import { useEffect, useRef, useState } from "react";
import AsyncStorage from "@react-native-async-storage/async-storage";
import type { JoinResponse, SessionPreview, SessionSnapshot } from "../shared/types";
import { getApiBaseUrl, getWsUrl } from "../config/api";
import { tStatic } from "../i18n";

const STORAGE_KEY = "negopoly:session";

type StoredSession = {
  sessionId: string;
  sessionCode: string;
  playerId: string;
};

async function readStoredSession(): Promise<StoredSession | null> {
  try {
    const raw = await AsyncStorage.getItem(STORAGE_KEY);
    if (!raw) return null;
    return JSON.parse(raw) as StoredSession;
  } catch {
    return null;
  }
}

async function writeStoredSession(session: StoredSession) {
  await AsyncStorage.setItem(STORAGE_KEY, JSON.stringify(session));
}

async function clearStoredSession() {
  await AsyncStorage.removeItem(STORAGE_KEY);
}

export function useSessionManager() {
  const [sessionId, setSessionId] = useState("");
  const [sessionCode, setSessionCode] = useState("");
  const [playerId, setPlayerId] = useState("");
  const [session, setSession] = useState<SessionSnapshot | null>(null);
  const [error, setError] = useState<string | null>(null);
  const [pendingTakeoverId, setPendingTakeoverId] = useState<string | null>(null);
  const [connectionState, setConnectionState] = useState<
    "idle" | "connecting" | "open" | "error"
  >("idle");
  const [tick, setTick] = useState(0);

  const wsRef = useRef<WebSocket | null>(null);

  useEffect(() => {
    let mounted = true;
    readStoredSession().then((stored) => {
      if (!mounted || !stored) return;
      setSessionId(stored.sessionId);
      setSessionCode(stored.sessionCode);
      setPlayerId(stored.playerId);
    });
    return () => {
      mounted = false;
    };
  }, []);

  useEffect(() => {
    const timer = setInterval(() => setTick((value) => value + 1), 1000);
    return () => clearInterval(timer);
  }, []);

  useEffect(() => {
    if (!sessionId || !playerId) {
      setConnectionState("idle");
      setSession(null);
      return;
    }

    setConnectionState("connecting");
    const ws = new WebSocket(getWsUrl(sessionId, playerId));
    wsRef.current = ws;

    ws.onopen = () => setConnectionState("open");
    ws.onmessage = (event) => {
      try {
        const message = JSON.parse(event.data);
        if (message.type === "state") {
          setSession(message.session as SessionSnapshot);
        }
        if (message.type === "error") {
          setError(message.message);
        }
        if (message.type === "takeover_approved") {
          const assignedId = message.assignedPlayerId as string;
          setPlayerId(assignedId);
          if (sessionId && sessionCode) {
            writeStoredSession({
              sessionId,
              sessionCode,
              playerId: assignedId,
            });
          }
        }
      } catch {
        setError(tStatic("error.parseResponse"));
      }
    };

    ws.onerror = () => setConnectionState("error");
    ws.onclose = (event) => {
      setConnectionState("error");
      const reason = typeof event?.reason === "string" ? event.reason : "";
      if (event?.code === 1008 && /session not found|player not found/i.test(reason)) {
        resetSession();
      }
    };

    const pingTimer = setInterval(() => {
      if (ws.readyState === WebSocket.OPEN) {
        ws.send(JSON.stringify({ type: "ping", sessionId, playerId }));
      }
    }, 15000);

    return () => {
      clearInterval(pingTimer);
      ws.close();
    };
  }, [sessionId, playerId]);

  useEffect(() => {
    if (!pendingTakeoverId) return;
    if (!wsRef.current || wsRef.current.readyState !== WebSocket.OPEN) return;
    if (!sessionId || !playerId) return;
    wsRef.current.send(
      JSON.stringify({
        type: "takeover_request",
        sessionId,
        playerId,
        dummyId: pendingTakeoverId,
      }),
    );
    setPendingTakeoverId(null);
  }, [pendingTakeoverId, sessionId, playerId]);

  async function createSession(bankerName: string) {
    setError(null);
    setSession(null);
    const response = await fetch(`${getApiBaseUrl()}/api/session`, {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({ bankerName }),
    });
    if (!response.ok) {
      setError(tStatic("error.createSession"));
      return null;
    }
    const data = (await response.json()) as JoinResponse;
    setSessionId(data.sessionId);
    setSessionCode(data.sessionCode);
    setPlayerId(data.playerId);
    await writeStoredSession({
      sessionId: data.sessionId,
      sessionCode: data.sessionCode,
      playerId: data.playerId,
    });
    return data;
  }

  async function joinSession(code: string, name: string) {
    setError(null);
    setSession(null);
    if (!code) {
      setError(tStatic("entry.alert.enterCode"));
      return null;
    }
    const storedNow = await readStoredSession();
    const reusePlayerId =
      storedNow && (storedNow.sessionCode === code || storedNow.sessionId === code)
        ? storedNow.playerId
        : undefined;

    const response = await fetch(`${getApiBaseUrl()}/api/session/${code}/join`, {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({ name, playerId: reusePlayerId }),
    });
    if (!response.ok) {
      setError(tStatic("error.joinSession"));
      return null;
    }
    const data = (await response.json()) as JoinResponse;
    setSessionId(data.sessionId);
    setSessionCode(data.sessionCode);
    setPlayerId(data.playerId);
    await writeStoredSession({
      sessionId: data.sessionId,
      sessionCode: data.sessionCode,
      playerId: data.playerId,
    });
    return data;
  }

  async function fetchSessionPreview(code: string): Promise<SessionPreview | null> {
    if (!code) return null;
    const response = await fetch(`${getApiBaseUrl()}/api/session/${code}/info`);
    if (!response.ok) {
      setError(tStatic("error.loadSessionInfo"));
      return null;
    }
    return (await response.json()) as SessionPreview;
  }

  function sendMessage(payload: Record<string, unknown>) {
    if (!wsRef.current || wsRef.current.readyState !== WebSocket.OPEN) {
      setError(tStatic("error.connectionNotReady"));
      return;
    }
    wsRef.current.send(JSON.stringify(payload));
  }

  async function resetSession() {
    try {
      await clearStoredSession();
    } catch {
      // Ignore storage errors on reset.
    }
    setSessionId("");
    setSessionCode("");
    setPlayerId("");
    setSession(null);
    setError(null);
    setPendingTakeoverId(null);
    setConnectionState("idle");
  }

  async function leaveSession() {
    const ws = wsRef.current;
    wsRef.current = null;
    if (ws && ws.readyState !== WebSocket.CLOSED) {
      try {
        ws.close();
      } catch {
        // Ignore failures while closing the socket.
      }
    }
    await resetSession();
  }

  const me = session?.players.find((player) => player.id === playerId) ?? null;
  const isBanker = me?.role === "banker";

  return {
    sessionId,
    sessionCode,
    playerId,
    session,
    me,
    isBanker,
    tick,
    error,
    connectionState,
    setError,
    createSession,
    joinSession,
    fetchSessionPreview,
    sendMessage,
    resetSession,
    leaveSession,
    setSessionId,
    setPlayerId,
    setSession,
    setPendingTakeoverId,
  };
}