import { useEffect, useMemo, useState } from 'react';
import { Link, useParams } from '@tanstack/react-router';
import { ArrowLeft, Bell, BellRing, CalendarPlus, Route, Shield, Star, Stethoscope } from 'lucide-react';
import { EloHistoryChart } from '@/components/EloHistoryChart';
import { pushSupported, serverPushKey, subscribeTeam, unsubscribePush } from '@/lib/push';
import { useFavoriteStore } from '@/stores/favoriteStore';
import { useTournamentStore } from '@/stores/tournamentStore';
import { Card, CardBody, CardHeader } from '@/components/ui/Card';
import { Badge } from '@/components/ui/Badge';
import { teamFlag } from '@/lib/teams';
import { fmt, useFormat, useT } from '@/lib/i18n';
import { hostAdvantage } from '@/lib/model/hosts';
import { knockoutAdvanceProb, predictMatch, type RatingsModel } from '@/lib/model/predict';
import { modelBracket, projectedSeeds, teamPath } from '@/lib/whatif';
import type { Fixture, TeamProfile } from '@/lib/types';

const pct = (x: number | null) => (x == null ? '—' : `${(x * 100).toFixed(1)}%`);

/** The model's most likely knockout run for this team, opponent by opponent. */
function RoadToFinal({ team }: { team: string }) {
  const t = useT();
  const snapshot = useTournamentStore((s) => s.snapshot);
  const model = useTournamentStore((s) => s.model);
  const [ratings, setRatings] = useState<RatingsModel | null>(null);

  useEffect(() => {
    let alive = true;
    fetch('/data/ratings.json')
      .then((r) => (r.ok ? r.json() : Promise.reject()))
      .then((d: RatingsModel) => alive && setRatings(d))
      .catch(() => {});
    return () => { alive = false; };
  }, []);

  const path = useMemo(() => {
    if (!snapshot || !model || !ratings) return null;
    const fixtures = snapshot.fixtures;
    const seeds = projectedSeeds(fixtures, model.odds);
    // Every team gets a road: if the model doesn't project this side out of
    // the group, slot them hypothetically as their group's runner-up.
    if (!Object.values(seeds).includes(team)) {
      const g = fixtures.find((f) => f.stage === 'group' && (f.home.team === team || f.away.team === team))?.group;
      if (!g) return null;
      seeds[`2${g}`] = team;
    }
    const advFor = (f: Fixture, home: string, away: string): number | null => {
      const adv = hostAdvantage(home, away, f.venue, ratings.params.homeAdvElo);
      const p = predictMatch(home, away, ratings, adv);
      return knockoutAdvanceProb(p.probs, p.eloHome, p.eloAway);
    };
    return teamPath(fixtures, seeds, modelBracket(fixtures, seeds, advFor), team);
  }, [snapshot, model, ratings, team]);

  const odds = model?.odds.find((o) => o.team === team);
  if (!path?.length || !odds) return null;
  const reach: Partial<Record<Fixture['stage'], number>> = {
    r32: odds.qualify, r16: odds.reachR16, qf: odds.reachQF, sf: odds.reachSF, final: odds.reachFinal,
  };

  return (
    <Card>
      <CardHeader className="flex items-center gap-2">
        <Route size={15} className="text-accent" />
        <span className="font-display font-bold text-ink">{t.team.road.title}</span>
      </CardHeader>
      <CardBody>
        <ul className="space-y-1.5">
          {path.map((p) => (
            <li key={p.num} className="flex items-center gap-2 text-sm">
              <span className="w-32 shrink-0 text-xs text-faint">{t.stage[p.stage]}</span>
              <span className="text-faint">{t.common.vs}</span>
              {p.opponent ? (
                <>
                  <span aria-hidden>{teamFlag(p.opponent)}</span>
                  <Link to="/team/$name" params={{ name: p.opponent }} className="truncate font-medium text-ink hover:text-accent">{p.opponent}</Link>
                </>
              ) : (
                <span className="italic text-faint">{t.team.road.tbd}</span>
              )}
              <span className="tnum ml-auto shrink-0 text-xs font-semibold text-ink">{pct(reach[p.stage] ?? null)}</span>
            </li>
          ))}
        </ul>
        <div className="mt-2 inline-flex rounded-full bg-gold/15 px-2.5 py-0.5 text-xs font-semibold text-gold">
          {fmt(t.team.road.winItAll, { pct: pct(odds.champion) })}
        </div>
        <p className="mt-2 text-[11px] text-faint">{t.team.road.note}</p>
      </CardBody>
    </Card>
  );
}

