[switch] Add trigger `on_state` (#10108)

esphome/components/switch/__init__.py

@@ -10,6 +10,7 @@ from esphome.const import (
     CONF_ID,
     CONF_INVERTED,
     CONF_MQTT_ID,
+    CONF_ON_STATE,
     CONF_ON_TURN_OFF,
     CONF_ON_TURN_ON,
     CONF_RESTORE_MODE,
@@ -56,6 +57,9 @@ TurnOnAction = switch_ns.class_("TurnOnAction", automation.Action)
 SwitchPublishAction = switch_ns.class_("SwitchPublishAction", automation.Action)
 
 SwitchCondition = switch_ns.class_("SwitchCondition", Condition)
+SwitchStateTrigger = switch_ns.class_(
+    "SwitchStateTrigger", automation.Trigger.template(bool)
+)
 SwitchTurnOnTrigger = switch_ns.class_(
     "SwitchTurnOnTrigger", automation.Trigger.template()
 )
@@ -77,6 +81,11 @@ _SWITCH_SCHEMA = (
             cv.Optional(CONF_RESTORE_MODE, default="ALWAYS_OFF"): cv.enum(
                 RESTORE_MODES, upper=True, space="_"
             ),
+            cv.Optional(CONF_ON_STATE): automation.validate_automation(
+                {
+                    cv.GenerateID(CONF_TRIGGER_ID): cv.declare_id(SwitchStateTrigger),
+                }
+            ),
             cv.Optional(CONF_ON_TURN_ON): automation.validate_automation(
                 {
                     cv.GenerateID(CONF_TRIGGER_ID): cv.declare_id(SwitchTurnOnTrigger),
@@ -140,6 +149,9 @@ async def setup_switch_core_(var, config):
 
     if (inverted := config.get(CONF_INVERTED)) is not None:
         cg.add(var.set_inverted(inverted))
+    for conf in config.get(CONF_ON_STATE, []):
+        trigger = cg.new_Pvariable(conf[CONF_TRIGGER_ID], var)
+        await automation.build_automation(trigger, [(bool, "x")], conf)
     for conf in config.get(CONF_ON_TURN_ON, []):
         trigger = cg.new_Pvariable(conf[CONF_TRIGGER_ID], var)
         await automation.build_automation(trigger, [], conf)

esphome/components/switch/automation.h

@@ -64,6 +64,13 @@ template<typename... Ts> class SwitchCondition : public Condition<Ts...> {
   bool state_;
 };
 
+class SwitchStateTrigger : public Trigger<bool> {
+ public:
+  SwitchStateTrigger(Switch *a_switch) {
+    a_switch->add_on_state_callback([this](bool state) { this->trigger(state); });
+  }
+};
+
 class SwitchTurnOnTrigger : public Trigger<> {
  public:
   SwitchTurnOnTrigger(Switch *a_switch) {

tests/components/switch/common.yaml

@@ -9,6 +9,18 @@ switch:
     name: "Template Switch"
     id: the_switch
     optimistic: true
+    on_state:
+      - if:
+          condition:
+            - lambda: return x;
+          then:
+            - logger.log: "Switch turned ON"
+          else:
+            - logger.log: "Switch turned OFF"
+    on_turn_on:
+      - logger.log: "Switch is now ON"
+    on_turn_off:
+      - logger.log: "Switch is now OFF"
 
 esphome:
   on_boot: