feat: add EventSensor class for temporary binary sensor activation

adexpressioncontext.py

@@ -1,5 +1,5 @@
 import pyparsing as pp
-from expressionparser import BaseExpressionContext
+from expressionparser import BaseExpressionContext, ExpressionParser
 
 class ADExpressionContext(BaseExpressionContext):
     def __init__(self,appdaemon_api, sensor_existence_validation = True):
@@ -13,6 +13,7 @@ class ADExpressionContext(BaseExpressionContext):
         self.sensors_default_value = dict()
         self.sensor_states = dict()
         self.sensor_existence_validation = sensor_existence_validation
+        self.local_expressions = {}
 
         self.declare_default_constants()
 
@@ -131,7 +132,22 @@ class ADExpressionContext(BaseExpressionContext):
     def get_entities_to_listen(self):
         return self.entities_to_listen
 
-    def get_constant_value(self,name): return self.variables[name]
+    def get_constant_value(self, name):
+        if name in self.local_expressions:
+            return self.local_expressions[name].eval()
+        return self.variables[name]
+
+    def declare_local_expression(self, name: str, expression_string: str):
+        assert name not in self.variables, f"'{name}' is already declared"
+        assert name.replace('_', '').isalnum() and name.isascii(), f"Invalid local expression name: {name}"
+        # Register as a constant placeholder so the variable parser recognises it
+        self.variables[name] = None
+        self.constants.append(name)
+        self.parser = None  # reset variable parser cache
+        # Parse the expression; set_context registers its sensor dependencies
+        # Store only the parsed tree so evaluation skips the top-level reset()
+        full_parser = ExpressionParser(expression_string, self)
+        self.local_expressions[name] = full_parser.parsed_data
 
     def declare_constant(self,name : str,value):
         def is_a_sensor(string):

eventhandler.py

@@ -42,6 +42,9 @@ import json
 #         <field>: <value>
 #       reset_data:                         # optional — latch reset filter
 #         <field>: <value>
+#       debounce_seconds: <float>           # optional — ignore re-triggers within
+#                                           #   this delay (seconds).  Useful for
+#                                           #   buttons that fire duplicate events.
 #
 # Usage:
 #   handler = EventHandler(ad_api, self.args['events_to_listen'], my_callback)
@@ -57,8 +60,10 @@ import json
 # =============================================================================
 
 class EventDispatcher:
-    def __init__(self,ad_api,event_name,callback,event_data,reset_data,event_context):
+    def __init__(self,ad_api,logger_interface,event_name,callback,event_data,reset_data,event_context,debounce_seconds=None):
-        self.ad_api = ad_api
+        self.ad_api = ad_api        
+        self.logger_interface = logger_interface
+
         event_data = self._resolve_zha_device_name(event_data)
         reset_data = self._resolve_zha_device_name(reset_data)
         self.event_name = event_name
@@ -67,6 +72,8 @@ class EventDispatcher:
         self.reset_data = reset_data
         self.waiting_for_reset = False
         self.event_context = event_context
+        self.debounce_seconds = debounce_seconds
+        self._last_trigger_time = None
         if event_data == None:
             self.ad_api.listen_event(self.on_event,event_name)
         else:
@@ -121,7 +128,7 @@ class EventDispatcher:
                 result = resp.read().decode('utf-8').strip()
                 return result if result else None
         except Exception as e:
-            self.ad_api.log_error(f"[EventDispatcher] Failed to resolve ZHA device name '{device_name}': {e}")
+            self.logger_interface.log_error(f"[EventDispatcher] Failed to resolve ZHA device name '{device_name}': {e}")
             return None
 
     def _resolve_zha_device_name(self, data):
@@ -134,10 +141,10 @@ class EventDispatcher:
         ieee = self._lookup_zha_ieee(name)
         resolved = {k: v for k, v in data.items() if k != 'device_name'}
         if ieee is not None:
-            self.ad_api.log_info(f"[EventDispatcher] Resolved ZHA device name '{name}' to IEEE '{ieee}'")
+            self.logger_interface.log_info(f"[EventDispatcher] Resolved ZHA device name '{name}' to IEEE '{ieee}'")
             resolved['device_ieee'] = ieee
         else:
-            self.ad_api.log_error(f"[EventDispatcher] ZHA device '{name}' not found — 'device_name' filter ignored")
+            self.logger_interface.log_error(f"[EventDispatcher] ZHA device '{name}' not found — 'device_name' filter ignored")
         return resolved
 
     def process_event(self,data):
@@ -159,6 +166,13 @@ class EventDispatcher:
 
