import { useState, useEffect } from 'react'
import { useMutation, useQueryClient } from '@tanstack/react-query'
import { toast } from 'sonner'
import { cardsApi, isCardsApiError } from '@/api/cards'
import { packsApi, isPacksApiError } from '@/api/packs'
import { formatApiError, getDetailedErrorMessage } from '@/lib/error-utils'
import type { GameCardDto } from '@/types/models'
import { Button } from './ui/button'
import { Input } from './ui/input'
import { Label } from './ui/label'
import { Textarea } from './ui/textarea'
import { Card, CardContent, CardDescription, CardHeader, CardTitle } from './ui/card'
import { Badge } from './ui/badge'
import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from './ui/select'
import { ChevronLeft, ChevronRight, Save, X } from 'lucide-react'

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

interface CardData {
  imageId: string
  packId: string
  original: string
  translation: string
  mnemo: string
  transcription: string
  transcriptionMnemo: string
  back: string
  imageBack?: string
  isSaved: boolean
  cardId?: string
}

interface BulkCardEditorProps {
  images: UploadedImage[]
  defaultPackId?: string
  onComplete: () => void
  onCancel: () => void
}

export function BulkCardEditor({ images, defaultPackId, onComplete, onCancel }: BulkCardEditorProps) {
  const queryClient = useQueryClient()
  const [currentIndex, setCurrentIndex] = useState(0)
  const [cardsData, setCardsData] = useState<Map<string, CardData>>(new Map())
  const [packsData, setPacksData] = useState<{ id: string; title: string }[]>([])

  // Load packs
  useEffect(() => {
    packsApi
      .getPacks({ page: 1, limit: 100, search: '' })
      .then((response) => {
        try {
          if (response && response.items && Array.isArray(response.items)) {
            const packs = response.items.map((pack: any) => ({ 
              id: String(pack.id || ''), 
              title: String(pack.title || pack.id || '') 
            }))
            setPacksData(packs)
          } else {
            console.warn('Unexpected packs response format:', response)
            setPacksData([])
          }
        } catch (error) {
          console.error('Error processing packs response:', error)
          setPacksData([])
        }
      })
      .catch((error) => {
        const errorMessage = isPacksApiError(error) 
          ? error.message 
          : formatApiError(error)
        console.error('Failed to load packs:', error)
        toast.error(`Failed to load packs: ${errorMessage}`)
        // Initialize with empty array so component doesn't crash
        setPacksData([])
      })
  }, [])

  // Initialize cards data
  useEffect(() => {
    if (images.length > 0) {
      const initialData = new Map<string, CardData>()
      images.forEach((image) => {
        initialData.set(image.id, {
          imageId: image.id,
          packId: defaultPackId || '',
          original: '',
          translation: '',
          mnemo: '',
          transcription: '',
          transcriptionMnemo: '',
          back: '',
          imageBack: undefined,
          isSaved: false,
        })
      })
      setCardsData(initialData)
    }
  }, [images, defaultPackId])

  const currentImage = images[currentIndex]
  const currentCard = currentImage ? cardsData.get(currentImage.id) : undefined

  const updateMutation = useMutation({
    mutationFn: (card: GameCardDto) => cardsApi.upsertCard(card),
    onSuccess: (response) => {
      queryClient.invalidateQueries({ queryKey: ['cards'] })
      if (currentImage) {
        const imageId = currentImage.id
        setCardsData((prev) => {
          const newData = new Map(prev)
          const cardData = newData.get(imageId)
          if (cardData && response.card) {
            newData.set(imageId, {
              ...cardData,
              isSaved: true,
              cardId: response.card.id,
            })
          }
          return newData
        })
      }
      toast.success('Card saved successfully')
    },
    onError: (error: unknown) => {
      const errorMessage = isCardsApiError(error) 
        ? error.message 
        : getDetailedErrorMessage(error, 'save', 'card')
      toast.error(errorMessage)
      console.error('Error saving card:', error)
    },
  })

  const handleFieldChange = (field: keyof CardData, value: string) => {
    if (!currentCard || !currentImage) return

    setCardsData((prev) => {
      const newData = new Map(prev)
      const cardData = newData.get(currentImage.id)
      if (cardData) {
        newData.set(currentImage.id, {
          ...cardData,
          [field]: value,
        })
      }
      return newData
    })
  }

  const handleSave = () => {
    if (!currentCard) return

    if (!currentCard.original.trim() || !currentCard.translation.trim() || !currentCard.mnemo.trim()) {
      toast.error('Original, translation and mnemo are required')
      return
    }

    const image = images.find((img) => img.id === currentCard.imageId)
    if (!image) return

    const cardData: GameCardDto = {
      id: currentCard.cardId || null,
      packId: currentCard.packId || undefined,
      original: currentCard.original.trim(),
      translation: currentCard.translation.trim(),
      mnemo: currentCard.mnemo.trim(),
      transcription: currentCard.transcription.trim() || undefined,
      transcriptionMnemo: currentCard.transcriptionMnemo.trim() || undefined,
      back: currentCard.back.trim() || undefined,
      image: image.base64,
      imageBack: currentCard.imageBack || undefined,
    }

    updateMutation.mutate(cardData)
  }

  const handleNext = () => {
    if (currentIndex < images.length - 1) {
      setCurrentIndex(currentIndex + 1)
    }
  }

  const handlePrevious = () => {
    if (currentIndex > 0) {
      setCurrentIndex(currentIndex - 1)
    }
  }

  const savedCount = Array.from(cardsData.values()).filter((card) => card.isSaved).length
  const totalCount = images.length

  // Wait for images and cards data to be initialized
  if (images.length === 0) {
    return (
      <div className="p-4">
        <p className="text-muted-foreground">No images uploaded</p>
      </div>
    )
  }

  if (!currentImage || !currentCard) {
    return (
      <div className="p-4">
        <p className="text-muted-foreground">Initializing card data...</p>
      </div>
    )
  }

  return (
    <div className="space-y-4">
      <div className="flex items-center justify-between">
        <div>
          <h2 className="text-2xl font-bold">Fill Card Details</h2>
          <p className="text-sm text-muted-foreground">
            Card {currentIndex + 1} of {totalCount} • {savedCount} saved
          </p>
        </div>
        <div className="flex items-center space-x-2">
          <Badge variant={currentCard.isSaved ? 'default' : 'secondary'}>
            {currentCard.isSaved ? 'Saved' : 'Not Saved'}
          </Badge>
          <Button variant="outline" onClick={onCancel}>
            <X className="h-4 w-4 mr-2" />
            Cancel
          </Button>
        </div>
      </div>

      <div className="grid grid-cols-1 lg:grid-cols-2 gap-6">
        {/* Image Preview */}
        <Card>
          <CardHeader>
            <CardTitle>Image Preview</CardTitle>
            <CardDescription>{currentImage.file?.name || 'Unknown'}</CardDescription>
          </CardHeader>
          <CardContent>
            <div className="relative aspect-square border rounded-lg overflow-hidden bg-muted">
              {currentImage.preview ? (
                <img
                  src={currentImage.preview}
                  alt={currentImage.file?.name || 'Card image'}
                  className="w-full h-full object-contain"
                  onError={(e) => {
                    console.error('Failed to load image:', currentImage.preview)
                    e.currentTarget.style.display = 'none'
                  }}
                />
              ) : (
                <div className="w-full h-full flex items-center justify-center text-muted-foreground">
                  Image preview not available
                </div>
              )}
            </div>
          </CardContent>
        </Card>

