[api] Reduce batch RAM usage by 33% via switch dispatch (#13199)

2026-02-08 00:31:58 +00:00 · 2026-01-13 17:58:06 -10:00
parent 8b49d465f8
commit c8cc29a991
5 changed files with 229 additions and 166 deletions
--- a/esphome/components/api/api_connection.cpp
+++ b/esphome/components/api/api_connection.cpp
@@ -265,8 +265,7 @@ void APIConnection::loop() {
      // If we can't send the ping request directly (tx_buffer full),
      // schedule it at the front of the batch so it will be sent with priority
      ESP_LOGW(TAG, "Buffer full, ping queued");
-      this->schedule_message_front_(nullptr, &APIConnection::try_send_ping_request, PingRequest::MESSAGE_TYPE,
-                                    PingRequest::ESTIMATED_SIZE);
+      this->schedule_message_front_(nullptr, PingRequest::MESSAGE_TYPE, PingRequest::ESTIMATED_SIZE);
      this->flags_.sent_ping = true;  // Mark as sent to avoid scheduling multiple pings
    }
  }
@@ -362,8 +361,8 @@ uint16_t APIConnection::encode_message_to_buffer(ProtoMessage &msg, uint8_t mess

 #ifdef USE_BINARY_SENSOR
 bool APIConnection::send_binary_sensor_state(binary_sensor::BinarySensor *binary_sensor) {
-  return this->send_message_smart_(binary_sensor, &APIConnection::try_send_binary_sensor_state,
-                                   BinarySensorStateResponse::MESSAGE_TYPE, BinarySensorStateResponse::ESTIMATED_SIZE);
+  return this->send_message_smart_(binary_sensor, BinarySensorStateResponse::MESSAGE_TYPE,
+                                   BinarySensorStateResponse::ESTIMATED_SIZE);
 }

 uint16_t APIConnection::try_send_binary_sensor_state(EntityBase *entity, APIConnection *conn, uint32_t remaining_size,
@@ -389,8 +388,7 @@ uint16_t APIConnection::try_send_binary_sensor_info(EntityBase *entity, APIConne

 #ifdef USE_COVER
 bool APIConnection::send_cover_state(cover::Cover *cover) {
-  return this->send_message_smart_(cover, &APIConnection::try_send_cover_state, CoverStateResponse::MESSAGE_TYPE,
-                                   CoverStateResponse::ESTIMATED_SIZE);
+  return this->send_message_smart_(cover, CoverStateResponse::MESSAGE_TYPE, CoverStateResponse::ESTIMATED_SIZE);
 }
 uint16_t APIConnection::try_send_cover_state(EntityBase *entity, APIConnection *conn, uint32_t remaining_size,
                                             bool is_single) {
@@ -430,8 +428,7 @@ void APIConnection::cover_command(const CoverCommandRequest &msg) {

 #ifdef USE_FAN
 bool APIConnection::send_fan_state(fan::Fan *fan) {
-  return this->send_message_smart_(fan, &APIConnection::try_send_fan_state, FanStateResponse::MESSAGE_TYPE,
-                                   FanStateResponse::ESTIMATED_SIZE);
+  return this->send_message_smart_(fan, FanStateResponse::MESSAGE_TYPE, FanStateResponse::ESTIMATED_SIZE);
 }
 uint16_t APIConnection::try_send_fan_state(EntityBase *entity, APIConnection *conn, uint32_t remaining_size,
                                           bool is_single) {
@@ -482,8 +479,7 @@ void APIConnection::fan_command(const FanCommandRequest &msg) {

 #ifdef USE_LIGHT
 bool APIConnection::send_light_state(light::LightState *light) {
-  return this->send_message_smart_(light, &APIConnection::try_send_light_state, LightStateResponse::MESSAGE_TYPE,
-                                   LightStateResponse::ESTIMATED_SIZE);
+  return this->send_message_smart_(light, LightStateResponse::MESSAGE_TYPE, LightStateResponse::ESTIMATED_SIZE);
 }
 uint16_t APIConnection::try_send_light_state(EntityBase *entity, APIConnection *conn, uint32_t remaining_size,
                                             bool is_single) {
@@ -569,8 +565,7 @@ void APIConnection::light_command(const LightCommandRequest &msg) {

 #ifdef USE_SENSOR
 bool APIConnection::send_sensor_state(sensor::Sensor *sensor) {
-  return this->send_message_smart_(sensor, &APIConnection::try_send_sensor_state, SensorStateResponse::MESSAGE_TYPE,
-                                   SensorStateResponse::ESTIMATED_SIZE);
+  return this->send_message_smart_(sensor, SensorStateResponse::MESSAGE_TYPE, SensorStateResponse::ESTIMATED_SIZE);
 }

 uint16_t APIConnection::try_send_sensor_state(EntityBase *entity, APIConnection *conn, uint32_t remaining_size,
@@ -598,8 +593,7 @@ uint16_t APIConnection::try_send_sensor_info(EntityBase *entity, APIConnection *

 #ifdef USE_SWITCH
 bool APIConnection::send_switch_state(switch_::Switch *a_switch) {
-  return this->send_message_smart_(a_switch, &APIConnection::try_send_switch_state, SwitchStateResponse::MESSAGE_TYPE,
-                                   SwitchStateResponse::ESTIMATED_SIZE);
+  return this->send_message_smart_(a_switch, SwitchStateResponse::MESSAGE_TYPE, SwitchStateResponse::ESTIMATED_SIZE);
 }

 uint16_t APIConnection::try_send_switch_state(EntityBase *entity, APIConnection *conn, uint32_t remaining_size,
@@ -633,8 +627,8 @@ void APIConnection::switch_command(const SwitchCommandRequest &msg) {

 #ifdef USE_TEXT_SENSOR
 bool APIConnection::send_text_sensor_state(text_sensor::TextSensor *text_sensor) {
-  return this->send_message_smart_(text_sensor, &APIConnection::try_send_text_sensor_state,
-                                   TextSensorStateResponse::MESSAGE_TYPE, TextSensorStateResponse::ESTIMATED_SIZE);
+  return this->send_message_smart_(text_sensor, TextSensorStateResponse::MESSAGE_TYPE,
+                                   TextSensorStateResponse::ESTIMATED_SIZE);
 }

 uint16_t APIConnection::try_send_text_sensor_state(EntityBase *entity, APIConnection *conn, uint32_t remaining_size,
@@ -658,8 +652,7 @@ uint16_t APIConnection::try_send_text_sensor_info(EntityBase *entity, APIConnect

 #ifdef USE_CLIMATE
 bool APIConnection::send_climate_state(climate::Climate *climate) {
-  return this->send_message_smart_(climate, &APIConnection::try_send_climate_state, ClimateStateResponse::MESSAGE_TYPE,
-                                   ClimateStateResponse::ESTIMATED_SIZE);
+  return this->send_message_smart_(climate, ClimateStateResponse::MESSAGE_TYPE, ClimateStateResponse::ESTIMATED_SIZE);
 }
 uint16_t APIConnection::try_send_climate_state(EntityBase *entity, APIConnection *conn, uint32_t remaining_size,
                                               bool is_single) {
@@ -754,8 +747,7 @@ void APIConnection::climate_command(const ClimateCommandRequest &msg) {

 #ifdef USE_NUMBER
 bool APIConnection::send_number_state(number::Number *number) {
-  return this->send_message_smart_(number, &APIConnection::try_send_number_state, NumberStateResponse::MESSAGE_TYPE,
-                                   NumberStateResponse::ESTIMATED_SIZE);
+  return this->send_message_smart_(number, NumberStateResponse::MESSAGE_TYPE, NumberStateResponse::ESTIMATED_SIZE);
 }

 uint16_t APIConnection::try_send_number_state(EntityBase *entity, APIConnection *conn, uint32_t remaining_size,
@@ -789,8 +781,7 @@ void APIConnection::number_command(const NumberCommandRequest &msg) {

 #ifdef USE_DATETIME_DATE
 bool APIConnection::send_date_state(datetime::DateEntity *date) {
-  return this->send_message_smart_(date, &APIConnection::try_send_date_state, DateStateResponse::MESSAGE_TYPE,
-                                   DateStateResponse::ESTIMATED_SIZE);
+  return this->send_message_smart_(date, DateStateResponse::MESSAGE_TYPE, DateStateResponse::ESTIMATED_SIZE);
 }
 uint16_t APIConnection::try_send_date_state(EntityBase *entity, APIConnection *conn, uint32_t remaining_size,
                                            bool is_single) {
@@ -818,8 +809,7 @@ void APIConnection::date_command(const DateCommandRequest &msg) {

 #ifdef USE_DATETIME_TIME
 bool APIConnection::send_time_state(datetime::TimeEntity *time) {
-  return this->send_message_smart_(time, &APIConnection::try_send_time_state, TimeStateResponse::MESSAGE_TYPE,
-                                   TimeStateResponse::ESTIMATED_SIZE);
+  return this->send_message_smart_(time, TimeStateResponse::MESSAGE_TYPE, TimeStateResponse::ESTIMATED_SIZE);
 }
 uint16_t APIConnection::try_send_time_state(EntityBase *entity, APIConnection *conn, uint32_t remaining_size,
                                            bool is_single) {
@@ -847,8 +837,8 @@ void APIConnection::time_command(const TimeCommandRequest &msg) {

 #ifdef USE_DATETIME_DATETIME
 bool APIConnection::send_datetime_state(datetime::DateTimeEntity *datetime) {
-  return this->send_message_smart_(datetime, &APIConnection::try_send_datetime_state,
-                                   DateTimeStateResponse::MESSAGE_TYPE, DateTimeStateResponse::ESTIMATED_SIZE);
+  return this->send_message_smart_(datetime, DateTimeStateResponse::MESSAGE_TYPE,
+                                   DateTimeStateResponse::ESTIMATED_SIZE);
 }
 uint16_t APIConnection::try_send_datetime_state(EntityBase *entity, APIConnection *conn, uint32_t remaining_size,
                                                bool is_single) {
@@ -878,8 +868,7 @@ void APIConnection::datetime_command(const DateTimeCommandRequest &msg) {

