data-entry-app/frontend/src/lib/session.ts

import { browser } from '$app/environment';
import { writable } from 'svelte/store';

export type OperatorSession = {
  name: string;
  email: string;
  role: string;
};

const STORAGE_KEY = 'data-entry-app-operator-session';

function readSession(): OperatorSession | null {
  if (!browser) {
    return null;
  }

  const value = localStorage.getItem(STORAGE_KEY);
  if (!value) {
    return null;
  }

  try {
    return JSON.parse(value) as OperatorSession;
  } catch {
    localStorage.removeItem(STORAGE_KEY);
    return null;
  }
}

function createOperatorSessionStore() {
  const store = writable<OperatorSession | null>(readSession());

  if (browser) {
    window.addEventListener('storage', (event) => {
      if (event.key === STORAGE_KEY) {
        store.set(readSession());
      }
    });
  }

  return {
    subscribe: store.subscribe,
    set(session: OperatorSession) {
      if (browser) {
        localStorage.setItem(STORAGE_KEY, JSON.stringify(session));
      }
      store.set(session);
    },
    clear() {
      if (browser) {
        localStorage.removeItem(STORAGE_KEY);
      }
      store.set(null);
    }
  };
}

export const operatorSession = createOperatorSessionStore();