import { useEffect, useState } from 'react';
import { clsx } from 'clsx';
import { trpc } from '../../lib/trpc';
import { Card } from '../ui/Card';
import { formatDuration, formatDurationCompact } from '../../lib/format-duration';
import { TIME_CATEGORIES } from '../../lib/time-categories';

const CATEGORY_LABEL: Record<string, string> = Object.fromEntries(
  TIME_CATEGORIES.map((c) => [c.value, c.label]),
);

// Tönungen pro Kategorie (für den horizontalen Balken).
const CATEGORY_TINT: Record<string, string> = {
  focus: 'bg-[var(--color-ink)]',
  meeting: 'bg-[var(--color-ampel-amber-fg)]',
  admin: 'bg-[var(--color-ink-muted)]',
  learning: 'bg-[var(--color-ampel-green-fg)]',
  break: 'bg-[var(--color-ink-faint)]',
  other: 'bg-[var(--color-border-strong)]',
};

function initials(name: string) {
  return name
    .split(/\s+/)
    .filter(Boolean)
    .slice(0, 2)
    .map((p) => p[0]?.toUpperCase() ?? '')
    .join('');
}

/** Anwesenheit (Lock-in → Feierabend bzw. jetzt) — reine Anzeige, kein Tracking. */
function presenceSecondsOf(it: {
  checkedInAt: string | null;
  checkedOutAt: string | null;
}): number | null {
  if (!it.checkedInAt) return null;
  const endMs = it.checkedOutAt ? new Date(it.checkedOutAt).getTime() : Date.now();
  return Math.max(0, Math.round((endMs - new Date(it.checkedInAt).getTime()) / 1000));
}

export function TeamTimeSection() {
  const team = trpc.time.teamToday.useQuery(undefined, { refetchInterval: 30_000 });
  const users = trpc.user.list.useQuery();

  // 1-Sekunden-Tick für lebendige aktive Timer.
  const [tick, setTick] = useState(0);
  useEffect(() => {
    const id = window.setInterval(() => setTick((t) => t + 1), 1000);
    return () => window.clearInterval(id);
  }, []);
  void tick;

  if (team.isPending || users.isPending) return null;
  const userMap = new Map((users.data ?? []).map((u) => [u.id, u.name]));
  const items = (team.data ?? [])
    .map((b) => ({ ...b, name: userMap.get(b.userId) ?? '—' }))
    .sort((a, b) => b.totalSeconds - a.totalSeconds);

  return (
    <section>
      <header className="mb-3 flex items-baseline justify-between">
        <h2 className="text-lg font-semibold">Zeit im Team heute</h2>
        <p className="text-xs text-[var(--color-ink-muted)]">
          {items.length} {items.length === 1 ? 'Person trackt' : 'Personen tracken'}
        </p>
      </header>
      {items.length === 0 ? (
        <Card.Root>
          <Card.Body>
            <p className="text-sm text-[var(--color-ink-muted)]">
              Heute hat noch niemand Zeit erfasst.
            </p>
          </Card.Body>
        </Card.Root>
      ) : (
        <div className="grid grid-cols-1 gap-3 md:grid-cols-2 lg:grid-cols-3">
          {items.map((it) => (
            <Card.Root key={it.userId}>
              <Card.Body>
                <div className="flex items-center gap-3">
                  <div
                    className="flex h-8 w-8 shrink-0 items-center justify-center rounded-full bg-[var(--color-brand)] text-xs font-semibold text-[var(--color-brand-fg)]"
                    aria-label={it.name}
                  >
                    {initials(it.name)}
                  </div>
                  <div className="min-w-0 flex-1">
                    <p className="truncate text-sm font-semibold">{it.name}</p>
                    <p className="text-xs text-[var(--color-ink-muted)]">
                      Gesamt:{' '}
                      <span className="font-mono">{formatDurationCompact(it.totalSeconds)}</span>
                      {it.trackedSeconds > it.totalSeconds + 60 && (
                        <span
                          className="text-[var(--color-ink-faint)]"
                          title="Über parallele Aufgaben getrackte Summe (zählt überlappende Zeit mehrfach)."
                        >
                          {' · getrackt '}
                          <span className="font-mono">
                            {formatDurationCompact(it.trackedSeconds)}
                          </span>
                        </span>
                      )}
                      {presenceSecondsOf(it) !== null && (
                        <span title="Anwesenheit: Lock-in bis Feierabend (bzw. jetzt) — unabhängig vom Tracking.">
                          {' · Anwesend: '}
                          <span className="font-mono">
                            {formatDurationCompact(presenceSecondsOf(it)!)}
                          </span>
                        </span>
                      )}
                    </p>
                  </div>
                </div>

                {it.active ? <ActiveLine active={it.active} /> : <IdleLine />}

                <Breakdown byCategory={it.byCategory} total={it.trackedSeconds} />
              </Card.Body>
            </Card.Root>
          ))}
        </div>
      )}
    </section>
  );
}

function ActiveLine({
  active,
}: {
  active: {
    startedAt: string;
    category: string;
    todoTitle: string | null;
    description: string | null;
  };
}) {
  const since = new Date(active.startedAt).getTime();
  const elapsed = Math.max(0, Math.round((Date.now() - since) / 1000));
  const label =
    active.todoTitle || active.description || CATEGORY_LABEL[active.category] || 'läuft';
  return (
    <div className="mt-3 flex items-center gap-2 rounded-[var(--radius-md)] bg-[var(--color-ampel-red-bg)] px-2.5 py-1.5 text-xs text-[var(--color-ampel-red-fg)]">
      <span className="relative flex h-1.5 w-1.5 items-center justify-center">
        <span className="absolute h-1.5 w-1.5 animate-ping rounded-full bg-current opacity-60" />
        <span className="relative h-1.5 w-1.5 rounded-full bg-current" />
      </span>
      <span className="flex-1 truncate font-medium">{label}</span>
      <span className="font-mono tabular-nums">{formatDuration(elapsed)}</span>
    </div>
  );
}

function IdleLine() {
  return <p className="mt-3 text-xs text-[var(--color-ink-faint)]">Aktuell kein Timer.</p>;
}

function Breakdown({ byCategory, total }: { byCategory: Record<string, number>; total: number }) {
  if (total === 0) return null;
  const ordered = TIME_CATEGORIES.map((c) => ({
    key: c.value,
    label: c.label,
    seconds: byCategory[c.value] ?? 0,
  })).filter((x) => x.seconds > 0);
  return (
    <div className="mt-3">
      <div className="flex h-1.5 w-full overflow-hidden rounded-full bg-[var(--color-border)]">
        {ordered.map((o) => (
          <div
            key={o.key}
            className={clsx('h-full', CATEGORY_TINT[o.key])}
            style={{ width: `${(o.seconds / total) * 100}%` }}
            title={`${o.label}: ${formatDurationCompact(o.seconds)}`}
          />
        ))}
      </div>
      <div className="mt-1.5 flex flex-wrap gap-x-2 gap-y-0.5 text-[10px] text-[var(--color-ink-muted)]">
        {ordered.map((o) => (
          <span key={o.key} className="inline-flex items-center gap-1">
            <span className={clsx('h-1.5 w-1.5 rounded-full', CATEGORY_TINT[o.key])} />
            {o.label} {formatDurationCompact(o.seconds)}
          </span>
        ))}
      </div>
    </div>
  );
}