android - Use GadgetBridge GPS data whenever it arrives

apps/android/boot.js

@@ -6,6 +6,7 @@
   var lastMsg; // for music messages - may not be needed now...
   var actInterval; // Realtime activity reporting interval when `act` is true
   var actHRMHandler; // For Realtime activity reporting
+  var gpsState = {}; // keep information on GPS via Gadgetbridge
 
   // this settings var is deleted after this executes to save memory
   var settings = require("Storage").readJSON("android.settings.json",1)||{};
@@ -139,6 +140,8 @@
       "gps": function() {
         const settings = require("Storage").readJSON("android.settings.json",1)||{};
         if (!settings.overwriteGps) return;
+
+        // modify event for using it as Bangle GPS event
         delete event.t;
         event.satellites = NaN;
         if (!isFinite(event.course)) event.course = NaN;
@@ -147,6 +150,28 @@
           event.lon = event.long;
           delete event.long;
         }
+
+        if (!gpsState.firstGPSEvent) {
+          // this is the first event, save time of arrival and deactivate internal GPS
+          gpsState.firstGPSEvent = Date.now();
+          Bangle.moveGPSPower(0);
+        } else {
+          if (!gpsState.interval){
+            // this is the second event, store the intervall for expecting the next GPS event
+            gpsState.interval = Date.now() - gpsState.firstGPSEvent;
+          }
+        }
+        // in any case, cleanup the GPS state in case no new events arrive
+        if (gpsState.timeoutGPS) clearTimeout(gpsState.timeoutGPS);
+        gpsState.timeoutGPS = setTimeout(()=>{
+          // reset state
+          gpsState.firstGPSEvent = undefined;
+          gpsState.timeoutGPS = undefined;
+          gpsState.interval = undefined;
+          // did not get an expected GPS event but have GPS clients, switch back to internal GPS
+          if (Bangle.isGPSOn()) Bangle.moveGPSPower(1);
+        }, (gpsState.interval || 10000) + 1000);
+
         Bangle.emit('GPS', event);
       },
       // {t:"is_gps_active"}
@@ -261,7 +286,7 @@
   if (settings.overwriteGps) { // if the overwrite option is set../
     const origSetGPSPower = Bangle.setGPSPower;
     // migrate all GPS clients to the other variant on connection events
-    let handleConnection = (state) => {
+    Bangle.moveGPSPower = (state) => {
       if (Bangle.isGPSOn()){
         let orig = Bangle._PWR.GPS;
         delete Bangle._PWR.GPS;
@@ -269,39 +294,50 @@
         Bangle._PWR.GPS = orig;
       }
     };
-    NRF.on('connect', ()=>{handleConnection(0);});
-    NRF.on('disconnect', ()=>{handleConnection(1);});
 
-    // Work around Serial1 for GPS not working when connected to something
+    // work around Serial1 for GPS not working when connected to something
     let serialTimeout;
     let wrap = function(f){
       return (s)=>{
         if (serialTimeout) clearTimeout(serialTimeout);
-        handleConnection(1);
+        Bangle.moveGPSPower(1);
         f(s);
         serialTimeout = setTimeout(()=>{
           serialTimeout = undefined;
-          if (NRF.getSecurityStatus().connected) handleConnection(0);
+          if (gpsState.firstGPSEvent) Bangle.moveGPSPower(0);
         }, 10000);
       };
     };
     Serial1.println = wrap(Serial1.println);
     Serial1.write = wrap(Serial1.write);
 
-    // Replace set GPS power logic to suppress activation of gps (and instead request it from the phone)
+    // update the GPS state on reconnect
+    NRF.on("connect", ()=>{
+      gbSend({ t: "gps_power", status: Bangle.isGPSOn() });
+    });
+
+    // replace set GPS power logic to suppress activation of gps (and instead request it from the phone)
     Bangle.setGPSPower = (isOn, appID) => {
-      // if not connected use internal GPS power function
-      if (!NRF.getSecurityStatus().connected) return origSetGPSPower(isOn, appID);
-      if (!Bangle._PWR) Bangle._PWR={};
-      if (!Bangle._PWR.GPS) Bangle._PWR.GPS=[];
-      if (!appID) appID="?";
-      if (isOn && !Bangle._PWR.GPS.includes(appID)) Bangle._PWR.GPS.push(appID);
-      if (!isOn && Bangle._PWR.GPS.includes(appID)) Bangle._PWR.GPS.splice(Bangle._PWR.GPS.indexOf(appID),1);
-      let pwr = Bangle._PWR.GPS.length>0;
+      let pwr;
+      if (!gpsState.firstGPSEvent){
+        // use internal GPS power function if no gps event has arrived from GadgetBridge
+        pwr = origSetGPSPower(isOn, appID);
+      } else {
+        // we currently expecting the next GPS event from GadgetBridge, keep track of GPS state per App
+        if (!Bangle._PWR) Bangle._PWR={};
+        if (!Bangle._PWR.GPS) Bangle._PWR.GPS=[];
+        if (!appID) appID="?";
+        if (isOn && !Bangle._PWR.GPS.includes(appID)) Bangle._PWR.GPS.push(appID);
+        if (!isOn && Bangle._PWR.GPS.includes(appID)) Bangle._PWR.GPS.splice(Bangle._PWR.GPS.indexOf(appID),1);
+        pwr = Bangle._PWR.GPS.length>0;
+        // stop internal GPS, no clients left
+        if (!pwr) origSetGPSPower(0);
+      }
+      // always update Gadgetbridge on current power state
       gbSend({ t: "gps_power", status: pwr });
       return pwr;
     };
-    // Allow checking for GPS via GadgetBridge
+    // allow checking for GPS via GadgetBridge
     Bangle.isGPSOn = () => {
       return !!(Bangle._PWR && Bangle._PWR.GPS && Bangle._PWR.GPS.length>0);
     };
@@ -313,4 +349,4 @@
 
   // remove settings object so it's not taking up RAM
   delete settings;
-})();
+})();