import { useState, useCallback } from 'react'
import { FileRejection } from 'react-dropzone'
import Button from '@/components/ui/Button'
import {
  Dialog,
  DialogContent,
  DialogDescription,
  DialogHeader,
  DialogTitle,
  DialogTrigger
} from '@/components/ui/Dialog'
import FileUploader from '@/components/ui/FileUploader'
import { toast } from 'sonner'
import { errorMessage } from '@/lib/utils'
import { uploadDocument } from '@/api/lightrag'

import { UploadIcon } from 'lucide-react'
import { useTranslation } from 'react-i18next'

export default function UploadDocumentsDialog() {
  const { t } = useTranslation()
  const [open, setOpen] = useState(false)
  const [isUploading, setIsUploading] = useState(false)
  const [progresses, setProgresses] = useState<Record<string, number>>({})
  const [fileErrors, setFileErrors] = useState<Record<string, string>>({})

  const handleRejectedFiles = useCallback(
    (rejectedFiles: FileRejection[]) => {
      // Process rejected files and add them to fileErrors
      rejectedFiles.forEach(({ file, errors }) => {
        // Get the first error message
        let errorMsg = errors[0]?.message || t('documentPanel.uploadDocuments.fileUploader.fileRejected', { name: file.name })
        
        // Simplify error message for unsupported file types
        if (errorMsg.includes('file-invalid-type')) {
          errorMsg = t('documentPanel.uploadDocuments.fileUploader.unsupportedType')
        }
        
        // Set progress to 100% to display error message
        setProgresses((pre) => ({
          ...pre,
          [file.name]: 100
        }))
        
        // Add error message to fileErrors
        setFileErrors(prev => ({
          ...prev,
          [file.name]: errorMsg
        }))
      })
    },
    [setProgresses, setFileErrors, t]
  )

  const handleDocumentsUpload = useCallback(
    async (filesToUpload: File[]) => {
      setIsUploading(true)
      
      // Only clear errors for files that are being uploaded, keep errors for rejected files
      setFileErrors(prev => {
        const newErrors = { ...prev };
        filesToUpload.forEach(file => {
          delete newErrors[file.name];
        });
        return newErrors;
      });
      
      // Show uploading toast
      const toastId = toast.loading(t('documentPanel.uploadDocuments.batch.uploading'))
      
      try {
        // Track errors locally to ensure we have the final state
        const uploadErrors: Record<string, string> = {}
        
        await Promise.all(
          filesToUpload.map(async (file) => {
            try {
              // Initialize upload progress
              setProgresses((pre) => ({
                ...pre,
                [file.name]: 0
              }))
              
              const result = await uploadDocument(file, (percentCompleted: number) => {
                console.debug(t('documentPanel.uploadDocuments.single.uploading', { name: file.name, percent: percentCompleted }))
                setProgresses((pre) => ({
                  ...pre,
                  [file.name]: percentCompleted
                }))
              })

              if (result.status === 'duplicated') {
                uploadErrors[file.name] = t('documentPanel.uploadDocuments.fileUploader.duplicateFile')
                setFileErrors(prev => ({
                  ...prev,
                  [file.name]: t('documentPanel.uploadDocuments.fileUploader.duplicateFile')
                }))
              } else if (result.status !== 'success') {
                uploadErrors[file.name] = result.message
                setFileErrors(prev => ({
                  ...prev,
                  [file.name]: result.message
                }))
              }
            } catch (err) {
              console.error(`Upload failed for ${file.name}:`, err)
              
              // Handle HTTP errors, including 400 errors
              let errorMsg = errorMessage(err)
              
              // If it's an axios error with response data, try to extract more detailed error info
              if (err && typeof err === 'object' && 'response' in err) {
                const axiosError = err as { response?: { status: number, data?: { detail?: string } } }
                if (axiosError.response?.status === 400) {
                  // Extract specific error message from backend response
                  errorMsg = axiosError.response.data?.detail || errorMsg
                }
                
                // Set progress to 100% to display error message
                setProgresses((pre) => ({
                  ...pre,
                  [file.name]: 100
                }))
              }
              
              // Record error message in both local tracking and state
              uploadErrors[file.name] = errorMsg
              setFileErrors(prev => ({
                ...prev,
                [file.name]: errorMsg
              }))
            }
          })
        )
        
        // Check if any files failed to upload using our local tracking
        const hasErrors = Object.keys(uploadErrors).length > 0
        
        // Update toast status
        if (hasErrors) {
          toast.error(t('documentPanel.uploadDocuments.batch.error'), { id: toastId })
        } else {
          toast.success(t('documentPanel.uploadDocuments.batch.success'), { id: toastId })
        }
      } catch (err) {
        console.error('Unexpected error during upload:', err)
        toast.error(t('documentPanel.uploadDocuments.generalError', { error: errorMessage(err) }), { id: toastId })
      } finally {
        setIsUploading(false)
      }
    },
    [setIsUploading, setProgresses, setFileErrors, t]
  )

  return (
    <Dialog
      open={open}
      onOpenChange={(open) => {
        if (isUploading) {
          return
        }
        if (!open) {
          setProgresses({})
          setFileErrors({})
        }
        setOpen(open)
      }}
    >
      <DialogTrigger asChild>
        <Button variant="default" side="bottom" tooltip={t('documentPanel.uploadDocuments.tooltip')} size="sm">
          <UploadIcon /> {t('documentPanel.uploadDocuments.button')}
        </Button>
      </DialogTrigger>
      <DialogContent className="sm:max-w-xl" onCloseAutoFocus={(e) => e.preventDefault()}>
        <DialogHeader>
          <DialogTitle>{t('documentPanel.uploadDocuments.title')}</DialogTitle>
          <DialogDescription>
            {t('documentPanel.uploadDocuments.description')}
          </DialogDescription>
        </DialogHeader>
        <FileUploader
          maxFileCount={Infinity}
          maxSize={200 * 1024 * 1024}
          description={t('documentPanel.uploadDocuments.fileTypes')}
          onUpload={handleDocumentsUpload}
          onReject={handleRejectedFiles}
          progresses={progresses}
          fileErrors={fileErrors}
          disabled={isUploading}
        />
      </DialogContent>
    </Dialog>
  )
}