Random colors for stats graphs

subscription/templates/subscription/stats.jinja

@@ -37,7 +37,7 @@
         {% for location in locations %}
             <th>{{ location[1] }}</th>
         {% endfor %}
-        <th>{% trans %}Total{% endtrans %}</th>
+        <th id="graphLabel">{% trans %}Total{% endtrans %}</th>
         {% for type in subscriptions_types %}
         <tr>
             <td><i class="types" >{{ subscriptions_types[type]['name'] }}</i></td>
@@ -61,38 +61,64 @@
 {% block script %}
 {{ super() }}
 <script>
+function getRandomColor() {
+    var letters = '0123456789ABCDEF';
+    var color = '#';
+    for (var i = 0; i < 6; i++ ) {
+        color += letters[Math.floor(Math.random() * 16)];
+    }
+    return color;
+}
+function getRandomColorUniq(list) {
+    var color = getRandomColor();
+    while (list.includes(color)){
+        color = getRandomColor();
+    }
+    return color;
+}
+function hexToRgb(hex) {
+    // Expand shorthand form (e.g. "03F") to full form (e.g. "0033FF")
+    var shorthandRegex = /^#?([a-f\d])([a-f\d])([a-f\d])$/i;
+    hex = hex.replace(shorthandRegex, function(m, r, g, b) {
+        return r + r + g + g + b + b;
+    });
+
+    var result = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(hex);
+    return result ? {
+        r: parseInt(result[1], 16),
+        g: parseInt(result[2], 16),
+        b: parseInt(result[3], 16)
+    } : null;
+}
+
 var ctx = document.getElementById("statsChart").getContext('2d');
 var labels = [];
 var total = [];
+var colors = [];
+var colors_dimmed = [];
 Array.from(document.getElementsByClassName("types")).forEach(function(element){
     labels.push(element.childNodes[0].data);
 });
 Array.from(document.getElementsByClassName("total")).forEach(function(element){
     total.push(element.childNodes[0].childNodes[0].data);
 });
+labels.forEach(function(element){
+    colors.push(getRandomColorUniq(colors));
+});
+colors.forEach(function(element){
+    var rgb_color = hexToRgb(element);
+    colors_dimmed.push('rgba(' + rgb_color.r + ', ' + rgb_color.g + ', ' + rgb_color.b + ', 0.2)');
+});
+console.log(colors);console.log(colors_dimmed);
 var myChart = new Chart(ctx, {
     type: 'bar',
     data: {
         labels: labels,
         datasets: [{
-            label: 'Nombre de cotisations',
+            label: document.getElementById("graphLabel").childNodes[0].data,
             data: total,
-            backgroundColor: [
-                'rgba(255, 99, 132, 0.2)',
-                'rgba(54, 162, 235, 0.2)',
-                'rgba(255, 206, 86, 0.2)',
-                'rgba(75, 192, 192, 0.2)',
-                'rgba(153, 102, 255, 0.2)',
-                'rgba(255, 159, 64, 0.2)'
-            ],
-            borderColor: [
-                'rgba(255,99,132,1)',
-                'rgba(54, 162, 235, 1)',
-                'rgba(255, 206, 86, 1)',
-                'rgba(75, 192, 192, 1)',
-                'rgba(153, 102, 255, 1)',
-                'rgba(255, 159, 64, 1)'
-            ],
+            backgroundColor: colors_dimmed,
+            borderColor: colors,
             borderWidth: 1
         }]
     },