         #special threatment for event
         if match_event_data and not self.waiting_for_reset:
+            if self.debounce_seconds is not None:
+                import time
+                now = time.monotonic()
+                if self._last_trigger_time is not None and (now - self._last_trigger_time) < self.debounce_seconds:
+                    return False
+                self._last_trigger_time = now
+
             if self.reset_data != None: 
                 self.waiting_for_reset = True
             
@@ -171,11 +185,15 @@ class EventDispatcher:
         return False
 
 class EventHandler:
-    def __init__(self, ad_api,events_block,callback,event_context = None): #event_context is passed back to the CB has a context
+    def __init__(self, ad_api,events_block,callback,event_context = None, logger_interface = None): #event_context is passed back to the CB has a context
         def register_event_with_params(event_block,callback,event_context):            
-            self.add_dispatcher(event_block['event_name'],callback,event_block['event_data'] if 'event_data' in event_block else None, event_block['reset_data'] if 'reset_data' in event_block else None,event_context)
+            self.add_dispatcher(event_block['event_name'],callback,event_block['event_data'] if 'event_data' in event_block else None, event_block['reset_data'] if 'reset_data' in event_block else None,event_context, event_block.get('debounce_seconds'))
 
         self.__ad_api = ad_api
+        if logger_interface:
+            self.__logger_interface = logger_interface
+        else:
+            self.__logger_interface = ad_api
         self.event_dispatchers = []
 
         if isinstance(events_block, list):
@@ -185,7 +203,8 @@ class EventHandler:
             for event_block in events_block.values():
                 register_event_with_params(event_block,callback,event_context)
 
-    def add_dispatcher(self,event_name,callback,event_data = None,reset_data = None ,event_context = None):
+    def add_dispatcher(self,event_name,callback,event_data = None,reset_data = None ,event_context = None, debounce_seconds = None):
-        self.__ad_api.log_info(f'Registering dispatcher {callback.__name__} for event "{event_name}" ({event_data})')
+        if self.__logger_interface:
-        dispatcher = EventDispatcher(self.__ad_api,event_name,callback,event_data,reset_data,event_context)
+            self.__logger_interface.log_info(f'Registering dispatcher {callback.__name__} for event "{event_name}" ({event_data})')
+        dispatcher = EventDispatcher(self.__ad_api,self.__logger_interface,event_name,callback,event_data,reset_data,event_context,debounce_seconds)
         self.event_dispatchers.append(dispatcher)

expressionparser.py

@@ -71,6 +71,7 @@ class EvaluateBase(object):
         if value == 'false': return False
         if value == False: return False
         if value == None: return False
+        if value == '': return False
         # this should be handle explicitely by the condition
         # edit: this is actually usefull if don't want disable to be evaluated as true
         if value == 'unavailable': return False

smartcondition.py

@@ -31,6 +31,7 @@ class Evaluator():
     __LOG_INIT                          = "log_init"
     __EXTRA_ENTITIES_TO_LISTEN          = "extra_entities_to_listen"
     __CONSTANTS                         = "constants"
+    __LOCAL_EXPRESSIONS_STRING          = "local_expressions"
     __UNAVAIBILITY_RESULT               = "unavaibility_result"
     
     def __init__(self, appdaemon_api, conditions_block,**kwargs):
@@ -313,6 +314,12 @@ class Evaluator():
                                     if disable_conditions_args:
                                         add_conditions_to_conditions_block(conditions_block,self.__DISABLE_CONDITIONS_STRING,disable_conditions_args)
 
+                                    local_expressions_args = param_parser.parse_args(self.__LOCAL_EXPRESSIONS_STRING, None)
+                                    if local_expressions_args:
+                                        if self.__LOCAL_EXPRESSIONS_STRING not in conditions_block:
+                                            conditions_block[self.__LOCAL_EXPRESSIONS_STRING] = {}
+                                        conditions_block[self.__LOCAL_EXPRESSIONS_STRING].update(local_expressions_args)
+
                                     if param_parser.parse_args(self.__TEMPLATE_CONDITIONS_STRING, None):
                                         self.__log(f"Template '{template}' contain recursive template",level = "ERROR")                                                            
                                     
