import {linearEvents, ErrorCode, isVastErrorCode} from '../tracker'
import {getSkipOffset} from '../vastSelectors'
import type {VastChain, Hooks, MacroData} from '../types'
import {VideoAdContainer} from '../adContainer'
import {findBestMedia} from './helpers/media/findBestMedia'
import {once} from './helpers/dom/once'
import {setupMetricHandlers} from './helpers/metrics/setupMetricHandlers'
import {updateMedia} from './helpers/media/updateMedia'
import {AdUnitError} from './helpers/adUnitError'
import {VideoAdUnit, _protected, type VideoAdUnitOptions} from './VideoAdUnit'

const {complete, error: errorEvent, skip} = linearEvents

const _private = Symbol('_private')

interface Private {
  handleMetric(event: string, data?: MacroData | AdUnitError): void
  drawIcons(): Promise<void>
}

/**
 * Options map to create a {@link VastAdUnit}
 */
export interface VastAdUnitOptions extends VideoAdUnitOptions {
  /**
   * Optional map with hooks to configure the behaviour of the ad.
   */
  hooks?: Hooks
}

/**
 * This class provides everything necessary to run a Vast ad.
 */
export class VastAdUnit extends VideoAdUnit {
  private [_private]: Private = {
    handleMetric: (event, data) => {
      switch (event) {
        case complete: {
          this[_protected].finish()
          break
        }

        case errorEvent: {
          if (data instanceof Error) {
            this.error = data
            this.errorCode =
              this.error?.code && isVastErrorCode(this.error.code)
                ? this.error.code
                : ErrorCode.VAST_PROBLEM_DISPLAYING_MEDIA_FILE
          }

          this[_protected].onErrorCallbacks.forEach((callback) =>
            callback(this.error, {
              adUnit: this,
              vastChain: this.vastChain
            })
          )
          this[_protected].finish()
          break
        }

        case skip: {
          this.cancel()
          break
        }
      }

      this.emit(event, {
        adUnit: this,
        data,
        type: event
      })
    },
    drawIcons: async (): Promise<void> => {
      if (this.isFinished()) {
        return
      }

      await this[_protected].drawIcons?.()

      if (this[_protected].hasPendingIconRedraws?.() && !this.isFinished()) {
        const {videoElement} = this.videoAdContainer

        once(videoElement, 'timeupdate', this[_private].drawIcons)
      }
    }
  }

  public assetUri?: string

  /** Ad unit type. Will be `VAST` for VastAdUnit */
  public type = 'VAST'

  private hooks: Hooks

  /**
   * Creates a {@link VastAdUnit}.
   *
   * @param vastChain The {@link VastChain} with all the {@link VastResponse}
   * @param videoAdContainer - container instance to place the ad
   * @param options Options Map
   */
  public constructor(
    vastChain: VastChain,
    videoAdContainer: VideoAdContainer,
    options: VastAdUnitOptions = {}
  ) {
    super(vastChain, videoAdContainer, options)

    const {onFinishCallbacks} = this[_protected]
    const {handleMetric} = this[_private]

    this.hooks = options.hooks || {}

    const removeMetricHandlers = setupMetricHandlers(
      {
        hooks: this.hooks,
        pauseOnAdClick: this.pauseOnAdClick,
        vastChain: this.vastChain,
        videoAdContainer: this.videoAdContainer
      },
      handleMetric
    )

    onFinishCallbacks.push(removeMetricHandlers)
  }

  /**
   * Starts the ad unit.
   *
   * @throws if called twice.
   * @throws if ad unit is finished.
   */
  public async start(): Promise<void> {
    this[_protected].throwIfFinished()

    if (this.isStarted()) {
      throw new AdUnitError('VastAdUnit already started')
    }

    const inlineAd = this.vastChain[0].ad
    const {videoElement} = this.videoAdContainer
    const media =
      inlineAd && findBestMedia(inlineAd, this.videoAdContainer, this.hooks)

    if (media) {
      if (this.icons) {
        await this[_private].drawIcons()
      }

      if (media?.src) {
        videoElement.src = media.src
        this.assetUri = media.src
      }

      videoElement.play()
    } else {
      const adUnitError = new AdUnitError("Can't find a suitable media to play")

      adUnitError.code = ErrorCode.VAST_LINEAR_ASSET_MISMATCH
      this[_private].handleMetric(errorEvent, adUnitError)
    }

    this[_protected].started = true
  }

  /**
   * Resumes a previously paused ad unit.
   *
   * @throws if ad unit is not started.
   * @throws if ad unit is finished.
   */
  public resume(): void {
    this.videoAdContainer.videoElement.play()
  }

  /**
   * Pauses the ad unit.
   *
   * @throws if ad unit is not started.
   * @throws if ad unit is finished.
   */
  public pause(): void {
    this.videoAdContainer.videoElement.pause()
  }

  /**
   * Skips the ad unit.
   *
   * @throws if ad unit is not started.
   * @throws if ad unit is finished.
   */
  public skip(): void {
    const inlineAd = this.vastChain[0].ad
    const skipoffset = inlineAd && getSkipOffset(inlineAd)
    const currentTimeMs = this.currentTime() * 1000

    if (typeof skipoffset === 'number' && currentTimeMs >= skipoffset) {
      this[_private].handleMetric(skip)
    }
  }

  /**
   * Returns true if the ad is paused and false otherwise
   */
  public paused(): boolean {
    return this.videoAdContainer.videoElement.paused
  }

  /**
   * Sets the volume of the ad unit.
   *
   * @throws if ad unit is not started.
   * @throws if ad unit is finished.
   *
   * @param volume must be a value between 0 and 1;
   */
  public setVolume(volume: number): void {
    this.videoAdContainer.videoElement.volume = volume
  }

  /**
   * Gets the volume of the ad unit.
   *
   * @throws if ad unit is not started.
   * @throws if ad unit is finished.
   *
   * @returns the volume of the ad unit.
   */
  public getVolume(): number {
    return this.videoAdContainer.videoElement.volume
  }

  /**
   * Cancels the ad unit.
   *
   * @throws if ad unit is finished.
   */
  public cancel(): void {
    this[_protected].throwIfFinished()

    this.videoAdContainer.videoElement.pause()

    this[_protected].finish()
  }

  /**
   * Returns the duration of the ad Creative or 0 if there is no creative.
   *
   * @returns the duration of the ad unit.
   */
  public duration(): number {
    if (!this.isStarted()) {
      return 0
    }

    return this.videoAdContainer.videoElement.duration
  }

  /**
   * Returns the current time of the ad Creative or 0 if there is no creative.
   *
   * @returns the current time of the ad unit.
   */
  public currentTime(): number {
    if (!this.isStarted()) {
      return 0
    }

    return this.videoAdContainer.videoElement.currentTime
  }

  /**
   * This method resizes the ad unit to fit the available space in the passed {@link VideoAdContainer}
   *
   * @param width the new width of the ad container.
   * @param height the new height of the ad container.
   * @param viewmode fullscreen | normal | thumbnail
   * @returns Promise that resolves once the unit was resized
   */
  public async resize(
    width: number,
    height: number,
    viewmode: string
  ): Promise<void> {
    await super.resize(width, height, viewmode)

    if (this.isStarted() && !this.isFinished()) {
      const inlineAd = this.vastChain[0].ad
      const {videoElement} = this.videoAdContainer
      const media =
        inlineAd && findBestMedia(inlineAd, this.videoAdContainer, this.hooks)

      if (media && videoElement.src !== media.src) {
        updateMedia(videoElement, media)
      }
    }
  }
}