 #ifdef USE_TEXT
 bool APIConnection::send_text_state(text::Text *text) {
-  return this->send_message_smart_(text, &APIConnection::try_send_text_state, TextStateResponse::MESSAGE_TYPE,
-                                   TextStateResponse::ESTIMATED_SIZE);
+  return this->send_message_smart_(text, TextStateResponse::MESSAGE_TYPE, TextStateResponse::ESTIMATED_SIZE);
 }

 uint16_t APIConnection::try_send_text_state(EntityBase *entity, APIConnection *conn, uint32_t remaining_size,
@@ -911,8 +900,7 @@ void APIConnection::text_command(const TextCommandRequest &msg) {

 #ifdef USE_SELECT
 bool APIConnection::send_select_state(select::Select *select) {
-  return this->send_message_smart_(select, &APIConnection::try_send_select_state, SelectStateResponse::MESSAGE_TYPE,
-                                   SelectStateResponse::ESTIMATED_SIZE);
+  return this->send_message_smart_(select, SelectStateResponse::MESSAGE_TYPE, SelectStateResponse::ESTIMATED_SIZE);
 }

 uint16_t APIConnection::try_send_select_state(EntityBase *entity, APIConnection *conn, uint32_t remaining_size,
@@ -956,8 +944,7 @@ void esphome::api::APIConnection::button_command(const ButtonCommandRequest &msg

 #ifdef USE_LOCK
 bool APIConnection::send_lock_state(lock::Lock *a_lock) {
-  return this->send_message_smart_(a_lock, &APIConnection::try_send_lock_state, LockStateResponse::MESSAGE_TYPE,
-                                   LockStateResponse::ESTIMATED_SIZE);
+  return this->send_message_smart_(a_lock, LockStateResponse::MESSAGE_TYPE, LockStateResponse::ESTIMATED_SIZE);
 }

 uint16_t APIConnection::try_send_lock_state(EntityBase *entity, APIConnection *conn, uint32_t remaining_size,
@@ -997,8 +984,7 @@ void APIConnection::lock_command(const LockCommandRequest &msg) {

 #ifdef USE_VALVE
 bool APIConnection::send_valve_state(valve::Valve *valve) {
-  return this->send_message_smart_(valve, &APIConnection::try_send_valve_state, ValveStateResponse::MESSAGE_TYPE,
-                                   ValveStateResponse::ESTIMATED_SIZE);
+  return this->send_message_smart_(valve, ValveStateResponse::MESSAGE_TYPE, ValveStateResponse::ESTIMATED_SIZE);
 }
 uint16_t APIConnection::try_send_valve_state(EntityBase *entity, APIConnection *conn, uint32_t remaining_size,
                                             bool is_single) {
@@ -1032,8 +1018,8 @@ void APIConnection::valve_command(const ValveCommandRequest &msg) {

 #ifdef USE_MEDIA_PLAYER
 bool APIConnection::send_media_player_state(media_player::MediaPlayer *media_player) {
-  return this->send_message_smart_(media_player, &APIConnection::try_send_media_player_state,
-                                   MediaPlayerStateResponse::MESSAGE_TYPE, MediaPlayerStateResponse::ESTIMATED_SIZE);
+  return this->send_message_smart_(media_player, MediaPlayerStateResponse::MESSAGE_TYPE,
+                                   MediaPlayerStateResponse::ESTIMATED_SIZE);
 }
 uint16_t APIConnection::try_send_media_player_state(EntityBase *entity, APIConnection *conn, uint32_t remaining_size,
                                                    bool is_single) {
@@ -1315,8 +1301,7 @@ void APIConnection::zwave_proxy_request(const ZWaveProxyRequest &msg) {

 #ifdef USE_ALARM_CONTROL_PANEL
 bool APIConnection::send_alarm_control_panel_state(alarm_control_panel::AlarmControlPanel *a_alarm_control_panel) {
-  return this->send_message_smart_(a_alarm_control_panel, &APIConnection::try_send_alarm_control_panel_state,
-                                   AlarmControlPanelStateResponse::MESSAGE_TYPE,
+  return this->send_message_smart_(a_alarm_control_panel, AlarmControlPanelStateResponse::MESSAGE_TYPE,
                                   AlarmControlPanelStateResponse::ESTIMATED_SIZE);
 }
 uint16_t APIConnection::try_send_alarm_control_panel_state(EntityBase *entity, APIConnection *conn,
@@ -1369,8 +1354,8 @@ void APIConnection::alarm_control_panel_command(const AlarmControlPanelCommandRe

 #ifdef USE_WATER_HEATER
 bool APIConnection::send_water_heater_state(water_heater::WaterHeater *water_heater) {
-  return this->send_message_smart_(water_heater, &APIConnection::try_send_water_heater_state,
-                                   WaterHeaterStateResponse::MESSAGE_TYPE, WaterHeaterStateResponse::ESTIMATED_SIZE);
+  return this->send_message_smart_(water_heater, WaterHeaterStateResponse::MESSAGE_TYPE,
+                                   WaterHeaterStateResponse::ESTIMATED_SIZE);
 }
 uint16_t APIConnection::try_send_water_heater_state(EntityBase *entity, APIConnection *conn, uint32_t remaining_size,
                                                    bool is_single) {
@@ -1419,10 +1404,11 @@ void APIConnection::on_water_heater_command_request(const WaterHeaterCommandRequ
 #endif

