import router from "../router";
import { useAuthStore } from "../store/auth";
import { useSessionStore } from "../store/session";
import { getToken, setToken, clearToken } from "../utils/auth";
import { extendToken, getLoginKey, unlockSession } from "../api/authClient";
import { encryptLoginPayload } from "../utils/loginCrypto";
import { parseJwtExp } from "./jwt";

export const IDLE_TIMEOUT_MINUTES = 30;
export const AUTO_LOGOUT_TIMEOUT_HOURS = 2;
export const EXTEND_EARLY_SECONDS = 120;
export const EXTEND_MIN_INTERVAL_SECONDS = 60;
export const UNLOCK_MAX_ATTEMPTS = 5;
export const LOGOUT_REASON_TIMEOUT = "timeout";
const LOGOUT_REASON_STORAGE_KEY = "ctms_logout_reason";

type BroadcastMessage =
  | { type: "ACTIVE"; at: number }
  | { type: "NETWORK"; at: number }
  | { type: "LOCK"; reason: string; email?: string; deadlineAt?: number }
  | { type: "TOKEN_UPDATED"; token: string }
  | { type: "LOGOUT"; reason?: string };

let idleTimer: number | null = null;
let extendPromise: Promise<{ token: string | null; authFailed: boolean }> | null = null;
let initialized = false;
const channel = typeof BroadcastChannel !== "undefined" ? new BroadcastChannel("ctms-auth") : null;

const getLastActiveAt = (session: ReturnType<typeof useSessionStore>) =>
  Math.max(session.lastUserActiveAt, session.lastNetworkActiveAt);

const reconcileSessionState = (now: number = Date.now()) => {
  const session = useSessionStore();
  if (session.locked) return false;
  const idleTimeoutMs = IDLE_TIMEOUT_MINUTES * 60 * 1000;
  const autoLogoutMs = AUTO_LOGOUT_TIMEOUT_HOURS * 60 * 60 * 1000;
  const lastActiveAt = getLastActiveAt(session);
  if (now - lastActiveAt > autoLogoutMs) {
    forceLogout(LOGOUT_REASON_TIMEOUT);
    return false;
  }
  if (now - lastActiveAt > idleTimeoutMs) {
    lockSession("idle");
    return false;
  }
  return true;
};

const broadcast = (message: BroadcastMessage) => {
  if (channel) {
    channel.postMessage(message);
  }
  try {
    localStorage.setItem("ctms_auth_broadcast", JSON.stringify({ ...message, ts: Date.now() }));
  } catch {
    /* ignore */
  }
};

const handleBroadcast = (message: BroadcastMessage) => {
  const session = useSessionStore();
  const auth = useAuthStore();
  if (message.type === "ACTIVE") {
    if (session.locked) return;
    session.recordUserActivity(message.at);
    scheduleIdleCheck();
  }
  if (message.type === "NETWORK") {
    if (session.locked) return;
    session.recordNetworkActivity(message.at);
    scheduleIdleCheck();
  }
  if (message.type === "LOCK") {
    const reason = message.reason as "idle" | "extend_failed" | "token_invalid";
    session.lock(reason || "idle", message.email, message.deadlineAt);
    scheduleIdleCheck();
  }
  if (message.type === "TOKEN_UPDATED") {
    auth.setToken(message.token);
    setToken(message.token);
    session.unlock();
  }
  if (message.type === "LOGOUT") {
    performLogout(message.reason);
  }
};

const scheduleIdleCheck = () => {
  if (idleTimer) {
    window.clearTimeout(idleTimer);
  }
  const session = useSessionStore();
  const now = Date.now();
  if (session.locked) {
    const remain = (session.lockAutoLogoutDeadlineAt || 0) - now;
    if (remain <= 0) {
      checkIdle();
      return;
    }
    idleTimer = window.setTimeout(checkIdle, remain);
    return;
  }
  const idleTimeoutMs = IDLE_TIMEOUT_MINUTES * 60 * 1000;
  const autoLogoutMs = AUTO_LOGOUT_TIMEOUT_HOURS * 60 * 60 * 1000;
  const lastActiveAt = getLastActiveAt(session);
  const idleRemain = lastActiveAt + idleTimeoutMs - now;
  const logoutRemain = lastActiveAt + autoLogoutMs - now;
  const nextCheck = Math.min(idleRemain, logoutRemain);
  if (nextCheck <= 0) {
    checkIdle();
    return;
  }
  idleTimer = window.setTimeout(checkIdle, nextCheck);
};

const checkIdle = () => {
  const session = useSessionStore();
  if (session.locked) {
    const deadlineAt = session.lockAutoLogoutDeadlineAt || 0;
    if (deadlineAt > 0 && Date.now() >= deadlineAt) {
      forceLogout(LOGOUT_REASON_TIMEOUT);
      return;
    }
    scheduleIdleCheck();
    return;
  }
  if (!reconcileSessionState(Date.now())) return;
  scheduleIdleCheck();
};

