handle opcode 9 invalid session and improve handling socket closure

discord/objects.hpp

@@ -28,6 +28,7 @@ enum class GatewayOp : int {
     UpdateStatus = 3,
     Resume = 6,
     Reconnect = 7,
+    InvalidSession = 9,
     Hello = 10,
     HeartbeatAck = 11,
     LazyLoadRequest = 14,
@@ -62,6 +63,28 @@ enum class GatewayEvent : int {
     INVITE_DELETE,
 };
 
+enum class GatewayCloseCode : uint16_t {
+    // discord
+    UnknownError = 4000,
+    UnknownOpcode = 4001,
+    DecodeError = 4002,
+    NotAuthenticated = 4003,
+    AuthenticationFailed = 4004,
+    AlreadyAuthenticated = 4005,
+    InvalidSequence = 4007,
+    RateLimited = 4008,
+    SessionTimedOut = 4009,
+    InvalidShard = 4010,
+    ShardingRequired = 4011,
+    InvalidAPIVersion = 4012,
+    InvalidIntents = 4013,
+    DisallowedIntents = 4014,
+
+    // internal
+    UserDisconnect = 4091,
+    Reconnecting = 4092,
+};
+
 struct GatewayMessage {
     GatewayOp Opcode;
     nlohmann::json Data;