import { useState, useRef, useEffect } from 'react'
import { useQuery } from '@tanstack/react-query'
import { Button } from './ui/button'
import { Card, CardContent, CardDescription, CardHeader, CardTitle } from './ui/card'
import { Label } from './ui/label'
import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from './ui/select'
import { Upload, X, Check } from 'lucide-react'
import { packsApi } from '@/api/packs'

interface UploadedImage {
  id: string
  file: File
  preview: string
  base64: string
}

interface BulkCardUploadProps {
  onImagesUploaded: (images: UploadedImage[], packId?: string) => void
  onClose: () => void
}

export function BulkCardUpload({ onImagesUploaded, onClose }: BulkCardUploadProps) {
  const fileInputRef = useRef<HTMLInputElement>(null)
  const [uploadedImages, setUploadedImages] = useState<UploadedImage[]>([])
  const [isDragging, setIsDragging] = useState(false)
  const [selectedPackId, setSelectedPackId] = useState<string>('')

  // Fetch packs for pack selection
  const { data: packsData } = useQuery({
    queryKey: ['packs', 1, 100, ''],
    queryFn: () => packsApi.getPacks({ page: 1, limit: 100, search: '' }),
  })

  const handleFileSelect = async (files: FileList) => {
    const newImages: UploadedImage[] = []

    for (let i = 0; i < files.length; i++) {
      const file = files[i]

      // Validate file type
      if (!file.type.startsWith('image/')) {
        continue
      }

      // Validate file size (max 5MB)
      const fileSizeMB = file.size / (1024 * 1024)
      if (fileSizeMB > 5) {
        continue
      }

      try {
        const base64 = await fileToBase64(file)
        const preview = URL.createObjectURL(file)
        
        newImages.push({
          id: `${Date.now()}-${i}`,
          file,
          preview,
          base64,
        })
      } catch (error) {
        console.error('Error processing file:', error)
      }
    }

    setUploadedImages((prev) => [...prev, ...newImages])
  }

  const handleInputChange = (e: React.ChangeEvent<HTMLInputElement>) => {
    const files = e.target.files
    if (files && files.length > 0) {
      handleFileSelect(files)
    }
    // Reset input value to allow selecting the same files again
    if (fileInputRef.current) {
      fileInputRef.current.value = ''
    }
  }

  const handleDragOver = (e: React.DragEvent) => {
    e.preventDefault()
    e.stopPropagation()
    setIsDragging(true)
  }

  const handleDragLeave = (e: React.DragEvent) => {
    e.preventDefault()
    e.stopPropagation()
    setIsDragging(false)
  }

  const handleDrop = (e: React.DragEvent) => {
    e.preventDefault()
    e.stopPropagation()
    setIsDragging(false)

    const files = e.dataTransfer.files
    if (files && files.length > 0) {
      handleFileSelect(files)
    }
  }

  const handleRemove = (id: string) => {
    setUploadedImages((prev) => {
      const image = prev.find((img) => img.id === id)
      if (image) {
        URL.revokeObjectURL(image.preview)
      }
      return prev.filter((img) => img.id !== id)
    })
  }

  const handleClearAll = () => {
    uploadedImages.forEach((img) => URL.revokeObjectURL(img.preview))
    setUploadedImages([])
  }

  const handleContinue = () => {
    if (uploadedImages.length > 0) {
      onImagesUploaded(uploadedImages, selectedPackId || undefined)
    }
  }

  return (
    <div className="space-y-4">
      <div className="flex items-center justify-between">
        <div>
          <h2 className="text-2xl font-bold">Bulk Card Upload</h2>
          <p className="text-sm text-muted-foreground">
            Upload multiple images, then fill in card details one by one
          </p>
        </div>
        <Button variant="outline" onClick={onClose}>
          <X className="h-4 w-4 mr-2" />
          Cancel
        </Button>
      </div>