function FixtureRow({ f, team }: { f: Fixture; team: string }) {
  const { t, kickoffDay, kickoffTime } = useFormat();
  const isHome = f.home.team === team;
  const opp = isHome ? f.away : f.home;
  const done = f.status === 'finished' || f.status === 'live';
  const us = isHome ? f.homeScore : f.awayScore;
  const them = isHome ? f.awayScore : f.homeScore;
  const res = done && us != null && them != null ? (us > them ? 'win' : us < them ? 'loss' : 'draw') : null;
  return (
    <Link to="/match/$num" params={{ num: String(f.num) }} className="flex items-center gap-2 rounded-md px-2 py-1.5 text-sm hover:bg-elevated">
      <span className="w-10 text-xs text-faint">{f.group ? fmt(t.team.groupShort, { group: f.group }) : f.stage !== 'group' ? t.team.stageShort[f.stage] : f.round}</span>
      <span className="text-faint">{t.common.vs}</span>
      <span aria-hidden className="grid w-5 place-items-center">{opp.team ? teamFlag(opp.team) : <Shield size={14} className="text-faint" />}</span>
      <span className="truncate text-ink">{opp.label}</span>
      <span
        className="shrink-0 rounded bg-elevated px-1 py-px text-[10px] font-bold uppercase text-faint"
        title={isHome ? t.team.homeGame : t.team.awayGame}
      >
        {isHome ? t.team.homeShort : t.team.awayShort}
      </span>
      <span className="ml-auto tnum text-faint">
        {done && us != null ? <span className="text-ink">{us}–{them}</span> : `${kickoffDay(f.kickoff)} ${kickoffTime(f.kickoff)}`}
      </span>
      {res && <span className={`grid h-5 w-5 place-items-center rounded text-[11px] font-bold ${res === 'win' ? 'bg-win/20 text-win' : res === 'loss' ? 'bg-loss/20 text-loss' : 'bg-draw/20 text-draw'}`}>{t.team.resultShort[res]}</span>}
    </Link>
  );
}

function FavoriteStar({ team }: { team: string }) {
  const t = useT();
  const favorite = useFavoriteStore((s) => s.favorite);
  const toggle = useFavoriteStore((s) => s.toggleFavorite);
  const active = favorite === team;
  return (
    <button
      type="button"
      onClick={() => toggle(team)}
      aria-label={active ? t.team.unfollow : t.team.follow}
      aria-pressed={active}
      className={`grid h-9 w-9 place-items-center rounded-md transition-colors ${active ? 'text-gold' : 'text-faint hover:text-ink'}`}
    >
      <Star size={20} fill={active ? 'currentColor' : 'none'} />
    </button>
  );
}

const PUSH_TEAM_KEY = 'cup26:push-team';

/** Goal/kickoff alerts for this team — shown only when the server has push
 *  enabled and the browser supports it. One followed team per device. */
function NotifyBell({ team }: { team: string }) {
  const t = useT();
  const [avail, setAvail] = useState(false);
  const [denied, setDenied] = useState(false);
  const [subTeam, setSubTeam] = useState<string | null>(() => {
    try { return localStorage.getItem(PUSH_TEAM_KEY); } catch { return null; }
  });

  useEffect(() => {
    let alive = true;
    void serverPushKey().then((k) => alive && setAvail(Boolean(k) && pushSupported()));
    return () => { alive = false; };
  }, []);

  if (!avail) return null;
  const active = subTeam === team;

