import { act, renderHook, waitFor } from "@testing-library/react"
import { mockIsIntersecting } from "react-intersection-observer/test-utils"
import { test, vi, describe, expect } from "vitest"
import { useScrollingPagination } from "./useScrollingPagination"

describe("useScrollingPagination", () => {
  test("loads more when element is in view", async () => {
    const loadNext = vi.fn()
    const { result } = renderHook(() =>
      useScrollingPagination({ hasNext: true, loadNext, isLoadingNext: false }),
    )

    const element = document.createElement("div")

    await act(() => {
      result.current.ref(element)
    })

    expect(result.current.isLoading).toBe(false)

    mockIsIntersecting(element, true)

    expect(result.current.isLoading).toBe(true)
    expect(loadNext).toHaveBeenCalled()

    await act(() => {
      mockIsIntersecting(element, false)
    })

    await waitFor(() => expect(result.current.isLoading).toBe(false))
  })

  test("does not load more if it's in view but doesn't have next page", async () => {
    const loadNext = vi.fn()
    const { result, rerender } = renderHook(
      ({ hasNext, loadNext, isLoadingNext }) =>
        useScrollingPagination({ hasNext, loadNext, isLoadingNext }),
      { initialProps: { hasNext: true, loadNext, isLoadingNext: false } },
    )

    const element = document.createElement("div")

    await act(() => {
      result.current.ref(element)
    })

    expect(result.current.isLoading).toBe(false)

    mockIsIntersecting(element, true)

    rerender({ hasNext: false, loadNext, isLoadingNext: false })

    await waitFor(() => expect(result.current.isLoading).toBe(false))
  })

  test("calls onError when loadNext fails", async () => {
    const error = new Error("Failed to load next items")
    const loadNext = vi.fn().mockRejectedValue(error)
    const onError = vi.fn()

    const { result } = renderHook(() =>
      useScrollingPagination({
        hasNext: true,
        loadNext,
        isLoadingNext: false,
        onError,
      }),
    )

    const element = document.createElement("div")

    await act(() => {
      result.current.ref(element)
    })

    expect(result.current.isLoading).toBe(false)

    mockIsIntersecting(element, true)

    expect(result.current.isLoading).toBe(true)
    expect(loadNext).toHaveBeenCalled()

    await waitFor(() => {
      expect(onError).toHaveBeenCalled()
    })
  })
})