import COS from 'cos-js-sdk-v5'
import { apiFetch } from '@/lib/api'

interface TempKeyResponse {
  credentials: {
    tmpSecretId: string
    tmpSecretKey: string
    sessionToken: string
  }
  startTime: number
  expiredTime: number
  bucket: string
  region: string
}

let cachedKey: TempKeyResponse | null = null

async function getTempKey(forceRefresh = false): Promise<TempKeyResponse> {
  const now = Math.floor(Date.now() / 1000)
  // 提前 60 秒失效，避免边界问题
  if (!forceRefresh && cachedKey && cachedKey.expiredTime - 60 > now) {
    return cachedKey
  }
  const res = await apiFetch('/api/cos/temp-key')
  if (!res.ok) {
    throw new Error('获取上传凭证失败')
  }
  const data = (await res.json()) as TempKeyResponse
  cachedKey = data
  return data
}

function buildCosClient(key: TempKeyResponse): COS {
  return new COS({
    getAuthorization: (_options, callback) => {
      callback({
        TmpSecretId: key.credentials.tmpSecretId,
        TmpSecretKey: key.credentials.tmpSecretKey,
        SecurityToken: key.credentials.sessionToken,
        StartTime: key.startTime,
        ExpiredTime: key.expiredTime,
      })
    },
  })
}

function randomFilename(originalName: string): string {
  const ext = originalName.split('.').pop() || 'jpg'
  const timestamp = Date.now()
  const randomStr = Math.random().toString(36).substring(2, 8)
  return `mini_game/images/${timestamp}_${randomStr}.${ext}`
}

/**
 * 上传单个文件到腾讯云 COS，返回可访问的 URL。
 */
export async function uploadToCos(file: File | Blob, originalName?: string): Promise<string> {
  const name = originalName || (file as File).name || 'upload.jpg'
  const key = await getTempKey()
  const cos = buildCosClient(key)
  const filename = randomFilename(name)

  return new Promise<string>((resolve, reject) => {
    cos.putObject(
      {
        Bucket: key.bucket,
        Region: key.region,
        Key: filename,
        Body: file as File,
      },
      (err) => {
        if (err) {
          reject(new Error(err.message || '上传失败'))
          return
        }
        const url = `https://${key.bucket}.cos.${key.region}.myqcloud.com/${filename}`
        resolve(url)
      }
    )
  })
}