feat: track oauth new-user result

backend/src/main/java/com/openisle/service/InviteService.java

@@ -0,0 +1,54 @@
+package com.openisle.service;
+
+import com.openisle.model.InviteToken;
+import com.openisle.model.User;
+import com.openisle.repository.InviteTokenRepository;
+import com.openisle.repository.UserRepository;
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Service;
+
+import java.time.LocalDate;
+import java.util.Optional;
+
+@Service
+@RequiredArgsConstructor
+public class InviteService {
+    private final InviteTokenRepository inviteTokenRepository;
+    private final UserRepository userRepository;
+    private final JwtService jwtService;
+    private final PointService pointService;
+
+    public String generate(String username) {
+        User inviter = userRepository.findByUsername(username).orElseThrow();
+        LocalDate today = LocalDate.now();
+        Optional<InviteToken> existing = inviteTokenRepository.findByInviterAndCreatedDate(inviter, today);
+        if (existing.isPresent()) {
+            return existing.get().getToken();
+        }
+        String token = jwtService.generateInviteToken(username);
+        InviteToken inviteToken = new InviteToken();
+        inviteToken.setToken(token);
+        inviteToken.setInviter(inviter);
+        inviteToken.setCreatedDate(today);
+        inviteToken.setUsageCount(0);
+        inviteTokenRepository.save(inviteToken);
+        return token;
+    }
+
+    public boolean validate(String token) {
+        try {
+            jwtService.validateAndGetSubjectForInvite(token);
+        } catch (Exception e) {
+            return false;
+        }
+        InviteToken invite = inviteTokenRepository.findById(token).orElse(null);
+        return invite != null && invite.getUsageCount() < 3;
+    }
+
+    public void consume(String token) {
+        InviteToken invite = inviteTokenRepository.findById(token).orElseThrow();
+        invite.setUsageCount(invite.getUsageCount() + 1);
+        inviteTokenRepository.save(invite);
+        pointService.awardForInvite(invite.getInviter().getUsername());
+    }
+}