"use client";

import {
  useCallback,
  useEffect,
  useRef,
  useState,
  type FormEvent,
} from "react";
import Link from "next/link";
import { useRouter } from "next/navigation";
import { Trophy, Users, CalendarClock, Plus, Copy } from "lucide-react";
import { api } from "@/lib/client-api";
import { useI18n } from "./I18nProvider";
import dynamic from "next/dynamic";
const MultiplayerGame = dynamic(
  () => import("./MultiplayerGame").then((module) => module.MultiplayerGame),
  { ssr: false },
);
import { roundClock } from "@/shared/round-clock";
import {
  serverLocalToIso,
  type TournamentRecord,
  type TournamentView,
} from "@/shared/tournaments";
import type { DifficultyPreset } from "@/shared/protocol";

type Events = {
  tournaments: TournamentRecord[];
  serverNow: number;
  serverTimezone: string;
};
function time(value: string, zone: string) {
  return new Intl.DateTimeFormat(undefined, {
    dateStyle: "medium",
    timeStyle: "short",
    timeZone: zone,
  }).format(new Date(value));
}
export function TournamentIndex({ signedIn }: { signedIn: boolean }) {
  const { t } = useI18n();
  const router = useRouter();
  const [events, setEvents] = useState<Events | null>(null);
  const [maps, setMaps] = useState<{ id: string; name: string }[]>([]);
  const [presets, setPresets] = useState<DifficultyPreset[]>([]);
  const [error, setError] = useState("");
  const [busy, setBusy] = useState(false);
  const [creating, setCreating] = useState(false);
  const [clock, setClock] = useState(0);
  const [timerMode, setTimerMode] = useState<"shared" | "perMini">("shared");
  const [roundSeconds, setRoundSeconds] = useState(450);
  const offset = useRef(0);
  const load = useCallback(async () => {
    try {
      const next = await api<Events>("tournaments");
      offset.current = next.serverNow - Date.now();
      setEvents(next);
      setClock(next.serverNow);
      setError("");
    } catch (e) {
      setError((e as Error).message);
    }
  }, []);
  useEffect(() => {
    void load();
    const timer = setInterval(() => {
      setClock(Date.now() + offset.current);
    }, 1000);
    const poll = setInterval(() => void load(), 30000);
    return () => {
      clearInterval(timer);
      clearInterval(poll);
    };
  }, [load]);
  useEffect(() => {
    if (!creating) return;
    let active = true;
    Promise.all([
      api<{ maps: { id: string; name: string }[] }>("catalog"),
      api<{ presets: DifficultyPreset[] }>("difficulty-presets"),
    ])
      .then(([catalog, difficulties]) => {
        if (active) {
          setMaps(catalog.maps);
          setPresets(difficulties.presets);
        }
      })
      .catch((e) => {
        if (active) setError(e.message);
      });
    return () => {
      active = false;
    };
  }, [creating]);
  async function create(event: FormEvent<HTMLFormElement>) {
    event.preventDefault();
    if (busy || !events) return;
    const form = new FormData(event.currentTarget);
    setBusy(true);
    setError("");
    try {
      const result = await api<{ id: string }>("tournaments", {
        name: form.get("name"),
        datasetId: form.get("dataset"),
        difficulty: form.get("difficulty"),
        playerLimit: Number(form.get("limit")),
        roundCount: Number(form.get("rounds")),
        roundTimeSeconds: Number(form.get("seconds")),
        timerMode: form.get("timerMode"),
        startsAt: serverLocalToIso(
          String(form.get("start")),
          events.serverTimezone,
        ),
        announceDiscord: form.has("discord"),
      });
      router.push(`/tournaments/${result.id}`);
    } catch (e) {
      setError((e as Error).message);
    } finally {
      setBusy(false);
    }
  }
  return (
    <div className="section tournament-page">
      <div className="section-heading">
        <div>
          <p className="eyebrow">
            <Trophy size={16} />
            {t("COMMUNITY TOURNAMENTS")}
          </p>
          <h1>{t("One world. Up to 32 rivals.")}</h1>
          <p className="muted">
            {t(
              "Every tournament round contains five mini-rounds. Everyone plays the same locations.",
            )}
          </p>
        </div>
        {signedIn ? (
          <button
            className="button primary"
            onClick={() => setCreating(!creating)}
          >
            <Plus size={16} />
            {t(creating ? "Close" : "Create tournament")}
          </button>
        ) : (
          <Link href="/log-in" className="button primary">
            {t("Log in to create or join")}
          </Link>
        )}
      </div>
      {events && (
        <p className="tournament-server-clock">
          <CalendarClock size={16} />
