import type { PropsWithChildren } from "react";
import { createContext, useContext, useEffect, useState } from "react";
import type { SessionView } from "@internal-mail/shared";
import { apiClient } from "../api/client";

type SessionContextValue = {
  session: SessionView;
  loading: boolean;
  authBusy: boolean;
  error: string | null;
  login: (email: string, password: string, totpCode?: string) => Promise<void>;
  logout: () => Promise<void>;
  refresh: () => Promise<void>;
};

const anonymousSession: SessionView = {
  authenticated: false,
  csrfToken: null,
  user: null
};

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

export const SessionProvider = ({ children }: PropsWithChildren) => {
  const [session, setSession] = useState<SessionView>(anonymousSession);
  const [loading, setLoading] = useState(true);
  const [authBusy, setAuthBusy] = useState(false);
  const [error, setError] = useState<string | null>(null);

  const refresh = async () => {
    try {
      const nextSession = await apiClient.getSession();
      setSession(nextSession);
      setError(null);
    } catch (requestError) {
      setSession(anonymousSession);
      setError(requestError instanceof Error ? requestError.message : "Unable to load session.");
    } finally {
      setLoading(false);
    }
  };

  useEffect(() => {
    void refresh();
  }, []);

  const value: SessionContextValue = {
    session,
    loading,
    authBusy,
    error,
    login: async (email, password, totpCode) => {
      try {
        setAuthBusy(true);
        const nextSession = await apiClient.login(email, password, totpCode);
        setSession(nextSession);
        setError(null);
      } finally {
        setAuthBusy(false);
      }
    },
    logout: async () => {
      try {
        setAuthBusy(true);
        await apiClient.logout();
        setSession(anonymousSession);
      } finally {
        setAuthBusy(false);
      }
    },
    refresh
  };

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

export const useSession = (): SessionContextValue => {
  const value = useContext(SessionContext);
  if (!value) {
    throw new Error("useSession must be used inside SessionProvider.");
  }

  return value;
};