  const toggle = async (): Promise<void> => {
    if (active) {
      await unsubscribePush();
      try { localStorage.removeItem(PUSH_TEAM_KEY); } catch { /* ok */ }
      setSubTeam(null);
      return;
    }
    const res = await subscribeTeam(team);
    if (res === 'subscribed') {
      try { localStorage.setItem(PUSH_TEAM_KEY, team); } catch { /* ok */ }
      setSubTeam(team);
      setDenied(false);
    } else if (res === 'denied') {
      setDenied(true);
    }
  };

  return (
    <span className="inline-flex items-center">
      <button
        type="button"
        onClick={() => void toggle()}
        aria-label={active ? t.team.notifyOff : t.team.notifyOn}
        aria-pressed={active}
        title={denied ? t.team.notifyDenied : active ? t.team.notifyOff : t.team.notifyOn}
        className={`grid h-9 w-9 place-items-center rounded-md transition-colors ${active ? 'text-accent' : 'text-faint hover:text-ink'}`}
      >
        {active ? <BellRing size={18} /> : <Bell size={18} />}
      </button>
      {denied && <span className="text-[11px] text-faint">{t.team.notifyDenied}</span>}
    </span>
  );
}

export function TeamProfilePage() {
  const { name } = useParams({ strict: false }) as { name: string };
  const t = useT();
  const [profile, setProfile] = useState<TeamProfile | null>(null);
  const [failed, setFailed] = useState(false);

  useEffect(() => {
    let alive = true;
    setProfile(null);
    setFailed(false);
    fetch(`/api/team/${encodeURIComponent(name)}`)
      .then((r) => (r.ok ? r.json() : Promise.reject()))
      .then((d: TeamProfile) => alive && setProfile(d))
      .catch(() => alive && setFailed(true));
    return () => { alive = false; };
  }, [name]);

  if (failed) return <div className="py-16 text-center text-muted">{t.team.unknown} <Link to="/groups" className="text-accent">{t.team.allTeams}</Link></div>;
  if (!profile) return <div className="h-80 animate-pulse rounded-xl border border-line bg-panel" />;

  const s = profile.standing;
  return (
    <div className="space-y-5">
      <Link to="/teams" className="inline-flex items-center gap-1.5 text-sm text-muted hover:text-ink">
        <ArrowLeft size={15} /> {t.team.allTeams}
      </Link>

      <Card>
        <CardBody className="flex flex-wrap items-center gap-4">
          <span aria-hidden className="text-5xl">{teamFlag(profile.team)}</span>
          <div>
            <h1 className="flex items-center gap-1 font-display text-2xl font-extrabold text-ink">
              <span className="mr-1">{profile.team}</span>
              <FavoriteStar team={profile.team} />
              <NotifyBell team={profile.team} />
            </h1>
            <div className="mt-1 flex flex-wrap items-center gap-2 text-sm">
              {profile.group && <Badge tone="neutral">{fmt(t.common.group, { group: profile.group })}</Badge>}
              <Badge tone="muted">{fmt(t.team.eloBadge, { rating: profile.elo })}</Badge>
              <Badge tone="gold">{fmt(t.team.titleOddsBadge, { pct: pct(profile.championOdds) })}</Badge>
              <Badge tone="accent">{fmt(t.team.advanceOddsBadge, { pct: pct(profile.qualifyOdds) })}</Badge>
              <a
                href={`/api/calendar.ics?team=${encodeURIComponent(profile.team)}`}
                download
                className="inline-flex items-center gap-1 rounded-full border border-line px-2 py-0.5 text-xs font-semibold text-muted transition-colors hover:border-line-strong hover:text-ink"
              >
                <CalendarPlus size={13} /> {t.team.addToCalendar}
              </a>
            </div>
          </div>
          {s && (
            <div className="ml-auto text-right text-sm">
              <div className="text-faint text-xs">{t.team.groupStanding}</div>
              <div className="tnum text-ink">{fmt(t.team.standingLine, { rank: s.rank, points: s.points, won: s.won, drawn: s.drawn, lost: s.lost, gd: s.gd > 0 ? `+${s.gd}` : s.gd })}</div>
            </div>
          )}
        </CardBody>
      </Card>

