import { useEffect, useState } from 'react';
import { api, FleetSnapshot, fmtBytes, fmtAge } from '../lib/api';
import { NodeCard } from '../components/NodeCard';
import { ProjectsPanel } from '../components/ProjectsPanel';

// FleetHealth landing — human-oriented single-pane-of-glass.
// Polls the aggregator's /api/v2/fleet every 10 s.
export function CommandCenter() {
  const [fleet, setFleet] = useState<FleetSnapshot | null>(null);
  const [err, setErr] = useState<string | null>(null);
  const [tick, setTick] = useState(0);

  useEffect(() => {
    api
      .fleet()
      .then((f) => {
        setFleet(f);
        setErr(null);
      })
      .catch((e) => setErr(String(e)));
  }, [tick]);

  useEffect(() => {
    const id = setInterval(() => setTick((t) => t + 1), 10_000);
    return () => clearInterval(id);
  }, []);

  const totals = fleet
    ? fleet.nodes.reduce(
        (a, n) => ({
          diskUsed: a.diskUsed + (n.filesystem?.used_bytes ?? 0),
          diskTotal: a.diskTotal + (n.filesystem?.total_bytes ?? 0),
          hotUsed: a.hotUsed + (n.hot?.used_bytes ?? 0),
          hotMax: a.hotMax + (n.hot?.max_bytes ?? 0),
          online: a.online + (n.online ? 1 : 0),
          mounted: a.mounted + (n.mount?.active ? 1 : 0),
        }),
        { diskUsed: 0, diskTotal: 0, hotUsed: 0, hotMax: 0, online: 0, mounted: 0 }
      )
    : null;

  return (
    <div className="space-y-6">
      <div>
        <h1 className="text-2xl font-semibold text-slate-100">Fleet health</h1>
        <div className="text-sm text-slate-500 mt-1">
          {fleet && (
            <>
              <span className="text-emerald-300">{totals?.online}</span>
              /{fleet.nodes.length} nodes online
              {' · '}
              {totals?.mounted}/{fleet.nodes.length} mounted
              {' · '}
              updated <span className="font-mono">{fmtAge(fleet.fetched_at_unix)}</span>
              {' · '}
              hosted by <span className="font-mono text-slate-300">{fleet.aggregator_name}</span>
            </>
          )}
        </div>
      </div>

      {err && (
        <div className="rounded border border-red-800 bg-red-950/40 p-3 text-red-300 text-sm">
          {err}
        </div>
      )}

      {totals && totals.diskTotal > 0 && (
        <div className="rounded-lg border border-slate-800 bg-slate-900/60 p-4 flex items-center justify-between">
          <div>
            <div className="text-xs uppercase tracking-wider text-slate-500">
              Fleet-wide storage
            </div>
            <div className="text-2xl font-semibold font-mono mt-1">
              {fmtBytes(totals.diskUsed)}{' '}
              <span className="text-slate-500 text-lg">/ {fmtBytes(totals.diskTotal)}</span>
            </div>
          </div>
          <div className="text-right text-slate-400 text-sm">
            <div>{Math.round((totals.diskUsed / totals.diskTotal) * 100)}% used</div>
            <div className="text-xs text-slate-500 mt-1">
              hot tier: {fmtBytes(totals.hotUsed)} / {fmtBytes(totals.hotMax)}
            </div>
          </div>
        </div>
      )}

      <section>
        <h2 className="text-lg font-semibold text-slate-100 mb-3">Nodes</h2>
        <div className="grid grid-cols-1 sm:grid-cols-2 lg:grid-cols-3 gap-4">
          {fleet?.nodes.map((n) => (
            <NodeCard key={n.node_name} node={n} />
          ))}
          {!fleet &&
            [1, 2, 3].map((i) => (
              <div
                key={i}
                className="rounded-lg border border-slate-800 bg-slate-900/40 p-5 h-64 animate-pulse"
              />
            ))}
        </div>
      </section>

      <ProjectsPanel />
    </div>
  );
}