const NAME_KEY = "spill.pong.lobbyName";

export function getSavedLobbyName() {
  try {
    return window.localStorage.getItem(NAME_KEY) || "";
  } catch {
    return "";
  }
}

export function saveLobbyName(name) {
  try {
    window.localStorage.setItem(NAME_KEY, name);
  } catch {
    // Ignore storage failures.
  }
}

export function getDefaultLobbyState() {
  return {
    connected: false,
    connecting: false,
    selfId: null,
    selfName: "",
    users: [],
    error: "",
    notices: [],
    reconnecting: false,
    incomingInvite: null,
    outgoingInvite: null,
    currentMatch: null
  };
}

function wsUrlFromWindow() {
  const { protocol, host } = window.location;
  const wsProtocol = protocol === "https:" ? "wss:" : "ws:";
  return `${wsProtocol}//${host}/ws`;
}

export function createLobbyClient({ onState, onNotice, onError, onMatchSignal } = {}) {
  let ws = null;
  let state = getDefaultLobbyState();
  let reconnectTimer = null;
  let manualDisconnect = false;
  let suppressNextCloseReconnect = false;
  let lastRequestedName = "";
  let reconnectAttempt = 0;
  let pingTimer = null;

  function clearReconnectTimer() {
    if (reconnectTimer) {
      window.clearTimeout(reconnectTimer);
      reconnectTimer = null;
    }
  }

  function clearPingTimer() {
    if (pingTimer) {
      window.clearInterval(pingTimer);
      pingTimer = null;
    }
  }

  function emit(patch) {
    state = { ...state, ...patch };
    onState?.(state);
  }

  function addNotice(text, kind = "info") {
    const item = { id: crypto.randomUUID(), text, kind, ts: Date.now() };
    const notices = [item, ...state.notices].slice(0, 6);
    emit({ notices });
    onNotice?.(item);
  }

  function send(payload) {
    if (!ws || ws.readyState !== WebSocket.OPEN) return false;
    ws.send(JSON.stringify(payload));
    return true;
  }

  function startPingLoop() {
    clearPingTimer();
    pingTimer = window.setInterval(() => {
      send({ type: "ping" });
    }, 15000);
  }

  function scheduleReconnect() {
    if (manualDisconnect) return;
    if (!lastRequestedName) return;
    clearReconnectTimer();

    reconnectAttempt += 1;
    const delayMs = Math.min(5000, 600 * 2 ** Math.min(reconnectAttempt, 3));
    emit({ reconnecting: true, connecting: true, connected: false });
    addNotice(`Tilkobling mistet. Prøver igjen om ${Math.round(delayMs / 1000)}s`, "warn");

    reconnectTimer = window.setTimeout(() => {
      connect(lastRequestedName);
    }, delayMs);
  }

