[BE] 변경된 요구사항에 맞게 API 전체 수정

server/src/main/java/server/haengdong/application/BillService.java

@@ -0,0 +1,177 @@
+package server.haengdong.application;
+
+import java.util.ArrayList;
+import java.util.List;
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+import server.haengdong.application.request.BillAppRequest;
+import server.haengdong.application.request.BillDetailUpdateAppRequest;
+import server.haengdong.application.request.BillDetailsUpdateAppRequest;
+import server.haengdong.application.request.BillUpdateAppRequest;
+import server.haengdong.application.response.BillDetailsAppResponse;
+import server.haengdong.application.response.LastBillMemberAppResponse;
+import server.haengdong.application.response.StepAppResponse;
+import server.haengdong.domain.action.Bill;
+import server.haengdong.domain.action.BillDetail;
+import server.haengdong.domain.action.BillRepository;
+import server.haengdong.domain.action.Member;
+import server.haengdong.domain.action.MemberRepository;
+import server.haengdong.domain.event.Event;
+import server.haengdong.domain.event.EventRepository;
+import server.haengdong.exception.HaengdongErrorCode;
+import server.haengdong.exception.HaengdongException;
+
+@RequiredArgsConstructor
+@Transactional(readOnly = true)
+@Service
+public class BillService {
+
+    private final BillRepository billRepository;
+    private final EventRepository eventRepository;
+    private final MemberRepository memberRepository;
+
+    @Transactional
+    public void saveBill(String eventToken, BillAppRequest request) {
+        Event event = getEvent(eventToken);
+        List<Long> memberIds = request.memberIds();
+        List<Member> members = memberIds.stream()
+                .map(this::findMember)
+                .toList();
+
+        Bill bill = request.toBill(event, members);
+        billRepository.save(bill);
+    }
+
+    private Member findMember(Long memberId) {
+        return memberRepository.findById(memberId)
+                .orElseThrow(() -> new HaengdongException(HaengdongErrorCode.MEMBER_NOT_FOUND));
+    }
+
+    public List<StepAppResponse> findSteps(String token) {
+        Event event = getEvent(token);
+        List<Bill> bills = billRepository.findByEvent(event);
+
+        return createStepAppResponses(bills);
+    }
+
+    private List<StepAppResponse> createStepAppResponses(List<Bill> bills) {
+        return divideByMembers(bills).stream()
+                .map(StepAppResponse::of)
+                .toList();
+    }
+
+    private static List<List<Bill>> divideByMembers(List<Bill> bills) {
+        List<List<Bill>> split = new ArrayList<>();
+        for (Bill bill : bills) {
+            if (split.isEmpty()) {
+                List<Bill> temp = new ArrayList<>();
+                temp.add(bill);
+                split.add(temp);
+                continue;
+            }
+            List<Bill> bills1 = split.get(split.size() - 1);
+            Bill find = bills1.get(0);
+            if (find.isSameMembers(bill)) {
+                bills1.add(bill);
+            } else {
+                List<Bill> temp = new ArrayList<>();
+                temp.add(bill);
+                split.add(temp);
+            }
+        }
+        return split;
+    }
+
+    @Transactional
+    public void updateBill(String token, Long billId, BillUpdateAppRequest request) {
+        Bill bill = getBill(billId);
+
+        validateToken(token, bill);
+
+        bill.update(request.title(), request.price());
+    }
+
+    private void validateToken(String token, Bill bill) {
+        Event event = bill.getEvent();
+        if (event.isTokenMismatch(token)) {
+            throw new HaengdongException(HaengdongErrorCode.BILL_NOT_FOUND);
+        }
+    }
+
+    @Transactional
+    public void deleteBill(String token, Long billId) {
+        Bill bill = getBill(billId);
+        validateToken(token, bill);
+        billRepository.deleteById(billId);
+    }
+
+    public BillDetailsAppResponse findBillDetails(String token, Long billId) {
+        Bill bill = billRepository.findById(billId)
+                .orElseThrow(() -> new HaengdongException(HaengdongErrorCode.BILL_NOT_FOUND));
+        validateToken(token, bill);
+
+        List<BillDetail> billDetails = bill.getBillDetails();
+        return BillDetailsAppResponse.of(billDetails);
+    }
+
+    @Transactional
+    public void updateBillDetails(String token, Long billId, BillDetailsUpdateAppRequest request) {
+        Bill bill = billRepository.findById(billId)
+                .orElseThrow(() -> new HaengdongException(HaengdongErrorCode.BILL_NOT_FOUND));
+
+        List<BillDetailUpdateAppRequest> billDetailUpdateAppRequests = request.billDetailUpdateAppRequests();
+
+        validateToken(token, bill);
+        validateBillDetailSize(billDetailUpdateAppRequests, bill);
+        validateTotalPrice(billDetailUpdateAppRequests, bill);
+
+        List<BillDetail> billDetails = bill.getBillDetails();
+
+        for (BillDetailUpdateAppRequest updateRequest : billDetailUpdateAppRequests) {
+            BillDetail detailToUpdate = billDetails.stream()
+                    .filter(detail -> detail.isSameId(updateRequest.id()))
+                    .findFirst()
+                    .orElseThrow(() -> new HaengdongException(HaengdongErrorCode.BILL_DETAIL_NOT_FOUND));
+
+            detailToUpdate.updatePrice(updateRequest.price());
+            detailToUpdate.updateIsFixed(updateRequest.isFixed());
+        }
+    }
+
+    private void validateBillDetailSize(List<BillDetailUpdateAppRequest> requests, Bill bill) {
+        List<Long> ids = requests.stream()
+                .map(BillDetailUpdateAppRequest::id)
+                .distinct()
+                .toList();
+        if (bill.getBillDetails().size() != ids.size()) {
+            throw new HaengdongException(HaengdongErrorCode.BILL_DETAIL_NOT_FOUND);
+        }
+    }
+
+    private void validateTotalPrice(
+            List<BillDetailUpdateAppRequest> billDetailUpdateAppRequests,
+            Bill bill
+    ) {
+        Long requestsPriceSum = calculateUpdatePriceSum(billDetailUpdateAppRequests);
+        if (!bill.isSamePrice(requestsPriceSum)) {
+            throw new HaengdongException(HaengdongErrorCode.BILL_PRICE_NOT_MATCHED);
+        }
+    }
+
+    private Long calculateUpdatePriceSum(List<BillDetailUpdateAppRequest> billDetailUpdateAppRequests) {
+        return billDetailUpdateAppRequests.stream()
+                .map(BillDetailUpdateAppRequest::price)
+                .reduce(0L, Long::sum);
+    }
+
+    private Event getEvent(String eventToken) {
+        return eventRepository.findByToken(eventToken)
+                .orElseThrow(() -> new HaengdongException(HaengdongErrorCode.EVENT_NOT_FOUND));
+    }
+
+    private Bill getBill(Long billId) {
+        return billRepository.findById(billId)
+                .orElseThrow(() -> new HaengdongException(HaengdongErrorCode.BILL_NOT_FOUND));
+    }
+}