Fixed Downloads

src/electron/ipc/AlbumArtHandler.ipc.ts

@@ -5,7 +5,7 @@ import { AlbumArtResult } from '../shared/interfaces/songDetails.interface'
 /**
  * Handles the 'album-art' event.
  */
-export default class AlbumArtHandler implements IPCInvokeHandler<'album-art'> {
+class AlbumArtHandler implements IPCInvokeHandler<'album-art'> {
   event: 'album-art' = 'album-art'
 
   /**
@@ -27,4 +27,6 @@ export default class AlbumArtHandler implements IPCInvokeHandler<'album-art'> {
       WHERE songID = ${songID};
     `
   }
-}
+}
+
+export const albumArtHandler = new AlbumArtHandler()

src/electron/ipc/BatchSongDetailsHandler.ipc.ts

@@ -5,7 +5,7 @@ import { VersionResult } from '../shared/interfaces/songDetails.interface'
 /**
  * Handles the 'batch-song-details' event.
  */
-export default class BatchSongDetailsHandler implements IPCInvokeHandler<'batch-song-details'> {
+class BatchSongDetailsHandler implements IPCInvokeHandler<'batch-song-details'> {
   event: 'batch-song-details' = 'batch-song-details'
 
   /**
@@ -27,4 +27,6 @@ export default class BatchSongDetailsHandler implements IPCInvokeHandler<'batch-
       WHERE songID IN (${songIDs.join(',')});
     `
   }
-}
+}
+
+export const batchSongDetailsHandler = new BatchSongDetailsHandler()

src/electron/ipc/SearchHandler.ipc.ts

@@ -6,7 +6,7 @@ import { escape } from 'mysql'
 /**
  * Handles the 'song-search' event.
  */
-export default class SearchHandler implements IPCInvokeHandler<'song-search'> {
+class SearchHandler implements IPCInvokeHandler<'song-search'> {
   event: 'song-search' = 'song-search'
 
   /**
@@ -39,4 +39,6 @@ export default class SearchHandler implements IPCInvokeHandler<'song-search'> {
       LIMIT ${20} OFFSET ${0};
     ` // TODO: add parameters for the limit and offset
   }
-}
+}
+
+export const searchHandler = new SearchHandler()

src/electron/ipc/SettingsHandler.ipc.ts

@@ -14,20 +14,20 @@ let settings: Settings
 /**
  * Handles the 'get-settings' event.
  */
-export class GetSettingsHandler implements IPCInvokeHandler<'get-settings'> {
+class GetSettingsHandler implements IPCInvokeHandler<'get-settings'> {
   event: 'get-settings' = 'get-settings'
 
   /**
    * @returns the current settings oject, or default settings if they couldn't be loaded.
    */
   handler() {
-    return GetSettingsHandler.getSettings()
+    return this.getSettings()
   }
 
   /**
    * @returns the current settings oject, or default settings if they couldn't be loaded.
    */
-  static getSettings() {
+  getSettings() {
     if (settings == undefined) {
       return defaultSettings
     } else {
@@ -40,7 +40,7 @@ export class GetSettingsHandler implements IPCInvokeHandler<'get-settings'> {
    * Otherwise, loads user settings from data directories.
    * If this process fails, default settings are used.
    */
-  static async initSettings() {
+  async initSettings() {
     try {
       // Create data directories if they don't exists
       for (const path of [dataPath, tempPath, themesPath]) {
@@ -67,7 +67,7 @@ export class GetSettingsHandler implements IPCInvokeHandler<'get-settings'> {
 /**
  * Handles the 'set-settings' event.
  */
-export class SetSettingsHandler implements IPCEmitHandler<'set-settings'> {
+class SetSettingsHandler implements IPCEmitHandler<'set-settings'> {
   event: 'set-settings' = 'set-settings'
 
   /**
@@ -85,4 +85,7 @@ export class SetSettingsHandler implements IPCEmitHandler<'set-settings'> {
     const settingsJSON = JSON.stringify(settings, undefined, 2)
     await writeFile(settingsPath, settingsJSON, 'utf8')
   }
-}
+}
+
+export const getSettingsHandler = new GetSettingsHandler()
+export const setSettingsHandler = new SetSettingsHandler()

src/electron/ipc/SongDetailsHandler.ipc.ts

@@ -5,7 +5,7 @@ import { VersionResult } from '../shared/interfaces/songDetails.interface'
 /**
  * Handles the 'song-details' event.
  */
-export default class SongDetailsHandler implements IPCInvokeHandler<'song-details'> {
+class SongDetailsHandler implements IPCInvokeHandler<'song-details'> {
   event: 'song-details' = 'song-details'
 
   /**
@@ -27,4 +27,6 @@ export default class SongDetailsHandler implements IPCInvokeHandler<'song-detail
       WHERE songID = ${songID};
     `
   }
-}
+}
+
+export const songDetailsHandler = new SongDetailsHandler()