 #ifdef USE_EVENT
-void APIConnection::send_event(event::Event *event, StringRef event_type) {
-  // get_last_event_type() returns StringRef pointing to null-terminated string literals from codegen
-  this->send_message_smart_(event, MessageCreator(event_type.c_str()), EventResponse::MESSAGE_TYPE,
-                            EventResponse::ESTIMATED_SIZE);
+// Event is a special case - unlike other entities with simple state fields,
+// events store their state in a member accessed via obj->get_last_event_type()
+void APIConnection::send_event(event::Event *event) {
+  this->send_message_smart_(event, EventResponse::MESSAGE_TYPE, EventResponse::ESTIMATED_SIZE,
+                            event->get_last_event_type_index());
 }
 uint16_t APIConnection::try_send_event_response(event::Event *event, StringRef event_type, APIConnection *conn,
                                                uint32_t remaining_size, bool is_single) {
@@ -1473,8 +1459,7 @@ uint16_t APIConnection::try_send_infrared_info(EntityBase *entity, APIConnection

 #ifdef USE_UPDATE
 bool APIConnection::send_update_state(update::UpdateEntity *update) {
-  return this->send_message_smart_(update, &APIConnection::try_send_update_state, UpdateStateResponse::MESSAGE_TYPE,
-                                   UpdateStateResponse::ESTIMATED_SIZE);
+  return this->send_message_smart_(update, UpdateStateResponse::MESSAGE_TYPE, UpdateStateResponse::ESTIMATED_SIZE);
 }
 uint16_t APIConnection::try_send_update_state(EntityBase *entity, APIConnection *conn, uint32_t remaining_size,
                                              bool is_single) {
@@ -1897,30 +1882,31 @@ void APIConnection::on_fatal_error() {
  this->flags_.remove = true;
 }

-void APIConnection::DeferredBatch::add_item(EntityBase *entity, MessageCreator creator, uint8_t message_type,
-                                            uint8_t estimated_size) {
+void APIConnection::DeferredBatch::add_item(EntityBase *entity, uint8_t message_type, uint8_t estimated_size,
+                                            uint8_t aux_data_index) {
  // Check if we already have a message of this type for this entity
  // This provides deduplication per entity/message_type combination
  // O(n) but optimized for RAM and not performance.
-  for (auto &item : items) {
-    if (item.entity == entity && item.message_type == message_type) {
-      // Replace with new creator
-      item.creator = creator;
-      return;
+  // Skip deduplication for events - they are edge-triggered, every occurrence matters
+#ifdef USE_EVENT
+  if (message_type != EventResponse::MESSAGE_TYPE)
+#endif
+  {
+    for (const auto &item : items) {
+      if (item.entity == entity && item.message_type == message_type)
+        return;  // Already queued
    }
  }
-
-  // No existing item found, add new one
-  items.emplace_back(entity, creator, message_type, estimated_size);
+  // No existing item found (or event), add new one
+  items.push_back({entity, message_type, estimated_size, aux_data_index});
 }

-void APIConnection::DeferredBatch::add_item_front(EntityBase *entity, MessageCreator creator, uint8_t message_type,
-                                                  uint8_t estimated_size) {
+void APIConnection::DeferredBatch::add_item_front(EntityBase *entity, uint8_t message_type, uint8_t estimated_size) {
  // Add high priority message and swap to front
  // This avoids expensive vector::insert which shifts all elements
  // Note: We only ever have one high-priority message at a time (ping OR disconnect)
  // If we're disconnecting, pings are blocked, so this simple swap is sufficient
-  items.emplace_back(entity, creator, message_type, estimated_size);
+  items.push_back({entity, message_type, estimated_size, AUX_DATA_UNUSED});
  if (items.size() > 1) {
    // Swap the new high-priority item to the front
    std::swap(items.front(), items.back());
@@ -1959,19 +1945,17 @@ void APIConnection::process_batch_() {
  if (num_items == 1) {
    const auto &item = this->deferred_batch_[0];

-    // Let the creator calculate size and encode if it fits
-    uint16_t payload_size =
-        item.creator(item.entity, this, std::numeric_limits<uint16_t>::max(), true, item.message_type);
+    // Let dispatch_message_ calculate size and encode if it fits
+    uint16_t payload_size = this->dispatch_message_(item, std::numeric_limits<uint16_t>::max(), true);

    if (payload_size > 0 && this->send_buffer(ProtoWriteBuffer{&shared_buf}, item.message_type)) {
 #ifdef HAS_PROTO_MESSAGE_DUMP
-      // Log messages after send attempt for VV debugging
-      // It's safe to use the buffer for logging at this point regardless of send result
+      // Log message after send attempt for VV debugging
      this->log_batch_item_(item);
 #endif
      this->clear_batch_();
    } else if (payload_size == 0) {
-      // Message too large
+      // Message too large to fit in available space
      ESP_LOGW(TAG, "Message too large to send: type=%u", item.message_type);
      this->clear_batch_();
    }
@@ -2016,9 +2000,9 @@ void APIConnection::process_batch_() {
  // Process items and encode directly to buffer (up to our limit)
  for (size_t i = 0; i < messages_to_process; i++) {
    const auto &item = this->deferred_batch_[i];
-    // Try to encode message
-    // The creator will calculate overhead to determine if the message fits
-    uint16_t payload_size = item.creator(item.entity, this, remaining_size, false, item.message_type);
+    // Try to encode message via dispatch
+    // The dispatch function calculates overhead to determine if the message fits
+    uint16_t payload_size = this->dispatch_message_(item, remaining_size, false);

    if (payload_size == 0) {
      // Message won't fit, stop processing
@@ -2084,18 +2068,129 @@ void APIConnection::process_batch_() {
  }
 }

