Add SHOW_DIRECTION configuration feature

Co-authored-by: fz6m <[email protected]>

Author: Copilot

app-rust/src/config.rs

@@ -20,6 +20,8 @@ pub struct Config {
     pub xiaomi_band: Option<bool>,
     #[serde(rename = "HEART_RATE_LABEL")]
     pub heart_rate_label: HashMap<String, Vec<String>>,
+    #[serde(rename = "SHOW_DIRECTION")]
+    pub show_direction: bool,
 }
 
 impl Default for Config {
@@ -49,6 +51,7 @@ impl Default for Config {
             apple_watch: false,
             xiaomi_band: Some(false),
             heart_rate_label,
+            show_direction: false,
         }
     }
 }
@@ -94,7 +97,7 @@ impl Config {
     }
 
     /// Get heart rate text based on BPM and configured thresholds
-    pub fn get_heart_rate_text(&self, bpm: u32) -> Option<String> {
+    pub fn get_heart_rate_text(&self, bpm: u32, previous_bpm: Option<u32>) -> Option<String> {
         // Find the appropriate threshold
         let thresholds: Vec<u32> = self.heart_rate_label.keys()
             .filter_map(|k| k.parse().ok())
@@ -123,6 +126,20 @@ impl Config {
             &labels[index]
         };
 
-        Some(label.replace("{{bpm}}", &bpm.to_string()))
+        let mut text = label.replace("{{bpm}}", &bpm.to_string());
+        
+        // Add direction indicator if enabled and previous BPM is available
+        if self.show_direction {
+            if let Some(prev_bpm) = previous_bpm {
+                if bpm > prev_bpm {
+                    text.push_str("【↑】");
+                } else if bpm < prev_bpm {
+                    text.push_str("【↓】");
+                }
+                // No indicator when values are equal
+            }
+        }
+        
+        Some(text)
     }
 }

app-rust/src/heart_rate.rs

@@ -28,6 +28,7 @@ pub struct HeartRateMonitor {
     start_time: Instant,
     heart_rate_count: u32,
     heart_rate_sum: u32,
+    previous_heart_rate: Option<u32>,
 }
 
 impl HeartRateMonitor {
@@ -51,6 +52,7 @@ impl HeartRateMonitor {
             start_time: Instant::now(),
             heart_rate_count: 0,
             heart_rate_sum: 0,
+            previous_heart_rate: None,
         }
     }
 
@@ -300,6 +302,9 @@ impl HeartRateMonitor {
         // Send OSC message (with rate limiting)
         self.send_osc_message(heart_rate).await?;
 
+        // Store current heart rate as previous for next iteration
+        self.previous_heart_rate = Some(heart_rate);
+
         Ok(())
     }
 
@@ -313,7 +318,7 @@ impl HeartRateMonitor {
             return Ok(());
         }
 
-        if let Some(text) = self.config.get_heart_rate_text(heart_rate) {
+        if let Some(text) = self.config.get_heart_rate_text(heart_rate, self.previous_heart_rate) {
             if let Some(osc_client) = &self.osc_client {
                 match osc_client.send_message(&text).await {
                     Ok(_) => {