Remove state cache usage from devices to reduce datastore size

There are some current usages of the state cache in the driver, but the
impact seems minimal.

drivers/SmartThings/philips-hue/src/fields.lua

@@ -30,7 +30,10 @@ local Fields = {
   PARENT_DEVICE_ID = "parent_device_id_local",
   RESOURCE_ID = "rid",
   RETRY_MIGRATION = "retry_migration",
-  WRAPPED_HUE = "_wrapped_hue"
+  WRAPPED_HUE = "_wrapped_hue",
+  COLOR_SATURATION = "color_saturation",
+  COLOR_HUE = "color_hue",
+  SWITCH_STATE = "switch_state_cache",
 }
 
 return Fields

drivers/SmartThings/philips-hue/src/handlers/attribute_emitters.lua

@@ -35,8 +35,10 @@ local function _emit_light_events_inner(light_device, light_repr)
 
     if light_repr.on and light_repr.on.on then
       light_device:emit_event(capabilities.switch.switch.on())
+      light_device:set_field(Fields.SWITCH_STATE, "on", {persist = true})
     elseif light_repr.on and not light_repr.on.on then
       light_device:emit_event(capabilities.switch.switch.off())
+      light_device:set_field(Fields.SWITCH_STATE, "off", {persist = true})
     end
 
     if light_repr.dimming then
@@ -96,6 +98,7 @@ local function _emit_light_events_inner(light_device, light_repr)
         )
       else
         light_device:emit_event(capabilities.colorControl.hue(adjusted_hue))
+        light_device:set_field(Fields.COLOR_HUE, adjusted_hue, {persist = true})
       end
 
       if utils.is_nan(adjusted_sat) then
@@ -107,6 +110,7 @@ local function _emit_light_events_inner(light_device, light_repr)
         )
       else
         light_device:emit_event(capabilities.colorControl.saturation(adjusted_sat))
+        light_device:set_field(Fields.COLOR_SATURATION, adjusted_sat, {persist = true})
       end
     end
   end

drivers/SmartThings/philips-hue/src/handlers/commands.lua

@@ -1,4 +1,3 @@
-local capabilities = require "st.capabilities"
 local log = require "log"
 local st_utils = require "st.utils"
 
@@ -92,8 +91,7 @@ local function do_switch_level_action(driver, device, args)
     return
   end
 
-  local is_off = device:get_latest_state(
-    "main", capabilities.switch.ID, capabilities.switch.switch.NAME) == "off"
+  local is_off = device:get_field(Fields.SWITCH_STATE) == "off"
 
   if is_off then
     local resp, err = hue_api:set_light_on_state(light_id, true)
@@ -178,7 +176,7 @@ end
 local function do_setHue_action(driver, device, args)
 
   -- Use existing 'saturation' value for device or set to 0 and pass arg values to function 'do_color_action'
-  local currentSaturation = device:get_latest_state("main", capabilities.colorControl.ID, capabilities.colorControl.saturation.NAME, 0)
+  local currentSaturation = device:get_field(Fields.COLOR_SATURATION) or 0
   args.args.color = {
     hue = args.args.hue,
     saturation = currentSaturation
@@ -193,7 +191,7 @@ end
 local function do_setSaturation_action(driver, device, args)
 
   -- Use existing 'hue' value for device or set to 0 and pass arg values to function 'do_color_action'
-  local currentHue = device:get_latest_state("main", capabilities.colorControl.ID, capabilities.colorControl.hue.NAME, 0)
+  local currentHue = device:get_field(Fields.COLOR_HUE) or 0
   args.args.color = {
     hue = currentHue,
     saturation = args.args.saturation

drivers/SmartThings/philips-hue/src/handlers/lifecycle_handlers/init.lua

@@ -1,5 +1,6 @@
 local log = require "log"
 local st_utils = require "st.utils"
+local capabilities = require "st.capabilities"
 
 local Discovery = require "disco"
 local Fields = require "fields"
@@ -43,6 +44,19 @@ local migration_handlers = utils.lazy_handler_loader("handlers.migration_handler
 ---@class LifecycleHandlers
 local LifecycleHandlers = {}
 
+local function emit_component_event_no_cache(device, component, capability_event)
+    if not device:supports_capability(capability_event.capability, component.id) then
+        local err_msg = string.format("Attempted to generate event for %s.%s but it does not support capability %s", device.id, component.id, capability_event.capability.NAME)
+        log.warn_with({ hub_logs = true }, err_msg)
+        return false, err_msg
+    end
+    local event, err = capabilities.emit_event(device, component.id, device.capability_channel, capability_event)
+    if err ~= nil then
+        log.warn_with({ hub_logs = true }, err)
+    end
+    return event, err
+end
+
 ---@param driver HueDriver
 ---@param device HueDevice
 ---@param ... any arguments for device specific handler
@@ -55,6 +69,10 @@ function LifecycleHandlers.device_init(driver, device, ...)
     )
   )
   inner_handlers[device_type].init(driver, device, ...)
+
+  -- Remove usage of the state cache for hue devices to avoid large datastores
+  device:set_field("__state_cache", nil, {persist = true})
+  device:extend_device("emit_component_event", emit_component_event_no_cache)
 end
 
 ---@param driver HueDriver