-uint16_t APIConnection::MessageCreator::operator()(EntityBase *entity, APIConnection *conn, uint32_t remaining_size,
-                                                   bool is_single, uint8_t message_type) const {
+// Dispatch message encoding based on message_type
+// Switch assigns function pointer, single call site for smaller code size
+uint16_t APIConnection::dispatch_message_(const DeferredBatch::BatchItem &item, uint32_t remaining_size,
+                                          bool is_single) {
 #ifdef USE_EVENT
-  // Special case: EventResponse uses const char * pointer
-  if (message_type == EventResponse::MESSAGE_TYPE) {
-    auto *e = static_cast<event::Event *>(entity);
-    return APIConnection::try_send_event_response(e, StringRef(data_.const_char_ptr), conn, remaining_size, is_single);
+  // Events need aux_data_index to look up event type from entity
+  if (item.message_type == EventResponse::MESSAGE_TYPE) {
+    // Skip if aux_data_index is invalid (should never happen in normal operation)
+    if (item.aux_data_index == DeferredBatch::AUX_DATA_UNUSED)
+      return 0;
+    auto *event = static_cast<event::Event *>(item.entity);
+    return try_send_event_response(event, StringRef::from_maybe_nullptr(event->get_event_type(item.aux_data_index)),
+                                   this, remaining_size, is_single);
  }
 #endif

-  // All other message types use function pointers
-  return data_.function_ptr(entity, conn, remaining_size, is_single);
+  // All other message types use function pointer lookup via switch
+  MessageCreatorPtr func = nullptr;
+
+// Macros to reduce repetitive switch cases
+#define CASE_STATE_INFO(entity_name, StateResp, InfoResp) \
+  case StateResp::MESSAGE_TYPE: \
+    func = &try_send_##entity_name##_state; \
+    break; \
+  case InfoResp::MESSAGE_TYPE: \
+    func = &try_send_##entity_name##_info; \
+    break;
+#define CASE_INFO_ONLY(entity_name, InfoResp) \
+  case InfoResp::MESSAGE_TYPE: \
+    func = &try_send_##entity_name##_info; \
+    break;
+
+  switch (item.message_type) {
+#ifdef USE_BINARY_SENSOR
+    CASE_STATE_INFO(binary_sensor, BinarySensorStateResponse, ListEntitiesBinarySensorResponse)
+#endif
+#ifdef USE_COVER
+    CASE_STATE_INFO(cover, CoverStateResponse, ListEntitiesCoverResponse)
+#endif
+#ifdef USE_FAN
+    CASE_STATE_INFO(fan, FanStateResponse, ListEntitiesFanResponse)
+#endif
+#ifdef USE_LIGHT
+    CASE_STATE_INFO(light, LightStateResponse, ListEntitiesLightResponse)
+#endif
+#ifdef USE_SENSOR
+    CASE_STATE_INFO(sensor, SensorStateResponse, ListEntitiesSensorResponse)
+#endif
+#ifdef USE_SWITCH
+    CASE_STATE_INFO(switch, SwitchStateResponse, ListEntitiesSwitchResponse)
+#endif
+#ifdef USE_BUTTON
+    CASE_INFO_ONLY(button, ListEntitiesButtonResponse)
+#endif
+#ifdef USE_TEXT_SENSOR
+    CASE_STATE_INFO(text_sensor, TextSensorStateResponse, ListEntitiesTextSensorResponse)
+#endif
+#ifdef USE_CLIMATE
+    CASE_STATE_INFO(climate, ClimateStateResponse, ListEntitiesClimateResponse)
+#endif
+#ifdef USE_NUMBER
+    CASE_STATE_INFO(number, NumberStateResponse, ListEntitiesNumberResponse)
+#endif
+#ifdef USE_DATETIME_DATE
+    CASE_STATE_INFO(date, DateStateResponse, ListEntitiesDateResponse)
+#endif
+#ifdef USE_DATETIME_TIME
+    CASE_STATE_INFO(time, TimeStateResponse, ListEntitiesTimeResponse)
+#endif
+#ifdef USE_DATETIME_DATETIME
+    CASE_STATE_INFO(datetime, DateTimeStateResponse, ListEntitiesDateTimeResponse)
+#endif
+#ifdef USE_TEXT
+    CASE_STATE_INFO(text, TextStateResponse, ListEntitiesTextResponse)
+#endif
+#ifdef USE_SELECT
+    CASE_STATE_INFO(select, SelectStateResponse, ListEntitiesSelectResponse)
+#endif
+#ifdef USE_LOCK
+    CASE_STATE_INFO(lock, LockStateResponse, ListEntitiesLockResponse)
+#endif
+#ifdef USE_VALVE
+    CASE_STATE_INFO(valve, ValveStateResponse, ListEntitiesValveResponse)
+#endif
+#ifdef USE_MEDIA_PLAYER
+    CASE_STATE_INFO(media_player, MediaPlayerStateResponse, ListEntitiesMediaPlayerResponse)
+#endif
+#ifdef USE_ALARM_CONTROL_PANEL
+    CASE_STATE_INFO(alarm_control_panel, AlarmControlPanelStateResponse, ListEntitiesAlarmControlPanelResponse)
+#endif
+#ifdef USE_WATER_HEATER
+    CASE_STATE_INFO(water_heater, WaterHeaterStateResponse, ListEntitiesWaterHeaterResponse)
+#endif
+#ifdef USE_CAMERA
+    CASE_INFO_ONLY(camera, ListEntitiesCameraResponse)
+#endif
+#ifdef USE_INFRARED
+    CASE_INFO_ONLY(infrared, ListEntitiesInfraredResponse)
+#endif
+#ifdef USE_EVENT
+    CASE_INFO_ONLY(event, ListEntitiesEventResponse)
+#endif
+#ifdef USE_UPDATE
+    CASE_STATE_INFO(update, UpdateStateResponse, ListEntitiesUpdateResponse)
+#endif
+    // Special messages (not entity state/info)
+    case ListEntitiesDoneResponse::MESSAGE_TYPE:
+      func = &try_send_list_info_done;
+      break;
+    case DisconnectRequest::MESSAGE_TYPE:
+      func = &try_send_disconnect_request;
+      break;
+    case PingRequest::MESSAGE_TYPE:
+      func = &try_send_ping_request;
+      break;
+    default:
+      return 0;
+  }
+
+#undef CASE_STATE_INFO
+#undef CASE_INFO_ONLY
+
+  return func(item.entity, this, remaining_size, is_single);
 }

