Implement SOS mode with color selection

apps/wristlight/ChangeLog

@@ -1,2 +1,3 @@
 0.01: New app!
 0.02: Minor code improvements
+0.03: Added SOS blinking functionality with user-selected color and touch interaction to set the main screen color. Minor code improvements

apps/wristlight/app.js

@@ -1,16 +1,17 @@
+var sosInterval;
+var currentColor = "#ffffff"; // last selected color
+
 function draw(color) {
   if (color == undefined) {
     color = -1;
   }
   g.clear();
   g.setColor(color);
   g.fillRect(0, 0, g.getWidth(), g.getHeight());
-}
 
-function draw2Pattern() {
-  const colors = ["ff0000", "8080ff", "00ff00",
-            "ffffff"];
-  drawPattern(2, colors);
+  // Store the current color only if it is a valid user-selected color
+  // "#000000" is used internally when blinking (SOS off state)
+  if (typeof color === "string" && color !== "#000000") currentColor = color;
 }
 
 function draw3Pattern() {
@@ -24,22 +25,62 @@ function drawPattern(size, colors) {
   g.clear();
   var w = g.getWidth() / size;
   var h = g.getHeight() / size;
+
+  // Draw selectable color blocks
   for (var i = 0; i < size; i++) {
     for (var j = 0; j < size; j++) {
       var color = colors[i*size + j];
       g.setColor("#" + color);
       g.fillRect(j * w, i * h, j * w + w, i * h + h);
     }
   }
+
+  // Touching a block sets the main screen color
   Bangle.on("touch", function(btn, xy) {
+    // If SOS mode is active, stop it when user interacts
+    if (sosInterval) {
+      clearInterval(sosInterval);
+      sosInterval = undefined;
+    }
+
     var x = parseInt((xy.x) / w);
     var y = parseInt((xy.y) / h);
     draw("#" + colors[y * size + x]);
   });
 }
 
-// Clear the screen once, at startup
-// draw immediately at first
+// Start SOS blinking using the selected color
+function startSOS() {
+  if (sosInterval) return;
+  var on = false;
+  sosInterval = setInterval(function() {
+    on = !on;
+    if (on) {
+      draw(currentColor); // active/on state
+    } else {
+      draw("#000000"); // off/black state
+    }
+  }, 200); // blinking frequency
+}
+
+// Stop SOS blinking
+function stopSOS() {
+  if (sosInterval) {
+    clearInterval(sosInterval);
+    sosInterval = undefined;
+  }
+}
+
+// Toggle SOS mode using the hardware button
+setWatch(function() {
+  if (sosInterval) {
+    stopSOS();
+  } else {
+    startSOS();
+  }
+}, BTN1, {repeat:true, edge:"rising"});
+
+// Show the color grid at startup
 draw3Pattern();
 
 /*

apps/wristlight/metadata.json

@@ -2,7 +2,7 @@
   "name": "Wrist Light",
   "shortName":"Wrist Light",
   "icon": "wristlight48.png",
-  "version": "0.02",
+  "version": "0.03",
   "description": "A flash light with different colors on your wrist",
   "tags": "flash,light",
   "allow_emulator":true,