src/electron/ipc/download/ChartDownload.ts

@@ -0,0 +1,272 @@
+import { FileDownloader } from './FileDownloader'
+import { tempPath } from '../../shared/Paths'
+import { join } from 'path'
+import { FileExtractor } from './FileExtractor'
+import { sanitizeFilename, interpolate } from '../../shared/UtilFunctions'
+import { emitIPCEvent } from '../../main'
+import { promisify } from 'util'
+import { randomBytes as _randomBytes, createHash } from 'crypto'
+import { mkdir as _mkdir } from 'fs'
+import { ProgressType, NewDownload } from 'src/electron/shared/interfaces/download.interface'
+import { downloadHandler } from './DownloadHandler'
+import { googleTimer } from './GoogleTimer'
+
+const randomBytes = promisify(_randomBytes)
+const mkdir = promisify(_mkdir)
+
+export class ChartDownload {
+
+  // This changes if the user needs to click 'retry' or 'continue'
+  run: () => void | Promise<void> = this.beginDownload
+  cancel: () => void
+
+  isArchive: boolean
+  isGoogle: boolean
+  title: string
+  header: string
+  description: string
+  percent = 0
+  type: ProgressType
+
+  private fileKeys: string[]
+  private fileValues: string[]
+  allFilesProgress = 0
+  individualFileProgressPortion: number
+
+  constructor(public versionID: number, private data: NewDownload) {
+    // Only iterate over the keys in data.links that have link values (not hashes)
+    this.fileKeys = Object.keys(data.links).filter(link => data.links[link].includes('.'))
+    this.fileValues = Object.values(data.links).filter(value => value.includes('.'))
+
+    this.isArchive = this.fileKeys.includes('archive')
+    this.isGoogle = !!this.fileValues.find(value => value.toLocaleLowerCase().includes('google'))
+    this.individualFileProgressPortion = 80 / this.fileKeys.length
+  }
+
+  /**
+   * Changes this download to reflect that it is waiting in the download queue.
+   */
+  setInQueue() {
+    this.title = `${this.data.avTagName} - ${this.data.artist}`
+    this.header = ''
+    this.description = 'Waiting for other downloads to finish...'
+    this.type = 'good'
+    this.cancel = () => { }
+    emitIPCEvent('download-updated', this)
+  }
+
+  /**
+   * Starts the download process.
+   */
+  async beginDownload() {
+    // Create a temporary folder to store the downloaded files
+    let chartPath: string
+    try {
+      chartPath = await this.createDownloadFolder()
+    } catch (e) {
+      this.run = this.beginDownload // Retry action
+      this.error('Access Error', e.message)
+      return
+    }
+
+    // For each actual download link in <this.data.links>, download the file to <chartPath>
+    for (let i = 0; i < this.fileKeys.length; i++) {
+      // INITIALIZE DOWNLOADER
+      const typeHash = createHash('md5').update(this.fileValues[i]).digest('hex')
+      // <this.data.links[typeHash]> stores the expected hash value found in the download header
+      const downloader = new FileDownloader(this.fileValues[i], chartPath, this.data.links[typeHash])
+      const downloadComplete = this.addDownloadEventListeners(downloader, i)
+
+      // DOWNLOAD THE NEXT FILE
+      if (this.isGoogle) { // If this is a google download...
+        // Wait for google rate limit
+        this.header = `[${this.fileKeys[i]}] (file ${i + 1}/${this.fileKeys.length})`
+        googleTimer.onTimerUpdate((remainingTime, totalTime) => {
+          this.description = `Waiting for Google rate limit... (${remainingTime}s)`
+          this.percent = this.allFilesProgress + interpolate(remainingTime, totalTime, 0, 0, this.individualFileProgressPortion / 2)
+          this.type = 'good'
+          emitIPCEvent('download-updated', this)
+        })
+        this.cancel = () => {
+          googleTimer.removeCallbacks()
+          this.onDownloadStop()
+          downloader.cancelDownload()
+        }
+        await new Promise<void>(resolve => googleTimer.onTimerReady(resolve))
+      }
+
+      this.cancel = () => {
+        this.onDownloadStop()
+        downloader.cancelDownload()
+      }
+      downloader.beginDownload()
+      await downloadComplete // Wait for this download to finish
+    }
+
+    // INITIALIZE FILE EXTRACTOR
+    const destinationFolderName = sanitizeFilename(`${this.data.artist} - ${this.data.avTagName} (${this.data.charter})`)
+    const extractor = new FileExtractor(chartPath, this.isArchive, destinationFolderName)
+    this.cancel = () => extractor.cancelExtract() // Make cancel button cancel the file extraction
+    this.addExtractorEventListeners(extractor)
+
+    // EXTRACT THE DOWNLOADED ARCHIVE
+    extractor.beginExtract()
+  }
+
+  /**
+   * Attempts to create a unique folder in Bridge's data paths. Throws an error if this fails.
+   */
+  private async createDownloadFolder() {
+    let retryCount = 0
+    let chartPath = ''
+
+    while (retryCount < 5) {
+      chartPath = join(tempPath, `chart_${(await randomBytes(5)).toString('hex')}`)
+      try {
+        await mkdir(chartPath)
+        return chartPath
+      } catch (e) {
+        console.log(`Error creating folder [${chartPath}], retrying with a different folder...`)
+        retryCount++
+      }
+    }
+
+    throw new Error(`Bridge was unable to create a directory at [${chartPath}]`)
+  }
+
+  /**
+   * Stops the download and displays an error message.
+   */
+  private error(header: string, description: string) {
+    this.header = header
+    this.description = description
+    this.type = 'error'
+    this.onDownloadStop()
+    emitIPCEvent('download-updated', this)
+  }
+
+  /**
+   * If this was a google download, allows a new google download to start.
+   */
+  private onDownloadStop() {
+    if (this.isGoogle) {
+      downloadHandler.isGoogleDownloading = false
+      downloadHandler.updateQueue()
+    }
+  }
+
+  /**
+   * Defines what happens in response to `FileDownloader` events.
+   */
+  private addDownloadEventListeners(downloader: FileDownloader, fileIndex: number) {
+    let fileProgress = 0
+
+    downloader.on('request', () => {
+      this.description = 'Sending request...'
+      fileProgress = this.individualFileProgressPortion / 2
+      this.percent = this.allFilesProgress + fileProgress
+      this.type = 'good'
+      emitIPCEvent('download-updated', this)
+    })
+
+    downloader.on('warning', (continueAnyway) => {
+      this.description = 'WARNING'
+      this.run = continueAnyway
+      this.type = 'warning'
+      this.onDownloadStop()
+      emitIPCEvent('download-updated', this)
+    })
+
+    let filesize = -1
+    downloader.on('download', (filename, _filesize) => {
+      this.header = `[${filename}] (file ${fileIndex + 1}/${this.fileKeys.length})`
+      if (_filesize != undefined) {
+        filesize = _filesize
+        this.description = 'Downloading... (0%)'
+      } else {
+        this.description = 'Downloading... (0 MB)'
+      }
+      this.type = 'good'
+      emitIPCEvent('download-updated', this)
+    })
+
+    downloader.on('downloadProgress', (bytesDownloaded) => {
+      if (filesize != -1) {
+        this.description = `Downloading... (${Math.round(1000 * bytesDownloaded / filesize) / 10}%)`
+        fileProgress = interpolate(bytesDownloaded, 0, filesize, this.individualFileProgressPortion / 2, this.individualFileProgressPortion)
+        this.percent = this.allFilesProgress + fileProgress
+      } else {
+        this.description = `Downloading... (${Math.round(bytesDownloaded / 1e+5) / 10} MB)`
+        this.percent = this.allFilesProgress + fileProgress
+      }
+      this.type = 'fastUpdate'
+      emitIPCEvent('download-updated', this)
+    })
+
+    downloader.on('error', (error, retry) => {
+      this.header = error.header
+      this.description = error.body
+      this.type = 'error'
+      this.run = () => { retry() }
+      this.onDownloadStop()
+      emitIPCEvent('download-updated', this)
+    })
+
+    // Returns a promise that resolves when the download is finished
+    return new Promise<void>(resolve => {
+      downloader.on('complete', () => {
+        this.allFilesProgress += this.individualFileProgressPortion
+        emitIPCEvent('download-updated', this)
+        resolve()
+      })
+    })
+  }
+
+  /**
+   * Defines what happens in response to `FileExtractor` events.
+   */
+  private addExtractorEventListeners(extractor: FileExtractor) {
+    let archive = ''
+
+    extractor.on('extract', (filename) => {
+      archive = filename
+      this.header = `[${archive}]`
+      this.description = 'Extracting...'
+      this.type = 'good'
+      emitIPCEvent('download-updated', this)
+    })
+
+    extractor.on('extractProgress', (percent, filecount) => {
+      this.header = `[${archive}] (${filecount} file${filecount == 1 ? '' : 's'} extracted)`
+      this.description = `Extracting... (${percent}%)`
+      this.percent = interpolate(percent, 0, 100, 80, 95)
+      this.type = 'fastUpdate'
+      emitIPCEvent('download-updated', this)
+    })
+
+    extractor.on('transfer', (filepath) => {
+      this.header = 'Moving files to library folder...'
+      this.description = filepath
+      this.percent = 95
+      this.type = 'good'
+      emitIPCEvent('download-updated', this)
+    })
+
+    extractor.on('error', (error, retry) => {
+      this.header = error.header
+      this.description = error.body
+      this.type = 'error'
+      this.run = retry
+      emitIPCEvent('download-updated', this)
+    })
+
+    extractor.on('complete', (filepath) => {
+      this.header = 'Download complete.'
+      this.description = filepath
+      this.percent = 100
+      this.type = 'done'
+      this.onDownloadStop()
+      emitIPCEvent('download-updated', this)
+    })
+  }
+}

