Add ability to playback downloaded videos

Videos that are downloaded will always show their downloaded version and not fetch either API.

#348

src/renderer/helpers/android.js

@@ -566,3 +566,47 @@ export async function addToDownloadQueue(downloadRequest) {
   event.data = downloadRequest
   window.dispatchEvent(event)
 }
+
+export async function getDownloadedVideos() {
+  const videoDirectory = await getVideosDirectory()
+  const videos = await videoDirectory.listFiles()
+  return videos
+}
+
+export async function getVideoInformationDownloaded(videoId, component) {
+  const videos = await getDownloadedVideos()
+  const matchingVideoFolders = videos.filter(video => video.fileName === videoId)
+  if (matchingVideoFolders.length > 0) {
+    const filesContainedInVideoDirectory = await matchingVideoFolders[0].listFiles()
+    const dataFiles = filesContainedInVideoDirectory.filter(file => file.fileName === 'data.json')
+    if (dataFiles.length > 0) {
+      const response = JSON.parse(await readFile(dataFiles[0].uri))
+      // now to dump all of the data pulled out of the download prompt data back into the page
+      component.videoTitle = response.title
+      component.channelId = response.channelId
+      component.channelName = response.channelName
+      component.channelThumbnail = response.channelThumbnail
+      component.videoPublished = response.published
+      component.channelSubscriptionCountText = response.channelSubscriptionCountText
+      component.videoLikeCount = response.likes
+      component.videoLengthSeconds = response.lengthSeconds
+      component.thumbnail = response.thumbnail
+      component.videoChapters = response.chapters
+      component.videoDescription = response.description
+      component.videoDescriptionHtml = response.descriptionHtml
+      component.videoSourceList = [
+        {
+          url: response.uri,
+          qualityLabel: 'unknown'// TODO pass through information from prompt
+        }
+      ]
+
+      component.activeFormat = 'legacy'
+      component.activeSourceList = component.videoSourceList
+      component.audioSourceList = null
+      component.dashSrc = null
+      component.isLoading = false
+      return response
+    }
+  }
+}

src/renderer/views/Watch/Watch.js

@@ -35,7 +35,7 @@ import {
   youtubeImageUrlToInvidious
 } from '../../helpers/api/invidious'
 import {
-  createMediaSession, getDownloadFormats
+  createMediaSession, getDownloadFormats, getVideoInformationDownloaded
 } from '../../helpers/android'
 import android from 'android'
 
@@ -275,18 +275,26 @@ export default defineComponent({
       this.checkIfPlaylist()
       this.checkIfTimestamp()
 
-      switch (this.backendPreference) {
-        case 'local':
-          this.getVideoInformationLocal(this.videoId)
-          break
-        case 'invidious':
-          this.getVideoInformationInvidious(this.videoId)
+      const promise = process.env.IS_ANDROID && this.$store.getters.getDownloadBehavior === 'download'
+        ? getVideoInformationDownloaded(this.videoId, this)
+        : new Promise((resolve, _reject) => resolve())
+
+      promise.then((downloadedInfo) => {
+        if (downloadedInfo === undefined) {
+          switch (this.backendPreference) {
+            case 'local':
+              this.getVideoInformationLocal(this.videoId)
+              break
+            case 'invidious':
+              this.getVideoInformationInvidious(this.videoId)
 
-          if (this.forceLocalBackendForLegacy) {
-            this.getVideoInformationLocal(this.videoId)
+              if (this.forceLocalBackendForLegacy) {
+                this.getVideoInformationLocal(this.videoId)
+              }
+              break
           }
-          break
-      }
+        }
+      })
     },
     async thumbnail() {
       if (process.env.IS_ANDROID) {
@@ -369,12 +377,19 @@ export default defineComponent({
 
       this.checkIfPlaylist()
       this.checkIfTimestamp()
+      const promise = process.env.IS_ANDROID && this.$store.getters.getDownloadBehavior === 'download'
+        ? getVideoInformationDownloaded(this.videoId, this)
+        : new Promise((resolve, _reject) => resolve())
 
-      if (!process.env.SUPPORTS_LOCAL_API || this.backendPreference === 'invidious') {
-        this.getVideoInformationInvidious()
-      } else {
-        this.getVideoInformationLocal()
-      }
+      promise.then((downloadedInfo) => {
+        if (downloadedInfo === undefined) {
+          if (!process.env.SUPPORTS_LOCAL_API || this.backendPreference === 'invidious') {
+            this.getVideoInformationInvidious()
+          } else {
+            this.getVideoInformationLocal()
+          }
+        }
+      })
 
       window.addEventListener('beforeunload', this.handleWatchProgress)
     },