import { createContext, useContext, useEffect, useState, useCallback, type ReactNode } from 'react';
import { useSearchParams, useNavigate } from 'react-router-dom';
import { pb } from '../../lib/pocketbase';

interface ImpersonatedTechInfo {
  id: string;
  email: string;
  displayName?: string;
}

interface TechnicianContextValue {
  effectiveUserId: string;
  isImpersonating: boolean;
  impersonatedTech: ImpersonatedTechInfo | null;
  stopImpersonation: () => void;
}

const TechnicianContext = createContext<TechnicianContextValue>({
  effectiveUserId: '',
  isImpersonating: false,
  impersonatedTech: null,
  stopImpersonation: () => {},
});

export function TechnicianProvider({ children }: { children: ReactNode }) {
  const [searchParams] = useSearchParams();
  const navigate = useNavigate();
  const viewAs = searchParams.get('view_as');
  const authUserId = pb.authStore.model?.id as string | undefined;
  const [impersonatedTech, setImpersonatedTech] = useState<ImpersonatedTechInfo | null>(null);

  const isImpersonating = !!viewAs && viewAs !== authUserId;
  const effectiveUserId = isImpersonating ? viewAs! : (authUserId || '');

  useEffect(() => {
    if (isImpersonating && viewAs) {
      pb.collection('users').getOne(viewAs).then((user) => {
        setImpersonatedTech({
          id: user.id,
          email: user.email as string,
          displayName: user.displayName as string | undefined,
        });
      }).catch(() => {
        setImpersonatedTech(null);
      });
    } else {
      setImpersonatedTech(null);
    }
  }, [isImpersonating, viewAs]);

  const stopImpersonation = useCallback(() => {
    navigate('/team');
  }, [navigate]);

  return (
    <TechnicianContext.Provider
      value={{
        effectiveUserId,
        isImpersonating,
        impersonatedTech,
        stopImpersonation,
      }}
    >
      {children}
    </TechnicianContext.Provider>
  );
}

export function useTechnicianContext(): TechnicianContextValue {
  return useContext(TechnicianContext);
}

export function useTechnicianNav() {
  const navigate = useNavigate();
  const [searchParams] = useSearchParams();
  const viewAs = searchParams.get('view_as');

  const buildTechUrl = useCallback(
    (path: string): string => {
      if (!viewAs) return path;
      const separator = path.includes('?') ? '&' : '?';
      return `${path}${separator}view_as=${encodeURIComponent(viewAs)}`;
    },
    [viewAs],
  );

  const navigateTech = useCallback(
    (path: string, opts?: { replace?: boolean; state?: unknown }) => {
      navigate(buildTechUrl(path), opts);
    },
    [navigate, buildTechUrl],
  );

  return { buildTechUrl, navigateTech };
}