export const initSessionManager = () => {
  if (initialized) return;
  initialized = true;
  const events = ["mousemove", "mousedown", "keydown", "touchstart", "scroll"];
  let lastSignal = 0;
  const onUserActivity = () => {
    const now = Date.now();
    if (now - lastSignal < 1000) return;
    lastSignal = now;
    markUserActive(now);
  };
  events.forEach((event) => window.addEventListener(event, onUserActivity, { passive: true }));
  window.addEventListener("focus", () => {
    checkIdle();
  });
  document.addEventListener("visibilitychange", () => {
    if (!document.hidden) {
      checkIdle();
    }
  });
  if (channel) {
    channel.onmessage = (event) => handleBroadcast(event.data as BroadcastMessage);
  }
  window.addEventListener("storage", (event) => {
    if (event.key !== "ctms_auth_broadcast" || !event.newValue) return;
    try {
      const message = JSON.parse(event.newValue) as BroadcastMessage;
      handleBroadcast(message);
    } catch {
      /* ignore */
    }
  });
  scheduleIdleCheck();
  startTokenKeepAlive();
};

export const markUserActive = (at: number = Date.now()) => {
  const session = useSessionStore();
  if (session.locked) return;
  if (!reconcileSessionState(at)) return;
  session.recordUserActivity(at);
  broadcast({ type: "ACTIVE", at });
  scheduleIdleCheck();
};

export const markNetworkActive = (at: number = Date.now()) => {
  const session = useSessionStore();
  if (session.locked) return;
  if (!reconcileSessionState(at)) return;
  session.recordNetworkActivity(at);
  broadcast({ type: "NETWORK", at });
  scheduleIdleCheck();
};

export const lockSession = (reason: "idle" | "extend_failed" | "token_invalid") => {
  const session = useSessionStore();
  const auth = useAuthStore();
  if (session.locked) return;
  const email = auth.user?.email || "";
  const autoLogoutMs = AUTO_LOGOUT_TIMEOUT_HOURS * 60 * 60 * 1000;
  const deadlineAt = getLastActiveAt(session) + autoLogoutMs;
  session.lock(reason, email, deadlineAt);
  broadcast({ type: "LOCK", reason, email, deadlineAt });
  scheduleIdleCheck();
};

const setLogoutReason = (reason?: string) => {
  try {
    if (!reason) {
      sessionStorage.removeItem(LOGOUT_REASON_STORAGE_KEY);
      return;
    }
    sessionStorage.setItem(LOGOUT_REASON_STORAGE_KEY, reason);
  } catch {
    /* ignore */
  }
};

export const consumeLogoutReason = () => {
  try {
    const reason = sessionStorage.getItem(LOGOUT_REASON_STORAGE_KEY);
    sessionStorage.removeItem(LOGOUT_REASON_STORAGE_KEY);
    return reason;
  } catch {
    return null;
  }
};

const performLogout = (reason?: string) => {
  setLogoutReason(reason);
  const auth = useAuthStore();
  const session = useSessionStore();
  auth.logout();
  session.unlock();
  clearToken();
  router.replace("/login");
};

export const forceLogout = (reason?: string) => {
  performLogout(reason);
  broadcast({ type: "LOGOUT", reason });
};

const updateToken = (token: string) => {
  const auth = useAuthStore();
  auth.setToken(token);
  setToken(token);
  broadcast({ type: "TOKEN_UPDATED", token });
};

export const extendAccessToken = async (reason: "early" | "response-401") => {
  const session = useSessionStore();
  const token = getToken();
  if (!token) return { token: null, authFailed: false };
  if (reason === "early") {
    const now = Date.now();
    if (now - session.lastExtendAt < EXTEND_MIN_INTERVAL_SECONDS * 1000) {
      return { token: null, authFailed: false };
    }
  }
  if (extendPromise) return extendPromise;
  extendPromise = (async () => {
    let authFailed = false;
    try {
      const { data } = await extendToken(token);
      session.setLastExtendAt(Date.now());
      updateToken(data.accessToken);
      return { token: data.accessToken, authFailed: false };
    } catch (err: any) {
      const status = err?.response?.status;
      if (status === 401) {
        lockSession("extend_failed");
        authFailed = true;
      } else if (status === 403) {
        forceLogout();
        authFailed = true;
      }
      return { token: null, authFailed };
    } finally {
      extendPromise = null;
    }
  })();
  return extendPromise;
};

export const startTokenKeepAlive = () => {
  window.setInterval(() => {
    const token = getToken();
    if (!token) return;
    const session = useSessionStore();
    if (session.locked) return;
    const expAt = parseJwtExp(token);
    if (!expAt) return;
    const remaining = expAt - Date.now();
    const timeoutMs = IDLE_TIMEOUT_MINUTES * 60 * 1000;
    const active = Date.now() - getLastActiveAt(session) < timeoutMs;
    if (active && remaining < EXTEND_EARLY_SECONDS * 1000) {
      void extendAccessToken("early");
    }
  }, 10000);
};

export const unlockWithPassword = async (email: string, password: string) => {
  const session = useSessionStore();
  const auth = useAuthStore();
  const { data: loginKey } = await getLoginKey();
  const ciphertext = await encryptLoginPayload(loginKey.public_key, {
    email,
    password,
    challenge: loginKey.challenge,
  });
  const { data } = await unlockSession({
    key_id: loginKey.key_id,
    challenge: loginKey.challenge,
    ciphertext,
  });
  updateToken(data.accessToken);
  session.unlock();
  try {
    await auth.fetchMe();
  } catch {
    // token已更新但用户信息拉取失败时，避免界面进入无角色状态
    forceLogout();
    throw new Error("无法获取用户信息，请重新登录");
  }
  markUserActive();
};