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)
  })
})