feat: 장바구니 담기 기능 및 도서 상세 페이지 개선

주요 변경 사항
- 장바구니 담기 API를 추가했습니다.
- useBook hook을 수정하여 장바구니 담기 기능과 상태 관리를 추가했습니다.
- AddToCart 컴포넌트를 생성하여 장바구니 담기 폼 구현했습니다.
- 도서 상세 페이지에 AddToCart 컴포넌트를 추가하여 장바구니 담기 기능을 제공했습니다.

관련 변경 사항
- cart.api.ts 파일 생성
- AddToCart.tsx 파일 생성
- useBook.ts 파일 수정
- BookDetail.tsx 파일 수정

client/src/api/cart.api.ts

@@ -0,0 +1,14 @@
+import { httpClient } from "./http";
+
+interface AddCartParams {
+	book_id: number;
+	quantity: number;
+}
+
+const addCart = async (params: AddCartParams) => {
+	const response = await httpClient.post('/cart', params)
+
+	return response.data
+};
+
+export default addCart;

client/src/components/book/AddToCart.tsx

@@ -0,0 +1,80 @@
+import { useState } from "react";
+import { Link } from "react-router-dom";
+import styled from "styled-components";
+import { useBook } from "../../hooks/useBook";
+import { BookDetail } from "../../models/book.model";
+import Button from "../common/Button";
+import { InputText } from "../common/InputText";
+
+interface Props {
+	book: BookDetail;
+}
+
+const AddToCart = ({ book }: Props) => {
+	const [quantity, setQuantity] = useState<number>(1)
+	const { addToCart, cartAdded } = useBook(book.id.toString());
+
+	const handleChange = (e: React.ChangeEvent<HTMLInputElement>) => {
+		setQuantity(Number(e.target.value))
+	}
+
+	const handleIncrease = () => {
+		setQuantity(quantity + 1)
+	}
+
+	const handleDecrease = () => {
+		if (quantity === 1) return
+		setQuantity(quantity - 1)
+	}
+
+	return (
+		<AddToCartStyle $added={cartAdded}>
+			<div>
+				<InputText inputType="number" value={quantity} onChange={handleChange}/>
+				<Button size="medium" scheme="normal" onClick={handleIncrease}>
+					+
+				</Button>
+				<Button size="medium" scheme="normal" onClick={handleDecrease}>
+					-
+				</Button>
+			</div>
+			<Button size="medium" scheme="primary" onClick={() => addToCart(quantity)}>
+				장바구니 담기
+			</Button>
+				<div className="added">
+					<p>장바구니에 추가되었습니다.</p>
+					<Link to="/cart">장바구니 이동</Link>
+				</div>
+		</AddToCartStyle>
+	);
+}
+
+interface AddToCartStyleProps {
+	$added: boolean;
+}
+
+const AddToCartStyle = styled.div<AddToCartStyleProps>`
+	display: flex;
+	justify-content: space-between;
+	align-items: center;
+
+	position: relative;
+
+	.added {
+		position: absolute;
+		right: 0;
+		bottom: -90px;
+		background: ${({ theme }) => theme.color.background};
+		border-radius: ${({ theme }) => theme.borderRadius.default};
+		padding: 8px 12px;
+		opacity: ${({ $added }) => $added ? "1" : "0"};
+		transition: all 0.5s ease;
+	}
+
+	p {
+		padding: 0 0 8px 0;
+		margin: 0;
+	}
+`;
+
+export default AddToCart;

client/src/hooks/useBook.ts

@@ -1,5 +1,6 @@
 import { useEffect, useState } from "react";
 import { fetchBook, likeBook, unlikeBook } from "../api/books.api";
+import addCart from "../api/cart.api";
 import { BookDetail } from "../models/book.model";
 import { useAuthStore } from "../store/authStore";
 import { useAlert } from "./useAlert";
@@ -8,6 +9,7 @@ export const useBook = (bookId: string | undefined) => {
 	const [book, setBook] = useState<BookDetail | null>(null);
 	const { isLoggedIn } = useAuthStore();
 	const showAlert = useAlert();
+	const [cartAdded, setCartAdded] = useState(false)
 
 	const likeToggle = () => {
 		if (!isLoggedIn) {
@@ -36,6 +38,20 @@ export const useBook = (bookId: string | undefined) => {
 		}
 	}
 
+	const addToCart = (quantity: number) => {
+		if (!book) return
+
+		addCart({
+			book_id: book.id,
+			quantity: quantity
+		}).then(() => {
+			setCartAdded(true)
+			setTimeout(() => {
+				setCartAdded(false)
+			}, 3000)
+		})
+	}
+
 	useEffect(() => {
 		if (!bookId) return;
 
@@ -44,5 +60,5 @@ export const useBook = (bookId: string | undefined) => {
 		})
 	}, [bookId])
 
-	return { book, likeToggle }
+	return { book, likeToggle, addToCart, cartAdded }
 }

client/src/pages/BookDetail.tsx

@@ -1,5 +1,6 @@
 import { Link, useParams } from "react-router-dom";
 import styled from "styled-components";
+import AddToCart from "../components/book/AddToCart";
 import LikeButton from "../components/book/LikeButton";
 import EllipsisBox from "../components/common/EllipisisBox";
 import Title from "../components/common/Title";
@@ -77,7 +78,9 @@ const BookDetail = () => {
           <div className="like">
             <LikeButton book={book} onClick={likeToggle} />
           </div>
-          <div className="add-cart">Cart</div>
+          <div className="add-cart">
+            <AddToCart book={book}/>
+          </div>
         </div>
       </header>
       <div className="content">