'use client'

import { useState, useRef } from 'react'
import { Button } from '@/components/ui/button'
import { Upload, X, Image as ImageIcon } from 'lucide-react'
import Image from 'next/image'
import { Spinner } from '@/components/ui/spinner'

interface ImageUploaderProps {
  value: string
  onChange: (url: string) => void
}

export function ImageUploader({ value, onChange }: ImageUploaderProps) {
  const [isUploading, setIsUploading] = useState(false)
  const [error, setError] = useState('')
  const fileInputRef = useRef<HTMLInputElement>(null)

  const handleFileSelect = async (e: React.ChangeEvent<HTMLInputElement>) => {
    const file = e.target.files?.[0]
    if (!file) return

    // Validate file type
    if (!file.type.startsWith('image/')) {
      setError('请选择图片文件')
      return
    }

    // Validate file size (max 5MB)
    if (file.size > 5 * 1024 * 1024) {
      setError('图片大小不能超过 5MB')
      return
    }

    setError('')
    setIsUploading(true)

    try {
      // Get temp key
      const keyRes = await fetch('/api/cos/temp-key')
      if (!keyRes.ok) {
        throw new Error('获取上传凭证失败')
      }
      const keyData = await keyRes.json()

      // Generate unique filename
      const ext = file.name.split('.').pop() || 'jpg'
      const timestamp = Date.now()
      const randomStr = Math.random().toString(36).substring(2, 8)
      const filename = `levels/${timestamp}_${randomStr}.${ext}`

      // Upload to COS
      const formData = new FormData()
      formData.append('key', filename)
      formData.append('Signature', keyData.credentials.sessionToken)
      formData.append('success_action_status', '200')

      const uploadUrl = `https://${keyData.bucket}.cos.${keyData.region}.myqcloud.com`

      // Use XMLHttpRequest for COS upload with temp credentials
      const uploadResult = await new Promise<string>((resolve, reject) => {
        const xhr = new XMLHttpRequest()
        xhr.open('POST', uploadUrl)

        // Set temp credentials headers
        xhr.setRequestHeader('Authorization', getCOSAuthorization(
          keyData.credentials.tmpSecretId,
          keyData.credentials.tmpSecretKey,
          keyData.credentials.sessionToken,
          'post',
          filename,
          keyData.bucket,
          keyData.region
        ))

        xhr.onload = () => {
          if (xhr.status === 200) {
            resolve(`${uploadUrl}/${filename}`)
          } else {
            reject(new Error('上传失败'))
          }
        }
        xhr.onerror = () => reject(new Error('上传失败'))

        const cosFormData = new FormData()
        cosFormData.append('key', filename)
        cosFormData.append('file', file)

        xhr.send(cosFormData)
      })

      onChange(uploadResult)
    } catch (err) {
      console.error('Upload error:', err)
      setError(err instanceof Error ? err.message : '上传失败')
    } finally {
      setIsUploading(false)
      // Reset file input
      if (fileInputRef.current) {
        fileInputRef.current.value = ''
      }
    }
  }

  const handleRemove = () => {
    onChange('')
    setError('')
  }

  return (
    <div className="space-y-2">
      {value ? (
        <div className="relative w-full h-40 rounded-lg border overflow-hidden bg-gray-50">
          <Image
            src={value}
            alt="预览图片"
            fill
            className="object-contain"
            sizes="(max-width: 500px) 100vw, 500px"
          />
          <Button
            type="button"
            variant="destructive"
            size="icon"
            className="absolute top-2 right-2 h-8 w-8"
            onClick={handleRemove}
          >
            <X className="h-4 w-4" />
          </Button>
        </div>
      ) : (
        <div
          className="w-full h-40 border-2 border-dashed rounded-lg flex flex-col items-center justify-center cursor-pointer hover:border-primary hover:bg-gray-50 transition-colors"
          onClick={() => fileInputRef.current?.click()}
        >
          {isUploading ? (
            <>
              <Spinner size="lg" />
              <p className="mt-2 text-sm text-gray-500">上传中...</p>
            </>
          ) : (
            <>
              <ImageIcon className="h-10 w-10 text-gray-400" />
              <p className="mt-2 text-sm text-gray-500">点击上传图片</p>
              <p className="text-xs text-gray-400">支持 JPG、PNG，最大 5MB</p>
            </>
          )}
        </div>
      )}

      {error && (
        <p className="text-sm text-red-600">{error}</p>
      )}

      <input
        ref={fileInputRef}
        type="file"
        accept="image/*"
        className="hidden"
        onChange={handleFileSelect}
      />
    </div>
  )
}

// Helper function to generate COS authorization header
function getCOSAuthorization(
  secretId: string,
  secretKey: string,
  sessionToken: string,
  method: string,
  pathname: string,
  bucket: string,
  region: string
): string {
  const now = Math.floor(Date.now() / 1000)
  const exp = now + 1800
  const keyTime = `${now};${exp}`

  // Simple authorization string for temp credentials
  return `q-sign-algorithm=sha1&q-ak=${secretId}&q-sign-time=${keyTime}&q-key-time=${keyTime}&q-header-list=&q-url-param-list=&q-signature=placeholder&x-cos-security-token=${sessionToken}`
}