import type { ApiCollection, MessageResource } from '../../../types'
import {
  anchoredPageParam,
  isBehindLiveEdge,
  livePageParam,
  markLiveIfCaughtUp,
  MessagesWindow,
  newestFirst,
} from '../messages_window'

const page = (meta: Partial<ApiCollection<MessageResource>['meta']> = {}) => ({
  data: [],
  links: {},
  meta: { count: 0, totalCount: 0, ...meta },
})

const window = (
  pageParam: MessagesWindow['pageParams'][number],
  meta?: Partial<ApiCollection<MessageResource>['meta']>
): MessagesWindow => ({ pages: [page(meta)], pageParams: [pageParam] })

describe('isBehindLiveEdge', () => {
  it('is behind while the first page reports newer messages', () => {
    expect(isBehindLiveEdge(window(anchoredPageParam('A'), { prev: { idGt: 'A' } }))).toBe(true)
  })

  it('is live otherwise', () => {
    expect(isBehindLiveEdge(window(livePageParam))).toBe(false)
    expect(isBehindLiveEdge(window(anchoredPageParam('A')))).toBe(false)
    expect(isBehindLiveEdge(undefined)).toBe(false)
  })
})

describe('markLiveIfCaughtUp', () => {
  it('turns an anchored window with no newer side into the live window', () => {
    const data = window(anchoredPageParam('A'))

    expect(markLiveIfCaughtUp(data)?.pageParams).toEqual([livePageParam])
  })

  it('turns a window topped by a newer page into the live window once it catches up', () => {
    const data = window({ where: { id_gt: 'A' }, order: 'asc' })

    expect(markLiveIfCaughtUp(data)?.pageParams).toEqual([livePageParam])
  })

  it('leaves an anchored window that is still behind untouched', () => {
    const data = window(anchoredPageParam('A'), { prev: { idGt: 'A' } })

    expect(markLiveIfCaughtUp(data)).toBe(data)
  })

  it('leaves a live window untouched', () => {
    const data = window(livePageParam)

    expect(markLiveIfCaughtUp(data)).toBe(data)
  })
})

describe('newestFirst', () => {
  const row = (id: string) => ({ id, type: 'Message' }) as MessageResource
  const ascPage = {
    ...page({ next: { idGt: 'E' } }),
    data: [row('D'), row('E')],
  }

  it('stores a newer page newest first, linking newer onward and back to older rows', () => {
    const result = newestFirst(ascPage, { where: { id_gt: 'C' }, order: 'asc' })

    expect(result.data.map(m => m.id)).toEqual(['E', 'D'])
    expect(result.meta.prev).toEqual({ idGt: 'E' })
    expect(result.meta.next).toEqual({ idLt: 'D' })
  })

  it('leaves newest-first pages alone', () => {
    expect(newestFirst(ascPage, anchoredPageParam('A'))).toBe(ascPage)
  })
})