          {t("Server time")}:{" "}
          {time(
            new Date(clock || events.serverNow).toISOString(),
            events.serverTimezone,
          )}{" "}
          · {events.serverTimezone}
        </p>
      )}
      {error && (
        <div className="notice error" role="alert">
          {t(error)}{" "}
          <button className="text-link" onClick={() => void load()}>
            {t("Try again")}
          </button>
        </div>
      )}
      {creating && signedIn && (
        <form className="tournament-form panel" onSubmit={create}>
          <h2>{t("Create tournament")}</h2>
          <label>
            {t("Tournament name")}
            <input
              name="name"
              required
              minLength={3}
              maxLength={80}
              placeholder={t("Saturday expedition")}
            />
          </label>
          <label>
            {t("Map")}
            <select name="dataset" required defaultValue="">
              <option value="" disabled>
                {t("Choose a map")}
              </option>
              {maps.map((map) => (
                <option key={map.id} value={map.id}>
                  {map.name}
                </option>
              ))}
            </select>
          </label>
          <label>
            {t("Difficulty")}
            <select name="difficulty" defaultValue="normal">
              <option value="easy">{t("Easy")}</option>
              <option value="normal">{t("Normal")}</option>
              <option value="hard">{t("Hard")}</option>
              {presets.map((preset) => (
                <option key={preset.id} value={preset.id}>
                  {preset.name}
                </option>
              ))}
            </select>
          </label>
          <label>
            {t("Player limit")}
            <input
              name="limit"
              type="number"
              min={2}
              max={32}
              defaultValue={32}
              required
            />
          </label>
          <label>
            {t("Tournament rounds")}
            <input
              name="rounds"
              type="number"
              min={1}
              max={10}
              defaultValue={3}
              required
            />
          </label>
          <label>
            {t("Timer mode")}
            <select
              name="timerMode"
              value={timerMode}
              onChange={(e) => {
                const mode = e.target.value as "shared" | "perMini";
                setTimerMode(mode);
                setRoundSeconds(mode === "shared" ? 450 : 90);
              }}
            >
              <option value="shared">
                {t("One budget for five mini-rounds")}
              </option>
              <option value="perMini">
                {t("Separate timer for each mini-round")}
              </option>
            </select>
          </label>
          <label>
            {t(
              timerMode === "shared"
                ? "Seconds per tournament round"
                : "Seconds per mini-round",
            )}
            <input
              name="seconds"
              type="number"
              min={15}
              max={timerMode === "shared" ? 3000 : 600}
              step={15}
              value={roundSeconds}
              onChange={(e) => setRoundSeconds(Number(e.target.value))}
              required
            />
          </label>
          <label>
            {t("Start time")} · {events?.serverTimezone ?? t("Server time")}
            <input
              name="start"
              type="datetime-local"
              required
              disabled={!events}
            />
          </label>
          <label className="tournament-checkbox">
            <input name="discord" type="checkbox" />
            {t("Announce in Discord 15 minutes before starting")}
          </label>
          <p className="muted">
            {t(
              "A shared budget starts with the first mini-round and keeps running between mini-rounds. Initial loading is excluded.",
            )}
          </p>
          <p className="muted">
            {t(
              "The organizer joins as a player. Registration closes at the scheduled start. At least two players are needed.",
            )}
          </p>
          <button
            disabled={busy || !events || !maps.length}
            className="button primary"
          >
            {t(busy ? "Creating…" : "Create tournament")}
          </button>
        </form>
      )}
      <div className="tournament-grid">
        {events?.tournaments.map((event) => (
          <Link
            className="tournament-card panel"
