// persistedRef : lecture initiale depuis localStorage, repli sur défaut, réécriture, robustesse.
import { describe, it, expect, beforeEach } from 'vitest';
import { nextTick } from 'vue';
import { forgetPersisted, persistedRef, readPersisted } from '../src/lib/persisted-ref';

function fakeStorage() {
  const m = new Map<string, string>();
  return {
    getItem: (k: string) => (m.has(k) ? (m.get(k) as string) : null),
    setItem: (k: string, v: string) => void m.set(k, v),
    removeItem: (k: string) => void m.delete(k),
    clear: () => m.clear(),
  };
}

describe('persistedRef', () => {
  beforeEach(() => {
    (globalThis as unknown as { localStorage: unknown }).localStorage = fakeStorage();
  });

  it('lit la valeur initiale depuis localStorage si présente', () => {
    localStorage.setItem('k', JSON.stringify(42));
    expect(persistedRef('k', 0).value).toBe(42);
  });

  it('retombe sur le défaut si la clé est absente', () => {
    expect(persistedRef('missing', 7).value).toBe(7);
  });

  it('retombe sur le défaut si le JSON est corrompu', () => {
    localStorage.setItem('bad', '{not json');
    expect(persistedRef('bad', 'def').value).toBe('def');
  });

  it('réécrit en localStorage au changement', async () => {
    const r = persistedRef('w', 1);
    r.value = 99;
    await nextTick();
    expect(JSON.parse(localStorage.getItem('w') as string)).toBe(99);
  });

  it('ne jette pas si localStorage est absent (env node sans DOM)', () => {
    delete (globalThis as unknown as { localStorage?: unknown }).localStorage;
    expect(() => persistedRef('x', 5)).not.toThrow();
    expect(persistedRef('x', 5).value).toBe(5);
  });
});

describe('readPersisted / forgetPersisted', () => {
  beforeEach(() => {
    (globalThis as unknown as { localStorage: unknown }).localStorage = fakeStorage();
  });

  it('lit une valeur brute sans créer de ref, et retombe sur le défaut', () => {
    localStorage.setItem('legacy', JSON.stringify(['a', 'b']));
    expect(readPersisted<string[]>('legacy', [])).toEqual(['a', 'b']);
    expect(readPersisted('absente', 'def')).toBe('def');
    localStorage.setItem('cassee', '{not json');
    expect(readPersisted('cassee', 'def')).toBe('def');
  });

  it('oublie une clé migrée (sans quoi la migration rejouerait au démarrage suivant)', () => {
    localStorage.setItem('legacy', '1');
    forgetPersisted('legacy');
    expect(localStorage.getItem('legacy')).toBeNull();
  });

  it('ne jette pas sans localStorage', () => {
    delete (globalThis as unknown as { localStorage?: unknown }).localStorage;
    expect(readPersisted('x', 5)).toBe(5);
    expect(() => forgetPersisted('x')).not.toThrow();
  });
});