Implement getSrt

dartdoc_options.yaml

@@ -0,0 +1,2 @@
+dartdoc:
+  showUndocumentedCategories: true

lib/src/channels/channels.dart

@@ -1,3 +1,6 @@
+/// APIs related to YouTube channels.
+///
+/// {@category Channels}
 library youtube_explode.channels;
 
 export 'channel.dart';

lib/src/playlists/playlists.dart

@@ -1,3 +1,6 @@
+/// APIs related to YouTube playlists.
+///
+/// {@category Playlists}
 library youtube_explode.playlists;
 
 export 'playlist.dart';

lib/src/search/search.dart

@@ -1,3 +1,6 @@
+/// APIs related to YouTube search queries.
+///
+/// {@category Search}
 library youtube_explode.search;
 
 export 'related_query.dart';

lib/src/videos/closed_captions/closed_caption_client.dart

@@ -33,7 +33,8 @@ class ClosedCaptionClient {
     return ClosedCaptionManifest(tracks);
   }
 
-  ///
+  /// Gets the actual closed caption track which is
+  /// identified by the specified metadata.
   Future<ClosedCaptionTrack> get(ClosedCaptionTrackInfo trackInfo) async {
     var response = await ClosedCaptionTrackResponse.get(
         _httpClient, trackInfo.url.toString());
@@ -44,4 +45,63 @@ class ClosedCaptionClient {
             e.getParts().map((f) => ClosedCaptionPart(f.text, f.offset))));
     return ClosedCaptionTrack(captions);
   }
+
+  Future<String> getSrt(ClosedCaptionTrackInfo trackInfo) async {
+    var track = await get(trackInfo);
+
+    var buffer = StringBuffer();
+    for (var i = 0; i < track.captions.length; i++) {
+      var caption = track.captions[i];
+
+      // Line number
+      buffer.writeln('${i + 1}');
+
+      // Time start --> time end
+      buffer.write(caption.offset.toSrtFormat());
+      buffer.write(' --> ');
+      buffer.write(caption.end.toSrtFormat());
+      buffer.writeln();
+
+      // Actual text
+      buffer.writeln(caption.text);
+      buffer.writeln();
+    }
+    return buffer.toString();
+  }
+}
+
+extension on Duration {
+  String toSrtFormat() {
+    String threeDigits(int n) {
+      if (n >= 1000) {
+        return n.toString().substring(0, 3);
+      }
+      if (n >= 100) {
+        return '$n';
+      }
+      if (n >= 10) {
+        return '0$n';
+      }
+      return '00$n';
+    }
+
+    String twoDigits(int n) {
+      if (n >= 10) {
+        return '$n';
+      }
+      return '0$n';
+    }
+
+    if (inMicroseconds < 0) {
+      return "-${-this}";
+    }
+    var twoDigitHours = twoDigits(inHours);
+    var twoDigitMinutes =
+    twoDigits(inMinutes.remainder(Duration.minutesPerHour));
+    var twoDigitSeconds =
+    twoDigits(inSeconds.remainder(Duration.secondsPerMinute));
+    var fourDigitsUs =
+    threeDigits(inMilliseconds.remainder(1000));
+    return "$twoDigitHours:$twoDigitMinutes:$twoDigitSeconds,$fourDigitsUs";
+  }
 }

lib/src/videos/videos.dart

@@ -1,3 +1,6 @@
+/// APIs related to YouTube videos.
+///
+/// {@category Videos}
 library youtube_explode.videos;
 
 export 'comments/comments.dart';

lib/youtube_explode_dart.dart

@@ -1,3 +1,4 @@
+/// Provides all the APIs implemented by this library.
 library youtube_explode;
 
 export 'src/channels/channels.dart';