import {
  createVideoAdUnit,
  VastAdUnit,
  VideoAdUnit,
  VpaidAdUnit
} from '../../adUnit'
import type {
  VastAdUnitOptions,
  VideoAdUnitOptions,
  VpaidAdUnitOptions
} from '../../adUnit'
import {VideoAdContainer} from '../../adContainer'
import {ErrorCode} from '../../tracker'
import {getInteractiveFiles, getMediaFiles} from '../../vastSelectors'
import {canPlay} from '../../adUnit/helpers/media/canPlay'
import {start, closeLinear} from '../../tracker/linearEvents'
import {adStopped, adUserClose} from '../../adUnit/helpers/vpaid/api'
import {VastError} from '../../vastRequest/helpers/vastError'
import type {VastChain, ParsedAd} from '../../types'

const validate = (
  vastChain: VastChain,
  videoAdContainer: VideoAdContainer
): void => {
  if (!Array.isArray(vastChain) || vastChain.length === 0) {
    throw new TypeError('Invalid vastChain')
  }

  if (!(videoAdContainer instanceof VideoAdContainer)) {
    throw new TypeError('Invalid VideoAdContainer')
  }
}

const hasVpaidCreative = (ad: ParsedAd): boolean =>
  Boolean(getInteractiveFiles(ad))

const hasVastCreative = (
  ad: ParsedAd,
  videoElement: HTMLVideoElement
): boolean => {
  const mediaFiles = getMediaFiles(ad)

  if (mediaFiles) {
    return mediaFiles.some((mediaFile) => canPlay(videoElement, mediaFile))
  }

  return false
}

export interface StartAdUnitOptions<T extends VideoAdUnit> {
  /**
   * Will be called once the ad is ready with the ad unit.
   *
   * @param adUnit the ad unit instance.
   */
  onAdReady(adUnit: T): void
}

const startAdUnit = <T extends VideoAdUnit, R extends VideoAdUnitOptions>(
  adUnit: T,
  {onAdReady}: StartAdUnitOptions<T> & R
): Promise<T> =>
  new Promise<T>((resolve, reject) => {
    const createRejectHandler = (event: string) => () =>
      reject(new Error(`Ad unit start rejected due to event '${event}'`))

    adUnit.onError(reject)
    adUnit.on(start, () => resolve(adUnit))
    adUnit.on(adUserClose, createRejectHandler(adUserClose))
    adUnit.on(closeLinear, createRejectHandler(closeLinear))
    adUnit.on(adStopped, createRejectHandler(adStopped))

    onAdReady(adUnit)
    adUnit.start()
  })

const tryToStartVpaidAd = (
  vastChain: VastChain,
  videoAdContainer: VideoAdContainer,
  options: VpaidAdUnitOptions & StartAdUnitOptions<VpaidAdUnit>
): Promise<VpaidAdUnit> => {
  const [{ad: inlineAd}] = vastChain

  if (!inlineAd || !hasVpaidCreative(inlineAd)) {
    const error = new VastError(
      'No valid creative found in the passed VAST chain'
    )

    error.code = ErrorCode.VAST_MEDIA_FILE_NOT_FOUND
    throw error
  }

  const adUnit = createVideoAdUnit(vastChain, videoAdContainer, {
    ...options,
    type: 'VPAID'
  })

  return startAdUnit<VpaidAdUnit, VpaidAdUnitOptions>(adUnit, options)
}

const startVastAd = (
  vastChain: VastChain,
  videoAdContainer: VideoAdContainer,
  options: VastAdUnitOptions & StartAdUnitOptions<VastAdUnit>
): Promise<VastAdUnit> => {
  const adUnit = createVideoAdUnit(vastChain, videoAdContainer, {
    ...options,
    type: 'VAST'
  })

  return startAdUnit(adUnit, options)
}

export type StartVideoAdOptions = VpaidAdUnitOptions &
  VastAdUnitOptions &
  StartAdUnitOptions<VastAdUnit | VpaidAdUnit>

export const startVideoAd = async (
  vastChain: VastChain,
  videoAdContainer: VideoAdContainer,
  options: StartVideoAdOptions
): Promise<VastAdUnit | VpaidAdUnit> => {
  validate(vastChain, videoAdContainer)

  try {
    return await tryToStartVpaidAd(vastChain, videoAdContainer, options)
  } catch (error) {
    const [{ad: inlineAd}] = vastChain

    if (inlineAd && hasVastCreative(inlineAd, videoAdContainer.videoElement)) {
      return startVastAd(vastChain, videoAdContainer, options)
    }

    throw error
  }
}