src/electron/ipc/download/DownloadHandler.ts

@@ -1,223 +1,52 @@
-import { FileDownloader } from './FileDownloader'
 import { IPCEmitHandler } from '../../shared/IPCHandler'
-import { createHash, randomBytes as _randomBytes } from 'crypto'
-import { tempPath } from '../../shared/Paths'
-import { promisify } from 'util'
-import { join } from 'path'
-import { Download, DownloadProgress } from '../../shared/interfaces/download.interface'
-import { emitIPCEvent } from '../../main'
+import { randomBytes as _randomBytes } from 'crypto'
+import { Download } from '../../shared/interfaces/download.interface'
 import { mkdir as _mkdir } from 'fs'
-import { FileExtractor } from './FileExtractor'
-import { sanitizeFilename, interpolate } from '../../shared/UtilFunctions'
-import { GetSettingsHandler } from '../SettingsHandler.ipc'
+import { ChartDownload } from './ChartDownload'
 
-const randomBytes = promisify(_randomBytes)
-const mkdir = promisify(_mkdir)
-
-export class DownloadHandler implements IPCEmitHandler<'download'> {
+class DownloadHandler implements IPCEmitHandler<'download'> {
   event: 'download' = 'download'
 
-  // TODO: replace needle with got (for cancel() method) (if before-headers event is possible?)
-
-  downloadCallbacks: { [versionID: number]: { cancel: () => void, retry: () => void, continue: () => void } } = {}
-  private allFilesProgress = 0
+  downloads: { [versionID: number]: ChartDownload } = {}
+  downloadQueue: ChartDownload[] = []
+  isGoogleDownloading = false // This is a lock controlled by only one ChartDownload at a time
 
   async handler(data: Download) {
-    switch (data.action) {
-      case 'cancel': this.downloadCallbacks[data.versionID].cancel(); return
-      case 'retry': this.downloadCallbacks[data.versionID].retry(); return
-      case 'continue': this.downloadCallbacks[data.versionID].continue(); return
-      case 'add': this.downloadCallbacks[data.versionID] = { cancel: () => { }, retry: () => { }, continue: () => { } }
-    }
-    // after this point, (data.action == add), so data.data should be defined
-
-    // Initialize download object
-    const download: DownloadProgress = {
-      versionID: data.versionID,
-      title: `${data.data.avTagName} - ${data.data.artist}`,
-      header: '',
-      description: '',
-      percent: 0,
-      type: 'good'
+    if (data.action == 'add') {
+      this.downloads[data.versionID] = new ChartDownload(data.versionID, data.data)
     }
 
