feat(session): add explicit leave and immediate slot release

components/maze32_lobby/include/maze32_lobby.h

@@ -66,6 +66,8 @@ maze32_lobby_result_t maze32_lobby_join_observer(maze32_lobby_t* lobby, int conn
 maze32_lobby_result_t maze32_lobby_restore(maze32_lobby_t* lobby, int connection_id,
                                            const char* token, maze32_session_t** session);
 void maze32_lobby_disconnect(maze32_lobby_t* lobby, int connection_id);
+int maze32_lobby_leave(maze32_lobby_t* lobby, int connection_id, maze32_role_t* role,
+                       unsigned int* player_slot);
 maze32_lobby_result_t maze32_lobby_start(maze32_lobby_t* lobby, int connection_id, uint64_t now_ms);
 int maze32_lobby_activate_if_due(maze32_lobby_t* lobby, uint64_t now_ms);
 void maze32_lobby_reset_match(maze32_lobby_t* lobby);

components/maze32_lobby/include/maze32_protocol.h

@@ -22,6 +22,7 @@ typedef enum {
     MAZE32_MESSAGE_MOVE,
     MAZE32_MESSAGE_DROP_KEY,
     MAZE32_MESSAGE_RESTART,
+    MAZE32_MESSAGE_LEAVE,
     MAZE32_MESSAGE_HEARTBEAT,
 } maze32_message_type_t;
 

components/maze32_lobby/maze32_lobby.c

@@ -167,6 +167,30 @@ void maze32_lobby_disconnect(maze32_lobby_t* lobby, int connection_id) {
     }
 }
 
+int maze32_lobby_leave(maze32_lobby_t* lobby, int connection_id, maze32_role_t* role,
+                       unsigned int* player_slot) {
+    if (lobby == NULL) {
+        return 0;
+    }
+    for (size_t index = 0U; index < MAZE32_SESSION_LIMIT; ++index) {
+        maze32_session_t* session = &lobby->sessions[index];
+        if (session->role != MAZE32_ROLE_NONE && session->connected &&
+            session->connection_id == connection_id) {
+            if (role != NULL) {
+                *role = session->role;
+            }
+            if (player_slot != NULL) {
+                *player_slot = session->player_slot;
+            }
+            memset(session, 0, sizeof(*session));
+            session->connection_id = -1;
+            lobby->revision++;
+            return 1;
+        }
+    }
+    return 0;
+}
+
 maze32_lobby_result_t maze32_lobby_start(maze32_lobby_t* lobby, int connection_id,
                                          uint64_t now_ms) {
     if (lobby == NULL || lobby->phase != MAZE32_LOBBY_WAITING) {

components/maze32_lobby/maze32_protocol.c

@@ -193,6 +193,9 @@ static maze32_message_type_t message_type(const char* value) {
     if (strcmp(value, "restart") == 0) {
         return MAZE32_MESSAGE_RESTART;
     }
+    if (strcmp(value, "leave") == 0) {
+        return MAZE32_MESSAGE_LEAVE;
+    }
     if (strcmp(value, "heartbeat") == 0) {
         return MAZE32_MESSAGE_HEARTBEAT;
     }