diff --git a/fsm.h b/fsm.h
index 3851344..587d73a 100644
--- a/fsm.h
+++ b/fsm.h
@@ -3,36 +3,59 @@
 //
 #ifndef QF_FSM_FSM_H
 #define QF_FSM_FSM_H
+#include <stdbool.h>
 #include <stdint.h>
+#define EVENT_QUEUE_LEN             16
+#define EVENT_QUEUE_HANDLE_MAX_SIZE 32
 typedef enum
 {
     FSM_OK,
     FSM_FAIL
 } fsm_result_e;
-
+typedef struct qf_fsm_event      fsm_event_t;
+typedef struct qf_fsm            fsm_handle_t;
+typedef struct qf_fsm_transition fsm_transition_t;
 typedef fsm_result_e (*fsm_cb)(void *userdata);
+typedef fsm_result_e (*fsm_event_queue_init)(void  *handle_ptr,
+                                             void  *data_ptr,
+                                             size_t size);
+typedef fsm_result_e (*fsm_event_queue_get)(void        *handle_ptr,
+                                            fsm_event_t *event);
+typedef fsm_result_e (*fsm_event_queue_put)(void        *handle_ptr,
+                                            fsm_event_t *event);
 typedef struct qf_fsm_state
 {
     uint16_t state;
     fsm_cb   on_exit;
+    fsm_cb   on_event;
     fsm_cb   on_entry;
     void    *user_data;
 } fsm_state_t;
-typedef struct qf_fsm_transition
+struct qf_fsm_transition
 {
     uint16_t state;
     uint16_t event;
+    uint16_t next_state;
     fsm_cb   on_action;
-} fsm_transition_t;
+};
 struct qf_fsm_event
 {
     uint16_t event;
     void    *user_data;
 };
-typedef struct qf_fsm
+struct qf_fsm
 {
-    uint16_t     current_state;
-    fsm_state_t *p_state_list;
-    
-} fsm_handle_t;
+    uint16_t             current_state;
+    uint16_t             num_states;
+    fsm_state_t         *p_state_list;
+    uint32_t             num_trans;
+    fsm_transition_t    *p_trans_list;
+    uint8_t              event_queue_handle[EVENT_QUEUE_HANDLE_MAX_SIZE];
+    fsm_event_t          event_queue[EVENT_QUEUE_LEN];
+    bool                 custom_queue;
+    fsm_event_queue_init event_queue_init;
+    fsm_event_queue_put  event_queue_put;
+    fsm_event_queue_get  event_queue_get;
+};
+
 #endif // QF_FSM_FSM_H