@@ -377,7 +384,19 @@ class Evaluator():
                     if self.__log_init:
                         self.__log(f"{constant_name} = {value}")
                     self.expression_context.declare_constant(constant_name,value)
-        
+
+            local_expressions = param_parser.parse_args(self.__LOCAL_EXPRESSIONS_STRING, None)
+            if local_expressions:
+                if self.__log_init:
+                    self.__log(f"declaring local expressions:")
+                for expr_name, expr_string in local_expressions.items():
+                    if self.__log_init:
+                        self.__log(f"{expr_name} = {expr_string}")
+                    self.expression_context.declare_local_expression(expr_name, str(expr_string))
+                # Ensure sensors referenced only in local_expressions are registered as
+                # listeners even if no condition string references them directly.
+                self.__add_to_entities_to_listen(self.expression_context.get_entities_to_listen())
+
 
             trigger_conditions_args = param_parser.parse_args(self.__TRIGGER_CONDITIONS_STRING,None)
             if trigger_conditions_args:

smartobject.py

@@ -135,6 +135,22 @@ class SmartObject(hass.Hass,LoggerInterface):
     # Called at the end of initialize() after all YAML args are processed.
     def on_initialize_smart_object(self): pass
 
+    # Presence simulation extension point.
+    # HomeAlarm can call this method by app name.
+    def start_presence_simulation(self, source_app=None, slot_name=None, payload=None):
+        self.log_error(
+            f"{self.name} does not implement start_presence_simulation "
+            f"(source_app={source_app}, slot_name={slot_name})"
+        )
+
+    # Presence simulation extension point.
+    # HomeAlarm can call this method by app name.
+    def stop_presence_simulation(self, source_app=None, slot_name=None, payload=None):
+        self.log_error(
+            f"{self.name} does not implement stop_presence_simulation "
+            f"(source_app={source_app}, slot_name={slot_name})"
+        )
+
     # ------------------------------------------------------------------
     # Dataset persistence helpers
     # ------------------------------------------------------------------

unit_tests/test_template.yaml

@@ -23,6 +23,10 @@ templates_library:
     trigger_conditions: binary_sensor.off == False
     blocking_conditions:
       - binary_sensor.on
+  T4:
+    local_expressions:
+      local_threshold: "binary_sensor.true ? 170 : 200"
+    trigger_conditions: sensor.int170 == local_threshold
 
 tests:
   test_1: 
@@ -44,3 +48,25 @@ tests:
     conditions: 
       template_conditions: <T2>,<T3>
       trigger_conditions: binary_sensor.true and binary_sensor.false
+
+  # local_expressions in a template
+  test_5_local_expr_in_template_true:
+    expected_result: Succeeded
+    conditions:
+      template_conditions: <T4>
+
+  # local_expressions declared directly in conditions block
+  test_6_local_expr_inline_true:
+    expected_result: Succeeded
+    conditions:
+      local_expressions:
+        my_threshold: "binary_sensor.true ? 17 : 200"
+      trigger_conditions: sensor.int17 == my_threshold
+
+  # local_expressions inline, condition not met
+  test_7_local_expr_inline_false:
+    expected_result: Failed
+    conditions:
+      local_expressions:
+        my_threshold: "binary_sensor.false ? 17 : 200"
+      trigger_conditions: sensor.int17 == my_threshold

virtualsensors.py

@@ -5,6 +5,7 @@ from kwargsparser import kwargsParser
 from expressionparser import ParsingException
 import time
 from logger_interface import LoggerInterface
+from ad_toolbox.eventhandler import EventHandler
 
 class VirtualSensorBase:
     def __init__(self,ad_api,logger_interface, virtual_sensor_name = None, sensor_name = None,super_entity_id = None, yaml_block = None,templates_library = None, constants = None, app_name = None,self_initialize = False):        
@@ -25,7 +26,8 @@ class VirtualSensorBase:
             self.virtual_sensor_name = sensor_name.split('.')[1]
         self.sensor_domain = self.sensor_name.split(".")[0]
 