-    // Create a temporary folder to store the downloaded files
-    let chartPath: string
-    try {
-      chartPath = await this.createDownloadFolder()
-    } catch (e) {
-      download.header = 'Access Error'
-      download.description = e.message
-      download.type = 'error'
-      this.downloadCallbacks[data.versionID].retry = () => { this.handler(data) }
-      emitIPCEvent('download-updated', download)
-      return
+    const download = this.downloads[data.versionID]
+
+    if (data.action == 'cancel') {
+      download.cancel() // Might change isGoogleDownloading and call updateQueue()
+      this.downloadQueue = this.downloadQueue.filter(download => download.versionID != data.versionID)
+      this.downloads[data.versionID] = undefined
+    } else {
+      download.setInQueue()
+      this.downloadQueue.push(download) // Add, retry, or continue will re-add the download to the queue
+      this.updateQueue()
     }
-
-    // For each actual download link in <data.data.links>, download the file to <chartPath>
-    // Only iterate over the keys in data.links that have link values (not hashes)
-    const fileKeys = Object.keys(data.data.links).filter(link => data.data.links[link].includes('.'))
-    for (let i = 0; i < fileKeys.length; i++) {
-      // INITIALIZE DOWNLOADER
-      // <data.data.links[typeHash]> stores the expected hash value found in the download header
-      const typeHash = createHash('md5').update(data.data.links[fileKeys[i]]).digest('hex')
-      const downloader = new FileDownloader(data.data.links[fileKeys[i]], chartPath, fileKeys.length, data.data.links[typeHash])
-      this.downloadCallbacks[data.versionID].cancel = () => downloader.cancelDownload() // Make cancel button cancel this download
-      const downloadComplete = this.addDownloadEventListeners(downloader, download, fileKeys, i)
-
-      // DOWNLOAD THE NEXT FILE
-      downloader.beginDownload()
-      await downloadComplete // Wait for this download to finish before downloading the next file
-    }
-
-    // INITIALIZE FILE EXTRACTOR
-    const destinationFolderName = sanitizeFilename(`${data.data.artist} - ${data.data.avTagName} (${data.data.charter})`)
-    const extractor = new FileExtractor(chartPath, fileKeys.includes('archive'), destinationFolderName)
-    this.downloadCallbacks[data.versionID].cancel = () => extractor.cancelExtract() // Make cancel button cancel the file extraction
-    this.addExtractorEventListeners(extractor, download)
-
-    // EXTRACT THE DOWNLOADED ARCHIVE
-    extractor.beginExtract()
   }
 
-  private async createDownloadFolder() {
-    let retryCount = 0
-    while (true) {
-      const randomString = (await randomBytes(5)).toString('hex')
-      const chartPath = join(tempPath, `chart_${randomString}`)
-      try {
-        await mkdir(chartPath)
-        return chartPath
-      } catch (e) {
-        if (retryCount > 5) {
-          throw new Error(`Bridge was unable to create a directory at [${chartPath}]`)
-        } else {
-          console.log(`Error creating folder [${chartPath}], retrying with a different folder...`)
-          retryCount++
-        }
+  /**
+   * Called when at least one download in the queue can potentially be started.
+   */
+  updateQueue() {
+    this.downloadQueue.sort((cd1: ChartDownload, cd2: ChartDownload) => {
+      const value1 = (cd1.isGoogle ? 100 : 0) + (99 - cd1.allFilesProgress)
+      const value2 = (cd2.isGoogle ? 100 : 0) + (99 - cd2.allFilesProgress)
+      return value1 - value2 // Sorts in the order to get the most downloads completed early
+    })
+
+    while (this.downloadQueue[0] != undefined && !(this.downloadQueue[0].isGoogle && this.isGoogleDownloading)) {
+      const nextDownload = this.downloadQueue.shift()
+      nextDownload.run()
+      if (nextDownload.isGoogle) {
+        this.isGoogleDownloading = true
       }
     }
   }
+}
 
-  private addDownloadEventListeners(downloader: FileDownloader, download: DownloadProgress, fileKeys: string[], i: number) {
-    const individualFileProgressPortion = 80 / fileKeys.length
-    let fileProgress = 0
-
-    downloader.on('wait', (waitTime) => {
-      download.header = `[${fileKeys[i]}] (file ${i + 1}/${fileKeys.length})`
-      download.description = `Waiting for Google rate limit... (${waitTime}s)`
-      download.type = 'wait'
-    })
-
-    downloader.on('waitProgress', (secondsRemaining, initialWaitTime) => {
-      download.description = `Waiting for Google rate limit... (${secondsRemaining}s)`
-      fileProgress = interpolate(secondsRemaining, initialWaitTime, 0, 0, individualFileProgressPortion / 2)
-      console.log(`${initialWaitTime} ... ${secondsRemaining} ... 0`)
-      download.percent = this.allFilesProgress + fileProgress
-      download.type = 'wait'
-      emitIPCEvent('download-updated', download)
-    })
-
-    downloader.on('request', () => {
-      download.description = `Sending request...`
-      fileProgress = individualFileProgressPortion / 2
-      download.percent = this.allFilesProgress + fileProgress
-      download.type = 'good'
-      emitIPCEvent('download-updated', download)
-    })
-
-    downloader.on('warning', (continueAnyway) => {
-      download.description = 'WARNING'
-      this.downloadCallbacks[download.versionID].continue = continueAnyway
-      download.type = 'warning'
-      emitIPCEvent('download-updated', download)
-    })
-
-    let filesize = -1
-    downloader.on('download', (filename, _filesize) => {
-      download.header = `[${filename}] (file ${i + 1}/${fileKeys.length})`
-      if (_filesize != undefined) {
-        filesize = _filesize
-        download.description = `Downloading... (0%)`
-      } else {
-        download.description = `Downloading... (0 MB)`
-      }
-      download.type = 'good'
-      emitIPCEvent('download-updated', download)
-    })
-
-    downloader.on('downloadProgress', (bytesDownloaded) => {
-      if (filesize != -1) {
-        download.description = `Downloading... (${Math.round(1000 * bytesDownloaded / filesize) / 10}%)`
-        fileProgress = interpolate(bytesDownloaded, 0, filesize, individualFileProgressPortion / 2, individualFileProgressPortion)
-        download.percent = this.allFilesProgress + fileProgress
-      } else {
-        download.description = `Downloading... (${Math.round(bytesDownloaded / 1e+5) / 10} MB)`
-        download.percent = this.allFilesProgress + fileProgress
-      }
-      download.type = 'good'
-      emitIPCEvent('download-updated', download)
-    })
-
-    downloader.on('error', (error, retry) => {
-      download.header = error.header
-      download.description = error.body
-      download.type = 'error'
-      this.downloadCallbacks[download.versionID].retry = retry
-      emitIPCEvent('download-updated', download)
-    })
-
-    // Returns a promise that resolves when the download is finished
-    return new Promise<void>(resolve => {
-      downloader.on('complete', () => {
-        emitIPCEvent('download-updated', download)
-        this.allFilesProgress += individualFileProgressPortion
-        resolve()
-      })
-    })
-  }
-
-  private addExtractorEventListeners(extractor: FileExtractor, download: DownloadProgress) {
-    let archive = ''
-
-    extractor.on('extract', (filename) => {
-      archive = filename
-      download.header = `[${archive}]`
-      download.description = `Extracting...`
-      download.type = 'good'
-      emitIPCEvent('download-updated', download)
-    })
-
-    extractor.on('extractProgress', (percent, filecount) => {
-      download.header = `[${archive}] (${filecount} file${filecount == 1 ? '' : 's'} extracted)`
-      download.description = `Extracting... (${percent}%)`
-      download.percent = interpolate(percent, 0, 100, 80, 95)
-      download.type = 'good'
-      emitIPCEvent('download-updated', download)
-    })
-
-    extractor.on('transfer', (filepath) => {
-      download.header = `Moving files to library folder...`
-      download.description = filepath
-      download.percent = 95
-      download.type = 'good'
-      emitIPCEvent('download-updated', download)
-    })
-
-    extractor.on('complete', (filepath) => {
-      download.header = `Download complete.`
-      download.description = filepath
-      download.percent = 100
-      download.type = 'done'
-      emitIPCEvent('download-updated', download)
-    })
-
-    extractor.on('error', (error, retry) => {
-      download.header = error.header
-      download.description = error.body
-      download.type = 'error'
-      this.downloadCallbacks[download.versionID].retry = retry
-      emitIPCEvent('download-updated', download)
-    })
-  }
-}
+export const downloadHandler = new DownloadHandler()

