src/main/java/com/acquirex/approval/service/ApprovalService.java

@@ -0,0 +1,66 @@
+package com.acquirex.approval.service;
+
+import com.acquirex.approval.domain.ApprovalRequest;
+import com.acquirex.approval.domain.ApprovalRequest.ApprovalStatus;
+import com.acquirex.approval.dto.ApprovalDto.Request;
+import com.acquirex.approval.dto.ApprovalDto.Response;
+import com.acquirex.approval.repository.ApprovalRequestRepository;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+import java.util.UUID;
+
+@Service
+public class ApprovalService {
+
+    private final ApprovalRequestRepository repository;
+
+    public ApprovalService(ApprovalRequestRepository repository) {
+        this.repository = repository;
+    }
+
+    @Transactional
+    public Response processApproval(Request requestDto) {
+        ApprovalRequest request = new ApprovalRequest(
+            requestDto.getCardNumber(),
+            requestDto.getMerchantId(),
+            requestDto.getAmount(),
+            requestDto.getCurrency()
+        );
+
+        ApprovalRequest saved = repository.save(request);
+
+        if (validateRequest(requestDto)) {
+            String approvalCode = generateApprovalCode();
+            saved.setStatus(ApprovalStatus.APPROVED);
+            saved.setApprovalCode(approvalCode);
+            repository.save(saved);
+            return Response.approved(saved.getId(), approvalCode, saved.getAmount(), saved.getCurrency());
+        } else {
+            saved.setStatus(ApprovalStatus.DECLINED);
+            repository.save(saved);
+            return Response.declined(saved.getId(), "Validation failed");
+        }
+    }
+
+    @Transactional(readOnly = true)
+    public ApprovalRequest findById(Long id) {
+        return repository.findById(id)
+            .orElseThrow(() -> new IllegalArgumentException("Approval request not found: " + id));
+    }
+
+    @Transactional(readOnly = true)
+    public long countPendingApprovals() {
+        return repository.countByStatus(ApprovalStatus.PENDING);
+    }
+
+    private boolean validateRequest(Request dto) {
+        if (dto.getAmount() == null || dto.getAmount().signum() <= 0) return false;
+        if (dto.getCardNumber() == null || dto.getCardNumber().length() < 13) return false;
+        if (dto.getMerchantId() == null || dto.getMerchantId().isEmpty()) return false;
+        return dto.getCurrency() != null && dto.getCurrency().length() == 3;
+    }
+
+    private String generateApprovalCode() {
+        return "APP-" + UUID.randomUUID().toString().substring(0, 8).toUpperCase();
+    }
+}