-        assert yaml_block ,f"{self.sensor_name} have a null Yaml block"
+        if not yaml_block:
+            self.log_error(f"{self.sensor_name} have a null Yaml block")
         self.yaml_block = yaml_block
         self.templates_library = templates_library
 
@@ -524,6 +526,34 @@ class BinarySensor(VirtualSensorBase):
         assert len(splitted_name) == 2,f"Invalid virtual sensor name : {virtual_sensor_name}"
         return f"binary_sensor.{splitted_name[1]}"
 
+# set a binary_sensor to true for x seconds when an event is received
+class EventSensor(VirtualSensorBase):
+    def initialize(self):
+        self.output_sensor = self.ad_api.get_entity(self.sensor_name)
+
+        if not self.output_sensor.exists():
+            self.output_sensor.set_state(state = 'off',attributes = self.attributes)
+
+        self.retain_time = self.yaml_block['retain_time']
+        self.cb_handle = None
+
+        self.event_handlers = []
+        if "activation_events" in self.yaml_block:
+            self.event_handlers.append(EventHandler(self.ad_api, self.yaml_block["activation_events"], self.on_activation_event,logger_interface = self.logger_interface))
+        
+    def on_activation_event(self, event_name, data, kwargs):
+        self.output_sensor.set_state(state = 'on')
+        if self.cb_handle is not None:
+            self.ad_api.cancel_timer(self.cb_handle)
+        self.cb_handle = self.ad_api.run_in(self.on_retain_time_elapsed, self.retain_time)
+
+    def on_retain_time_elapsed(self, kwargs):
+        self.output_sensor.set_state(state = 'off')
+        self.cb_handle = None
+
+    def generate_sensor_name(self,virtual_sensor_name):
+        return f"binary_sensor.{virtual_sensor_name}"
+
 class ValueSensor(VirtualSensorBase):
     def initialize(self):
         # should be done in the base class
@@ -608,6 +638,8 @@ class VirtualSensors():
                 self.virtual_sensors[f"sensor.{splitted_sensor[1]}"] = ValueSelector(self.ad_api,self.logger_interface,splitted_sensor[1],super_entity_id = super_entity_id,yaml_block = yaml_block['sensors'][sensor],constants = constants,templates_library = templates_library,app_name = app_name)
             elif splitted_sensor[0] == 'retain_condition':
                 self.virtual_sensors[f"binary_sensor.{splitted_sensor[1]}"] = RetainCondition(self.ad_api,self.logger_interface,splitted_sensor[1],super_entity_id = super_entity_id,yaml_block = yaml_block['sensors'][sensor],constants = constants,templates_library = templates_library,app_name = app_name)
+            elif splitted_sensor[0] == 'event_sensor':
+                self.virtual_sensors[f"binary_sensor.{splitted_sensor[1]}"] = EventSensor(self.ad_api,self.logger_interface,splitted_sensor[1],super_entity_id = super_entity_id,yaml_block = yaml_block['sensors'][sensor],constants = constants,templates_library = templates_library,app_name = app_name)
             else:
                 self.logger_interface.log_error(f"Invalid sensor prefix {splitted_sensor[0]}")
 

vscode-appdaemon/package.json

@@ -96,10 +96,20 @@
       }
     ],
     "keybindings": [
+      {
+        "command": "appdaemon.goToVirtualSensor",
+        "key": "ctrl+shift+v",
+        "mac": "cmd+shift+v"
+      },
       {
         "command": "appdaemon.goToApp",
         "key": "ctrl+shift+a",
         "mac": "cmd+shift+a"
+      },
+      {
+        "command": "appdaemon.goToVirtualSensor",
+        "key": "ctrl+shift+v",
+        "mac": "cmd+shift+v"
       }
     ]
   },

vscode-appdaemon/src/extension.ts

@@ -75,6 +75,122 @@ async function findAllApps(): Promise<Array<{
     return results;
 }
 
