text: import React, { useState, useEffect } from "react";
  import { Link } from "react-router-dom";
  import { Form, Button } from "react-bootstrap";
  import { useSelector } from "react-redux";
  import Message from "../components/Message";
  import Loader from "../components/Loader";
  import FormContainer from "../components/FormContainer";
  import { useMutation, useQuery } from "react-query";
  import {
    fetchProduct,
    updateProduct,
    uploadImage,
  } from "../services/productServices";
  
  const ProductEditScreen = ({ match, history }) => {
    const productId = match.params.id;
  
    const [name, setName] = useState("");
    const [price, setPrice] = useState(0);
    const [image, setImage] = useState("");
    const [brand, setBrand] = useState("");
    const [category, setCategory] = useState("");
    const [countInStock, setCountInStock] = useState(0);
    const [description, setDescription] = useState("");
    const [uploading, setUploading] = useState(false);
    const [validationError, setValidationError] = useState("");
  
    const { data: product, isLoading, isError, error } = useQuery(
      ["product", match.params.id],
      fetchProduct
    );
    const userLogin = useSelector((state) => state.userLogin);
    const { userInfo } = userLogin;
  
    const productUpdateMut = useMutation(updateProduct, {
      onSuccess: (data, variable, con) => {
        history.push("/admin/productlist");
      },
    });
  
    const uploadImageMut = useMutation(uploadImage, {
      onMutate: () => {
        setUploading(true);
      },
      onError: () => {
        setUploading(false);
      },
      onSuccess: (data) => {
        setUploading(false);
        setImage(data);
        setUploading(false);
      },
    });
  
    const uploadFileHandler = async (e) => {
      const image = e.target.files[0];
      uploadImageMut.mutate({ image, token: userInfo.token });
    };
    useEffect(() => {
      if (product) {
        setName(product.name);
        setPrice(product.price);
        setImage(product.image);
        setBrand(product.brand);
        setCategory(product.category);
        setCountInStock(product.countInStock);
        setDescription(product.description);
      }
    }, [product]);
  
    const submitHandler = (e) => {
      e.preventDefault();
  
      if (countInStock < 0) {
        setValidationError("Invalid stock");
        return;
      }
  
      productUpdateMut.mutate({
        product: {
          _id: productId,
          name,
          price,
          image,
          brand,
          category,
          description,
          countInStock,
        },
        token: userInfo.token,
      });
    };
  
    return (
      <>
        <Link to="/admin/productlist" className="btn btn-light my-3">
          Go Back
        </Link>
        <FormContainer>
          <h1>Edit Product</h1>
          {productUpdateMut.isLoading && <Loader />}
          {productUpdateMut.isError && (
            <Message variant="danger">{productUpdateMut.error.message}</Message>
          )}
          {validationError && (
            <Message variant="danger">{validationError}</Message>
          )}
          {isLoading ? (
            <Loader />
          ) : isError ? (
            <Message variant="danger">{error.message}</Message>
          ) : (
            <Form onSubmit={submitHandler}>
              <Form.Group controlId="name">
                <Form.Label>Name</Form.Label>
                <Form.Control
                  type="name"
                  placeholder="Enter name"
                  value={name}
                  onChange={(e) => setName(e.target.value)}
                ></Form.Control>
              </Form.Group>
  
              <Form.Group controlId="price">
                <Form.Label>Price</Form.Label>
                <Form.Control
                  type="number"
                  placeholder="Enter price"
                  value={price}
                  onChange={(e) => setPrice(e.target.value)}
                ></Form.Control>
              </Form.Group>
  
              <Form.Group controlId="image">
                <Form.Label>Image</Form.Label>
                <Form.Control
                  type="text"
                  placeholder="Enter image url"
                  value={image}
                  onChange={(e) => setImage(e.target.value)}
                ></Form.Control>
                <Form.File
                  id="image-file"
                  label="Choose File"
                  custom
                  onChange={uploadFileHandler}
                ></Form.File>
                {uploading && <Loader />}
              </Form.Group>
  
              <Form.Group controlId="brand">
                <Form.Label>Brand</Form.Label>
                <Form.Control
                  type="text"
                  placeholder="Enter brand"
                  value={brand}
                  onChange={(e) => setBrand(e.target.value)}
                ></Form.Control>
              </Form.Group>
  
              <Form.Group controlId="countInStock">
                <Form.Label>Count In Stock</Form.Label>
                <Form.Control
                  type="number"
                  placeholder="Enter countInStock"
                  value={countInStock}
                  onChange={(e) => setCountInStock(e.target.value)}
                ></Form.Control>
              </Form.Group>
  
              <Form.Group controlId="category">
                <Form.Label>Category</Form.Label>
                <Form.Control
                  type="text"
                  placeholder="Enter category"
                  value={category}
                  onChange={(e) => setCategory(e.target.value)}
                ></Form.Control>
              </Form.Group>
  
              <Form.Group controlId="description">
                <Form.Label>Description</Form.Label>
                <Form.Control
                  type="text"
                  placeholder="Enter description"
                  value={description}
                  onChange={(e) => setDescription(e.target.value)}
                ></Form.Control>
              </Form.Group>
  
              <Button type="submit" variant="primary">
                Update
              </Button>
            </Form>
          )}
        </FormContainer>
      </>
    );
  };
  
  export default ProductEditScreen;
  