fix(P2-2): Add JWT handler in application layer

packages/application/auth/jwt_handler.py

@@ -0,0 +1,59 @@
+"""JWT token handling implementation (application layer)."""
+
+from datetime import datetime, timedelta
+from typing import Any, Dict, Optional
+
+import jwt
+from jwt.exceptions import ExpiredSignatureError, InvalidTokenError
+
+
+def create_access_token(
+    payload: Dict[str, Any],
+    secret_key: str,
+    algorithm: str = "HS256",
+    expires_minutes: int = 30,
+) -> str:
+    """Create a JWT access token."""
+    now = datetime.utcnow()
+    expires = now + timedelta(minutes=expires_minutes)
+    payload["iat"] = now
+    payload["exp"] = expires
+    return jwt.encode(payload, secret_key, algorithm=algorithm)
+
+
+def create_refresh_token(
+    payload: Dict[str, Any],
+    secret_key: str,
+    algorithm: str = "HS256",
+    expires_days: int = 30,
+) -> str:
+    """Create a JWT refresh token."""
+    now = datetime.utcnow()
+    expires = now + timedelta(days=expires_days)
+    payload["iat"] = now
+    payload["exp"] = expires
+    return jwt.encode(payload, secret_key, algorithm=algorithm)
+
+
+def decode_token(
+    token: str,
+    secret_key: str,
+    algorithms: list[str] = None,
+) -> Dict[str, Any]:
+    """Decode and verify a JWT token."""
+    if algorithms is None:
+        algorithms = ["HS256"]
+    try:
+        return jwt.decode(token, secret_key, algorithms=algorithms)
+    except ExpiredSignatureError:
+        raise ValueError("Token has expired")
+    except InvalidTokenError as e:
+        raise ValueError(f"Invalid token: {e}")
+
+
+def decode_token_unsafe(token: str) -> Optional[Dict[str, Any]]:
+    """Decode a JWT token without signature verification."""
+    try:
+        return jwt.decode(token, options={"verify_signature": False})
+    except Exception:
+        return None