import { describe, expect, it } from 'vitest';
import { readVisitedPots, recordVisitedPot } from './visitedPots';

function createMockStorage(): Storage {
  const store = new Map<string, string>();
  return {
    getItem: (key: string) => store.get(key) ?? null,
    setItem: (key: string, value: string) => void store.set(key, value),
    removeItem: (key: string) => void store.delete(key),
    clear: () => store.clear(),
    key: () => null,
    get length() {
      return store.size;
    },
  };
}

describe('visited pots storage', () => {
  it('returns an empty list when nothing is stored', () => {
    expect(readVisitedPots(createMockStorage())).toEqual([]);
  });

  it('records a visited pot', () => {
    const storage = createMockStorage();
    recordVisitedPot(storage, {
      slug: 'abc',
      name: 'Lisbon Trip',
      currency: 'EUR',
    });
    expect(readVisitedPots(storage)).toEqual([
      expect.objectContaining({
        slug: 'abc',
        name: 'Lisbon Trip',
        currency: 'EUR',
      }),
    ]);
  });

  it('moves a re-visited pot to the front instead of duplicating it', () => {
    const storage = createMockStorage();
    recordVisitedPot(storage, {
      slug: 'abc',
      name: 'Lisbon Trip',
      currency: 'EUR',
    });
    recordVisitedPot(storage, {
      slug: 'def',
      name: 'Ski Weekend',
      currency: 'CHF',
    });
    recordVisitedPot(storage, {
      slug: 'abc',
      name: 'Lisbon Trip',
      currency: 'EUR',
    });

    const pots = readVisitedPots(storage);
    expect(pots).toHaveLength(2);
    expect(pots[0]?.slug).toBe('abc');
  });

  it('updates the stored name and currency on revisit', () => {
    const storage = createMockStorage();
    recordVisitedPot(storage, {
      slug: 'abc',
      name: 'Old Name',
      currency: 'EUR',
    });
    recordVisitedPot(storage, {
      slug: 'abc',
      name: 'New Name',
      currency: 'USD',
    });

    expect(readVisitedPots(storage)).toEqual([
      expect.objectContaining({
        slug: 'abc',
        name: 'New Name',
        currency: 'USD',
      }),
    ]);
  });

  it('ignores malformed JSON', () => {
    const storage = createMockStorage();
    storage.setItem('stb:visited-pots', '{not json');
    expect(readVisitedPots(storage)).toEqual([]);
  });

  it('caps the list at 20 entries, keeping the most recent', () => {
    const storage = createMockStorage();
    for (let i = 0; i < 25; i++) {
      recordVisitedPot(storage, {
        slug: `pot-${i}`,
        name: `Pot ${i}`,
        currency: 'EUR',
      });
    }

    const pots = readVisitedPots(storage);
    expect(pots).toHaveLength(20);
    expect(pots[0]?.slug).toBe('pot-24');
    expect(pots.some((p) => p.slug === 'pot-0')).toBe(false);
  });
});