import { useState, useEffect, useMemo, useRef, type ChangeEvent } from 'react'
import { Formik } from 'formik'
import * as Yup from 'yup'
import { pInput as PInput, Dropdown, p as P, ImageUploader } from 'web-components'
import ProductsSelector from './ProductsSelector'
import { trpc } from '@/lib/trpc-client'
import { useUploadToObjectStorage } from '@/hooks/useUploadToObjectStorage'
import type { CreateStoreInput } from '@packages/shared'

// Store form values — required description + product selection on top of CreateStoreInput
export type StoreFormData = Omit<CreateStoreInput, 'description'> & {
  description: string
  products: number[]
}

interface StoreFormProps {
  mode: 'create' | 'edit'
  initialValues: StoreFormData
  onSubmit: (values: StoreFormData) => void
  isLoading: boolean
  storeId?: number
}

const validationSchema = Yup.object().shape({
  name: Yup.string().required('Name is required'),
  description: Yup.string(),
  imageUrl: Yup.string(),
  owner: Yup.number().required('Owner is required'),
  products: Yup.array().of(Yup.number()),
})

function StoreForm({ mode, initialValues, onSubmit, isLoading, storeId }: StoreFormProps) {
  const { data: staffData } = trpc.admin.staffUser.getStaff.useQuery()
  const { data: productsData } = trpc.admin.product.getProducts.useQuery()

  const [formInitialValues, setFormInitialValues] = useState<StoreFormData>(initialValues)
  const [selectedImages, setSelectedImages] = useState<{ blob: Blob; mimeType: string }[]>([])
  const [displayImages, setDisplayImages] = useState<{ uri?: string }[]>([])
  const fileInputRef = useRef<HTMLInputElement>(null)

  // For edit mode, pre-select SKUs belonging to this store's products
  const initialSelectedProducts = useMemo(() => {
    if (mode !== 'edit' || !productsData?.products) return []
    return productsData.products
      .filter(p => p.storeId === storeId)
      .flatMap(p => (p.skus || []).map(sku => sku.id))
  }, [mode, productsData?.products, storeId])

  useEffect(() => {
    setFormInitialValues({
      ...initialValues,
      products: initialSelectedProducts,
    })
  }, [initialValues, initialSelectedProducts])

  const existingImageUrls = useMemo(
    () => (formInitialValues.imageUrl ? [formInitialValues.imageUrl] : []),
    [formInitialValues.imageUrl]
  )

  const staffOptions = staffData?.staff.map((staff: { id: number; name: string }) => ({
    label: staff.name,
    value: staff.id,
  })) || []

  const { uploadSingle, isUploading } = useUploadToObjectStorage()

  const handleImagePick = () => {
    fileInputRef.current?.click()
  }

  const handleFileChange = (e: ChangeEvent<HTMLInputElement>) => {
    const files = Array.from(e.target.files || [])
    if (files.length === 0) {
      setSelectedImages([])
      setDisplayImages([])
      return
    }
    const file = files[0]
    setSelectedImages([{ blob: file, mimeType: file.type || 'image/jpeg' }])
    setDisplayImages([{ uri: URL.createObjectURL(file) }])
    e.target.value = ''
  }

  const handleRemoveImage = (uri: string) => {
    const index = displayImages.findIndex(img => img.uri === uri)
    if (index !== -1) {
      const newDisplay = displayImages.filter((_, i) => i !== index)
      const newFiles = selectedImages.filter((_, i) => i !== index)
      setDisplayImages(newDisplay)
      setSelectedImages(newFiles)
    }
  }

  return (
    <Formik
      initialValues={formInitialValues}
      validationSchema={validationSchema}
      onSubmit={onSubmit}
      enableReinitialize
    >
      {({ handleChange, handleSubmit, values, setFieldValue, errors, touched }) => {
        const submit = async () => {
          try {
            let imageUrl: string | undefined

            if (selectedImages.length > 0) {
              const { blob, mimeType } = selectedImages[0]
              const { presignedUrl } = await uploadSingle(blob, mimeType, 'store')
              imageUrl = presignedUrl
            }

            onSubmit({ ...values, imageUrl })
          } catch (error) {
            console.error('Upload error:', error)
            window.alert('Error: Failed to upload image')
          }
        }

        return (
          <div>
            <input
              ref={fileInputRef}
              type="file"
              accept="image/*"
              onChange={handleFileChange}
              className="hidden"
            />
            <PInput
              topLabel="Store Name"
              placeholder="Enter store name"
              value={values.name}
              onChange={handleChange('name')}
              error={!!(touched.name && errors.name)}
              style={{ marginBottom: 16 }}
            />
            <PInput
              topLabel="Description"
              placeholder="Enter store description"
              multiline
              numberOfLines={3}
              value={values.description}
              onChange={handleChange('description')}
              error={!!(touched.description && errors.description)}
              style={{ marginBottom: 16 }}
            />
            <div className="mb-4">
              <P className="mb-1 text-sm text-gray-500 font-medium">Owner</P>
              <Dropdown
                label="Select owner"
                value={values.owner}
                options={staffOptions}
                onValueChange={(value) => setFieldValue('owner', Number(value))}
                className="mb-4"
              />
            </div>
            <ProductsSelector
              value={values.products || []}
              onChange={(value) => setFieldValue('products', value)}
              multiple={true}
              label="Products"
              placeholder="Select products"
              isDisabled={(sku) => sku.storeId !== null && sku.storeId !== storeId}
              labelFormat={(sku) => `${sku.productName} - ₹${sku.price}`}
            />
            <div className="mb-6">
              <P className="text-sm font-bold text-gray-700 mb-3 uppercase tracking-wider block">Store Image</P>
              <ImageUploader
                images={displayImages}
                existingImageUrls={existingImageUrls}
                onAddImage={handleImagePick}
                onRemoveImage={handleRemoveImage}
                onRemoveExistingImage={() =>
                  setFormInitialValues((prev) => ({
                    ...prev,
                    imageUrl: undefined,
                  }))
                }
                allowMultiple={false}
              />
            </div>
            <button
              type="button"
              onClick={submit}
              disabled={isLoading || isUploading}
              className={`px-4 py-2 rounded-lg shadow-lg items-center mt-2 text-white text-lg font-bold w-full disabled:opacity-70 ${isLoading || isUploading ? 'bg-gray-400' : 'bg-blue-500'}`}
            >
              {isUploading ? 'Uploading...' : isLoading ? (mode === 'create' ? 'Creating...' : 'Updating...') : (mode === 'create' ? 'Create Store' : 'Update Store')}
            </button>
          </div>
        )
      }}
    </Formik>
  )
}

export default StoreForm