Add jwt token parsing

src/main/java/com/litoralregas/backend_gateway/auth/JwtDebugController.java

@@ -0,0 +1,28 @@
+package com.litoralregas.backend_gateway.auth;
+
+import com.litoralregas.backend_gateway.security.JwtService;
+import org.springframework.web.bind.annotation.*;
+
+import java.util.Map;
+
+@RestController
+@RequestMapping("/debug/jwt")
+public class JwtDebugController {
+
+    private final JwtService jwtService;
+
+    public JwtDebugController(JwtService jwtService) {
+        this.jwtService = jwtService;
+    }
+
+    @PostMapping
+    public Map<String, Object> debug(@RequestBody String token) {
+
+        return Map.of(
+                "valid", jwtService.isValid(token),
+                "username", jwtService.extractUsername(token),
+                "clientId", jwtService.extractClientId(token),
+                "role", jwtService.extractRole(token)
+        );
+    }
+}

src/main/java/com/litoralregas/backend_gateway/security/JwtService.java

@@ -1,6 +1,8 @@
 package com.litoralregas.backend_gateway.security;
 
 import com.litoralregas.backend_gateway.user.UserEntity;
+import io.jsonwebtoken.Claims;
+import io.jsonwebtoken.JwtException;
 import io.jsonwebtoken.Jwts;
 import io.jsonwebtoken.security.Keys;
 import org.springframework.stereotype.Service;
@@ -39,4 +41,46 @@ public class JwtService {
                 jwtProperties.getSecret().getBytes(StandardCharsets.UTF_8)
         );
     }
+
+    private Claims getClaims(String token) {
+
+        return Jwts.parser()
+                .verifyWith(getSigningKey())
+                .build()
+                .parseSignedClaims(token)
+                .getPayload();
+    }
+
+    public boolean isValid(String token) {
+
+        try {
+            getClaims(token);
+            return true;
+        } catch (JwtException ex) {
+            return false;
+        }
+    }
+
+    public String extractUsername(String token) {
+        return getClaims(token).getSubject();
+    }
+
+    public Long extractClientId(String token) {
+
+        Object value = getClaims(token).get("clientId");
+
+        if (value instanceof Integer integer) {
+            return integer.longValue();
+        }
+
+        if (value instanceof Long longValue) {
+            return longValue;
+        }
+
+        return Long.parseLong(value.toString());
+    }
+
+    public String extractRole(String token) {
+        return getClaims(token).get("role", String.class);
+    }
 }