import { Suspense, lazy, useState } from 'react';
import { Button, Modal, Space, Spin, Upload, message } from 'antd';
import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query';
import { api } from '../api/client';

const PdfPreview = lazy(() => import('./PdfPreview').then((m) => ({ default: m.PdfPreview })));

type FileRow = { id: string; fileName: string; size: number; mimeType: string; bizType?: string };

export const FILE_KIND_LABEL: Record<string, string> = {
  BID_ANNOUNCE: '招标 / 询价文件',
  BID_FILE: '投标附件',
  BID_FORMAL: '正式标书',
  BID_PROOF: '递交 / 保证金证明',
  CONTRACT: '合同扫描件',
  CONTRACT_ACCEPT: '验收单',
  CONTRACT_AWARD: '中标通知书',
  PROJECT: '项目附件',
  PROJECT_ACCEPT: '验收材料',
  PURCHASE: '采购合同',
  PURCHASE_ACCEPT: '采购验收',
  EXPENSE: '发票 / 凭证',
  LOAN: '借据 / 凭证',
  USER_AVATAR: '头像',
  USER_ID_PHOTO: '证件照',
  EMPLOYEE_ID_PHOTO: '证件照',
  EMPLOYEE_ID_FRONT: '身份证正面',
  EMPLOYEE_ID_BACK: '身份证反面',
  EMPLOYEE_CERT: '个人证书',
  EMPLOYEE_LABOR: '劳动合同',
  NOTICE: '通知附件',
};

/** 纠正 multer latin1 解出来的中文文件名。 */
export function displayFileName(name: string) {
  if (!name) return '附件';
  if (/[\u4e00-\u9fff]/.test(name)) return name;
  try {
    const bytes = Uint8Array.from(name, (c) => c.charCodeAt(0) & 0xff);
    const decoded = new TextDecoder('utf-8').decode(bytes);
    if (/[\u4e00-\u9fff]/.test(decoded) && !decoded.includes('\uFFFD')) return decoded;
  } catch {
    /* keep original */
  }
  return name;
}

function sniffMime(bytes: Uint8Array, name?: string, declared?: string) {
  const declaredType = (declared || '').toLowerCase();
  if (bytes.length >= 4 && bytes[0] === 0x25 && bytes[1] === 0x50 && bytes[2] === 0x44 && bytes[3] === 0x46) {
    return 'application/pdf';
  }
  if (bytes.length >= 3 && bytes[0] === 0xff && bytes[1] === 0xd8 && bytes[2] === 0xff) return 'image/jpeg';
  if (bytes.length >= 8 && bytes[0] === 0x89 && bytes[1] === 0x50 && bytes[2] === 0x4e && bytes[3] === 0x47) {
    return 'image/png';
  }
  if (bytes.length >= 6 && bytes[0] === 0x47 && bytes[1] === 0x49 && bytes[2] === 0x46) return 'image/gif';
  if (declaredType.startsWith('image/') || declaredType === 'application/pdf') return declaredType;
  if (/\.pdf$/i.test(name || '')) return 'application/pdf';
  if (/\.(png|jpe?g|gif|webp|bmp)$/i.test(name || '')) {
    const ext = (name || '').split('.').pop()?.toLowerCase();
    if (ext === 'jpg' || ext === 'jpeg') return 'image/jpeg';
    if (ext === 'png') return 'image/png';
    if (ext === 'gif') return 'image/gif';
    if (ext === 'webp') return 'image/webp';
    if (ext === 'bmp') return 'image/bmp';
  }
  return declaredType;
}

function isPreviewable(name: string, mime?: string) {
  const type = (mime || '').toLowerCase();
  if (type.startsWith('image/') || type === 'application/pdf') return true;
  return /\.(png|jpe?g|gif|webp|bmp|pdf)$/i.test(name);
}

