Update mouse

data/js/mouse.js

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+// Enum available loco mode
+var LOCO_MODE = {
+    ANALOG: 0,  // Analog mode is for old DC locomotives that use a variable voltage on the track to control speed.
+    MARKLIN: 1, // Märklin mode is for old marklin analog AC (with relay dir) Märklin locomotives.
+    DCC: 2      // DCC mode is for Digital Command Control, a standard for digital model railway control.
+};
+
+var LOCO_DIR = {
+    FORWARD: 0, // Forward direction
+    BACKWARD: 1 // Backward direction
+};
+
+var Loco = {
+    Mode: LOCO_MODE.DCC,
+    ID: 0,
+    Speed: 0,
+    Dir: LOCO_DIR.FORWARD,
+    Scale: 1,    // Example real loco speed is 45Kmh/max, so what are step (128 for digital to represent 0-200Kmh) per Kmh
+    MaxSpeed: 100, // Max speed in DCC step (<129) to reach scale speed (e.g. 45Kmh)
+    setMode: function(mode) {
+        this.Mode = mode;
+    },
+    setID: function(id) {
+        this.ID = id;
+    },
+    setSpeed: function(speed) {
+        this.Speed = speed;
+        setSpeed(speed); // Update the speedometer needle
+    },
+    setDir: function(dir) {
+        this.Dir = dir;
+    }
+};
+
+/**
+ * Update the speedometer based on the slider value. The slider value is expected to be in the range 0-128, 
+ * when a value is received, it is converted to a speed in Kmh based on the loco's scale and max speed, 
+ * then the speedometer needle is updated accordingly.
+ * 
+ * @param {int} value 
+ */
+function updateSpeedometer(value) {
+    Loco.setSpeed(parseInt(value));
+}
+
+/**
+ * Speed is expected to be in the range 0-200. This function maps it to an angle for the needle.
+ * at 100Kmh, needle is vertical, it's length is 50px, and it rotates from -120deg (0 speed) to +120deg (max speed).
+ * At speed=100, x2=150, y2=70
+ */
+function setSpeed(speed) 
+{
+    // Clamp speed
+    speed = Math.max(0, Math.min(200, speed));
+    // Map speed to angle: 0 = -120deg, 100 = 0deg, 200 = +120deg
+    var angle = -120 + (speed / 200) * 240;
+    var rad = angle * Math.PI / 180;
+    var r = 50; // needle length
+    var cx = 150, cy = 120;
+    var x2 = cx + r * Math.sin(rad); // Use sin for x, cos for y to match SVG coordinate system
+    var y2 = cy - r * Math.cos(rad);
+    document.getElementById('needle').setAttribute('x2', x2);
+    document.getElementById('needle').setAttribute('y2', y2);
+}
+
+// Example: set speed to 0 initially
+setSpeed(0);