[Refactor/Bugfix] Expense, Member 구조 개선 및 UI 업데이트

Data/Sources/DTO/Expense/Request/CreateExpenseRequestDTO.swift

@@ -13,27 +13,7 @@ public struct CreateExpenseRequestDTO: Encodable {
     let amount: Double
     let currency: String
     let expenseDate: String
+    let payerId: String
     let category: String
     let participantIds: [String]
 }
-
-extension Expense {
-    func toCreateRequestDTO() -> CreateExpenseRequestDTO {
-        // yyyy-MM-dd 형식으로 날짜 변환 (사용자가 선택한 날짜 그대로 전송)
-        let dateFormatter = DateFormatter()
-        dateFormatter.dateFormat = "yyyy-MM-dd"
-        dateFormatter.calendar = Calendar(identifier: .gregorian)
-        dateFormatter.locale = Locale(identifier: "en_US_POSIX")
-        // Plain date는 timezone 변환하지 않음 (기본값 = TimeZone.current)
-        let dateString = dateFormatter.string(from: expenseDate)
-
-        return CreateExpenseRequestDTO(
-            title: title,
-            amount: amount,
-            currency: currency,
-            expenseDate: dateString,
-            category: category.rawValue,
-            participantIds: participants.map { $0.id }
-        )
-    }
-}

Data/Sources/DTO/Expense/Request/UpdateExpenseRequestDTO.swift

@@ -17,25 +17,3 @@ public struct UpdateExpenseRequestDTO: Encodable {
     let payerId: String
     let participantIds: [String]
 }
-
-extension Expense {
-    func toUpdateRequestDTO() -> UpdateExpenseRequestDTO {
-        // yyyy-MM-dd 형식으로 날짜 변환 (사용자가 선택한 날짜 그대로 전송)
-        let dateFormatter = DateFormatter()
-        dateFormatter.dateFormat = "yyyy-MM-dd"
-        dateFormatter.calendar = Calendar(identifier: .gregorian)
-        dateFormatter.locale = Locale(identifier: "en_US_POSIX")
-        // Plain date는 timezone 변환하지 않음 (기본값 = TimeZone.current)
-        let dateString = dateFormatter.string(from: expenseDate)
-
-        return UpdateExpenseRequestDTO(
-            title: title,
-            amount: amount,
-            currency: currency,
-            expenseDate: dateString,
-            category: category.rawValue,
-            payerId: payerId,
-            participantIds: participants.map { $0.id }
-        )
-    }
-}

Data/Sources/DTO/Expense/Response/TravelExpenseResponseDTO.swift

@@ -16,23 +16,9 @@ public struct ExpenseDTO: Codable {
     let convertedAmount: Double
     let expenseDate: String
     let category: String
-    let payerId: String
-    let payerName: String
+    let payer: MemberDTO
     let authorId: String
-    let participants: [ParticipantDTO]
-
-    struct ParticipantDTO: Codable {
-        let memberId: String
-        let name: String
-
-        func toDomain() -> TravelMember {
-            TravelMember(
-                id: memberId,
-                name: name,
-                role: .member
-            )
-        }
-    }
+    let expenseMembers: [MemberDTO]
 
     func toDomain() -> Expense? {
         // yyyy-MM-dd 날짜 파싱 (서버에서 받은 날짜 그대로 사용)
@@ -50,7 +36,7 @@ public struct ExpenseDTO: Codable {
         let expenseCategory = ExpenseCategory(rawValue: category) ?? .other
 
         // Participant 변환
-        let members = participants.map { $0.toDomain() }
+        let members = expenseMembers.map { $0.toDomain() }
 
         return Expense(
             id: id,
@@ -60,8 +46,7 @@ public struct ExpenseDTO: Codable {
             convertedAmount: convertedAmount,
             expenseDate: date,
             category: expenseCategory,
-            payerId: payerId,
-            payerName: payerName,
+            payer: payer.toDomain(),
             participants: members
         )
     }

Data/Sources/DTO/Member/FetchMemberResponseDTO.swift

@@ -9,28 +9,8 @@ import Foundation
 import Domain
 
 public struct FetchMemberResponseDTO: Decodable {
-    let currentUser: MemberInfo
-    let members: [MemberInfo]
-
-    struct MemberInfo: Decodable {
-        let userId: String
-        let name: String
-        let email: String?
-        let role: String
-        let avatarUrl: String?
-    }
-}
-
-private extension FetchMemberResponseDTO.MemberInfo {
-    func toDomain() -> TravelMember {
-        TravelMember(
-            id: userId,
-            name: name,
-            role: MemberRole(rawValue: role.lowercased()) ?? .member,
-            email: email,
-            avatarUrl: avatarUrl
-        )
-    }
+    let currentUser: MemberDTO
+    let members: [MemberDTO]
 }
 
 extension FetchMemberResponseDTO {

Data/Sources/DTO/Member/MemberDTO.swift

@@ -0,0 +1,29 @@
+//
+//  TravelMemberDTO.swift
+//  Data
+//
+//  Created by 홍석현 on 12/12/25.
+//
+
+import Foundation
+import Domain
+
+public struct MemberDTO: Codable {
+    let userId: String
+    let name: String
+    let email: String?
+    let role: String?
+    let avatarUrl: String?
+}
+
+public extension MemberDTO {
+    func toDomain() -> TravelMember {
+        TravelMember(
+            id: userId,
+            name: name,
+            role: MemberRole(value: role),
+            email: email,
+            avatarUrl: avatarUrl
+        )
+    }
+}

Data/Sources/Repository/Expense/ExpenseRepository.swift

@@ -56,14 +56,31 @@ public final class ExpenseRepository: ExpenseRepositoryProtocol {
         }
     }
 
-    public func save(travelId: String, expense: Expense) async throws {
-        let requestDTO = expense.toCreateRequestDTO()
+    public func save(travelId: String, input: ExpenseInput) async throws {
+        let requestDTO = CreateExpenseRequestDTO(
+            title: input.title,
+            amount: input.amount,
+            currency: input.currency,
+            expenseDate: input.formatExpenseDate(),
+            payerId: input.payerId,
+            category: input.category.rawValue,
+            participantIds: input.participantIds
+        )
+
         try await remote.createExpense(travelId: travelId, body: requestDTO)
     }
 
-    public func update(travelId: String, expense: Expense) async throws {
-        let requestDTO = expense.toUpdateRequestDTO()
-        try await remote.updateExpense(travelId: travelId, expenseId: expense.id, body: requestDTO)
+    public func update(travelId: String, expenseId: String, input: ExpenseInput) async throws {
+        let requestDTO = UpdateExpenseRequestDTO(
+            title: input.title,
+            amount: input.amount,
+            currency: input.currency,
+            expenseDate: input.formatExpenseDate(),
+            category: input.category.rawValue,
+            payerId: input.payerId,
+            participantIds: input.participantIds
+        )
+        try await remote.updateExpense(travelId: travelId, expenseId: expenseId, body: requestDTO)
     }
 
     public func delete(travelId: String, expenseId: String) async throws {