src/electron/ipc/download/FileDownloader.ts

@@ -2,150 +2,67 @@ import { generateUUID, sanitizeFilename } from '../../shared/UtilFunctions'
 import * as fs from 'fs'
 import * as path from 'path'
 import * as needle from 'needle'
-import { GetSettingsHandler } from '../SettingsHandler.ipc'
+// TODO: replace needle with got (for cancel() method) (if before-headers event is possible?)
+import { getSettingsHandler } from '../SettingsHandler.ipc'
+const getSettings = getSettingsHandler.getSettings
 
 type EventCallback = {
-  'wait': (waitTime: number) => void
-  'waitProgress': (secondsRemaining: number, initialWaitTime: number) => void
   'request': () => void
   'warning': (continueAnyway: () => void) => void
   'download': (filename: string, filesize?: number) => void
   'downloadProgress': (bytesDownloaded: number) => void
-  'complete': () => void
   'error': (error: DownloadError, retry: () => void) => void
+  'complete': () => void
 }
 type Callbacks = { [E in keyof EventCallback]: EventCallback[E] }
 
 export type DownloadError = { header: string, body: string }
 
+/**
+ * Downloads a file from `url` to `destinationFolder` and verifies that its hash matches `expectedHash`.
+ * Will handle google drive virus scan warnings. Provides event listeners for download progress.
+ * On error, provides the ability to retry.
+ */
 export class FileDownloader {
   private readonly RETRY_MAX = 2
-  private static fileQueue: { // Stores the overall order that files should be downloaded
-    destinationFolder: string
-    fileCount: number
-    clock?: () => void
-  }[]
-  private static waitTime: number
 
   private callbacks = {} as Callbacks
   private retryCount: number
   private wasCanceled = false
 
-  constructor(private url: string, private destinationFolder: string, private numFiles: number, private expectedHash?: string) {
-    if (FileDownloader.fileQueue == undefined) {
-      // First initialization
-      FileDownloader.fileQueue = []
-      let lastRateLimitDelay = GetSettingsHandler.getSettings().rateLimitDelay
-      FileDownloader.waitTime = 0
-      setInterval(() => {
-        if (FileDownloader.waitTime > 0) { // Update current countdown if this setting changes
-          let newRateLimitDelay = GetSettingsHandler.getSettings().rateLimitDelay
-          if (newRateLimitDelay != lastRateLimitDelay) {
-            FileDownloader.waitTime -= Math.min(lastRateLimitDelay - newRateLimitDelay, FileDownloader.waitTime - 1)
-            lastRateLimitDelay = newRateLimitDelay
-          }
-          FileDownloader.waitTime--
-        }
-        FileDownloader.fileQueue.forEach(download => { if (download.clock != undefined) download.clock() })
-        if (FileDownloader.waitTime <= 0 && FileDownloader.fileQueue.length != 0) {
-          FileDownloader.waitTime = GetSettingsHandler.getSettings().rateLimitDelay
-        }
-      }, 1000)
-    }
-  }
+  /**
+   * @param url The download link.
+   * @param destinationFolder The path to where this file should be stored.
+   * @param expectedHash The hash header value that is expected for this file.
+   */
+  constructor(private url: string, private destinationFolder: string, private expectedHash?: string) { }
   
   /**
-   * Calls <callback> when <event> fires.
-   * @param event The event to listen for.
-   * @param callback The function to be called when the event fires.
+   * Calls `callback` when `event` fires.
    */
   on<E extends keyof EventCallback>(event: E, callback: EventCallback[E]) {
     this.callbacks[event] = callback
   }
 