async function fetchBizFileBlob(id: string, mime?: string, name?: string) {
  const raw = (await api.get(`/files/${id}`, { responseType: 'blob' })) as unknown;
  let blob: Blob | null = null;
  if (raw instanceof Blob) blob = raw;
  else if (raw && typeof raw === 'object' && (raw as { data?: unknown }).data instanceof Blob) {
    blob = (raw as { data: Blob }).data;
  }
  if (!blob) throw new Error('无法读取附件');
  const head = new Uint8Array(await blob.slice(0, 24).arrayBuffer());
  const headText = new TextDecoder().decode(head).trimStart();
  if (headText.startsWith('{') || headText.startsWith('<')) {
    const full = await blob.text();
    try {
      const parsed = JSON.parse(full) as { message?: string };
      throw new Error(parsed.message || '无法打开附件');
    } catch (e) {
      if (e instanceof Error && e.message !== '无法打开附件' && !e.message.includes('JSON')) throw e;
      throw new Error('无法打开附件');
    }
  }
  const type = sniffMime(head, name, mime || blob.type);
  if (type && blob.type !== type) return new Blob([await blob.arrayBuffer()], { type });
  return blob;
}

export async function downloadBizFile(id: string, name: string) {
  const blob = await fetchBizFileBlob(id, undefined, name);
  const url = URL.createObjectURL(blob);
  const a = document.createElement('a');
  a.href = url;
  a.download = displayFileName(name);
  a.click();
  URL.revokeObjectURL(url);
}

export function nonImageFiles(files?: FileRow[]) {
  return (files || []).filter((f) => !(f.mimeType || '').startsWith('image/'));
}

export async function uploadBizFile(bizType: string, bizId: string, file: File) {
  const fd = new FormData();
  fd.append('file', file);
  fd.append('bizType', bizType);
  fd.append('bizId', bizId);
  const res = (await api.post('/files', fd)) as { data: FileRow };
  return res.data;
}

export function IdScanUpload({
  label,
  bizType,
  bizId,
  fileId,
  onDone,
}: {
  label: string;
  bizType: string;
  bizId: string;
  fileId?: string | null;
  onDone?: () => void | Promise<void>;
}) {
  return (
    <Space wrap>
      <Upload
        showUploadList={false}
        accept="image/*,.pdf"
        customRequest={async (opt) => {
          try {
            const fd = new FormData();
            fd.append('file', opt.file as File);
            fd.append('bizType', bizType);
            fd.append('bizId', bizId);
            await api.post('/files', fd);
            message.success(`${label}已上传`);
            await onDone?.();
            opt.onSuccess?.({}, new XMLHttpRequest());
          } catch (e) {
            message.error((e as Error).message);
            opt.onError?.(e as Error);
          }
        }}
      >
        <Button>{fileId ? '重新上传' : `上传${label}`}</Button>
      </Upload>
      {fileId ? (
        <BizFileActions
          file={{
            id: fileId,
            fileName: `${label}.jpg`,
            size: 0,
            mimeType: 'image/jpeg',
            bizType,
          }}
        />
      ) : (
        <span style={{ color: '#cf1322' }}>未上传</span>
      )}
    </Space>
  );
}

export type FilePreview =
  | { kind: 'image'; url: string; fileName: string }
  | { kind: 'pdf'; data: ArrayBuffer; fileName: string }
  | { kind: 'html'; html: string; fileName: string };

export async function loadBizPreview(id: string, mime?: string, name?: string): Promise<FilePreview | null> {
  const display = displayFileName(name || '');
  const blob = await fetchBizFileBlob(id, mime, display);
  if (isPreviewable(display, blob.type)) {
    const isImage = (blob.type || '').startsWith('image/') || /\.(png|jpe?g|gif|webp|bmp)$/i.test(display);
    if (isImage) {
      return { kind: 'image', url: URL.createObjectURL(blob), fileName: display || '图片' };
    }
    const buf = await blob.arrayBuffer();
    return { kind: 'pdf', data: buf.slice(0), fileName: display || '附件.pdf' };
  }
  const buffer = await blob.arrayBuffer();
  if (/\.docx$/i.test(display) || blob.type === 'application/vnd.openxmlformats-officedocument.wordprocessingml.document') {
    const mammoth = await import('mammoth/mammoth.browser');
    const result = await mammoth.convertToHtml({ arrayBuffer: buffer });
    return {
      kind: 'html',
      fileName: display || 'Word 文档',
      html: `<style>body{font:15px/1.7 system-ui;padding:24px;color:#222}img{max-width:100%}table{border-collapse:collapse}td,th{border:1px solid #ddd;padding:6px}</style>${result.value}`,
    };
  }
  if (/\.(xlsx?|csv)$/i.test(display) || /spreadsheet|ms-excel|csv/i.test(blob.type)) {
    const XLSX = await import('xlsx');
    const workbook = XLSX.read(buffer, { type: 'array' });
    const sheets = workbook.SheetNames.map((sheetName) => {
      const heading = `<h2>${sheetName.replace(/[&<>"']/g, (c) => ({ '&': '&amp;', '<': '&lt;', '>': '&gt;', '"': '&quot;', "'": '&#39;' })[c]!)}</h2>`;
      return heading + XLSX.utils.sheet_to_html(workbook.Sheets[sheetName]);
    }).join('');
    return {
      kind: 'html',
      fileName: display || 'Excel 表格',
      html: `<style>body{font:14px/1.5 system-ui;padding:20px;color:#222}table{border-collapse:collapse;margin-bottom:28px}td,th{border:1px solid #bbb;padding:5px 8px;white-space:nowrap}tr:first-child{background:#f5f5f5}</style>${sheets}`,
    };
  }
  await downloadBizFile(id, display);
  message.info('旧版 Word .doc 等格式已下载，请用本地软件打开');
  return null;
}

