"use client";

import {
  createContext,
  useCallback,
  useContext,
  useEffect,
  useMemo,
  useState,
  type ReactNode,
} from "react";
import {
  clearSharedAuthCookies,
  hydrateLocalTokensFromSharedCookies,
  SHARED_ACCESS_TOKEN_KEY,
  SHARED_REFRESH_TOKEN_KEY,
  writeSharedAuthCookies,
} from "./shared-auth-cookie";

export type AuthBusinessMembership = {
  id: string;
  name: string;
  slug: string;
  isOwner: boolean;
  teamRole: string | null;
};

export type AuthUser = {
  id: string;
  firstName?: string;
  lastName?: string;
  cellNumber?: string;
  email?: string;
  roles?: string[];
  isSuperAdmin?: boolean;
  businesses?: AuthBusinessMembership[];
};

type SessionContextValue = {
  user: AuthUser | null;
  isAuthenticated: boolean;
  ready: boolean;
  businessId: string;
  isWebsiteAdmin: boolean;
  logout: () => void;
  getAccessToken: () => string | null;
};

function normalizeUser(raw: Partial<AuthUser> & { id?: string | number }): AuthUser | null {
  if (raw.id == null) return null;
  return {
    id: String(raw.id),
    firstName: raw.firstName ?? undefined,
    lastName: raw.lastName ?? undefined,
    cellNumber: raw.cellNumber ?? undefined,
    email: raw.email ?? undefined,
    roles: Array.isArray(raw.roles) ? raw.roles : undefined,
    isSuperAdmin: Boolean(raw.isSuperAdmin),
    businesses: Array.isArray(raw.businesses)
      ? raw.businesses.map((business) => ({
          id: String(business.id),
          name: business.name,
          slug: business.slug,
          isOwner: Boolean(business.isOwner),
          teamRole: business.teamRole ?? null,
        }))
      : undefined,
  };
}

export function isWebsiteAdminForBusiness(user: AuthUser | null | undefined, businessId: string): boolean {
  if (!user || !businessId) return false;
  if (user.isSuperAdmin || user.roles?.includes("super_admin")) return true;
  return Boolean(
    user.businesses?.some(
      (business) => String(business.id) === String(businessId) && (business.isOwner || Boolean(business.teamRole)),
    ),
  );
}

const SessionContext = createContext<SessionContextValue | null>(null);

function readToken(key: string): string | null {
  try {
    return localStorage.getItem(key);
  } catch {
    return null;
  }
}

function writeToken(key: string, value: string | null) {
  try {
    if (value) localStorage.setItem(key, value);
    else localStorage.removeItem(key);
  } catch {
    // ignore
  }
}

export function SessionProvider({
  children,
  businessId,
}: {
  children: ReactNode;
  businessId: string;
}) {
  const [user, setUser] = useState<AuthUser | null>(null);
  const [ready, setReady] = useState(false);

  const getAccessToken = useCallback(() => {
    hydrateLocalTokensFromSharedCookies(SHARED_ACCESS_TOKEN_KEY, SHARED_REFRESH_TOKEN_KEY);
    return readToken(SHARED_ACCESS_TOKEN_KEY);
  }, []);

  const clearTokens = useCallback(() => {
    writeToken(SHARED_ACCESS_TOKEN_KEY, null);
    writeToken(SHARED_REFRESH_TOKEN_KEY, null);
    writeToken("accessToken", null);
    writeToken("meshkee_access_token", null);
    clearSharedAuthCookies();
    setUser(null);
  }, []);

  useEffect(() => {
    const token = getAccessToken();
    if (!token) {
      setReady(true);
      return;
    }

    const refresh = readToken(SHARED_REFRESH_TOKEN_KEY);
    writeSharedAuthCookies(token, refresh ?? undefined);

    fetch("/api/auth/me", { headers: { Authorization: `Bearer ${token}` } })
      .then(async (res) => {
        if (res.status === 401) {
          clearTokens();
          return;
        }
        if (!res.ok) return;
        const data = (await res.json()) as { user?: AuthUser } & AuthUser;
        const next = normalizeUser(data.user ?? data);
        if (next) setUser(next);
      })
      .catch(() => undefined)
      .finally(() => setReady(true));
  }, [clearTokens, getAccessToken]);

  const logout = useCallback(() => {
    clearTokens();
  }, [clearTokens]);

  const isWebsiteAdmin = useMemo(() => isWebsiteAdminForBusiness(user, businessId), [user, businessId]);

  const value = useMemo(
    () => ({
      user,
      isAuthenticated: Boolean(user),
      ready,
      businessId,
      isWebsiteAdmin,
      logout,
      getAccessToken,
    }),
    [user, ready, businessId, isWebsiteAdmin, logout, getAccessToken],
  );

  return <SessionContext.Provider value={value}>{children}</SessionContext.Provider>;
}

export function useSession() {
  const ctx = useContext(SessionContext);
  if (!ctx) throw new Error("useSession must be used within SessionProvider");
  return ctx;
}