   /**
-   * Wait RATE_LIMIT_DELAY seconds between each download,
-   * then download the file.
+   * Download the file.
    */
   beginDownload() {
     // Check that the library folder has been specified
-    if (GetSettingsHandler.getSettings().libraryPath == undefined) {
+    if (getSettings().libraryPath == undefined) {
       this.callbacks.error({ header: 'Library folder not specified', body: 'Please go to the settings to set your library folder.' }, () => this.beginDownload())
       return
     }
-
-    // Skip the fileQueue if the file is not from Google
-    if (!this.url.toLocaleLowerCase().includes('google')) {
-      this.requestDownload()
-      return
-    }
-    // The starting point of a progress bar should be recalculated each clock cycle
-    // It will be what it would have been if rateLimitDelay was that value the entire time
-    this.initWaitTime()
-    // This is the number of seconds that had elapsed since the last file download (at the time of starting this download)
-    const initialTimeSinceLastDownload = GetSettingsHandler.getSettings().rateLimitDelay - FileDownloader.waitTime
-    const initialQueueCount = this.getQueueCount()
-    let waitTime = this.getWaitTime(initialTimeSinceLastDownload, initialQueueCount)
-    this.callbacks.wait(waitTime)
-    if (waitTime == 0) {
-      FileDownloader.waitTime = GetSettingsHandler.getSettings().rateLimitDelay
-      this.requestDownload()
-      return
-    }
-
-    const fileQueue = FileDownloader.fileQueue.find(queue => queue.destinationFolder == this.destinationFolder)
-    fileQueue.clock = () => {
-      if (this.wasCanceled) { this.removeFromQueue(); return } // CANCEL POINT
-      waitTime = this.getWaitTime(GetSettingsHandler.getSettings().rateLimitDelay - FileDownloader.waitTime, this.getQueueCount())
-      if (waitTime == 0) {
-        this.requestDownload()
-        fileQueue.clock = undefined
-      }
-      this.callbacks.waitProgress(waitTime, this.getWaitTime(initialTimeSinceLastDownload, this.getQueueCount()))
-    }
-  }
-
-  private getWaitTime(timeSinceLastDownload: number, queueCount: number) {
-    const rateLimitDelay = GetSettingsHandler.getSettings().rateLimitDelay
-    return (queueCount * rateLimitDelay) + Math.max(0, rateLimitDelay - timeSinceLastDownload)
-  }
-
-  private initWaitTime() {
-    this.retryCount = 0
-    const entry = FileDownloader.fileQueue.find(entry => entry.destinationFolder == this.destinationFolder)
-    if (entry == undefined) {
-      // Note: assumes that either all the chart files are from Google, or none of the chart files are from Google
-      FileDownloader.fileQueue.push({ destinationFolder: this.destinationFolder, fileCount: this.numFiles })
-    }
+  
+    this.requestDownload()
   }
 
   /**
-   * Returns the number of files in front of this file in the fileQueue
-   */
-  private getQueueCount() {
-    let fileCount = 0
-    for (let entry of FileDownloader.fileQueue) {
-      if (entry.destinationFolder != this.destinationFolder) {
-        fileCount += entry.fileCount
-      } else {
-        break
-      }
-    }
-
-    return fileCount
-  }
-
-  private removeFromQueue() {
-    const index = FileDownloader.fileQueue.findIndex(entry => entry.destinationFolder == this.destinationFolder)
-    FileDownloader.fileQueue.splice(index, 1)
-  }
-
-  /**
-   * Sends a request to download the file at <this.url>.
+   * Sends a request to download the file at `this.url`.
    * @param cookieHeader the "cookie=" header to include this request.
    */
   private requestDownload(cookieHeader?: string) {
-    if (this.wasCanceled) { this.removeFromQueue(); return } // CANCEL POINT
+    if (this.wasCanceled) { return } // CANCEL POINT
     this.callbacks.request()
     let uuid = generateUUID()
     const req = needle.get(this.url, {
@@ -176,7 +93,7 @@ export class FileDownloader {
     })
 
     req.on('header', (statusCode, headers: Headers) => {
-      if (this.wasCanceled) { this.removeFromQueue(); return } // CANCEL POINT
+      if (this.wasCanceled) { return } // CANCEL POINT
       if (statusCode != 200) {
         this.callbacks.error({ header: 'Connection failed', body: `Server returned status code: ${statusCode}` }, () => this.beginDownload())
         return
@@ -187,23 +104,21 @@ export class FileDownloader {
         this.handleHTMLResponse(req, headers['set-cookie'])
       } else {
         const fileName = this.getDownloadFileName(headers)
-        const downloadHash = this.getDownloadHash(headers)
-        if (this.expectedHash !== undefined && downloadHash !== this.expectedHash) {
+        this.handleDownloadResponse(req, fileName, headers['content-length'])
+
+        if (this.expectedHash !== undefined && this.getDownloadHash(headers) !== this.expectedHash) {
           req.pause()
           this.callbacks.warning(() => {
-            this.handleDownloadResponse(req, fileName, headers['content-length'])
             req.resume()
           })
-        } else {
-          this.handleDownloadResponse(req, fileName, headers['content-length'])
         }
       }
     })
   }
 
   /**
-   * A Google Drive HTML response to a download request means this is the "file too large to scan for viruses" warning.
-   * This function sends the request that results from clicking "download anyway".
+   * A Google Drive HTML response to a download request usually means this is the "file too large to scan for viruses" warning.
+   * This function sends the request that results from clicking "download anyway", or throws an error if it can't be found.
    * @param req The download request.
    * @param cookieHeader The "cookie=" header of this request.
    */
@@ -232,10 +147,10 @@ export class FileDownloader {
   }
 
   /**
-   * Pipes the data from a download response to <filename> and extracts it if <isArchive> is true.
+   * Pipes the data from a download response to `fileName`.
    * @param req The download request.
    * @param fileName The name of the output file.
-   * @param contentLength The number of bytes to be downloaded.
+   * @param contentLength The number of bytes to be downloaded. If undefined, download progress is indicated by MB, not %.
    */
   private handleDownloadResponse(req: NodeJS.ReadableStream, fileName: string, contentLength?: number) {
     this.callbacks.download(fileName, contentLength)
@@ -252,18 +167,13 @@ export class FileDownloader {
     })
 
     req.on('end', () => {
+      if (this.wasCanceled) { return } // CANCEL POINT
       this.callbacks.complete()
-      const index = FileDownloader.fileQueue.findIndex(entry => entry.destinationFolder == this.destinationFolder)
-      FileDownloader.fileQueue[index].fileCount--
-      if (FileDownloader.fileQueue[index].fileCount == 0) {
-        FileDownloader.fileQueue.splice(index, 1)
-      }
     })
   }
 
