localise chart + make daily data reachable on touch/keyboard

src/components/dashboard/usage-display.tsx

@@ -1,6 +1,6 @@
 "use client";
 
-import { useTranslations } from "next-intl";
+import { useTranslations, useLocale } from "next-intl";
 import { useEffect, useState, useCallback } from "react";
 import { BudgetEditableCard } from "@/components/dashboard/budget-editable-card";
 
@@ -84,42 +84,149 @@ function formatMonth(month: string, locale: string): string {
 }
 
 function UsageChart({ data }: { data: DailyUsage[] }) {
+  const t = useTranslations("usage");
+  const locale = useLocale();
+  // Which day's detail is shown in the readout. Defaults to the most
+  // recent day; hover (mouse), tap (touch) or focus (keyboard) all
+  // update it. The previous version put per-day numbers only in SVG
+  // <title> hover tooltips, which are unreachable on touch devices and
+  // invisible to keyboard users — this readout fixes both.
+  const [selected, setSelected] = useState<number | null>(null);
+
   if (!data.length) return null;
-  const maxTokens = Math.max(...data.map((d) => d.inputTokens + d.outputTokens), 1);
+
+  const maxTokens = Math.max(
+    ...data.map((d) => d.inputTokens + d.outputTokens),
+    1
+  );
   const barW = Math.max(4, Math.floor(600 / data.length) - 2);
   const h = 120;
 