export function AttachmentPreviewModal({
  preview,
  onClose,
}: {
  preview: FilePreview | null;
  onClose: () => void;
}) {
  return (
    <Modal
      title={preview?.fileName || '预览'}
      open={Boolean(preview)}
      onCancel={onClose}
      footer={null}
      width="80vw"
      destroyOnClose
    >
      {preview?.kind === 'image' ? (
        <img src={preview.url} alt={preview.fileName} style={{ width: '100%' }} />
      ) : preview?.kind === 'pdf' ? (
        <Suspense fallback={<Spin />}>
          <PdfPreview data={preview.data} fileName={preview.fileName} />
        </Suspense>
      ) : preview?.kind === 'html' ? (
        <iframe
          title={preview.fileName}
          sandbox=""
          srcDoc={preview.html}
          style={{ width: '100%', height: '72vh', border: 0 }}
        />
      ) : null}
    </Modal>
  );
}

export function BizFileActions({
  file,
  onDelete,
}: {
  file: FileRow;
  onDelete?: () => void;
}) {
  const [preview, setPreview] = useState<FilePreview | null>(null);
  const name = displayFileName(file.fileName);
  const kindLabel = file.bizType && FILE_KIND_LABEL[file.bizType] ? `【${FILE_KIND_LABEL[file.bizType]}】` : '';

  const closePreview = () => {
    if (preview?.kind === 'image') URL.revokeObjectURL(preview.url);
    setPreview(null);
  };

  const openPreview = async () => {
    try {
      const next = await loadBizPreview(file.id, file.mimeType, name);
      if (next) setPreview(next);
    } catch (e) {
      message.error(e instanceof Error ? e.message : '无法打开附件');
    }
  };

  return (
    <>
      <Button type="link" onClick={() => void openPreview()}>
        {kindLabel}
        {name}
      </Button>
      <Button type="link" onClick={() => void downloadBizFile(file.id, name)}>
        下载
      </Button>
      {onDelete ? (
        <Button type="link" danger onClick={onDelete}>
          删除
        </Button>
      ) : null}
      <AttachmentPreviewModal preview={preview} onClose={closePreview} />
    </>
  );
}

export function BizFileList({ files, empty = '没有附件' }: { files?: FileRow[]; empty?: string }) {
  const rows = files || [];
  if (!rows.length) return <p style={{ color: 'var(--mute)' }}>{empty}</p>;
  return (
    <ul style={{ paddingLeft: 18, marginBottom: 16 }}>
      {rows.map((f) => (
        <li key={f.id}>
          <BizFileActions file={f} />
        </li>
      ))}
    </ul>
  );
}

export function BizFileUpload({
  bizType,
  bizId,
  files,
  disabled,
  label,
  extra,
  queryKey,
  onUploaded,
}: {
  bizType: string;
  bizId?: string;
  files?: FileRow[];
  disabled?: boolean;
  label?: string;
  extra?: string;
  queryKey: unknown[];
  onUploaded?: () => void;
}) {
  const qc = useQueryClient();
  const rows = files || [];
  const del = useMutation({
    mutationFn: (id: string) => api.delete(`/files/${id}`),
    onSuccess: () => {
      message.success('已删除附件');
      qc.invalidateQueries({ queryKey });
      onUploaded?.();
    },
    onError: (e: Error) => message.error(e.message),
  });