      <Card>
        <CardHeader>
          <CardTitle>Upload Images</CardTitle>
          <CardDescription>
            Select multiple image files or drag and drop them here
          </CardDescription>
        </CardHeader>
        <CardContent>
          <div className="space-y-4 mb-4">
            <div className="space-y-2">
              <Label htmlFor="packId">Pack (optional)</Label>
              <Select
                value={selectedPackId || undefined}
                onValueChange={(value: string) => {
                  const packId = value === '__none__' ? '' : value
                  setSelectedPackId(packId)
                }}
              >
                <SelectTrigger>
                  <SelectValue placeholder="Select a pack (optional)" />
                </SelectTrigger>
                <SelectContent>
                  <SelectItem value="__none__">None</SelectItem>
                  {packsData?.items && packsData.items.length > 0 ? (
                    packsData.items.map((pack) => (
                      <SelectItem key={pack.id} value={pack.id}>
                        {pack.title || pack.id}
                      </SelectItem>
                    ))
                  ) : null}
                </SelectContent>
              </Select>
              <p className="text-xs text-muted-foreground">
                Selected pack will be applied to all uploaded cards
              </p>
            </div>
          </div>
          <div
            className={`border-2 border-dashed rounded-lg p-8 text-center cursor-pointer transition-colors ${
              isDragging
                ? 'border-primary bg-primary/5'
                : 'border-muted-foreground/25 hover:border-muted-foreground/50'
            }`}
            onDragOver={handleDragOver}
            onDragLeave={handleDragLeave}
            onDrop={handleDrop}
            onClick={() => fileInputRef.current?.click()}
          >
            <input
              ref={fileInputRef}
              type="file"
              accept="image/*"
              multiple
              onChange={handleInputChange}
              className="hidden"
            />
            <div className="flex flex-col items-center justify-center space-y-4">
              <Upload className="h-12 w-12 text-muted-foreground" />
              <div className="text-lg">
                <span className="text-primary font-medium">Click to upload</span> or drag and drop
              </div>
              <p className="text-sm text-muted-foreground">
                PNG, JPG, GIF up to 5MB each. Multiple files supported.
              </p>
            </div>
          </div>
        </CardContent>
      </Card>

      {uploadedImages.length > 0 && (
        <Card>
          <CardHeader>
            <div className="flex items-center justify-between">
              <div>
                <CardTitle>Uploaded Images ({uploadedImages.length})</CardTitle>
                <CardDescription>
                  Review uploaded images and continue to fill in card details
                </CardDescription>
              </div>
              <Button variant="outline" size="sm" onClick={handleClearAll}>
                <X className="h-4 w-4 mr-2" />
                Clear All
              </Button>
            </div>
          </CardHeader>
          <CardContent>
            <div className="grid grid-cols-2 md:grid-cols-3 lg:grid-cols-4 gap-4 max-h-[500px] overflow-y-auto">
              {uploadedImages.map((image) => (
                <div key={image.id} className="relative group">
                  <div className="relative aspect-square border rounded-lg overflow-hidden bg-muted">
                    <img
                      src={image.preview}
                      alt={image.file.name}
                      className="w-full h-full object-cover"
                    />
                    <div className="absolute inset-0 bg-black/0 group-hover:bg-black/50 transition-colors flex items-center justify-center">
                      <Button
                        variant="destructive"
                        size="sm"
                        className="opacity-0 group-hover:opacity-100 transition-opacity"
                        onClick={(e) => {
                          e.stopPropagation()
                          handleRemove(image.id)
                        }}
                      >
                        <X className="h-4 w-4" />
                      </Button>
                    </div>
                  </div>
                  <p className="text-xs text-muted-foreground mt-1 truncate" title={image.file.name}>
                    {image.file.name}
                  </p>
                </div>
              ))}
            </div>
          </CardContent>
        </Card>
      )}

      {uploadedImages.length > 0 && (
        <div className="flex justify-end space-x-2">
          <Button variant="outline" onClick={onClose}>
            Cancel
          </Button>
          <Button onClick={handleContinue}>
            <Check className="h-4 w-4 mr-2" />
            Continue to Fill Details ({uploadedImages.length} cards)
          </Button>
        </div>
      )}
    </div>
  )
}

// Helper function to convert file to base64
function fileToBase64(file: File): Promise<string> {
  return new Promise((resolve, reject) => {
    const reader = new FileReader()
    reader.onload = () => {
      const result = reader.result as string
      // Remove data:image/...;base64, prefix
      const base64 = result.split(',')[1]
      resolve(base64)
    }
    reader.onerror = reject
    reader.readAsDataURL(file)
  })
}