            href={`/tournaments/${event.id}`}
            key={event.id}
          >
            <div className="tournament-card-top">
              <Trophy size={24} />
              <span className={`tournament-status ${event.status}`}>
                {t(event.status)}
              </span>
            </div>
            <h2>{event.name}</h2>
            <p>
              <CalendarClock size={15} />
              {time(event.starts_at, event.server_timezone)} ·{" "}
              {event.server_timezone}
            </p>
            <p>
              <Users size={15} />
              {t("Up to {count} players", { count: event.player_limit })} ·{" "}
              {t("{count} tournament rounds", { count: event.round_count })}
            </p>
            <span className="text-link">{t("Open tournament")} →</span>
          </Link>
        ))}
      </div>
      {events && !events.tournaments.length && (
        <div className="empty-state">
          <Trophy size={36} />
          <h2>{t("The next champion could be you.")}</h2>
          <p>
            {t(
              "Create the first community tournament or check back for upcoming events.",
            )}
          </p>
        </div>
      )}
    </div>
  );
}

export function TournamentLobby({
  id,
  signedIn,
}: {
  id: string;
  signedIn: boolean;
}) {
  const { t, formatNumber } = useI18n();
  const [event, setEvent] = useState<TournamentView | null>(null);
  const [error, setError] = useState("");
  const [busy, setBusy] = useState(false);
  const [copied, setCopied] = useState(false);
  const [editing, setEditing] = useState(false);
  const acting = useRef(false),
    version = useRef(0);
  const latest = useRef<TournamentView | null>(null);
  const clock = useRef<ReturnType<typeof roundClock> | null>(null);
  const accept = useCallback((next: TournamentView, sent: number) => {
    clock.current = roundClock(next.serverNow, sent, performance.now());
    latest.current = next;
    setEvent(next);
    setError("");
  }, []);
  const load = useCallback(async () => {
    if (acting.current) return;
    const current = ++version.current,
      sent = performance.now();
    try {
      const next = await api<TournamentView>(`tournaments/${id}`);
      if (current === version.current) accept(next, sent);
    } catch (e) {
      if (current === version.current) setError((e as Error).message);
    }
  }, [id, accept]);
  useEffect(() => {
    let stopped = false;
    let timer: ReturnType<typeof setTimeout>;
    const poll = async () => {
      await load();
      if (
        !stopped &&
        !["finished", "cancelled"].includes(latest.current?.status ?? "")
      )
        timer = setTimeout(poll, document.hidden ? 5000 : 2000);
    };
    void poll();
    const resume = () => {
      if (!document.hidden) void load();
    };
    document.addEventListener("visibilitychange", resume);
    return () => {
      stopped = true;
      version.current++;
      clearTimeout(timer);
      document.removeEventListener("visibilitychange", resume);
    };
  }, [load]);
  const action = useCallback(
    async (type: string, payload: object = {}) => {
      if (acting.current) return false;
      acting.current = true;
      setBusy(true);
      const current = ++version.current,
        sent = performance.now();
      try {
        const next = await api<TournamentView>(
          `tournaments/${id}/${type}`,
          payload,
        );
        if (current === version.current) accept(next, sent);
        return true;
      } catch (e) {
        if (current === version.current) setError((e as Error).message);
        return false;
      } finally {
        acting.current = false;
        setBusy(false);
      }
    },
    [id, accept],
  );
  const remaining = useCallback(
    (deadline: string) =>
      clock.current?.remaining(deadline, performance.now()) ?? 0,
    [],
  );
  const room = event?.currentRoom;
  const owner = event?.you === event?.ownerId && !!event?.you;
  const joined = !!event?.players.some((p) => p.accountId === event.you);
  const gameAction = useCallback(
    (type: string, payload: object = {}) =>
      action(type, { ...payload, tournamentRound: event?.currentRound ?? 0 }),
    [action, event?.currentRound],
  );
  if (!event)
    return (
      <div className="section tournament-page">
        <Link href="/tournaments">← {t("Tournaments")}</Link>
        {error ? (
          <div role="alert" className="notice error">
            {t(error)}{" "}
            <button onClick={() => void load()} className="button">
              {t("Try again")}
            </button>
          </div>
        ) : (