+// ── Virtual Sensor parsing ─────────────────────────────────────────────────
+
+type VirtualSensorEntry = {
+    sensorId: string;
+    line: number;
+    appName: string;
+    uri: vscode.Uri;
+    fileName: string;
+};
+
+type VSSectionType = 'sensors' | 'continuous_conditions' | 'averagers' | 'binary_sensors' | 'value_selectors' | 'retain_conditions' | 'default_values' | '';
+
+function mapVirtualSensorId(key: string, section: VSSectionType): string | null {
+    if (section === 'default_values') {
+        return /^(binary_sensor|sensor)\.[a-z0-9_]+$/.test(key) ? key : null;
+    }
+    if (section === 'sensors') {
+        const dot = key.indexOf('.');
+        if (dot < 0) { return null; }
+        const prefix = key.slice(0, dot);
+        const name = key.slice(dot + 1);
+        switch (prefix) {
+            case 'sensor': case 'value_selector': case 'averager': return `sensor.${name}`;
+            case 'binary_sensor': case 'continuous_condition': case 'retain_condition': return `binary_sensor.${name}`;
+            default: return null;
+        }
+    }
+    if (section === 'continuous_conditions' || section === 'retain_conditions' || section === 'binary_sensors') {
+        return key.includes('.') ? null : `binary_sensor.${key}`;
+    }
+    if (section === 'averagers' || section === 'value_selectors') {
+        return key.includes('.') ? null : `sensor.${key}`;
+    }
+    return null;
+}
+
+function parseVSSectionName(raw: string, indent: number): VSSectionType {
+    const re = new RegExp(`^\\s{${indent}}(sensors|continuous_conditions|averagers|binary_sensors|value_selectors|retain_conditions|default_values):\\s*$`);
+    const m = raw.match(re);
+    return m ? m[1] as VSSectionType : '';
+}
+
+function parseVirtualSensorsFromText(text: string): Array<{ sensorId: string; line: number; appName: string }> {
+    const lines = text.split('\n');
+    const entries: Array<{ sensorId: string; line: number; appName: string }> = [];
+
+    let currentApp = '';
+    let isVSApp = false;               // module: virtualsensors
+    let vsSection: VSSectionType = ''; // active sub-section in VirtualSensorsApp at indent=2
+    let inVSKey = false;               // in virtual_sensors: sub-block of another app
+    let nestedSection: VSSectionType = ''; // active sub-section in virtual_sensors: at indent=4
+
+    for (let i = 0; i < lines.length; i++) {
+        const raw = lines[i];
+        const trimmed = raw.trimStart();
+        if (!trimmed || trimmed.startsWith('#')) { continue; }
+        const indent = raw.length - trimmed.length;
+
+        if (indent === 0) {
+            const m = raw.match(/^([a-z][a-z0-9_]*):\s*$/);
+            currentApp = m ? m[1] : '';
+            isVSApp = false; vsSection = ''; inVSKey = false; nestedSection = '';
+            continue;
+        }
+
+        if (indent === 2) {
+            vsSection = ''; inVSKey = false; nestedSection = '';
+            if (/^\s+module:\s*virtualsensors/.test(raw)) {
+                isVSApp = true;
+            } else if (isVSApp) {
+                vsSection = parseVSSectionName(raw, 2);
+            } else {
+                if (/^\s+virtual_sensors:\s*$/.test(raw)) { inVSKey = true; }
+            }
+            continue;
+        }
+
+        if (indent === 4) {
+            nestedSection = '';
+            if (isVSApp && vsSection) {
+                const km = raw.match(/^\s+([a-z][a-z0-9_.]+):/);
+                if (km) {
+                    const sensorId = mapVirtualSensorId(km[1], vsSection);
+                    if (sensorId) { entries.push({ sensorId, line: i, appName: currentApp }); }
+                }
+            } else if (inVSKey) {
+                nestedSection = parseVSSectionName(raw, 4);
+            }
+            continue;
+        }
+
+        if (indent === 6 && inVSKey && nestedSection) {
+            const km = raw.match(/^\s+([a-z][a-z0-9_.]+):/);
+            if (km) {
+                const sensorId = mapVirtualSensorId(km[1], nestedSection);
+                if (sensorId) { entries.push({ sensorId, line: i, appName: currentApp }); }
+            }
+        }
+    }
+    return entries;
+}
+
+async function findAllVirtualSensors(): Promise<VirtualSensorEntry[]> {
+    const yamlFiles = await vscode.workspace.findFiles('**/*.yaml', '**/node_modules/**');
+    const results: VirtualSensorEntry[] = [];
+    for (const uri of yamlFiles) {
+        let doc: vscode.TextDocument;
+        try { doc = await vscode.workspace.openTextDocument(uri); } catch { continue; }
+        const fileName = vscode.workspace.asRelativePath(uri);
+        for (const e of parseVirtualSensorsFromText(doc.getText())) {
+            results.push({ ...e, uri, fileName });
+        }
+    }
+    return results;
+}
+
 // ── Symbol Providers ─────────────────────────────────────────────────────────
 