      <Card>
        <CardHeader><span className="font-display font-bold text-ink">{t.team.eloHistory}</span></CardHeader>
        <CardBody>
          <EloHistoryChart team={profile.team} />
        </CardBody>
      </Card>

      <RoadToFinal team={profile.team} />

      <div className="grid gap-5 md:grid-cols-[1.3fr_1fr]">
        <Card>
          <CardHeader><span className="font-display font-bold text-ink">{t.team.fixtures}</span></CardHeader>
          <CardBody className="space-y-0.5">
            {profile.fixtures.map((f) => <FixtureRow key={f.num} f={f} team={profile.team} />)}
          </CardBody>
        </Card>

        <div className="space-y-5">
          {profile.injuries.length > 0 && (
            <Card>
              <CardHeader className="flex items-center gap-2">
                <Stethoscope size={15} className="text-gold" />
                <span className="font-display font-bold text-ink">{t.team.injuriesTitle}</span>
              </CardHeader>
              <CardBody>
                <ul className="space-y-1.5">
                  {profile.injuries.map((i) => (
                    <li key={i.player} className="flex items-center gap-2 text-sm">
                      <span className="truncate text-ink-soft">{i.player}</span>
                      <span className="ml-auto shrink-0 text-[11px] text-faint">{i.reason ?? i.status ?? ''}</span>
                    </li>
                  ))}
                </ul>
              </CardBody>
            </Card>
          )}
          {profile.discipline.length > 0 && (
            <Card>
              <CardHeader><span className="font-display font-bold text-ink">{t.team.discipline}</span></CardHeader>
              <CardBody>
                <ul className="space-y-1.5">
                  {profile.discipline.map((p) => (
                    <li key={p.player} className="flex flex-wrap items-center gap-2 text-sm">
                      <span className="truncate text-ink-soft">{p.player}</span>
                      <span className="flex items-center gap-0.5" aria-hidden>
                        {Array.from({ length: p.yellows }).map((_, i) => <span key={`y${i}`} className="inline-block h-3.5 w-2.5 rounded-[2px] bg-gold" />)}
                        {Array.from({ length: p.reds }).map((_, i) => <span key={`r${i}`} className="inline-block h-3.5 w-2.5 rounded-[2px] bg-loss" />)}
                      </span>
                      {p.suspendedNext && (
                        <span className="ml-auto rounded-full bg-loss/15 px-2 py-0.5 text-[11px] font-semibold text-loss">
                          {p.suspendedFor != null ? fmt(t.team.suspChipFor, { num: p.suspendedFor }) : t.team.suspChipNext}
                        </span>
                      )}
                      {!p.suspendedNext && p.pending === 1 && (
                        <span className="ml-auto rounded-full bg-gold/15 px-2 py-0.5 text-[11px] font-semibold text-gold">{t.team.atRiskChip}</span>
                      )}
                    </li>
                  ))}
                </ul>
              </CardBody>
            </Card>
          )}
          <Card>
            <CardHeader><span className="font-display font-bold text-ink">{t.team.allTimeTopScorers}</span></CardHeader>
            <CardBody>
              {profile.keyPlayers.length ? (
                <ol className="space-y-1.5">
                  {profile.keyPlayers.map((p, i) => (
                    <li key={p.name} className="flex items-center gap-2 text-sm">
                      <span className="w-4 text-right text-xs font-bold text-faint">{i + 1}</span>
                      <span className="truncate text-ink-soft">{p.name}</span>
                      <span className="tnum ml-auto font-semibold text-ink">{p.goals}</span>
                      {p.pens ? <span className="text-[11px] text-faint">{fmt(t.common.pensShort, { n: p.pens })}</span> : null}
                    </li>
                  ))}
                </ol>
              ) : <p className="text-sm text-faint">{t.common.noData}</p>}
            </CardBody>
          </Card>
        </div>
      </div>
    </div>
  );
}