import React from 'react'
import { render, waitFor } from '@testing-library/react'
import { beforeEach, describe, expect, it, vi } from 'vitest'
import useLazyProfileCollections from './useLazyProfileCollections'

function Harness({ username = 'alice', initial = null, enabled = false }) {
  const state = useLazyProfileCollections({
    username,
    initialCollections: initial,
    enabled,
  })

  return <output data-testid="state">{JSON.stringify(state)}</output>
}

describe('useLazyProfileCollections', () => {
  beforeEach(() => vi.restoreAllMocks())

  it('does not request while the profile remains on Posts', () => {
    const fetchMock = vi.spyOn(globalThis, 'fetch')
    render(<Harness />)
    expect(fetchMock).not.toHaveBeenCalled()
  })

  it('requests once on first Collections activation and reuses the result', async () => {
    const fetchMock = vi.spyOn(globalThis, 'fetch').mockResolvedValue({
      ok: true,
      json: async () => ({ data: [{ id: 1, title: 'One' }] }),
    })
    const view = render(<Harness />)

    view.rerender(<Harness enabled />)
    await waitFor(() => expect(fetchMock).toHaveBeenCalledTimes(1))
    await waitFor(() => expect(JSON.parse(view.getByTestId('state').textContent).items).toHaveLength(1))

    view.rerender(<Harness enabled={false} />)
    view.rerender(<Harness enabled />)
    expect(fetchMock).toHaveBeenCalledTimes(1)
  })

  it('treats an empty response as loaded and does not refetch', async () => {
    const fetchMock = vi.spyOn(globalThis, 'fetch').mockResolvedValue({ ok: true, json: async () => ({ data: [] }) })
    const view = render(<Harness enabled />)

    await waitFor(() => expect(JSON.parse(view.getByTestId('state').textContent).loaded).toBe(true))
    view.rerender(<Harness enabled={false} />)
    view.rerender(<Harness enabled />)
    expect(fetchMock).toHaveBeenCalledTimes(1)
  })

  it('uses direct Collections SSR data without a lazy request', () => {
    const fetchMock = vi.spyOn(globalThis, 'fetch')
    const initial = [{ id: 9, title: 'SSR collection' }]
    const view = render(<Harness initial={initial} enabled />)

    expect(fetchMock).not.toHaveBeenCalled()
    expect(JSON.parse(view.getByTestId('state').textContent).items).toEqual(initial)
  })

  it('ignores a stale response after profile navigation', async () => {
    let resolveAlice
    const fetchMock = vi.spyOn(globalThis, 'fetch').mockImplementation(() => new Promise((resolve) => { resolveAlice = resolve }))
    const view = render(<Harness username="alice" enabled />)
    await waitFor(() => expect(fetchMock).toHaveBeenCalledTimes(1))

    view.rerender(<Harness username="bob" enabled />)
    resolveAlice({ ok: true, json: async () => ({ data: [{ id: 'alice' }] }) })
    await waitFor(() => expect(JSON.parse(view.getByTestId('state').textContent).items).toEqual([]))
  })
})