feat(frontend): 12-month heatmap component

packages/frontend/src/components/Heatmap.tsx

@@ -0,0 +1,91 @@
+import { useMemo } from 'react';
+
+interface HeatmapPoint { day: string; sessions: number; attempts: number; }
+
+export function Heatmap({ points }: { points: HeatmapPoint[] }) {
+  const grid = useMemo(() => {
+    const map = new Map<string, HeatmapPoint>();
+    for (const p of points) map.set(p.day, p);
+    const today = new Date();
+    today.setUTCHours(0, 0, 0, 0);
+    const lastSat = new Date(today);
+    while (lastSat.getUTCDay() !== 6) lastSat.setUTCDate(lastSat.getUTCDate() + 1);
+
+    const weeks: { date: Date; data?: HeatmapPoint }[][] = [];
+    const cursor = new Date(lastSat);
+    cursor.setUTCDate(cursor.getUTCDate() - 53 * 7 + 1);
+    for (let w = 0; w < 53; w++) {
+      const col: { date: Date; data?: HeatmapPoint }[] = [];
+      for (let d = 0; d < 7; d++) {
+        const key = `${cursor.getUTCFullYear()}-${cursor.getUTCMonth()}-${cursor.getUTCDate()}`;
+        col.push({ date: new Date(cursor), data: map.get(key) });
+        cursor.setUTCDate(cursor.getUTCDate() + 1);
+      }
+      weeks.push(col);
+    }
+    return weeks;
+  }, [points]);
+
+  function colorFor(attempts: number): string {
+    if (attempts === 0) return 'bg-slate-100 dark:bg-slate-800';
+    if (attempts < 5) return 'bg-success-200 dark:bg-success-400/30';
+    if (attempts < 15) return 'bg-success-400 dark:bg-success-400/60';
+    if (attempts < 50) return 'bg-success-500 dark:bg-success-500/80';
+    return 'bg-success-700 dark:bg-success-500';
+  }
+
+  const monthLabels = useMemo(() => {
+    const labels: { col: number; text: string }[] = [];
+    let lastMonth = -1;
+    grid.forEach((col, i) => {
+      const m = col[0]!.date.getUTCMonth();
+      if (m !== lastMonth) {
+        labels.push({ col: i, text: ['jan','feb','mrt','apr','mei','jun','jul','aug','sep','okt','nov','dec'][m]! });
+        lastMonth = m;
+      }
+    });
+    return labels;
+  }, [grid]);
+
+  const todayKey = (() => {
+    const t = new Date();
+    return `${t.getUTCFullYear()}-${t.getUTCMonth()}-${t.getUTCDate()}`;
+  })();
+
+  return (
+    <div className="overflow-x-auto">
+      <div className="inline-block">
+        <div className="relative ml-8 mb-1 h-4 text-xs text-slate-500">
+          {monthLabels.map((m, i) => (
+            <span key={i} className="absolute" style={{ left: m.col * 16 }}>{m.text}</span>
+          ))}
+        </div>
+        <div className="flex gap-1">
+          <div className="flex flex-col gap-1 pt-0">
+            {['Ma', '', 'Wo', '', 'Vr', '', ''].map((label, i) => (
+              <span key={i} className="h-3 w-6 text-[10px] leading-3 text-slate-500">{label}</span>
+            ))}
+          </div>
+          <div className="flex gap-1">
+            {grid.map((col, i) => (
+              <div key={i} className="flex flex-col gap-1">
+                {col.map((cell, j) => {
+                  const key = `${cell.date.getUTCFullYear()}-${cell.date.getUTCMonth()}-${cell.date.getUTCDate()}`;
+                  const isToday = key === todayKey;
+                  const a = cell.data?.attempts ?? 0;
+                  return (
+                    <div
+                      key={j}
+                      title={`${cell.date.toISOString().slice(0, 10)} — ${a} pogingen, ${cell.data?.sessions ?? 0} sessies`}
+                      className={`h-3 w-3 rounded-sm ${colorFor(a)} ${isToday ? 'ring-1 ring-brand-600' : ''}`}
+                    />
+                  );
+                })}
+              </div>
+            ))}
+          </div>
+        </div>
+      </div>
+    </div>
+  );
+}