import React, { useState, useEffect, useCallback, forwardRef, useImperativeHandle, useMemo } from 'react';
import { View, TouchableOpacity } from 'react-native';
import { Formik, FieldArray } from 'formik';
import * as Yup from 'yup';
import { MyTextInput, BottomDropdown, MyText, useTheme, DatePicker, tw, useFocusCallback, Checkbox, ImageUploaderNeo, ImageUploaderNeoItem, ImageUploaderNeoPayload } from 'common-ui';
import MaterialIcons from '@expo/vector-icons/MaterialIcons';
import { trpc } from '../trpc-client';

interface ProductFormData {
  name: string;
  shortDescription: string;
  longDescription: string;
  unitId: number;
  storeId: number;
  price: string;
  marketPrice: string;
  isSuspended: boolean;
  isFlashAvailable: boolean;
  flashPrice: string;
  deals: Deal[];
    tagIds: number[];
    productQuantity: number;
}

interface Deal {
  quantity: string;
  price: string;
  validTill: Date | null;
}

export interface ProductFormRef {
  clearImages: () => void;
}

interface ProductFormProps {
  mode: 'create' | 'edit';
  initialValues: ProductFormData;
  onSubmit: (values: ProductFormData, images: ImageUploaderNeoPayload[], imagesToDelete: string[]) => void;
  isLoading: boolean;
  existingImages?: ImageUploaderNeoItem[];
  existingImageKeys?: string[];
}

const unitOptions = [
  { label: 'Kg', value: 1 },
  { label: 'Litre', value: 2 },
  { label: 'Dozen', value: 3 },
  { label: 'Unit Piece', value: 4 },
];

const ProductForm = forwardRef<ProductFormRef, ProductFormProps>(({
  mode,
  initialValues,
  onSubmit,
  isLoading,
  existingImages = [],
  existingImageKeys = [],
}, ref) => {
  const { theme } = useTheme();
  const [images, setImages] = useState<ImageUploaderNeoItem[]>(existingImages);

  // Sync images state when existingImages prop changes (e.g., when async query data arrives)
  useEffect(() => {
    setImages(existingImages);
  }, [existingImages]);

  const { data: storesData } = trpc.common.getStoresSummary.useQuery();
  const storeOptions = storesData?.stores.map(store => ({
    label: store.name,
    value: store.id,
  })) || [];

  const { data: tagsData } = trpc.admin.product.getProductTags.useQuery();
  const tagOptions = tagsData?.tags.map(tag => ({
    label: tag.tagName,
    value: tag.id.toString(),
  })) || [];

  // Build signed URL -> S3 key mapping for existing images
  const signedUrlToKey = useMemo(() => {
    const map: Record<string, string> = {};
    existingImages.forEach((img, i) => {
      if (existingImageKeys[i]) {
        map[img.imgUrl] = existingImageKeys[i];
      }
    });
    return map;
  }, [existingImages, existingImageKeys]);

  return (
    <Formik
      initialValues={initialValues}
      onSubmit={(values) => {
        // New images have mimeType set, existing images have mimeType === null
        const newImages = images.filter(img => img.mimeType !== null);
        const deletedImageKeys = existingImages
          .filter(existing => !images.some(current => current.imgUrl === existing.imgUrl))
          .map(deleted => signedUrlToKey[deleted.imgUrl])
          .filter(Boolean);

        onSubmit(
          values,
          newImages.map(img => ({ url: img.imgUrl, mimeType: img.mimeType })),
          deletedImageKeys,
        );
      }}
      enableReinitialize
    >
      {({ handleChange, handleSubmit, values, setFieldValue, resetForm }) => {
        const clearForm = useCallback(() => {
          setImages([]);
          resetForm();
        }, [resetForm]);

        useFocusCallback(clearForm);

        useImperativeHandle(ref, () => ({
          clearImages: clearForm,
        }), [clearForm]);

        const submit = () => handleSubmit();

        return (
          <View>
            <MyTextInput
              topLabel="Product Name"
              placeholder="Enter product name"
              value={values.name}
              onChangeText={handleChange('name')}
              style={{ marginBottom: 16 }}
            />
            <MyTextInput
              topLabel="Short Description"
              placeholder="Enter short description"
              multiline
              numberOfLines={2}
              value={values.shortDescription}
              onChangeText={handleChange('shortDescription')}
              style={{ marginBottom: 16 }}
            />
            <MyTextInput
              topLabel="Long Description"
              placeholder="Enter detailed description"
              multiline
              numberOfLines={4}
              value={values.longDescription}
              onChangeText={handleChange('longDescription')}
              style={{ marginBottom: 16 }}
            />

