fix: duplicate email creation and added balance update

src/main/java/com/example/expencetrackerapi/dto/request/UpdateAccountRequest.java

@@ -1,11 +1,14 @@
 package com.example.expencetrackerapi.dto.request;
 
 import jakarta.validation.constraints.Email;
+import jakarta.validation.constraints.Positive;
 import jakarta.validation.constraints.Size;
 import lombok.AllArgsConstructor;
 import lombok.Data;
 import lombok.NoArgsConstructor;
 
+import java.math.BigDecimal;
+
 @Data
 @NoArgsConstructor
 @AllArgsConstructor
@@ -14,5 +17,9 @@ public class UpdateAccountRequest {
   @Size(min = 2, max = 100, message = "Name must be between 2 and 100 characters")
   private String fullName;
 
-  @Email private String email;
+    @Email
+    private String email;
+
+    @Positive
+    private BigDecimal currentBalance;
 }

src/main/java/com/example/expencetrackerapi/repository/AccountRepository.java

@@ -2,5 +2,9 @@
 
 import com.example.expencetrackerapi.entity.Account;
 import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
 
-public interface AccountRepository extends JpaRepository<Account, Long> {}
+@Repository
+public interface AccountRepository extends JpaRepository<Account, Long> {
+    Account findAccountByEmail(String email);
+}

src/main/java/com/example/expencetrackerapi/service/AccountService.java

@@ -8,60 +8,85 @@
 import com.example.expencetrackerapi.exception.ResourceNotFoundException;
 import com.example.expencetrackerapi.mapper.AccountMapper;
 import com.example.expencetrackerapi.repository.AccountRepository;
+import org.springframework.stereotype.Service;
+
 import java.util.ArrayList;
 import java.util.List;
-import org.springframework.stereotype.Service;
 
 @Service
 public class AccountService {
-  private final AccountRepository accountRepository;
-  private final AccountMapper accountMapper;
+    private final AccountRepository accountRepository;
+    private final AccountMapper accountMapper;
+
+    public AccountService(AccountRepository accountRepository, AccountMapper accountMapper) {
+        this.accountRepository = accountRepository;
+        this.accountMapper = accountMapper;
+    }
+
+    public List<AccountResponseSummary> findAll() {
+        List<Account> accounts = accountRepository.findAll();
+        List<AccountResponseSummary> summary = new ArrayList<>();
+
+        for (Account account : accounts) {
+            summary.add(accountMapper.toSummary(account));
+        }
+        return summary;
+    }
+
+    public Account findById(Long id) {
+        return accountRepository
+                .findById(id)
+                .orElseThrow(() -> new ResourceNotFoundException("Account not found with this id: " + id));
+    }
 
-  public AccountService(AccountRepository accountRepository, AccountMapper accountMapper) {
-    this.accountRepository = accountRepository;
-    this.accountMapper = accountMapper;
-  }
+    public AccountResponse create(CreateAccountRequest request) {
+        checkEmailExists(request.getEmail());
 
-  public List<AccountResponseSummary> findAll() {
-    List<Account> accounts = accountRepository.findAll();
-    List<AccountResponseSummary> summary = new ArrayList<>();
+        Account account = new Account();
+        account.setEmail(request.getEmail());
+        account.setFullName(request.getFullName());
+        account.setCurrentBalance(request.getCurrentBalance());
+        accountRepository.save(account);
 
-    for (Account account : accounts) {
-      summary.add(accountMapper.toSummary(account));
+        return accountMapper.toResponse(account);
     }
-    return summary;
-  }
-
-  public Account findById(Long id) {
-    return accountRepository
-        .findById(id)
-        .orElseThrow(() -> new ResourceNotFoundException("Account not found with this id: " + id));
-  }
-
-  public AccountResponse create(CreateAccountRequest request) {
-    Account account = new Account();
-    account.setEmail(request.getEmail());
-    account.setFullName(request.getFullName());
-    account.setCurrentBalance(request.getCurrentBalance());
-    accountRepository.save(account);
-
-    return accountMapper.toResponse(account);
-  }
-
-  public AccountResponse update(Long id, UpdateAccountRequest request) {
-    Account account = findById(id);
-    if (request.getEmail() != null) {
-      account.setEmail(request.getEmail());
+
+    public AccountResponse update(Long id, UpdateAccountRequest request) {
+        checkEmailExists(request.getEmail());
+
+        Account account = findById(id);
+        if (request.getEmail() != null) {
+            account.setEmail(request.getEmail());
+        }
+        if (request.getFullName() != null) {
+            account.setFullName(request.getFullName());
+        }
+        if (request.getCurrentBalance() != null) {
+            account.setCurrentBalance(request.getCurrentBalance());
+        }
+
+        if (request.getFullName() != null) {
+            account.setFullName(request.getFullName());
+
+        }
+        accountRepository.save(account);
+        return accountMapper.toResponse(account);
+    }
+
+    public void checkEmailExists(String email) {
+        Account account = accountRepository.findAccountByEmail(email);
+
+        if (account == null) {
+            return;
+        } else {
+            throw new IllegalArgumentException("Account with this email exists");
+        }
     }
-    if (request.getFullName() != null) {
-      account.setFullName(request.getFullName());
+
+    public void delete(Long id) {
+        Account account = findById(id);
+        accountRepository.delete(account);
     }
-    accountRepository.save(account);
-    return accountMapper.toResponse(account);
-  }
-
-  public void delete(Long id) {
-    Account account = findById(id);
-    accountRepository.delete(account);
-  }
 }
+
+