInputRef?: Ref<HTMLInputElement | null>;
  /**
   * 校验失败时的提示（**用界面的 toast，不要 window.alert** —— 用户 2026-09-23 要求）。
   * 不传时退回 console.warn（验证脚本等无界面场景）。
   */
  notify?: (message: string) => void;
}) {
  const notify = (message: string) => {
    if (options?.notify) {
      options.notify(message);
      return;
    }
    console.warn('[upload]', message);
  };

  const uploadedFiles = ref<BusinessAssistantUploadedFile[]>([]);
  const internalImageInputRef = ref<HTMLInputElement | null>(null);
  const internalFileInputRef = ref<HTMLInputElement | null>(null);
  const imageInputRef = options?.imageInputRef ?? internalImageInputRef;
  const fileInputRef = options?.fileInputRef ?? internalFileInputRef;
  const draftFilesByKey = new Map<string, BusinessAssistantUploadedFile[]>();
  let activeDraftKey = DRAFT_HOME_KEY;

  const triggerImageUpload = () => imageInputRef.value?.click();
  const triggerFileUpload = () => fileInputRef.value?.click();

  const getFileExtension = (fileName: string) => fileName.split('.').pop()?.toLowerCase() || '';

  /**
   * 图片是否受支持 —— **按扩展名**判（2026-09-23 修）。
   *
   * ⚠️ 原来写的是 `file.type.startsWith('image/') || 扩展名在白名单里`，等于
   * **任何 `image/*` 都放行**：SVG / BMP / TIFF / HEIC 全被当图片收下，
   * 与白名单和给用户的提示（JPEG、PNG、GIF、WebP）自相矛盾。
   * 现在**只有白名单里的扩展名算数**；文件名没有扩展名时（例如某些粘贴来的图）
   * 才退回看 MIME，仍需落在白名单里（`image/jpeg` → `jpeg`）。
   */
  const isSupportedImageFile = (file: File) => {
    const extension = getFileExtension(file.name);
    if (extension) {
      return SUPPORTED_IMAGE_EXTENSIONS.includes(extension);
    }
    const fromMime = String(file.type || '').replace(/^image\//i, '').toLowerCase();
    return Boolean(fromMime) && SUPPORTED_IMAGE_EXTENSIONS.includes(fromMime);
  };

  const isSupportedAttachmentFile = (file: File) => {
    const extension = getFileExtension(file.name);
    return SUPPORTED_ATTACHMENT_EXTENSIONS.includes(extension);
  };

  const isSupportedDropFile = (file: File) => isSupportedImageFile(file) || isSupportedAttachmentFile(file);

  const getFileList = (files: FileList | File[] | null) => {
    if (!files) return [];
    return Array.isArray(files) ? files : Array.from(files);
  };

  const getFileDedupKey = (file: File) =>
    [file.name, file.size, file.lastModified, file.type].join('__');

  const getUploadedFileDedupKey = (file: BusinessAssistantUploadedFile) =>
    [file.name, file.size, file.lastModified, file.type].join('__');

  const syncActiveDraft = () => {
    draftFilesByKey.set(activeDraftKey, uploadedFiles.value);
  };

  const updateUploadedFile = (id: string, patch: Partial<BusinessAssistantUploadedFile>) => {
    const index = uploadedFiles.value.findIndex((file) => file.id === id);
    if (index === -1) {
      return;
    }

    uploadedFiles.value[index] = {
      ...uploadedFiles.value[index],
      ...patch,
    };
    syncActiveDraft();
  };

  const setUploadDraftKey = (key?: string | null) => {
    syncActiveDraft();
    activeDraftKey = key || DRAFT_HOME_KEY;
    uploadedFiles.value = draftFilesByKey.get(activeDraftKey) || [];
    syncActiveDraft();
  };

  const clearUploadDraft = (key?: string | null) => {
    const draftKey = key || activeDraftKey;
    const files = draftFilesByKey.get(draftKey) || [];
    files.forEach((file) => {
      file.abort?.();
      if (file.url?.startsWith('blob:')) {
        URL.revokeObjectURL(file.url);
      }
    });
    draftFilesByKey.delete(draftKey);
    if (draftKey === activeDraftKey) {
      uploadedFiles.value = [];
      syncActiveDraft();
    }
  };



  const uploadFile = async (file: File, uploadItem: BusinessAssistantUploadedFile) => {
    const abortController = new AbortController();
    const abortSignature = () => abortController.abort();
    updateUploadedFile(uploadItem.id, { abort: abortSignature });

    try {
      // 2026-09-23 起改用 **DMS 的文件服务**（用户指定）：返回的是**相对路径**，
      // 它随聊天请求体的 `pictures` / `files` 发给后端（见 file-upload.ts 的实测契约）。
      // （更早那版是直传厂商 OSS，实现已在 2026-09-24 按用户要求删除，见 git 历史。）
      const relativePath = await uploadDmsAttachment(file, {
        isImage: Boolean(uploadItem.isImage),
        signal: abortController.signal,
      });
      const currentFile = uploadedFiles.value.find((item) => item.id === uploadItem.id);
      const localPreviewUrl = currentFile?.url;
      // 展示地址：相对路径直接打不开，要拼上代理前缀（实测 `/dms` + 相对路径 = 200）。
      // 图片才需要；非图片在气泡里显示成文件条，用不上 url。
      const displayUrl = currentFile?.isImage ? buildDmsFileDisplayUrl(relativePath) : undefined;
      updateUploadedFile(uploadItem.id, {
        status: 'success',
        progress: 100,
        // ⚠️ 两个字段分工不同，别混：
        //   fileUrl —— **相对路径**，随请求体 pictures / files 发给后端
        //   url     —— **可显示地址**（拼了代理前缀），只给预览用
        fileUrl: relativePath,
        url: displayUrl,
        abort: undefined,
      });
      // 本地 blob 用完就撤（换成代理地址后不再需要）
      if (localPreviewUrl?.startsWith('blob:') && localPreviewUrl !== displayUrl) {
        URL.revokeObjectURL(localPreviewUrl);
      }
    } catch (error) {
      if (abortController.signal.aborted || (error instanceof Error && error.message === '上传已取消')) {
        return;
      }
      updateUploadedFile(uploadItem.id, {
        status: 'error',
        errorMsg: error instanceof Error ? error.message : '上传异常',
        abort: undefined,
      });
    }
  };

