feat: implement CardService

src/main/java/com/example/bankcards/service/CardService.java

@@ -0,0 +1,175 @@
+package com.example.bankcards.service;
+
+import com.example.bankcards.dto.CardResponse;
+import com.example.bankcards.dto.CreateCardRequest;
+import com.example.bankcards.dto.TransferRequest;
+import com.example.bankcards.entity.Card;
+import com.example.bankcards.entity.CardStatus;
+import com.example.bankcards.entity.User;
+import com.example.bankcards.exception.AccessDeniedException;
+import com.example.bankcards.exception.BadRequestException;
+import com.example.bankcards.exception.ResourceNotFoundException;
+import com.example.bankcards.repository.CardRepository;
+import com.example.bankcards.repository.UserRepository;
+import com.example.bankcards.util.CardEncryptionUtil;
+import lombok.RequiredArgsConstructor;
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.Pageable;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+@Service
+@RequiredArgsConstructor
+public class CardService {
+
+    private final CardRepository cardRepository;
+    private final UserRepository userRepository;
+    private final CardEncryptionUtil encryptionUtil;
+
+    public CardResponse createCard(CreateCardRequest request) {
+        User owner = userRepository
+            .findById(request.getOwnerId())
+            .orElseThrow(() ->
+                new ResourceNotFoundException(
+                    "User not found: " + request.getOwnerId()
+                )
+            );
+
+        String encrypted = encryptionUtil.encrypt(request.getCardNumber());
+        Card card = Card.builder()
+            .cardNumberEncrypted(encrypted)
+            .owner(owner)
+            .expiryDate(request.getExpiryDate())
+            .status(CardStatus.ACTIVE)
+            .balance(request.getInitialBalance())
+            .build();
+        return toResponse(cardRepository.save(card));
+    }
+
+    public Page<CardResponse> getAllCards(Pageable pageable) {
+        return cardRepository.findAll(pageable).map(this::toResponse);
+    }
+
+    public Page<CardResponse> getMyCards(
+        String username,
+        CardStatus status,
+        Pageable pageable
+    ) {
+        User user = userRepository
+            .findByUsername(username)
+            .orElseThrow(() -> new ResourceNotFoundException("User not found"));
+        if (status != null) {
+            return cardRepository
+                .findByOwnerIdAndStatus(user.getId(), status, pageable)
+                .map(this::toResponse);
+        }
+        return cardRepository
+            .findByOwnerId(user.getId(), pageable)
+            .map(this::toResponse);
+    }
+
+    public CardResponse getCard(Long id, String username, boolean isAdmin) {
+        Card card = cardRepository
+            .findById(id)
+            .orElseThrow(() ->
+                new ResourceNotFoundException("Card not found: " + id)
+            );
+        if (!isAdmin && !card.getOwner().getUsername().equals(username)) {
+            throw new AccessDeniedException("Access denied");
+        }
+        return toResponse(card);
+    }
+
+    public CardResponse blockCard(Long id) {
+        Card card = cardRepository
+            .findById(id)
+            .orElseThrow(() ->
+                new ResourceNotFoundException("Card not found: " + id)
+            );
+        card.setStatus(CardStatus.BLOCKED);
+        return toResponse(cardRepository.save(card));
+    }
+
+    public CardResponse activateCard(Long id) {
+        Card card = cardRepository
+            .findById(id)
+            .orElseThrow(() ->
+                new ResourceNotFoundException("Card not found: " + id)
+            );
+        card.setStatus(CardStatus.ACTIVE);
+        return toResponse(cardRepository.save(card));
+    }
+
+    public void deleteCard(Long id) {
+        if (!cardRepository.existsById(id)) {
+            throw new ResourceNotFoundException("Card not found: " + id);
+        }
+        cardRepository.deleteById(id);
+    }
+
+    public void requestBlock(Long id, String username) {
+        Card card = cardRepository
+            .findById(id)
+            .orElseThrow(() ->
+                new ResourceNotFoundException("Card not found: " + id)
+            );
+        if (!card.getOwner().getUsername().equals(username)) {
+            throw new AccessDeniedException("Access denied");
+        }
+        card.setStatus(CardStatus.BLOCKED);
+        cardRepository.save(card);
+    }
+
+    @Transactional
+    public void transfer(TransferRequest request, String username) {
+        Card from = cardRepository
+            .findById(request.getFromCardId())
+            .orElseThrow(() ->
+                new ResourceNotFoundException("Source card not found")
+            );
+        Card to = cardRepository
+            .findById(request.getToCardId())
+            .orElseThrow(() ->
+                new ResourceNotFoundException("Destination card not found")
+            );
+
+        if (!from.getOwner().getUsername().equals(username)) {
+            throw new AccessDeniedException(
+                "Source card does not belong to you"
+            );
+        }
+        if (!to.getOwner().getUsername().equals(username)) {
+            throw new AccessDeniedException(
+                "Destination card does not belong to you"
+            );
+        }
+        if (from.getStatus() != CardStatus.ACTIVE) {
+            throw new BadRequestException("Source card is not active");
+        }
+        if (to.getStatus() != CardStatus.ACTIVE) {
+            throw new BadRequestException("Destination card is not active");
+        }
+        if (from.getBalance().compareTo(request.getAmount()) < 0) {
+            throw new BadRequestException("Insufficient balance");
+        }
+
+        from.setBalance(from.getBalance().subtract(request.getAmount()));
+        to.setBalance(to.getBalance().add(request.getAmount()));
+        cardRepository.save(from);
+        cardRepository.save(to);
+    }
+
+    public CardResponse toResponse(Card card) {
+        CardResponse response = new CardResponse();
+        response.setId(card.getId());
+        String decrypted = encryptionUtil.decrypt(
+            card.getCardNumberEncrypted()
+        );
+        response.setMaskedNumber(encryptionUtil.mask(decrypted));
+        response.setOwnerUsername(card.getOwner().getUsername());
+        response.setExpiryDate(card.getExpiryDate());
+        response.setStatus(card.getStatus());
+        response.setBalance(card.getBalance());
+        return response;
+    }
+}