import type { OssSignData } from '@/api/upload';
import { fetchOssSign } from '@/api/upload';

/**
 * OSS 上传类型
 * 1=证件照 2=赛事封面 3=头像 4=富文本 5=Banner
 */
export const OssUploadType = {
  IdCard: '1',
  EventCover: '2',
  Avatar: '3',
  RichText: '4',
  Banner: '5',
} as const;

export type OssUploadTypeValue = (typeof OssUploadType)[keyof typeof OssUploadType];

/**
 * 生成唯一文件名：16 位大小写字母+数字随机串.ext
 */
export function genFileName(filePath: string, fileName?: string): string {
  let suffix = '';
  if (fileName) {
    const dot = fileName.lastIndexOf('.');
    suffix = dot >= 0 ? fileName.slice(dot).toLowerCase() : '';
  }
  if (!suffix && filePath) {
    const dot = filePath.lastIndexOf('.');
    suffix = dot >= 0 ? filePath.slice(dot).toLowerCase() : '';
  }
  if (!suffix) suffix = '.jpg';

  const random = Array.from({ length: 16 }, () => {
    const chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
    return chars.charAt(Math.floor(Math.random() * chars.length));
  }).join('');

  return `${random}${suffix}`;
}

/** 根据签名和文件名构建 OSS 上传 FormData 字段 */
export function buildOssFormData(sign: OssSignData, fileName: string): Record<string, string> {
  return {
    key: `${sign.dir}${fileName}`,
    policy: sign.policy,
    'x-oss-signature': sign.signature,
    'x-oss-signature-version': 'OSS4-HMAC-SHA256',
    'x-oss-credential': sign.x_oss_credential,
    'x-oss-date': sign.x_oss_date,
    'x-oss-security-token': sign.security_token,
    success_action_status: '200',
  };
}

/**
 * 使用已有签名上传单个文件到 OSS（Web 版，fetch + FormData）
 */
export async function uploadFileWithSign(file: File, sign: OssSignData): Promise<string> {
  const fileName = genFileName(file.name, file.name);
  const key = `${sign.dir}${fileName}`;

  const formData = new FormData();
  Object.entries(buildOssFormData(sign, fileName)).forEach(([k, v]) => {
    formData.append(k, v);
  });
  formData.append('file', file);

  const res = await fetch(sign.host, {
    method: 'POST',
    body: formData,
  });

  if (!res.ok) {
    throw new Error(`OSS 上传失败：${res.status} ${res.statusText}`);
  }

  return `${sign.host}/${key}`;
}

/**
 * 上传单个文件到 OSS
 * @returns 文件访问 URL
 */
export async function uploadFile(file: File, type: OssUploadTypeValue): Promise<{ url: string }> {
  const sign = await fetchOssSign(type);
  const url = await uploadFileWithSign(file, sign);
  return { url };
}

/**
 * 逐张上传文件到 OSS（同一批复用同一签名，单张失败不影响后续）
 */
export async function uploadFilesOneByOne(
  files: File[],
  type: OssUploadTypeValue,
  options?: {
    onSuccess?: (url: string, index: number) => void | Promise<void>;
    onError?: (error: unknown, index: number) => void;
  },
): Promise<{ successCount: number; failCount: number }> {
  if (files.length === 0) {
    return { successCount: 0, failCount: 0 };
  }

  const sign = await fetchOssSign(type);
  let successCount = 0;
  let failCount = 0;

  for (let i = 0; i < files.length; i++) {
    try {
      const url = await uploadFileWithSign(files[i], sign);
      successCount++;
      await options?.onSuccess?.(url, i);
    } catch (err) {
      failCount++;
      options?.onError?.(err, i);
    }
  }

  return { successCount, failCount };
}