  const handleFiles = (files: FileList | File[] | null, isImage: boolean) => {
    const fileList = getFileList(files);
    if (fileList.length === 0) return;

    const existingFileKeys = new Set(uploadedFiles.value.map(getUploadedFileDedupKey));

    fileList.forEach((file) => {
      const fileKey = getFileDedupKey(file);
      if (existingFileKeys.has(fileKey)) {
        return;
      }

      const maxSize = isImage ? MAX_IMAGE_SIZE : MAX_FILE_SIZE;
      const isSupported = isImage ? isSupportedImageFile(file) : isSupportedAttachmentFile(file);

      if (!isSupported) {
        // 不支持的格式：**提示 + 不加入输入框**（这里 return 就是不加）
        notify(
          isImage
            ? `「${file.name}」格式不支持，图片请用 ${SUPPORTED_IMAGE_LABEL}`
            : `「${file.name}」格式不支持，文件请用 ${SUPPORTED_ATTACHMENT_LABEL}`
        );
        return;
      }

      if (file.size > maxSize) {
        notify(`「${file.name}」超过大小限制（${isImage ? '20MB' : '50MB'}）`);
        return;
      }

      const uploadItem: BusinessAssistantUploadedFile = {
        id: createBusinessAssistantId(),
        name: file.name,
        size: file.size,
        type: file.type,
        lastModified: file.lastModified,
        progress: 0,
        status: 'uploading',
        isImage,
        url: isImage ? URL.createObjectURL(file) : undefined,
      };
      existingFileKeys.add(fileKey);
      uploadedFiles.value.push(uploadItem);
      syncActiveDraft();
      void uploadFile(file, uploadItem);
    });

    if (isImage && imageInputRef.value) imageInputRef.value.value = '';
    if (!isImage && fileInputRef.value) fileInputRef.value.value = '';
  };

  const handleImageSelected = (event: Event) => {
    handleFiles((event.target as HTMLInputElement).files, true);
  };

  const handleFileSelected = (event: Event) => {
    handleFiles((event.target as HTMLInputElement).files, false);
  };

  const removeUploadedFile = (id: string) => {
    const index = uploadedFiles.value.findIndex((file) => file.id === id);
    if (index === -1) return;

    const file = uploadedFiles.value[index];
    file.abort?.();
    if (file.url?.startsWith('blob:')) {
      URL.revokeObjectURL(file.url);
    }
    uploadedFiles.value.splice(index, 1);
    syncActiveDraft();
  };

  const consumeSuccessfulFileTransmission = (filePos: number): BusinessAssistantInputFileTransmission => {
    const successfulFiles = uploadedFiles.value.filter((file) => file.status === 'success' && file.fileUrl);
    const successfulIds = new Set(successfulFiles.map((file) => file.id));
    const files = successfulFiles.map((file) => file.fileUrl as string);
    // ⚠️ 两个字段分工不同（2026-09-23 换 DMS 后尤其明显），**别混**：
    //   fileUrl —— 相对路径，随请求体 `pictures` / `files` 发给后端（toChatAttachmentUrls 取它）
    //   url     —— 可显示地址，气泡里的 <img src> 取它
    // 这里曾经只填 `url: file.fileUrl`（那时 fileUrl 还是 OSS 绝对地址，能直接当 src）。
    // 换成 DMS 相对路径后那一行就成了 bug：气泡里的图**不显示**（相对路径经 dev server
    // 返回的是 index.html，<img> 解不出来）。用户 2026-09-23 报「提交之后看不到图片了」。
    // 显示地址在这里**按相对路径重新拼**（不沿用上传时的 file.url）：那条路径可能还是
    // 本地 blob（已被 revoke）或压根没来得及写，重拼一次才是确定的。
    const attachments = successfulFiles.map((file) => ({
      id: file.id,
      name: file.name,
      size: file.size,
      isImage: file.isImage,
      fileUrl: file.fileUrl as string,
      url: file.isImage ? buildDmsFileDisplayUrl(file.fileUrl as string) || undefined : undefined,
    }));

    uploadedFiles.value = uploadedFiles.value.filter((file) => !successfulIds.has(file.id));
    syncActiveDraft();

    return {
      files,
      file_pos: files.map(() => filePos),
      attachments,
    };
  };

  return {
    uploadedFiles,
    imageInputRef,
    fileInputRef,
    triggerImageUpload,
    triggerFileUpload,
    handleFiles,
    handleImageSelected,
    handleFileSelected,
    removeUploadedFile,
    isSupportedImageFile,
    isSupportedAttachmentFile,
    isSupportedDropFile,
    consumeSuccessfulFileTransmission,
    setUploadDraftKey,
    clearUploadDraft,
  };
}