 class ADDocumentSymbolProvider implements vscode.DocumentSymbolProvider {
@@ -97,9 +213,9 @@ class ADDocumentSymbolProvider implements vscode.DocumentSymbolProvider {
 
 class ADWorkspaceSymbolProvider implements vscode.WorkspaceSymbolProvider {
     async provideWorkspaceSymbols(query: string): Promise<vscode.SymbolInformation[]> {
-        const apps = await findAllApps();
         const lq = query.toLowerCase();
-        return apps
+        const [apps, sensors] = await Promise.all([findAllApps(), findAllVirtualSensors()]);
+        const appSymbols = apps
             .filter(a => !lq || a.appName.toLowerCase().includes(lq))
             .map(a => new vscode.SymbolInformation(
                 a.appName,
@@ -107,6 +223,102 @@ class ADWorkspaceSymbolProvider implements vscode.WorkspaceSymbolProvider {
                 `module: ${a.moduleName}`,
                 new vscode.Location(a.uri, new vscode.Position(a.line, 0))
             ));
+        const sensorSymbols = sensors
+            .filter(s => !lq || s.sensorId.toLowerCase().includes(lq))
+            .map(s => new vscode.SymbolInformation(
+                s.sensorId,
+                vscode.SymbolKind.Variable,
+                s.appName,
+                new vscode.Location(s.uri, new vscode.Position(s.line, 0))
+            ));
+        return [...appSymbols, ...sensorSymbols];
+    }
+}
+
+class ADVirtualSensorDefinitionProvider implements vscode.DefinitionProvider {
+    // Simple cache: reset on save
+    private cache: VirtualSensorEntry[] | undefined;
+    private cacheExpiry = 0;
+
+    constructor(private haClient: HAClient) {}
+
+    invalidate() { this.cache = undefined; }
+
+    async getSensors(): Promise<VirtualSensorEntry[]> {
+        const now = Date.now();
+        if (this.cache && now < this.cacheExpiry) { return this.cache; }
+        this.cache = await findAllVirtualSensors();
+        this.cacheExpiry = now + 5000; // 5 s TTL
+        return this.cache;
+    }
+
+    async provideDefinition(
+        document: vscode.TextDocument,
+        position: vscode.Position
+    ): Promise<vscode.Definition | undefined> {
+        // Match any entity ID pattern (same as hover provider)
+        const wordRange = document.getWordRangeAtPosition(
+            position,
+            /[a-z][a-z_]*\.[a-z0-9][a-z0-9_]*/
+        );
+        if (!wordRange) { return undefined; }
+        const entityId = document.getText(wordRange);
+
+        // 1. Check virtual sensor index (parsed from YAML)
+        const sensors = await this.getSensors();
+        const vsMatch = sensors.find(s => s.sensorId === entityId);
+        if (vsMatch) {
+            return new vscode.Location(vsMatch.uri, new vscode.Position(vsMatch.line, 0));
+        }
+
+        // 2. Fallback: check HA entity's ad_app attribute → navigate to that app
+        const entity = this.haClient.getEntity(entityId);
+        const adApp = entity?.attributes?.ad_app as string | undefined;
+        if (!adApp) { return undefined; }
+        const apps = await findAllApps();
+        const appMatch = apps.find(a => a.appName === adApp);
+        if (!appMatch) { return undefined; }
+        return new vscode.Location(appMatch.uri, new vscode.Position(appMatch.line, 0));
+    }
+}
+
+class ADVirtualSensorHoverProvider implements vscode.HoverProvider {
+    constructor(
+        private haClient: HAClient,
+        private defProvider: ADVirtualSensorDefinitionProvider
+    ) {}
+
+    async provideHover(
+        document: vscode.TextDocument,
+        position: vscode.Position
+    ): Promise<vscode.Hover | undefined> {
+        // Find a virtual sensor whose definition is on this exact line
+        const sensors = await this.defProvider.getSensors();
+        const match = sensors.find(
+            s => s.uri.fsPath === document.uri.fsPath && s.line === position.line
+        );
+        if (!match) { return undefined; }
+
+        const entity = this.haClient.getEntity(match.sensorId);
+        if (!entity) { return undefined; }
+
+        const md = new vscode.MarkdownString();
+        md.isTrusted = true;
+        const friendly = entity.attributes?.friendly_name as string | undefined;
+        md.appendMarkdown(`### ${friendly || entity.entity_id}\n\n`);
+        md.appendMarkdown(`| | |\n|---|---|\n`);
+        md.appendMarkdown(`| **Entity** | \`${entity.entity_id}\` |\n`);
+        md.appendMarkdown(`| **State** | **\`${entity.state}\`** |\n`);
+        if (entity.attributes) {
+            const skip = new Set(['friendly_name', 'icon', 'entity_picture', 'supported_features', 'supported_color_modes']);
+            for (const [key, value] of Object.entries(entity.attributes).filter(([k]) => !skip.has(k)).slice(0, 12)) {
+                const display = typeof value === 'object' ? JSON.stringify(value) : String(value);
+                const truncated = display.length > 60 ? display.substring(0, 57) + '...' : display;
+                md.appendMarkdown(`| ${key.replace(/\|/g, '\\|')} | \`${truncated.replace(/\|/g, '\\|')}\` |\n`);
+            }
+        }
+        md.appendMarkdown(`\n*Last changed: ${entity.last_changed}*`);
+        return new vscode.Hover(md);
     }
 }
 
