"use client";
import { Username } from "./Username";

import { useCallback, useEffect, useRef, useState } from "react";
import { MessageCircle, Send, X } from "lucide-react";
import { api } from "@/lib/client-api";
import {
  chatMessageSchema,
  type RoomChat as ChatView,
} from "@/shared/multiplayer";
import { useI18n } from "./I18nProvider";

export function RoomChat({
  id,
  playerId,
  available,
  playing,
  endpoint,
}: {
  id: string;
  playerId: string | null;
  available: boolean;
  playing: boolean;
  endpoint?: string;
}) {
  const { t } = useI18n();
  const [open, setOpen] = useState(false);
  const [messages, setMessages] = useState<ChatView["messages"]>([]);
  const [text, setText] = useState("");
  const [error, setError] = useState("");
  const [sending, setSending] = useState(false);
  const [lastRead, setLastRead] = useState(0n);
  const version = useRef(0);
  const inFlight = useRef(false);
  const initialized = useRef(false);
  const pending = useRef<{ text: string; clientId: string } | null>(null);
  const input = useRef<HTMLInputElement>(null);
  const toggle = useRef<HTMLButtonElement>(null);
  const log = useRef<HTMLDivElement>(null);
  const followLatest = useRef(true);
  const enabled = !!playerId && available;
  const accept = useCallback((view: ChatView) => {
    setMessages(view.messages);
    if (!initialized.current) {
      initialized.current = true;
      setLastRead(BigInt(view.messages.at(-1)?.id ?? "0"));
    }
    setError("");
  }, []);
  const load = useCallback(async () => {
    if (inFlight.current) return;
    const current = ++version.current;
    try {
      const view = await api<ChatView>(endpoint ?? `rooms/${id}/chat`);
      if (current === version.current) accept(view);
    } catch (failure) {
      if (current === version.current) setError((failure as Error).message);
    }
  }, [id, endpoint, accept]);
  useEffect(() => {
    if (!enabled) return;
    let stopped = false;
    let timer: ReturnType<typeof setTimeout>;
    const poll = async () => {
      await load();
      if (!stopped) timer = setTimeout(poll, document.hidden ? 5000 : 2000);
    };
    void poll();
    const resume = () => {
      if (!document.hidden) void load();
    };
    document.addEventListener("visibilitychange", resume);
    return () => {
      stopped = true;
      version.current++;
      clearTimeout(timer);
      document.removeEventListener("visibilitychange", resume);
    };
  }, [enabled, load]);
  useEffect(() => {
    if (open) {
      setLastRead(BigInt(messages.at(-1)?.id ?? "0"));
      if (log.current && followLatest.current)
        log.current.scrollTop = log.current.scrollHeight;
    }
  }, [open, messages]);
  useEffect(() => {
    if (open) {
      followLatest.current = true;
      if (log.current) log.current.scrollTop = log.current.scrollHeight;
      input.current?.focus();
    }
  }, [open]);
  async function send() {
    if (inFlight.current || !enabled) return;
    const draft = text.trim();
    const body =
      pending.current?.text === draft
        ? pending.current
        : { text: draft, clientId: crypto.randomUUID() };
    if (!chatMessageSchema.safeParse(body).success) {
      setError("Write a message of 1–500 characters without hidden controls");
      return;
    }
    pending.current = body;
    inFlight.current = true;
    setSending(true);
    setError("");
    const current = ++version.current;
    try {
      const view = await api<ChatView>(endpoint ?? `rooms/${id}/chat`, body);
      if (current === version.current) {
        accept(view);
        followLatest.current = true;
        setText("");
        pending.current = null;
      }
    } catch (failure) {
      if (current === version.current) setError((failure as Error).message);
    } finally {
      inFlight.current = false;
      setSending(false);
      input.current?.focus();
    }
  }
  if (!enabled) return null;
  const unread = messages.filter(
    (message) => message.playerId !== playerId && BigInt(message.id) > lastRead,
  ).length;
  return (
    <aside
      className={`room-chat${playing ? " room-chat-playing" : ""}`}
      aria-label={t("Room chat")}
    >
      <button
        ref={toggle}
        className="button room-chat-toggle"
        aria-expanded={open}
        aria-controls="room-chat-panel"
        onClick={() => setOpen((value) => !value)}
      >
        <MessageCircle size={18} aria-hidden="true" /> {t("Chat")}
        {unread > 0 && (
          <span
            className="room-chat-unread"
            aria-label={t("{count} unread messages", { count: unread })}
          >
            {unread}
          </span>
        )}
      </button>
      <section
        id="room-chat-panel"
        hidden={!open}
        onKeyDown={(event) => {
          if (event.key === "Escape") {
            setOpen(false);
            toggle.current?.focus();
          }
        }}
      >
        <div className="room-chat-heading">
          <strong>{t("Room chat")}</strong>
          <button
            type="button"
            aria-label={t("Close chat")}
            onClick={() => {
              setOpen(false);
              toggle.current?.focus();
            }}
          >
            <X size={18} />
          </button>
        </div>
        <div
          className="room-chat-log"
          ref={log}
          role="log"
          aria-live={open ? "polite" : "off"}
          aria-relevant="additions"
          aria-label={t("Chat messages")}
          onScroll={(event) => {
            const element = event.currentTarget;
            followLatest.current =
              element.scrollHeight - element.scrollTop - element.clientHeight <
              40;
          }}
        >
          {!messages.length && (
            <p className="muted">{t("Say hello to your teammates.")}</p>
          )}
          {messages.map((message) => (
            <p
              key={message.id}
              className={message.playerId === playerId ? "room-chat-mine" : ""}
            >
              <strong>
                <Username name={message.name} appearance={message.appearance} />
                {message.tag && <small> · {message.tag}</small>}
                {message.playerId === playerId && ` ${t("(you)")}`}
              </strong>
              <span>{message.text}</span>
            </p>
          ))}
        </div>
        {error && (
          <p className="error-message" role="alert">
            {t(error)}{" "}
            <button className="text-link" onClick={() => void load()}>
              {t("Retry")}
            </button>
          </p>
        )}
        <form
          onSubmit={(event) => {
            event.preventDefault();
            void send();
          }}
        >
          <label className="sr-only" htmlFor="room-chat-input">
            {t("Message")}
          </label>
          <input
            id="room-chat-input"
            ref={input}
            value={text}
            maxLength={500}
            autoComplete="off"
            disabled={sending}
            placeholder={t("Message your teammates…")}
            onChange={(event) => setText(event.target.value)}
          />
          <button
            className="button primary"
            disabled={sending || !text.trim()}
            aria-label={t("Send message")}
          >
            <Send size={18} aria-hidden="true" />
          </button>
        </form>
      </section>
    </aside>
  );
}