+  const activeIndex = selected ?? data.length - 1;
+  const active = data[activeIndex];
+
+  const dayLabel = (iso: string) => {
+    const [y, m, dd] = iso.split("-").map(Number);
+    return new Date(y, m - 1, dd).toLocaleDateString(locale, {
+      month: "short",
+      day: "numeric",
+    });
+  };
+
+  const barAria = (d: DailyUsage) =>
+    `${dayLabel(d.date)}: ${fmt(d.inputTokens)} ${t("inputTokens")}, ${fmt(
+      d.outputTokens
+    )} ${t("outputTokens")}, ${chf(d.spend)}`;
+
   return (
-    <div className="overflow-x-auto">
-      <svg
-        viewBox={`0 0 ${Math.max(data.length * (barW + 2), 600)} ${h + 24}`}
-        className="w-full h-36"
-        preserveAspectRatio="xMinYMid meet"
-      >
-        {data.map((d, i) => {
-          const total = d.inputTokens + d.outputTokens;
-          const totalH = (total / maxTokens) * h;
-          const inputH = (d.inputTokens / maxTokens) * h;
-          const x = i * (barW + 2);
-          return (
-            <g key={d.date}>
-              <title>{d.date}: {fmt(d.inputTokens)} in / {fmt(d.outputTokens)} out — {chf(d.spend)}</title>
-              <rect x={x} y={h - totalH} width={barW} height={totalH - inputH} rx={1} fill="var(--color-accent)" opacity={0.3} />
-              <rect x={x} y={h - inputH} width={barW} height={inputH} rx={1} fill="var(--color-accent)" opacity={0.7} />
-              {i % 7 === 0 && (
-                <text x={x + barW / 2} y={h + 14} textAnchor="middle" fill="var(--color-text-muted)" fontSize="8">{d.date.slice(8)}</text>
-              )}
-            </g>
-          );
-        })}
-      </svg>
+    <div>
+      {/* Readout — the touch/keyboard-accessible equivalent of the old
+          hover-only tooltip. Always reflects the active day. */}
+      <div className="flex flex-wrap items-baseline gap-x-3 gap-y-1 mb-2 text-xs">
+        <span className="font-medium text-text-primary">
+          {dayLabel(active.date)}
+        </span>
+        <span className="text-text-secondary tabular-nums">
+          {fmt(active.inputTokens)} {t("inputTokens")}
+        </span>
+        <span className="text-text-secondary tabular-nums">
+          {fmt(active.outputTokens)} {t("outputTokens")}
+        </span>
+        <span className="text-accent tabular-nums">{chf(active.spend)}</span>
+      </div>
+
+      <div className="overflow-x-auto">
+        <svg
+          viewBox={`0 0 ${Math.max(data.length * (barW + 2), 600)} ${h + 24}`}
+          className="w-full h-36"
+          preserveAspectRatio="xMinYMid meet"
+          role="group"
+          aria-label={t("dailyBreakdown")}
+        >
+          {data.map((d, i) => {
+            const total = d.inputTokens + d.outputTokens;
+            const totalH = (total / maxTokens) * h;
+            const inputH = (d.inputTokens / maxTokens) * h;
+            const x = i * (barW + 2);
+            const isActive = i === activeIndex;
+            return (
+              <g
+                key={d.date}
+                role="button"
+                tabIndex={0}
+                aria-label={barAria(d)}
+                aria-pressed={isActive}
+                className="cursor-pointer focus:outline-none"
+                onClick={() => setSelected(i)}
+                onMouseEnter={() => setSelected(i)}
+                onFocus={() => setSelected(i)}
+                onKeyDown={(e) => {
+                  if (e.key === "Enter" || e.key === " ") {
+                    e.preventDefault();
+                    setSelected(i);
+                  }
+                }}
+              >
+                <title>{barAria(d)}</title>
+                {/* Full-height transparent hit area so thin bars stay
+                    easy to tap on touch screens. */}
+                <rect x={x} y={0} width={barW} height={h} fill="transparent" />
+                <rect
+                  x={x}
+                  y={h - totalH}
+                  width={barW}
+                  height={Math.max(0, totalH - inputH)}
+                  rx={1}
+                  fill="var(--color-accent)"
+                  opacity={isActive ? 0.5 : 0.3}
+                />
+                <rect
+                  x={x}
+                  y={h - inputH}
+                  width={barW}
+                  height={inputH}
+                  rx={1}
+                  fill="var(--color-accent)"
+                  opacity={isActive ? 1 : 0.7}
+                />
+                {isActive && (
+                  <rect
+                    x={x - 1}
+                    y={Math.max(0, h - totalH) - 1}
+                    width={barW + 2}
+                    height={Math.max(2, totalH) + 1}
+                    rx={1.5}
+                    fill="none"
+                    stroke="var(--color-accent)"
+                    strokeWidth={1}
+                  />
+                )}
+                {i % 7 === 0 && (
+                  <text
+                    x={x + barW / 2}
+                    y={h + 14}
+                    textAnchor="middle"
+                    fill="var(--color-text-muted)"
+                    fontSize="8"
+                  >
+                    {d.date.slice(8)}
+                  </text>
+                )}
+              </g>
+            );
+          })}
+        </svg>
+      </div>
       <div className="flex items-center gap-4 text-xs text-text-muted mt-1">
         <span className="flex items-center gap-1">
-          <span className="inline-block h-2 w-2 rounded-sm bg-accent opacity-70" /> Input
+          <span className="inline-block h-2 w-2 rounded-sm bg-accent opacity-70" />{" "}
+          {t("legendInput")}
         </span>
         <span className="flex items-center gap-1">
-          <span className="inline-block h-2 w-2 rounded-sm bg-accent opacity-30" /> Output
+          <span className="inline-block h-2 w-2 rounded-sm bg-accent opacity-30" />{" "}
+          {t("legendOutput")}
         </span>
+        <span className="ml-auto text-text-muted/70">{t("chartHint")}</span>
       </div>
     </div>
   );
@@ -161,6 +268,7 @@ export function UsageDisplay({
   canEditBudget?: boolean;
 }) {
   const t = useTranslations("usage");
+  const locale = useLocale();
   const [month, setMonth] = useState(getCurrentMonth);
   const [data, setData] = useState<UsageData | null>(null);
   const [loading, setLoading] = useState(true);
@@ -202,7 +310,7 @@ export function UsageDisplay({
           ←
         </button>
         <span className="font-display text-sm font-medium text-text-primary">
-          {formatMonth(month, "en")}
+          {formatMonth(month, locale)}
         </span>
         <button
           onClick={() => setMonth((m) => shiftMonth(m, 1))}