          <p role="status">{t("Loading tournament…")}</p>
        )}
      </div>
    );
  async function edit(e: FormEvent<HTMLFormElement>) {
    e.preventDefault();
    if (!event) return;
    const form = new FormData(e.currentTarget);
    try {
      if (
        await action("edit", {
          startsAt: serverLocalToIso(
            String(form.get("start")),
            event.serverTimezone,
          ),
          playerLimit: Number(form.get("limit")),
          announceDiscord: form.has("discord"),
        })
      )
        setEditing(false);
    } catch (failure) {
      setError((failure as Error).message);
    }
  }
  return (
    <>
      {event.status === "running" && room?.you && (
        <div className="tournament-play">
          <div className="tournament-game-heading">
            <Trophy size={18} />
            {event.name} ·{" "}
            {t("Tournament round {round} of {total}", {
              round: event.currentRound + 1,
              total: event.roundCount,
            })}
          </div>
          <MultiplayerGame
            key={`${room.id}:${room.round}`}
            id={room.id}
            mediaPath={`tournaments/${id}/media?tournamentRound=${event.currentRound}`}
            room={room}
            busy={busy}
            action={gameAction}
            embedded
            leaveLabel="View tournament standings"
            remaining={remaining}
            onLeave={() => {
              document
                .getElementById("tournament-standings")
                ?.scrollIntoView({ behavior: "instant" });
            }}
          />
        </div>
      )}
      <div className="section tournament-page" id="tournament-standings">
        <Link href="/tournaments" className="text-link">
          ← {t("Tournaments")}
        </Link>
        <div className="section-heading">
          <div>
            <p className="eyebrow">
              <Trophy size={16} />
              {t(event.status)}
            </p>
            <h1>{event.name}</h1>
            <p>
              {time(event.startsAt, event.serverTimezone)} ·{" "}
              {event.serverTimezone}
            </p>
          </div>
          <button
            className="button"
            onClick={async () => {
              try {
                await navigator.clipboard.writeText(window.location.href);
                setCopied(true);
              } catch {
                setError("Copy the tournament link from your address bar");
              }
            }}
          >
            <Copy size={16} />
            {t(copied ? "Copied!" : "Copy invite")}
          </button>
        </div>
        {error && (
          <div className="notice error" role="alert">
            {t(error)}
          </div>
        )}
        <div className="tournament-facts">
          <span>
            <Users size={16} />
            {event.players.length} / {event.playerLimit}
          </span>
          <span>
            {t("{count} tournament rounds", { count: event.roundCount })} × 5{" "}
            {t("mini-rounds")}
          </span>
          <span>
            {event.roundTimeSeconds}{" "}
            {t(
              event.timerMode === "shared"
                ? "seconds per tournament round"
                : "seconds per mini-round",
            )}
          </span>
        </div>
        {owner && event.announceDiscord && (
          <p role="status" className="muted">
            {t("Discord announcement")}:{" "}
            {t(event.announcementState ?? "pending")}
          </p>
        )}
        {event.status === "scheduled" && (
          <div className="tournament-actions">
            {!signedIn ? (
              <Link className="button primary" href="/log-in">
                {t("Log in to create or join")}
              </Link>
            ) : joined ? (
              <>
                <span className="notice">
                  {t(
                    "You’re registered. Stay on this page when the tournament starts.",
                  )}
                </span>
                {!owner && (
                  <button
                    className="button"
                    disabled={busy}
                    onClick={() => void action("leave")}
                  >
                    {t("Leave tournament")}
                  </button>
                )}
              </>
            ) : (
              <button
                className="button primary"
                disabled={busy || event.players.length >= event.playerLimit}
                onClick={() => void action("join")}
              >
                {t(
                  event.players.length >= event.playerLimit
                    ? "Tournament is full"