   /**
-   * Extracts the downloaded file's filename from <headers> or <url>, depending on the file's host server.
-   * @param url The URL of this request.
+   * Extracts the downloaded file's filename from `headers` or `this.url`, depending on the file's host server.
    * @param headers The response headers for this request.
    */
   private getDownloadFileName(headers: Headers) {
@@ -284,14 +194,13 @@ export class FileDownloader {
   }
 
   /**
-   * Extracts the downloaded file's hash from <headers>, depending on the file's host server.
-   * @param url The URL of the request.
+   * Extracts the downloaded file's hash from `headers`, depending on the file's host server.
    * @param headers The response headers for this request.
    */
   private getDownloadHash(headers: Headers): string {
     if (headers['server'] && headers['server'] == 'cloudflare' || this.url.startsWith('https://public.fightthe.pw/')) {
       // Cloudflare and Chorus specific jazz
-      return String(headers['content-length']) // No good hash is provided in the header, so this is the next best thing
+      return String(headers['content-length']) // No actual hash is provided in the header, so this is the next best thing
     } else {
       // GDrive specific jazz
       return headers['x-goog-hash']

src/electron/ipc/download/FileExtractor.ts

@@ -6,7 +6,8 @@ import { join, extname } from 'path'
 import * as node7z from 'node-7z'
 import * as zipBin from '7zip-bin'
 import * as unrarjs from 'node-unrar-js'
-import { GetSettingsHandler } from '../SettingsHandler.ipc'
+import { getSettingsHandler } from '../SettingsHandler.ipc'
+const getSettings = getSettingsHandler.getSettings
 
 const readdir = promisify(_readdir)
 const unlink = promisify(_unlink)
@@ -33,9 +34,7 @@ export class FileExtractor {
   constructor(private sourceFolder: string, private isArchive: boolean, private destinationFolderName: string) { }
 
   /**
-   * Calls <callback> when <event> fires.
-   * @param event The event to listen for.
-   * @param callback The function to be called when the event fires.
+   * Calls `callback` when `event` fires.
    */
   on<E extends keyof EventCallback>(event: E, callback: EventCallback[E]) {
     this.callbacks[event] = callback
@@ -45,7 +44,7 @@ export class FileExtractor {
    * Starts the chart extraction process.
    */
   async beginExtract() {
-    this.libraryFolder = (await GetSettingsHandler.getSettings()).libraryPath
+    this.libraryFolder = getSettings().libraryPath
     const files = await readdir(this.sourceFolder)
     if (this.isArchive) {
       this.extract(files[0])
@@ -55,8 +54,7 @@ export class FileExtractor {
   }
 
   /**
-   * Extracts the file at <filename> to <this.sourceFolder>.
-   * @param filename The name of the archive file.
+   * Extracts the file at `filename` to `this.sourceFolder`.
    */
   private extract(filename: string) {
     if (this.wasCanceled) { return } // CANCEL POINT
@@ -64,6 +62,7 @@ export class FileExtractor {
     const source = join(this.sourceFolder, filename)
 
     if (extname(filename) == '.rar') {
+
       // Use node-unrar-js to extract the archive
       try {
         let extractor = unrarjs.createExtractorFromFile(source, this.sourceFolder)
@@ -73,7 +72,9 @@ export class FileExtractor {
         return
       }
       this.transfer(source)
+
     } else {
+
       // Use node-7z to extract the archive
       const stream = node7z.extractFull(source, this.sourceFolder, { $progress: true, $bin: zipBin.path7za })
 
@@ -88,11 +89,12 @@ export class FileExtractor {
       stream.on('end', () => {
         this.transfer(source)
       })
+
     }
   }
 
   /**
-   * Deletes the archive at <archiveFilepath>, then transfers the extracted chart to <this.libraryFolder>.
+   * Deletes the archive at `archiveFilepath`, then transfers the extracted chart to `this.libraryFolder`.
    */
   private async transfer(archiveFilepath?: string) {
     if (this.wasCanceled) { return } // CANCEL POINT
@@ -109,33 +111,40 @@ export class FileExtractor {
 
       // Delete archive
       if (archiveFilepath != undefined) {
-        await unlink(archiveFilepath)
+        try {
+          await unlink(archiveFilepath)
+        } catch (e) {
+          if (e.code != 'ENOENT') {
+            throw new Error(`Could not delete the archive file at [${archiveFilepath}]`)
+          }
+        }
       }
 
       // Check if it extracted to a folder instead of a list of files
-      let files = await readdir(this.sourceFolder)
-      const isFolderArchive = (files.length < 2 && !(await lstat(join(this.sourceFolder, files[0]))).isFile())
+      let sourceFolder = this.sourceFolder
+      let files = await readdir(sourceFolder)
+      const isFolderArchive = (files.length < 2 && !(await lstat(join(sourceFolder, files[0]))).isFile())
       if (isFolderArchive) {
-        this.sourceFolder = join(this.sourceFolder, files[0])
-        files = await readdir(this.sourceFolder)
+        sourceFolder = join(sourceFolder, files[0])
+        files = await readdir(sourceFolder)
       }
 
       if (this.wasCanceled) { return } // CANCEL POINT
 
       // Copy the files from the temporary directory to the destination
       for (const file of files) {
-        await copyFile(join(this.sourceFolder, file), join(destinationFolder, file))
-        await unlink(join(this.sourceFolder, file))
+        await copyFile(join(sourceFolder, file), join(destinationFolder, file))
+        await unlink(join(sourceFolder, file))
       }
 
