// src/store/context.tsx
// WizardContext, WizardProvider, and useWizard hook.
// useWizard throws if used outside WizardProvider — prevents silent "undefined state" bugs.

import React, { createContext, useContext, useReducer } from 'react';
import { WizardState, WizardAction, INITIAL_STATE } from './types';
import { wizardReducer } from './reducer';

interface WizardContextValue {
  state: WizardState;
  dispatch: React.Dispatch<WizardAction>;
}

const WizardContext = createContext<WizardContextValue | null>(null);

export function WizardProvider({ children }: { children: React.ReactNode }) {
  const [state, dispatch] = useReducer(wizardReducer, INITIAL_STATE);
  return (
    <WizardContext.Provider value={{ state, dispatch }}>
      {children}
    </WizardContext.Provider>
  );
}

export function useWizard(): WizardContextValue {
  const ctx = useContext(WizardContext);
  if (!ctx) throw new Error('useWizard must be used inside <WizardProvider>');
  return ctx;
}