                    : "Join tournament",
                )}
              </button>
            )}
            {owner && (
              <>
                <button
                  className="button"
                  disabled={busy}
                  onClick={() => setEditing(!editing)}
                >
                  {t("Tournament settings")}
                </button>
                <button
                  className="button danger"
                  disabled={busy}
                  onClick={() => void action("cancel")}
                >
                  {t("Cancel tournament")}
                </button>
              </>
            )}
          </div>
        )}
        {editing && owner && event.status === "scheduled" && (
          <form className="tournament-form panel" onSubmit={edit}>
            <label>
              {t("Start time")} · {event.serverTimezone}
              <input
                name="start"
                type="datetime-local"
                required
                defaultValue={new Intl.DateTimeFormat("sv-SE", {
                  timeZone: event.serverTimezone,
                  year: "numeric",
                  month: "2-digit",
                  day: "2-digit",
                  hour: "2-digit",
                  minute: "2-digit",
                  hourCycle: "h23",
                })
                  .format(new Date(event.startsAt))
                  .replace(" ", "T")}
              />
            </label>
            <label>
              {t("Player limit")}
              <input
                name="limit"
                type="number"
                min={Math.max(2, event.players.length)}
                max={32}
                required
                defaultValue={event.playerLimit}
              />
            </label>
            <label className="tournament-checkbox">
              <input
                name="discord"
                type="checkbox"
                defaultChecked={event.announceDiscord}
              />
              {t("Announce in Discord 15 minutes before starting")}
            </label>
            <p className="muted">
              {t("Already-sent announcements are not posted again.")}
            </p>
            <button className="button primary" disabled={busy}>
              {t("Save settings")}
            </button>
          </form>
        )}
        {event.status === "finished" && (
          <div className="tournament-winner panel">
            <Trophy size={34} />
            <div>
              <p className="eyebrow">{t("TOURNAMENT CHAMPION")}</p>
              <h2>
                {event.players.find((p) => p.accountId === event.winnerId)
                  ?.name ?? t("Explorer")}
              </h2>
              <p>
                {t(
                  "The latest tournament champion holds first place on the global leaderboard for seven days.",
                )}
              </p>
              <Link href="/leaderboard" className="text-link">
                {t("Global leaderboard")} →
              </Link>
            </div>
          </div>
        )}
        {event.status === "cancelled" && (
          <p role="status" className="notice">
            {t(
              "This tournament was cancelled. Scheduled tournaments need at least two eligible players at the start.",
            )}
          </p>
        )}
        <h2>
          {t(
            event.status === "finished"
              ? "Final standings"
              : "Tournament standings",
          )}
        </h2>
        <p className="muted">
          {t(
            "Points count after each mini-round closes. Ties use total distance, then registration order.",
          )}
        </p>
        <div className="leaderboard-table-wrap">
          <table className="leaderboard-table">
            <thead>
              <tr>
                <th scope="col">{t("Rank")}</th>
                <th scope="col">{t("Explorer")}</th>
                <th scope="col">{t("Total points")}</th>
              </tr>
            </thead>
            <tbody>
              {event.players.map((player) => (
                <tr
                  key={player.accountId}
                  className={
                    player.accountId === event.you ? "your-row" : undefined
                  }
                >
                  <td>{player.rank}</td>
                  <th scope="row">
                    {player.name}
                    {player.accountId === event.winnerId ? " 🏆" : ""}
                  </th>
                  <td>{formatNumber(player.total)}</td>
                </tr>
              ))}
            </tbody>
          </table>
        </div>
      </div>
    </>
  );
}