Add timeline car import and CO2 trip stats

templates/trip/stats.html

@@ -6,6 +6,14 @@
 
 {% block title %}{{ heading }} - Edward Betts{% endblock %}
 
+{% block style %}
+<style>
+.co2-chart {
+  height: 240px;
+}
+</style>
+{% endblock %}
+
 {% macro stat_list(id, label, counter, show_top=5) %}
   <div class="mb-2">
     <strong>{{ label }}:</strong> {{ counter | count }}
@@ -24,6 +32,14 @@
   </div>
 {% endmacro %}
 
+{% macro format_co2(co2_kg) %}
+  {% if co2_kg >= 1000 %}
+    {{ "{:,.2f}".format(co2_kg / 1000.0) }} tonnes
+  {% else %}
+    {{ "{:,.0f}".format(co2_kg) }} kg
+  {% endif %}
+{% endmacro %}
+
 {% block content %}
 <div class="container-fluid">
   <h1>Trip statistics</h1>
@@ -39,10 +55,21 @@
           {% for transport_type, distance in distances_by_transport_type %}
             <div class="ms-3">{{ transport_type | title }}: {{ format_distance(distance) }}</div>
           {% endfor %}
+          {% if total_co2_kg %}
+            <div class="mt-2">CO₂: {{ format_co2(total_co2_kg) }}</div>
+          {% endif %}
+          {% for transport_type, co2_kg in co2_by_transport_type %}
+            <div class="ms-3">{{ transport_type | title }} CO₂: {{ format_co2(co2_kg) }}</div>
+          {% endfor %}
         </div>
         <div class="col-md-6">
           <div>Flight segments: {{ overall_stats.flight_count }}</div>
           <div>Train segments: {{ overall_stats.train_count }}</div>
+          {% if co2_by_transport_type %}
+            <div class="co2-chart mt-3">
+              <canvas id="overall-co2-chart"></canvas>
+            </div>
+          {% endif %}
         </div>
       </div>
 
@@ -79,12 +106,12 @@
             <div>Flight segments: {{ year_stats.flight_count or 0 }}</div>
             <div>Train segments: {{ year_stats.train_count or 0 }}</div>
             {% if year_stats.co2_kg %}
-              <div>CO₂:
-                {% if year_stats.co2_kg >= 1000 %}
-                  {{ "{:,.2f}".format(year_stats.co2_kg / 1000.0) }} tonnes
-                {% else %}
-                  {{ "{:,.0f}".format(year_stats.co2_kg) }} kg
-                {% endif %}
+              <div>CO₂: {{ format_co2(year_stats.co2_kg) }}</div>
+              {% for transport_type, co2_kg in year_stats.co2_by_transport_type.items() %}
+                <div class="ms-3">{{ transport_type | title }} CO₂: {{ format_co2(co2_kg) }}</div>
+              {% endfor %}
+              <div class="co2-chart mt-3">
+                <canvas id="co2-chart-{{ year }}"></canvas>
               </div>
             {% endif %}
           </div>
@@ -119,3 +146,72 @@
   {% endfor %}
 </div>
 {% endblock %}
+
+{% block scripts %}
+<script src="https://cdn.jsdelivr.net/npm/chart.js"></script>
+<script>
+const co2ChartColors = [
+  "#4e79a7",
+  "#f28e2b",
+  "#e15759",
+  "#76b7b2",
+  "#59a14f",
+  "#edc948",
+  "#b07aa1",
+  "#ff9da7",
+  "#9c755f",
+  "#bab0ac",
+];
+
+function titleCase(value) {
+  return value.replace(/\b\w/g, char => char.toUpperCase());
+}
+
+function co2TooltipLabel(context) {
+  const label = context.label || "";
+  const value = context.parsed || 0;
+  return `${label}: ${value.toLocaleString(undefined, { maximumFractionDigits: 1 })} kg`;
+}
+
+function renderCo2Chart(id, values) {
+  const canvas = document.getElementById(id);
+  if (!canvas || !values || values.length === 0) {
+    return;
+  }
+
+  new Chart(canvas.getContext("2d"), {
+    type: "pie",
+    data: {
+      labels: values.map(item => titleCase(item[0])),
+      datasets: [{
+        data: values.map(item => item[1]),
+        backgroundColor: co2ChartColors,
+      }],
+    },
+    options: {
+      responsive: true,
+      maintainAspectRatio: false,
+      plugins: {
+        legend: {
+          position: "right",
+        },
+        tooltip: {
+          callbacks: {
+            label: co2TooltipLabel,
+          },
+        },
+      },
+    },
+  });
+}
+
+renderCo2Chart("overall-co2-chart", {{ co2_by_transport_type | tojson }});
+{% for year, year_stats in yearly_stats | dictsort(reverse=True) %}
+{% set year_co2_by_transport_type = year_stats.co2_by_transport_type | default({}) %}
+renderCo2Chart(
+  "co2-chart-{{ year }}",
+  {{ year_co2_by_transport_type.items() | list | tojson }}
+);
+{% endfor %}
+</script>
+{% endblock %}