feat(frontend): chart dashboard queue activity

frontend/src/pages/DashboardPage.tsx

@@ -5,12 +5,10 @@ import { toast } from "sonner";
 
 import { api } from "../api";
 import { eventTitle } from "../constants";
-import { DateTime } from "../components/DateTime";
 import { EmptyState } from "../components/EmptyState";
 import { StatCard } from "../components/StatCard";
-import { StatusBadge } from "../components/StatusBadge";
 import { StatusIcon } from "../components/StatusIcon";
-import type { Health, Job, JobEvent, JobStats } from "../types";
+import type { Health, Job, JobEvent, JobStats, JobStatus } from "../types";
 
 const emptyStats: JobStats = {
   total: 0,
@@ -20,6 +18,39 @@ const emptyStats: JobStats = {
   oldest_queued_at: null
 };
 
+function BarMetric({ label, value, max, tone = "neutral" }: { label: string; value: number; max: number; tone?: string }) {
+  const width = max > 0 ? Math.max(4, Math.round((value / max) * 100)) : 0;
+  return (
+    <div className="metric-bar-row">
+      <span>{label}</span>
+      <div className="metric-track">
+        <i className={tone} style={{ width: `${width}%` }} />
+      </div>
+      <strong>{value}</strong>
+    </div>
+  );
+}
+
+function MiniHistogram({ data }: { data: Array<{ label: string; value: number; tone: string }> }) {
+  const max = Math.max(...data.map((item) => item.value), 1);
+  return (
+    <div className="histogram" aria-label="histogram">
+      {data.map((item) => {
+        const height = item.value > 0 ? Math.max(12, Math.round((item.value / max) * 100)) : 4;
+        return (
+          <div className="histogram-item" key={item.label}>
+            <div className="histogram-column">
+              <i className={item.tone} style={{ height: `${height}%` }} />
+            </div>
+            <span>{item.label}</span>
+            <strong>{item.value}</strong>
+          </div>
+        );
+      })}
+    </div>
+  );
+}
+
 export function DashboardPage() {
   const [jobs, setJobs] = useState<Job[]>([]);
   const [events, setEvents] = useState<JobEvent[]>([]);
@@ -30,7 +61,7 @@ export function DashboardPage() {
     const [jobsData, statsData, eventsData, healthData] = await Promise.all([
       api.listJobs(),
       api.getStats(),
-      api.listEvents({ limit: 8 }),
+      api.listEvents({ limit: 50 }),
       api.health()
     ]);
     setJobs(jobsData);
@@ -45,7 +76,40 @@ export function DashboardPage() {
     return () => window.clearInterval(id);
   }, [refresh]);
 
-  const recentJobs = useMemo(() => jobs.slice(0, 6), [jobs]);
+  const recentJobs = useMemo(() => jobs.slice(0, 20), [jobs]);
+  const recentJobStatusData = useMemo(() => {
+    const counts: Record<JobStatus, number> = { queued: 0, running: 0, succeeded: 0, failed: 0 };
+    recentJobs.forEach((job) => {
+      counts[job.status] += 1;
+    });
+    return [
+      { label: "Queued", value: counts.queued, tone: "queued" },
+      { label: "Running", value: counts.running, tone: "running" },
+      { label: "Succeeded", value: counts.succeeded, tone: "succeeded" },
+      { label: "Failed", value: counts.failed, tone: "failed" }
+    ];
+  }, [recentJobs]);
+  const pressureData = useMemo(
+    () => [
+      { label: "Queued", value: stats.by_status.queued, tone: "queued" },
+      { label: "Running", value: stats.by_status.running, tone: "running" },
+      { label: "Retry backoff", value: stats.retries_pending, tone: "orange" },
+      { label: "Overdue locks", value: stats.overdue_running, tone: "failed" },
+      { label: "Failed", value: stats.by_status.failed, tone: "failed" }
+    ],
+    [stats]
+  );
+  const eventData = useMemo(() => {
+    const counts = events.reduce<Record<string, number>>((accumulator, event) => {
+      accumulator[event.type] = (accumulator[event.type] ?? 0) + 1;
+      return accumulator;
+    }, {});
+    return Object.entries(counts)
+      .sort((a, b) => b[1] - a[1])
+      .slice(0, 6)
+      .map(([type, value]) => ({ label: eventTitle(type), value, tone: type.includes("fail") ? "failed" : type.includes("success") ? "succeeded" : "running" }));
+  }, [events]);
+  const maxPressure = Math.max(...pressureData.map((item) => item.value), 1);
 
   return (
     <div className="page">
@@ -74,16 +138,18 @@ export function DashboardPage() {
               View jobs
             </Link>
           </div>
-          <div className="compact-list">
-            {recentJobs.map((job) => (
-              <Link className="compact-row" key={job.id} to={`/jobs/${job.id}`}>
-                <StatusBadge status={job.status} />
-                <span>{job.type}</span>
-                <DateTime value={job.created_at} />
-              </Link>
-            ))}
-            {!recentJobs.length && <EmptyState title="No jobs yet" />}
-          </div>
+          {recentJobs.length ? (
+            <>
+              <MiniHistogram data={recentJobStatusData} />
+              <div className="job-tick-chart" aria-label="latest jobs">
+                {recentJobs.slice(0, 16).map((job) => (
+                  <Link className={`job-tick ${job.status}`} key={job.id} title={`${job.type} ${job.status}`} to={`/jobs/${job.id}`} />
+                ))}
+              </div>
+            </>
+          ) : (
+            <EmptyState title="No jobs yet" />
+          )}
         </section>
 
         <section className="panel">
@@ -91,22 +157,13 @@ export function DashboardPage() {
             <h3>Queue Pressure</h3>
             <Clock3 size={16} />
           </div>
-          <div className="compact-list">
-            <div className="compact-row">
-              <strong>Retries pending</strong>
-              <span>{stats.retries_pending}</span>
-              <span className="muted-text">backoff</span>
-            </div>
-            <div className="compact-row">
-              <strong>Oldest queued</strong>
-              <span>{stats.oldest_queued_at ? "waiting" : "none"}</span>
-              <DateTime value={stats.oldest_queued_at} />
-            </div>
-            <div className="compact-row">
-              <strong>Failed jobs</strong>
-              <span>{stats.by_status.failed}</span>
-              <span className="muted-text">retryable</span>
-            </div>
+          <div className="metric-bars">
+            {pressureData.map((item) => (
+              <BarMetric key={item.label} label={item.label} max={maxPressure} tone={item.tone} value={item.value} />
+            ))}
+          </div>
+          <div className="dashboard-footnote">
+            <span>{stats.oldest_queued_at ? "Oldest queued job is waiting" : "No queued backlog"}</span>
           </div>
         </section>
 
@@ -115,16 +172,7 @@ export function DashboardPage() {
             <h3>Recent Events</h3>
             <RotateCcw size={16} />
           </div>
-          <div className="compact-list">
-            {events.map((event) => (
-              <Link className="compact-row" key={event.id} to={`/jobs/${event.job}`}>
-                <strong>{eventTitle(event.type)}</strong>
-                <span>{event.attempt ? `attempt ${event.attempt}` : "new"}</span>
-                <DateTime value={event.created_at} />
-              </Link>
-            ))}
-            {!events.length && <EmptyState title="No events yet" />}
-          </div>
+          {eventData.length ? <MiniHistogram data={eventData} /> : <EmptyState title="No events yet" />}
         </section>
       </section>
     </div>