 uint16_t APIConnection::try_send_list_info_done(EntityBase *entity, APIConnection *conn, uint32_t remaining_size,
--- a/esphome/components/api/api_connection.h
+++ b/esphome/components/api/api_connection.h
@@ -12,6 +12,7 @@
 #include "esphome/core/string_ref.h"

 #include <functional>
+#include <limits>
 #include <vector>

 namespace esphome::api {
@@ -38,8 +39,8 @@ class APIConnection final : public APIServerConnection {
  void loop();

  bool send_list_info_done() {
-    return this->schedule_message_(nullptr, &APIConnection::try_send_list_info_done,
-                                   ListEntitiesDoneResponse::MESSAGE_TYPE, ListEntitiesDoneResponse::ESTIMATED_SIZE);
+    return this->schedule_message_(nullptr, ListEntitiesDoneResponse::MESSAGE_TYPE,
+                                   ListEntitiesDoneResponse::ESTIMATED_SIZE);
  }
 #ifdef USE_BINARY_SENSOR
  bool send_binary_sensor_state(binary_sensor::BinarySensor *binary_sensor);
@@ -178,7 +179,7 @@ class APIConnection final : public APIServerConnection {
 #endif

 #ifdef USE_EVENT
-  void send_event(event::Event *event, StringRef event_type);
+  void send_event(event::Event *event);
 #endif

 #ifdef USE_UPDATE
@@ -540,33 +541,17 @@ class APIConnection final : public APIServerConnection {
  // Function pointer type for message encoding
  using MessageCreatorPtr = uint16_t (*)(EntityBase *, APIConnection *, uint32_t remaining_size, bool is_single);

-  class MessageCreator {
-   public:
-    MessageCreator(MessageCreatorPtr ptr) { data_.function_ptr = ptr; }
-    explicit MessageCreator(const char *str_value) { data_.const_char_ptr = str_value; }
-
-    // Call operator - uses message_type to determine union type
-    uint16_t operator()(EntityBase *entity, APIConnection *conn, uint32_t remaining_size, bool is_single,
-                        uint8_t message_type) const;
-
-   private:
-    union Data {
-      MessageCreatorPtr function_ptr;
-      const char *const_char_ptr;
-    } data_;  // 4 bytes on 32-bit, 8 bytes on 64-bit
-  };
-
  // Generic batching mechanism for both state updates and entity info
  struct DeferredBatch {
-    struct BatchItem {
-      EntityBase *entity;      // Entity pointer
-      MessageCreator creator;  // Function that creates the message when needed
-      uint8_t message_type;    // Message type for overhead calculation (max 255)
-      uint8_t estimated_size;  // Estimated message size (max 255 bytes)
+    // Sentinel value for unused aux_data_index
+    static constexpr uint8_t AUX_DATA_UNUSED = std::numeric_limits<uint8_t>::max();

-      // Constructor for creating BatchItem
-      BatchItem(EntityBase *entity, MessageCreator creator, uint8_t message_type, uint8_t estimated_size)
-          : entity(entity), creator(creator), message_type(message_type), estimated_size(estimated_size) {}
+    struct BatchItem {
+      EntityBase *entity;                       // 4 bytes - Entity pointer
+      uint8_t message_type;                     // 1 byte - Message type for protocol and dispatch
+      uint8_t estimated_size;                   // 1 byte - Estimated message size (max 255 bytes)
+      uint8_t aux_data_index{AUX_DATA_UNUSED};  // 1 byte - For events: index into entity's event_types
+      // 1 byte padding
    };

    std::vector<BatchItem> items;
@@ -575,10 +560,11 @@ class APIConnection final : public APIServerConnection {
    // No pre-allocation - log connections never use batching, and for
    // connections that do, buffers are released after initial sync anyway