@@ -166,6 +378,15 @@ export async function activate(context: vscode.ExtensionContext) {
         { scheme: 'file', language: 'python' }
     ];
 
+    const virtualSensorDefProvider = new ADVirtualSensorDefinitionProvider(haClient);
+
+    // Invalidate definition cache on save so edits are picked up immediately
+    context.subscriptions.push(
+        vscode.workspace.onDidSaveTextDocument(doc => {
+            if (doc.languageId === 'yaml') { virtualSensorDefProvider.invalidate(); }
+        })
+    );
+
     context.subscriptions.push(
         vscode.languages.registerCompletionItemProvider(
             selector,
@@ -182,12 +403,46 @@ export async function activate(context: vscode.ExtensionContext) {
         ),
         vscode.languages.registerWorkspaceSymbolProvider(
             new ADWorkspaceSymbolProvider()
+        ),
+        vscode.languages.registerDefinitionProvider(
+            { scheme: 'file', language: 'yaml' },
+            virtualSensorDefProvider
+        ),
+        vscode.languages.registerHoverProvider(
+            { scheme: 'file', language: 'yaml' },
+            new ADVirtualSensorHoverProvider(haClient, virtualSensorDefProvider)
         )
     );
 
     // ── Commands ─────────────────────────────────────────────────────────────
 
     context.subscriptions.push(
+        vscode.commands.registerCommand('appdaemon.goToVirtualSensor', async () => {
+            const sensors = await findAllVirtualSensors();
+            if (sensors.length === 0) {
+                vscode.window.showWarningMessage('AppDaemon: No virtual sensors found in workspace');
+                return;
+            }
+            type SensorItem = vscode.QuickPickItem & { sensor: VirtualSensorEntry };
+            const items: SensorItem[] = sensors.map(s => ({
+                label: `$(circuit-board) ${s.sensorId}`,
+                description: s.fileName,
+                detail: `in ${s.appName}`,
+                sensor: s
+            }));
+            const picked = await vscode.window.showQuickPick(items, {
+                placeHolder: 'Go to virtual sensor…',
+                matchOnDescription: true,
+                matchOnDetail: true
+            });
+            if (!picked) { return; }
+            const doc = await vscode.workspace.openTextDocument(picked.sensor.uri);
+            const editor = await vscode.window.showTextDocument(doc);
+            const pos = new vscode.Position(picked.sensor.line, 0);
+            editor.selection = new vscode.Selection(pos, pos);
+            editor.revealRange(new vscode.Range(pos, pos), vscode.TextEditorRevealType.InCenter);
+        }),
+
         vscode.commands.registerCommand('appdaemon.goToApp', async () => {
             const apps = await findAllApps();
             if (apps.length === 0) {