feat: 为 PointMonitorInfo 添加旧值追踪和值变化检测

src/event.rs

@@ -131,6 +131,18 @@ impl EventManager {
                         };
 
                         if let Some(point_id) = point_id {
+                            // 从缓存中读取旧值
+                            let monitor_data = connection_manager.get_point_monitor_data_read_guard().await;
+                            let old_monitor_info = monitor_data.get(&point_id);
+
+                            let (old_value, old_timestamp, value_changed) = if let Some(old_info) = old_monitor_info {
+                                let changed = old_info.value != payload.value || 
+                                             old_info.timestamp != payload.timestamp;
+                                (old_info.value.clone(), old_info.timestamp, changed)
+                            } else {
+                                (None, None, false)
+                            };
+
                             let monitor = crate::telemetry::PointMonitorInfo {
                                 protocol: payload.protocol.clone(),
                                 source_id,
@@ -142,6 +154,9 @@ impl EventManager {
                                 value: payload.value.clone(),
                                 value_type: payload.value_type.clone(),
                                 value_text: payload.value_text.clone(),
+                                old_value,
+                                old_timestamp,
+                                value_changed,
                             };
 
                             if let Err(e) = connection_manager.update_point_monitor_data(monitor.clone()).await {

src/telemetry.rs

@@ -43,6 +43,7 @@ impl PointQuality {
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
 #[serde(tag = "kind", content = "value", rename_all = "snake_case")]
+#[derive(PartialEq)]
 pub enum DataValue {
     Null,
     Bool(bool),
@@ -85,6 +86,9 @@ pub struct PointMonitorInfo {
     pub value: Option<DataValue>,
     pub value_type: Option<ValueType>,
     pub value_text: Option<String>,
+    pub old_value: Option<DataValue>,
+    pub old_timestamp: Option<DateTime<Utc>>,
+    pub value_changed: bool,
 }
 
 impl PointMonitorInfo {