-    // Add item to the batch
-    void add_item(EntityBase *entity, MessageCreator creator, uint8_t message_type, uint8_t estimated_size);
+    // Add item to the batch (with deduplication)
+    void add_item(EntityBase *entity, uint8_t message_type, uint8_t estimated_size,
+                  uint8_t aux_data_index = AUX_DATA_UNUSED);
    // Add item to the front of the batch (for high priority messages like ping)
-    void add_item_front(EntityBase *entity, MessageCreator creator, uint8_t message_type, uint8_t estimated_size);
+    void add_item_front(EntityBase *entity, uint8_t message_type, uint8_t estimated_size);

    // Clear all items
    void clear() {
@@ -592,6 +578,7 @@ class APIConnection final : public APIServerConnection {
    bool empty() const { return items.empty(); }
    size_t size() const { return items.size(); }
    const BatchItem &operator[](size_t index) const { return items[index]; }
+
    // Release excess capacity - only releases if items already empty
    void release_buffer() {
      // Safe to call: batch is processed before release_buffer is called,
@@ -663,17 +650,15 @@ class APIConnection final : public APIServerConnection {
    this->flags_.batch_scheduled = false;
  }

-#ifdef HAS_PROTO_MESSAGE_DUMP
-  // Helper to log a proto message from a MessageCreator object
-  void log_proto_message_(EntityBase *entity, const MessageCreator &creator, uint8_t message_type) {
-    this->flags_.log_only_mode = true;
-    creator(entity, this, MAX_BATCH_PACKET_SIZE, true, message_type);
-    this->flags_.log_only_mode = false;
-  }
+  // Dispatch message encoding based on message_type - replaces function pointer storage
+  // Switch assigns pointer, single call site for smaller code size
+  uint16_t dispatch_message_(const DeferredBatch::BatchItem &item, uint32_t remaining_size, bool is_single);

+#ifdef HAS_PROTO_MESSAGE_DUMP
  void log_batch_item_(const DeferredBatch::BatchItem &item) {
-    // Use the helper to log the message
-    this->log_proto_message_(item.entity, item.creator, item.message_type);
+    this->flags_.log_only_mode = true;
+    this->dispatch_message_(item, MAX_BATCH_PACKET_SIZE, true);
+    this->flags_.log_only_mode = false;
  }
 #endif

@@ -698,63 +683,31 @@ class APIConnection final : public APIServerConnection {
  // Helper method to send a message either immediately or via batching
  // Tries immediate send if should_send_immediately_() returns true and buffer has space
  // Falls back to batching if immediate send fails or isn't applicable
-  bool send_message_smart_(EntityBase *entity, MessageCreatorPtr creator, uint8_t message_type,
-                           uint8_t estimated_size) {
+  bool send_message_smart_(EntityBase *entity, uint8_t message_type, uint8_t estimated_size,
+                           uint8_t aux_data_index = DeferredBatch::AUX_DATA_UNUSED) {
    if (this->should_send_immediately_(message_type) && this->helper_->can_write_without_blocking()) {
-      // Now actually encode and send
-      if (creator(entity, this, MAX_BATCH_PACKET_SIZE, true) &&
+      DeferredBatch::BatchItem item{entity, message_type, estimated_size, aux_data_index};
+      if (this->dispatch_message_(item, MAX_BATCH_PACKET_SIZE, true) &&
          this->send_buffer(ProtoWriteBuffer{&this->parent_->get_shared_buffer_ref()}, message_type)) {
 #ifdef HAS_PROTO_MESSAGE_DUMP
-        // Log the message in verbose mode
-        this->log_proto_message_(entity, MessageCreator(creator), message_type);
+        this->log_batch_item_(item);
 #endif
        return true;
      }
-
-      // If immediate send failed, fall through to batching
    }
-
-    // Fall back to scheduled batching
-    return this->schedule_message_(entity, creator, message_type, estimated_size);
-  }
-
-  // Overload for MessageCreator (used by events which need to capture event_type)
-  bool send_message_smart_(EntityBase *entity, MessageCreator creator, uint8_t message_type, uint8_t estimated_size) {
-    // Try to send immediately if message type should bypass batching and buffer has space
-    if (this->should_send_immediately_(message_type) && this->helper_->can_write_without_blocking()) {
-      // Now actually encode and send
-      if (creator(entity, this, MAX_BATCH_PACKET_SIZE, true, message_type) &&
-          this->send_buffer(ProtoWriteBuffer{&this->parent_->get_shared_buffer_ref()}, message_type)) {
-#ifdef HAS_PROTO_MESSAGE_DUMP
-        // Log the message in verbose mode
-        this->log_proto_message_(entity, creator, message_type);
-#endif
-        return true;
-      }
-
-      // If immediate send failed, fall through to batching
-    }
-
-    // Fall back to scheduled batching
-    return this->schedule_message_(entity, creator, message_type, estimated_size);
+    return this->schedule_message_(entity, message_type, estimated_size, aux_data_index);
  }

