TTMusic/entry/src/main/ets/common/util/PlayQueueHelper.ets

import { StrUtil } from '@pura/harmony-utils'
import { VideoItem } from '../../viewmodel/VideoItem'

export enum QueueInsertStatus {
  INVALID_SONG = 0,
  START_PLAY = 1,
  INSERTED = 2,
  ALREADY_PLAYING = 3
}

export interface QueueInsertResult {
  status: QueueInsertStatus
  queue: VideoItem[]
  currentIndex: number
  insertedIndex: number
}

function resolveCurrentQueueIndex(queue: VideoItem[], currentFilePath: string, fallbackIndex: number): number {
  if (queue.length <= 0) {
    return -1
  }
  if (StrUtil.isNotEmpty(currentFilePath)) {
    const queueIndex = queue.findIndex((item: VideoItem) => item.filePath === currentFilePath)
    if (queueIndex >= 0) {
      return queueIndex
    }
  }
  if (fallbackIndex >= 0 && fallbackIndex < queue.length) {
    return fallbackIndex
  }
  return 0
}

export function insertSongToNextPlayQueue(queue: VideoItem[], currentFilePath: string, fallbackIndex: number,
  song: VideoItem): QueueInsertResult {
  if (!song || StrUtil.isEmpty(song.filePath)) {
    return {
      status: QueueInsertStatus.INVALID_SONG,
      queue: queue.slice(),
      currentIndex: resolveCurrentQueueIndex(queue, currentFilePath, fallbackIndex),
      insertedIndex: -1
    }
  }

  if (queue.length <= 0) {
    return {
      status: QueueInsertStatus.START_PLAY,
      queue: [song],
      currentIndex: 0,
      insertedIndex: 0
    }
  }

  const nextQueue = queue.slice()
  let currentIndex = resolveCurrentQueueIndex(nextQueue, currentFilePath, fallbackIndex)
  const currentPath = currentIndex >= 0 && currentIndex < nextQueue.length ? nextQueue[currentIndex].filePath : ''
  if (song.filePath === currentPath) {
    return {
      status: QueueInsertStatus.ALREADY_PLAYING,
      queue: nextQueue,
      currentIndex,
      insertedIndex: currentIndex
    }
  }

  const existingIndex = nextQueue.findIndex((item: VideoItem) => item.filePath === song.filePath)
  if (existingIndex >= 0) {
    const movedSong = nextQueue.splice(existingIndex, 1)[0]
    if (existingIndex < currentIndex) {
      currentIndex -= 1
    }
    nextQueue.splice(currentIndex + 1, 0, movedSong)
  } else {
    nextQueue.splice(currentIndex + 1, 0, song)
  }

  return {
    status: QueueInsertStatus.INSERTED,
    queue: nextQueue,
    currentIndex,
    insertedIndex: currentIndex + 1
  }
}