  function handleMessage(message) {
    switch (message.type) {
      case "connected":
        return;
      case "hello_ok":
        emit({
          connected: true,
          connecting: false,
          reconnecting: false,
          selfId: message.selfId,
          selfName: message.name,
          error: ""
        });
        reconnectAttempt = 0;
        addNotice(`Pålogget som ${message.name}`);
        return;
      case "lobby_state":
        emit({ users: Array.isArray(message.users) ? message.users : [] });
        return;
      case "invite_sent":
        emit({
          outgoingInvite: {
            inviteId: message.inviteId,
            toId: message.toId,
            toName: message.toName
          }
        });
        addNotice(`Invitasjon sendt til ${message.toName}`);
        return;
      case "invite_received":
        emit({
          incomingInvite: {
            inviteId: message.inviteId,
            fromId: message.fromId,
            fromName: message.fromName
          }
        });
        addNotice(`Invitasjon fra ${message.fromName}`);
        return;
      case "invite_replied":
        emit({ incomingInvite: null });
        return;
      case "invite_declined":
        emit({ outgoingInvite: null });
        addNotice(`${message.byName || "Motstander"} avslo invitasjonen`, "warn");
        return;
      case "invite_canceled":
        if (state.incomingInvite?.inviteId === message.inviteId) {
          emit({ incomingInvite: null });
          addNotice("Invitasjonen ble trukket tilbake", "warn");
        }
        if (state.outgoingInvite?.inviteId === message.inviteId) {
          emit({ outgoingInvite: null });
        }
        return;
      case "match_started":
      case "match_created":
      case "match_ready_state":
        emit({
          incomingInvite: null,
          outgoingInvite: null,
          currentMatch: {
            matchId: message.matchId,
            opponent: message.opponent,
            role: message.role,
            ready: message.ready || { self: false, opponent: false },
            started: Boolean(message.started)
          }
        });
        if (message.type === "match_created") {
          addNotice(`Match opprettet mot ${message.opponent?.name || "motstander"}`);
        }
        if (message.type === "match_started") {
          addNotice(`Kamp startet mot ${message.opponent?.name || "motstander"}`);
        }
        return;
      case "match_ended":
        emit({ currentMatch: null });
        addNotice(
          message.reason === "disconnect"
            ? "Motstander mistet forbindelsen"
            : "Kamp avsluttet",
          "warn"
        );
        return;
      case "match_signal":
        onMatchSignal?.(message);
        return;
      case "error":
        emit({ error: message.message || "Feil" });
        onError?.(message);
        return;
      default:
        return;
    }
  }

  function connect(name, url = wsUrlFromWindow()) {
    const cleanName = String(name || "").trim();
    if (!cleanName) {
      emit({ error: "Skriv inn et navn først" });
      return;
    }

    if (ws && (ws.readyState === WebSocket.OPEN || ws.readyState === WebSocket.CONNECTING)) {
      suppressNextCloseReconnect = true;
      ws.close();
    }

    manualDisconnect = false;
    lastRequestedName = cleanName;
    clearReconnectTimer();
    emit({
      connecting: true,
      reconnecting: reconnectAttempt > 0,
      connected: false,
      error: "",
      selfName: cleanName
    });
    saveLobbyName(cleanName);

    ws = new WebSocket(url);

    ws.addEventListener("open", () => {
      startPingLoop();
      send({ type: "hello", name: cleanName });
    });

    ws.addEventListener("message", (event) => {
      try {
        handleMessage(JSON.parse(event.data));
      } catch {
        emit({ error: "Ugyldig svar fra server" });
      }
    });

    ws.addEventListener("close", () => {
      clearPingTimer();
      const lostActiveMatch = Boolean(state.currentMatch);
      emit({
        connecting: false,
        connected: false,
        selfId: null,
        users: [],
        reconnecting: false,
        incomingInvite: null,
        outgoingInvite: null,
        currentMatch: null
      });
      if (lostActiveMatch) {
        addNotice("Match avsluttet fordi forbindelsen ble brutt", "warn");
      }
      if (suppressNextCloseReconnect) {
        suppressNextCloseReconnect = false;
        return;
      }
      scheduleReconnect();
    });

    ws.addEventListener("error", () => {
      emit({ error: "Kunne ikke koble til lobby-server" });
    });
  }

  function disconnect() {
    manualDisconnect = true;
    reconnectAttempt = 0;
    suppressNextCloseReconnect = false;
    clearReconnectTimer();
    clearPingTimer();
    ws?.close();
    ws = null;
    emit({ reconnecting: false });
  }

  function invite(toId) {
    emit({ error: "" });
    send({ type: "invite_send", toId });
  }

  function replyInvite(inviteId, accept) {
    emit({ error: "" });
    send({ type: "invite_reply", inviteId, accept });
    if (!accept) emit({ incomingInvite: null });
  }

  function leaveMatch() {
    send({ type: "leave_match" });
  }

  function setReady(ready) {
    send({ type: "match_ready", ready: Boolean(ready) });
  }

  function sendMatchSignal(payload) {
    return send({ type: "match_signal", payload });
  }

  return {
    connect,
    disconnect,
    invite,
    replyInvite,
    leaveMatch,
    setReady,
    sendMatchSignal,
    getState() {
      return state;
    }
  };
}