stopwatch: Save state to storage

This keeps the stopwatch running in the background.

apps/stopwatch/ChangeLog

@@ -1,3 +1,4 @@
 0.01: first release
 0.02: Adjust for touch events outside of screen g dimensions
 0.03: Do not register as watch, manually start clock on button
+0.04: Keep running in background by saving state

apps/stopwatch/metadata.json

@@ -1,7 +1,7 @@
 {
   "id": "stopwatch",
   "name": "Stopwatch Touch",
-  "version": "0.03",
+  "version": "0.04",
   "description": "A touch based stop watch for Bangle JS 2",
   "icon": "stopwatch.png",
   "screenshots": [{"url":"screenshot1.png"},{"url":"screenshot2.png"},{"url":"screenshot3.png"}],

apps/stopwatch/stopwatch.app.js

@@ -1,9 +1,21 @@
+const CONFIGFILE = "stopwatch.json";
+
+const now = Date.now();
+const config = Object.assign({
+    state: {
+        total: now,
+        start: now,
+        current: now,
+        running: false,
+    }
+}, require("Storage").readJSON(CONFIGFILE,1) || {});
+
 let w = g.getWidth();
 let h = g.getHeight();
-let tTotal = Date.now();
-let tStart = tTotal;
-let tCurrent = tTotal;
-let running = false;
+let tTotal = config.state.total;
+let tStart = config.state.start;
+let tCurrent = config.state.current;
+let running = config.state.running;
 let timeY = 2*h/5;
 let displayInterval;
 let redrawButtons = true;
@@ -15,6 +27,14 @@ const pause_img = atob("GBiBAf////////////////wYP/wYP/wYP/wYP/wYP/wYP/wYP/wYP/wY
 const play_img = atob("GBjBAP//AAAAAAAAAAAIAAAOAAAPgAAP4AAP+AAP/AAP/wAP/8AP//AP//gP//gP//AP/8AP/wAP/AAP+AAP4AAPgAAOAAAIAAAAAAAAAAA=");
 const reset_img = atob("GBiBAf////////////AAD+AAB+f/5+f/5+f/5+cA5+cA5+cA5+cA5+cA5+cA5+cA5+cA5+f/5+f/5+f/5+AAB/AAD////////////w==");
 
+function saveState() {
+    config.state.total = tTotal;
+    config.state.start = tStart;
+    config.state.current = tCurrent;
+    config.state.running = running;
+    require("Storage").writeJSON(CONFIGFILE, config);
+}
+
 function log_debug(o) {
   //console.log(o);
 }
@@ -106,6 +126,7 @@ function stopStart() {
   } else {
     draw();
   }
+  saveState();
 }
 
 function setButtonImages() {
@@ -130,6 +151,7 @@ function lapReset() {
     g.clearRect(0,24,w,h);
     draw();
   }
+  saveState();
 }
 
 // simple on screen button class
@@ -226,5 +248,10 @@ g.fillRect(0,0,w,h);
 
 Bangle.loadWidgets();
 Bangle.drawWidgets();
-draw();
+setButtonImages();
+if (running) {
+    startTimer();
+} else {
+    draw();
+}
 setWatch(() => load(), BTN, { repeat: false, edge: "falling" });