        {/* Form */}
        <Card>
          <CardHeader>
            <CardTitle>Card Information</CardTitle>
            <CardDescription>Fill in the details for this card</CardDescription>
          </CardHeader>
          <CardContent className="space-y-4">
            <div className="space-y-2">
              <Label htmlFor="packId">Pack ID (optional)</Label>
              <Select
                value={currentCard.packId || undefined}
                onValueChange={(value: string) => {
                  // If "none" is selected, clear the packId
                  const packId = value === '__none__' ? '' : value
                  handleFieldChange('packId', packId)
                }}
              >
                <SelectTrigger>
                  <SelectValue placeholder="Select a pack (optional)" />
                </SelectTrigger>
                <SelectContent>
                  <SelectItem value="__none__">None</SelectItem>
                  {packsData && packsData.length > 0 ? (
                    packsData.map((pack) => (
                      <SelectItem key={pack.id} value={pack.id}>
                        {pack.title || pack.id}
                      </SelectItem>
                    ))
                  ) : null}
                </SelectContent>
              </Select>
            </div>

            <div className="grid grid-cols-2 gap-4">
              <div className="space-y-2">
                <Label htmlFor="original">Original *</Label>
                <Input
                  id="original"
                  value={currentCard.original}
                  onChange={(e) => handleFieldChange('original', e.target.value)}
                  placeholder="e.g. cerdo"
                />
              </div>
              <div className="space-y-2">
                <Label htmlFor="translation">Translation *</Label>
                <Input
                  id="translation"
                  value={currentCard.translation}
                  onChange={(e) => handleFieldChange('translation', e.target.value)}
                  placeholder="e.g. pig"
                />
              </div>
            </div>

            <div className="space-y-2">
              <Label htmlFor="mnemo">Mnemo *</Label>
              <Input
                id="mnemo"
                value={currentCard.mnemo}
                onChange={(e) => handleFieldChange('mnemo', e.target.value)}
                placeholder="e.g. [pig] with heart"
              />
            </div>

            <div className="grid grid-cols-2 gap-4">
              <div className="space-y-2">
                <Label htmlFor="transcription">Transcription</Label>
                <Input
                  id="transcription"
                  value={currentCard.transcription}
                  onChange={(e) => handleFieldChange('transcription', e.target.value)}
                  placeholder="e.g. sɛrdo"
                />
              </div>
              <div className="space-y-2">
                <Label htmlFor="transcriptionMnemo">Transcription Mnemo</Label>
                <Input
                  id="transcriptionMnemo"
                  value={currentCard.transcriptionMnemo}
                  onChange={(e) => handleFieldChange('transcriptionMnemo', e.target.value)}
                  placeholder="e.g. pig with heart"
                />
              </div>
            </div>

            <div className="space-y-2">
              <Label htmlFor="back">Back Side</Label>
              <Textarea
                id="back"
                value={currentCard.back}
                onChange={(e) => handleFieldChange('back', e.target.value)}
                placeholder="Additional information on the back of the card"
                rows={3}
              />
            </div>

            <div className="flex items-center space-x-2 pt-4">
              <Button
                variant="outline"
                onClick={handlePrevious}
                disabled={currentIndex === 0}
              >
                <ChevronLeft className="h-4 w-4 mr-2" />
                Previous
              </Button>
              <Button
                onClick={handleSave}
                disabled={updateMutation.isPending}
                className="flex-1"
              >
                <Save className="h-4 w-4 mr-2" />
                {updateMutation.isPending ? 'Saving...' : currentCard.isSaved ? 'Update' : 'Save'}
              </Button>
              <Button
                variant="outline"
                onClick={handleNext}
                disabled={currentIndex === images.length - 1}
              >
                Next
                <ChevronRight className="h-4 w-4 ml-2" />
              </Button>
            </div>
          </CardContent>
        </Card>
      </div>

      {/* Progress indicator */}
      <Card>
        <CardContent className="pt-6">
          <div className="space-y-2">
            <div className="flex items-center justify-between text-sm">
              <span>Progress</span>
              <span>{savedCount} / {totalCount} saved</span>
            </div>
            <div className="w-full bg-muted rounded-full h-2">
              <div
                className="bg-primary h-2 rounded-full transition-all"
                style={{ width: `${(savedCount / totalCount) * 100}%` }}
              />
            </div>
          </div>
          {savedCount === totalCount && (
            <div className="mt-4 flex justify-end">
              <Button onClick={onComplete}>
                Complete
              </Button>
            </div>
          )}
        </CardContent>
      </Card>
    </div>
  )
}