  return (
    <div style={{ marginBottom: 16 }}>
      {label ? <div style={{ marginBottom: 8 }}>{label}</div> : null}
      {extra ? <p style={{ color: 'var(--mute)', marginBottom: 8 }}>{extra}</p> : null}
      {!bizId ? (
        <p style={{ color: 'var(--mute)' }}>保存后再上传附件。</p>
      ) : (
        <>
          <ul style={{ paddingLeft: 18 }}>
            {rows.map((f) => (
              <li key={f.id}>
                <BizFileActions file={f} onDelete={disabled ? undefined : () => del.mutate(f.id)} />
              </li>
            ))}
            {!rows.length ? <li style={{ color: 'var(--mute)' }}>还没有附件</li> : null}
          </ul>
          {!disabled ? (
            <Upload
              multiple
              showUploadList={false}
              beforeUpload={() => true}
              customRequest={async (opt) => {
                try {
                  const fd = new FormData();
                  fd.append('file', opt.file as File);
                  fd.append('bizType', bizType);
                  fd.append('bizId', bizId);
                  await api.post('/files', fd);
                  message.success('已上传');
                  qc.invalidateQueries({ queryKey });
                  onUploaded?.();
                  opt.onSuccess?.({}, new XMLHttpRequest());
                } catch (e) {
                  const err = e as Error;
                  message.error(err.message);
                  opt.onError?.(err);
                }
              }}
            >
              <Button>上传附件</Button>
            </Upload>
          ) : null}
        </>
      )}
    </div>
  );
}

export function FileAttachments({
  bizType,
  bizId,
  disabled,
  label,
}: {
  bizType: 'EXPENSE' | 'LOAN';
  bizId?: string;
  disabled?: boolean;
  label: string;
}) {
  const qc = useQueryClient();
  const q = useQuery({
    queryKey: [bizType === 'EXPENSE' ? 'expense' : 'loan', bizId],
    enabled: Boolean(bizId),
    queryFn: () => api.get(bizType === 'EXPENSE' ? `/expenses/${bizId}` : `/loans/${bizId}`),
  });
  const files = ((q.data?.data?.files ?? []) as FileRow[]);
  const del = useMutation({
    mutationFn: (id: string) => api.delete(`/files/${id}`),
    onSuccess: () => {
      message.success('已删除附件');
      qc.invalidateQueries({ queryKey: [bizType === 'EXPENSE' ? 'expense' : 'loan', bizId] });
    },
    onError: (e: Error) => message.error(e.message),
  });

  return (
    <div style={{ marginBottom: 16 }}>
      <div style={{ marginBottom: 8 }}>{label}</div>
      {!bizId ? (
        <p style={{ color: 'var(--mute)' }}>先保存草稿，再上传发票或凭证。</p>
      ) : (
        <>
          <ul style={{ paddingLeft: 18 }}>
            {files.map((f) => (
              <li key={f.id}>
                <BizFileActions file={f} onDelete={disabled ? undefined : () => del.mutate(f.id)} />
              </li>
            ))}
            {!files.length ? <li style={{ color: 'var(--mute)' }}>还没有附件</li> : null}
          </ul>
          {!disabled ? (
            <Upload
              showUploadList={false}
              beforeUpload={() => true}
              customRequest={async (opt) => {
                try {
                  const fd = new FormData();
                  fd.append('file', opt.file as File);
                  fd.append('bizType', bizType);
                  fd.append('bizId', bizId);
                  await api.post('/files', fd);
                  message.success('已上传');
                  qc.invalidateQueries({ queryKey: [bizType === 'EXPENSE' ? 'expense' : 'loan', bizId] });
                  opt.onSuccess?.({}, new XMLHttpRequest());
                } catch (e) {
                  const err = e as Error;
                  message.error(err.message);
                  opt.onError?.(err);
                }
              }}
            >
              <Button>上传发票 / 凭证</Button>
            </Upload>
          ) : null}
        </>
      )}
    </div>
  );
}