  // Helper function to schedule a deferred message with known message type
-  bool schedule_message_(EntityBase *entity, MessageCreator creator, uint8_t message_type, uint8_t estimated_size) {
-    this->deferred_batch_.add_item(entity, creator, message_type, estimated_size);
+  bool schedule_message_(EntityBase *entity, uint8_t message_type, uint8_t estimated_size,
+                         uint8_t aux_data_index = DeferredBatch::AUX_DATA_UNUSED) {
+    this->deferred_batch_.add_item(entity, message_type, estimated_size, aux_data_index);
    return this->schedule_batch_();
  }

-  // Overload for function pointers (for info messages and current state reads)
-  bool schedule_message_(EntityBase *entity, MessageCreatorPtr function_ptr, uint8_t message_type,
-                         uint8_t estimated_size) {
-    return schedule_message_(entity, MessageCreator(function_ptr), message_type, estimated_size);
-  }
-
  // Helper function to schedule a high priority message at the front of the batch
-  bool schedule_message_front_(EntityBase *entity, MessageCreatorPtr function_ptr, uint8_t message_type,
-                               uint8_t estimated_size) {
-    this->deferred_batch_.add_item_front(entity, MessageCreator(function_ptr), message_type, estimated_size);
+  bool schedule_message_front_(EntityBase *entity, uint8_t message_type, uint8_t estimated_size) {
+    this->deferred_batch_.add_item_front(entity, message_type, estimated_size);
    return this->schedule_batch_();
  }

--- a/esphome/components/api/api_server.cpp
+++ b/esphome/components/api/api_server.cpp
@@ -318,13 +318,11 @@ API_DISPATCH_UPDATE(water_heater::WaterHeater, water_heater)
 #endif

 #ifdef USE_EVENT
-// Event is a special case - unlike other entities with simple state fields,
-// events store their state in a member accessed via obj->get_last_event_type()
 void APIServer::on_event(event::Event *obj) {
  if (obj->is_internal())
    return;
  for (auto &c : this->clients_)
-    c->send_event(obj, obj->get_last_event_type());
+    c->send_event(obj);
 }
 #endif

@@ -615,8 +613,7 @@ void APIServer::on_shutdown() {
    if (!c->send_message(req, DisconnectRequest::MESSAGE_TYPE)) {
      // If we can't send the disconnect request directly (tx_buffer full),
      // schedule it at the front of the batch so it will be sent with priority
-      c->schedule_message_front_(nullptr, &APIConnection::try_send_disconnect_request, DisconnectRequest::MESSAGE_TYPE,
-                                 DisconnectRequest::ESTIMATED_SIZE);
+      c->schedule_message_front_(nullptr, DisconnectRequest::MESSAGE_TYPE, DisconnectRequest::ESTIMATED_SIZE);
    }
  }
 }
--- a/esphome/components/api/list_entities.h
+++ b/esphome/components/api/list_entities.h
@@ -9,11 +9,10 @@ namespace esphome::api {
 class APIConnection;

 // Macro for generating ListEntitiesIterator handlers
-// Calls schedule_message_ with try_send_*_info
+// Calls schedule_message_ which dispatches to try_send_*_info
 #define LIST_ENTITIES_HANDLER(entity_type, EntityClass, ResponseType) \
  bool ListEntitiesIterator::on_##entity_type(EntityClass *entity) { /* NOLINT(bugprone-macro-parentheses) */ \
-    return this->client_->schedule_message_(entity, &APIConnection::try_send_##entity_type##_info, \
-                                            ResponseType::MESSAGE_TYPE, ResponseType::ESTIMATED_SIZE); \
+    return this->client_->schedule_message_(entity, ResponseType::MESSAGE_TYPE, ResponseType::ESTIMATED_SIZE); \
  }

 class ListEntitiesIterator : public ComponentIterator {
--- a/esphome/components/event/event.h
+++ b/esphome/components/event/event.h
@@ -1,6 +1,7 @@
 #pragma once

 #include <cstring>
+#include <limits>
 #include <string>
 #include <vector>

@@ -48,6 +49,24 @@ class Event : public EntityBase, public EntityBase_DeviceClass {
  /// Return the last triggered event type, or empty StringRef if no event triggered yet.
  StringRef get_last_event_type() const { return StringRef::from_maybe_nullptr(this->last_event_type_); }

+  /// Return event type by index, or nullptr if index is out of bounds.
+  const char *get_event_type(uint8_t index) const {
+    return index < this->types_.size() ? this->types_[index] : nullptr;
+  }
+
+  /// Return index of last triggered event type, or max uint8_t if no event triggered yet.
+  uint8_t get_last_event_type_index() const {
+    if (this->last_event_type_ == nullptr)
+      return std::numeric_limits<uint8_t>::max();
+    // Most events have <3 types, uint8_t is sufficient for all reasonable scenarios
+    const uint8_t size = static_cast<uint8_t>(this->types_.size());
+    for (uint8_t i = 0; i < size; i++) {
+      if (this->types_[i] == this->last_event_type_)
+        return i;
+    }
+    return std::numeric_limits<uint8_t>::max();
+  }
+
  /// Check if an event has been triggered.
  bool has_event() const { return this->last_event_type_ != nullptr; }