            <ImageUploaderNeo
              images={images}
              onImageAdd={(payloads) => setImages(prev => [...prev, ...payloads.map(p => ({ imgUrl: p.url, mimeType: p.mimeType }))])}
              onImageRemove={(payload) => setImages(prev => prev.filter(img => img.imgUrl !== payload.url))}
              allowMultiple={true}
            />

            <BottomDropdown
              topLabel='Unit'
              label="Unit"
              value={values.unitId}
              options={unitOptions}
              onValueChange={(value) => setFieldValue('unitId', value)}
              placeholder="Select unit"
              style={{ marginBottom: 16 }}
            />
            <MyTextInput
              topLabel="Product Quantity"
              placeholder="Enter product quantity"
              keyboardType="numeric"
              value={values.productQuantity.toString()}
              onChangeText={(text) => setFieldValue('productQuantity', text)}
              style={{ marginBottom: 16 }}
            />
            <BottomDropdown
              topLabel="Store"
              label="Store"
              value={values.storeId}
              options={storeOptions}
              onValueChange={(value) => setFieldValue('storeId', value)}
              placeholder="Select store"
              style={{ marginBottom: 16 }}
            />
            <BottomDropdown
              topLabel="Tags"
              label="Tags"
              value={values.tagIds.map(id => id.toString())}
              options={tagOptions}
              onValueChange={(value) => setFieldValue('tagIds', (value as string[]).map(id => parseInt(id)))}
              multiple={true}
              placeholder="Select tags"
              style={{ marginBottom: 16 }}
            />
            <MyTextInput
              topLabel="Unit Price"
              placeholder="Enter unit price"
              keyboardType="numeric"
              value={values.price}
              onChangeText={handleChange('price')}
              style={{ marginBottom: 16 }}
            />
             <MyTextInput
               topLabel="Market Price (Optional)"
               placeholder="Enter market price"
               keyboardType="numeric"
               value={values.marketPrice}
               onChangeText={handleChange('marketPrice')}
               style={{ marginBottom: 16 }}
             />

              <View style={tw`flex-row items-center mb-4`}>
               <Checkbox
                 checked={values.isSuspended}
                 onPress={() => setFieldValue('isSuspended', !values.isSuspended)}
                 style={tw`mr-3`}
               />
               <MyText style={tw`text-gray-700 font-medium`}>Suspend Product</MyText>
             </View>

             <View style={tw`flex-row items-center mb-4`}>
               <Checkbox
                 checked={values.isFlashAvailable}
                 onPress={() => {
                   setFieldValue('isFlashAvailable', !values.isFlashAvailable);
                   if (values.isFlashAvailable) setFieldValue('flashPrice', '');
                 }}
                 style={tw`mr-3`}
               />
               <MyText style={tw`text-gray-700 font-medium`}>Flash Available</MyText>
             </View>

             {values.isFlashAvailable && (
               <MyTextInput
                 topLabel="Flash Price"
                 placeholder="Enter flash price"
                 keyboardType="numeric"
                 value={values.flashPrice}
                 onChangeText={handleChange('flashPrice')}
                 style={{ marginBottom: 16 }}
               />
             )}

             <TouchableOpacity
               onPress={submit}
               disabled={isLoading}
               style={tw`px-4 py-2 rounded-lg shadow-lg items-center mt-2 ${isLoading ? 'bg-gray-400' : 'bg-blue-500'}`}
             >
              <MyText style={tw`text-white text-lg font-bold`}>
                {isLoading ? (mode === 'create' ? 'Creating...' : 'Updating...') : (mode === 'create' ? 'Create Product' : 'Update Product')}
              </MyText>
            </TouchableOpacity>
          </View>
        );
      }}
    </Formik>
  );
});

ProductForm.displayName = 'ProductForm';

export default ProductForm;