       // Delete the temporary folders
-      await rmdir(this.sourceFolder)
+      await rmdir(sourceFolder)
       if (isFolderArchive) {
-        await rmdir(join(this.sourceFolder, '..'))
+        await rmdir(join(sourceFolder, '..'))
       }
       this.callbacks.complete(destinationFolder)
     } catch (e) {
-      this.callbacks.error({ header: 'Transfer Failed', body: `Unable to transfer downloaded files to the library folder: ${e.name}` }, undefined)
+      this.callbacks.error({ header: 'Transfer Failed', body: `Unable to transfer downloaded files to the library folder: ${e.name}` }, () => this.transfer(archiveFilepath))
     }
   }
 

src/electron/ipc/download/GoogleTimer.ts

@@ -0,0 +1,50 @@
+import { getSettingsHandler } from '../SettingsHandler.ipc'
+const getSettings = getSettingsHandler.getSettings
+
+class GoogleTimer {
+
+  private rateLimitCounter = Infinity
+  private onReadyCallback: () => void
+  private updateCallback: (remainingTime: number, totalTime: number) => void
+
+  constructor() {
+    setInterval(() => {
+      this.rateLimitCounter++
+      if (this.isReady() && this.onReadyCallback != undefined) {
+        this.activateTimerReady()
+      } else if (this.updateCallback != undefined) {
+        const delay = getSettings().rateLimitDelay
+        this.updateCallback(delay - this.rateLimitCounter, delay)
+      }
+    }, 1000)
+  }
+
+  onTimerReady(callback: () => void) {
+    this.onReadyCallback = callback
+    if (this.isReady()) {
+      this.activateTimerReady()
+    }
+  }
+
+  onTimerUpdate(callback: (remainingTime: number, totalTime: number) => void) {
+    this.updateCallback = callback
+  }
+
+  removeCallbacks() {
+    this.onReadyCallback = undefined
+    this.updateCallback = undefined
+  }
+
+  private isReady() {
+    return this.rateLimitCounter > getSettings().rateLimitDelay
+  }
+
+  private activateTimerReady() {
+    this.rateLimitCounter = 0
+    const onReadyCallback = this.onReadyCallback
+    this.removeCallbacks()
+    onReadyCallback()
+  }
+}
+
+export const googleTimer = new GoogleTimer()

src/electron/main.ts

@@ -5,7 +5,7 @@ import * as url from 'url'
 // IPC Handlers
 import { getIPCInvokeHandlers, getIPCEmitHandlers, IPCEmitEvents } from './shared/IPCHandler'
 import Database from './shared/Database'
-import { GetSettingsHandler } from './ipc/SettingsHandler.ipc'
+import { getSettingsHandler } from './ipc/SettingsHandler.ipc'
 
 let mainWindow: BrowserWindow
 const args = process.argv.slice(1)
@@ -15,7 +15,7 @@ restrictToSingleInstance()
 handleOSXWindowClosed()
 app.on('ready', () => {
   // Load settings from file before the window is created
-  GetSettingsHandler.initSettings().then(createBridgeWindow)
+  getSettingsHandler.initSettings().then(createBridgeWindow)
 })
 
 /**

src/electron/shared/ElectronUtilFunctions.ts

@@ -1,10 +1,10 @@
 import { basename } from 'path'
-import { GetSettingsHandler } from '../ipc/SettingsHandler.ipc'
+import { getSettingsHandler } from '../ipc/SettingsHandler.ipc'
 
 /**
  * @returns The relative filepath from the library folder to `absoluteFilepath`.
  */
 export function getRelativeFilepath(absoluteFilepath: string) {
-  const settings = GetSettingsHandler.getSettings()
+  const settings = getSettingsHandler.getSettings()
   return basename(settings.libraryPath) + absoluteFilepath.substring(settings.libraryPath.length)
 }

src/electron/shared/IPCHandler.ts

@@ -1,13 +1,13 @@
 import { SongSearch, SongResult } from './interfaces/search.interface'
 import { VersionResult, AlbumArtResult } from './interfaces/songDetails.interface'
-import SearchHandler from '../ipc/SearchHandler.ipc'
-import SongDetailsHandler from '../ipc/SongDetailsHandler.ipc'
-import AlbumArtHandler from '../ipc/AlbumArtHandler.ipc'
+import { searchHandler } from '../ipc/SearchHandler.ipc'
+import { songDetailsHandler } from '../ipc/SongDetailsHandler.ipc'
+import { albumArtHandler } from '../ipc/AlbumArtHandler.ipc'
 import { Download, DownloadProgress } from './interfaces/download.interface'
-import { DownloadHandler } from '../ipc/download/DownloadHandler'
+import { downloadHandler } from '../ipc/download/DownloadHandler'
 import { Settings } from './Settings'
-import BatchSongDetailsHandler from '../ipc/BatchSongDetailsHandler.ipc'
-import { GetSettingsHandler, SetSettingsHandler } from '../ipc/SettingsHandler.ipc'
+import { batchSongDetailsHandler } from '../ipc/BatchSongDetailsHandler.ipc'
+import { getSettingsHandler, setSettingsHandler } from '../ipc/SettingsHandler.ipc'
 
 /**
  * To add a new IPC listener:
@@ -19,11 +19,11 @@ import { GetSettingsHandler, SetSettingsHandler } from '../ipc/SettingsHandler.i
 
 export function getIPCInvokeHandlers(): IPCInvokeHandler<keyof IPCInvokeEvents>[] {
   return [
-    new GetSettingsHandler(),
-    new SearchHandler(),
-    new SongDetailsHandler(),
-    new BatchSongDetailsHandler(),
-    new AlbumArtHandler()
+    getSettingsHandler,
+    searchHandler,
+    songDetailsHandler,
+    batchSongDetailsHandler,
+    albumArtHandler
   ]
 }
 
@@ -64,8 +64,8 @@ export interface IPCInvokeHandler<E extends keyof IPCInvokeEvents> {
 
 export function getIPCEmitHandlers(): IPCEmitHandler<keyof IPCEmitEvents>[] {
   return [
-    new DownloadHandler(),
-    new SetSettingsHandler()
+    downloadHandler,
+    setSettingsHandler
   ]
 }
 

src/electron/shared/interfaces/download.interface.ts

@@ -26,5 +26,11 @@ export interface DownloadProgress {
   header: string
   description: string
   percent: number
-  type: 'good' | 'warning' | 'error' | 'cancel' | 'done' | 'wait'
-}
+  type: ProgressType
+}
+
+export type ProgressType = 'good' | 'warning' | 'error' | 'cancel' | 'done' | 'fastUpdate'
+// export function downloadSorter(p1: DownloadProgress, p2: DownloadProgress) {
+//   return 0
+//   // return p1 - p2 // negative if p1 < p2
+// }