From 7cb41f8018b92ff403c63c14d3e354d6755b658f Mon Sep 17 00:00:00 2001
From: Mattia <hexer504@gmail.com>
Date: Wed, 14 Jul 2021 22:36:25 +0200
Subject: [PATCH] Version 1.9.10 Closes #139

---
 CHANGELOG.md                                  |  3 +
 lib/src/channels/channel.dart                 |  5 +-
 lib/src/channels/channel_client.dart          |  5 +-
 .../responses/channel_page.dart               | 63 +++++++++++++++++++
 pubspec.yaml                                  |  2 +-
 test/channel_test.dart                        |  1 +
 6 files changed, 75 insertions(+), 4 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 32d6b3d..ea74ef4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,6 @@
+## 1.9.10
+- Close #139: Implement Channel.subscribersCount.
+
 ## 1.9.9
 - Fix issue #134 (Error when getting the hls manifest from a livestream)
 
diff --git a/lib/src/channels/channel.dart b/lib/src/channels/channel.dart
index 8c47ba1..ef654f6 100644
--- a/lib/src/channels/channel.dart
+++ b/lib/src/channels/channel.dart
@@ -16,8 +16,11 @@ class Channel with EquatableMixin {
   /// URL of the channel's logo image.
   final String logoUrl;
 
+  /// The (approximate) channel subscriber's count.
+  final int? subscribersCount;
+
   /// Initializes an instance of [Channel]
-  Channel(this.id, this.title, this.logoUrl);
+  Channel(this.id, this.title, this.logoUrl, this.subscribersCount);
 
   @override
   String toString() => 'Channel ($title)';
diff --git a/lib/src/channels/channel_client.dart b/lib/src/channels/channel_client.dart
index 4539279..7fc8e66 100644
--- a/lib/src/channels/channel_client.dart
+++ b/lib/src/channels/channel_client.dart
@@ -30,7 +30,8 @@ class ChannelClient {
     id = ChannelId.fromString(id);
     var channelPage = await ChannelPage.get(_httpClient, id.value);
 
-    return Channel(id, channelPage.channelTitle, channelPage.channelLogoUrl);
+    return Channel(id, channelPage.channelTitle, channelPage.channelLogoUrl,
+        channelPage.subscribersCount);
   }
 
   /// Gets the metadata associated with the channel of the specified user.
@@ -42,7 +43,7 @@ class ChannelClient {
     var channelPage =
         await ChannelPage.getByUsername(_httpClient, username.value);
     return Channel(ChannelId(channelPage.channelId), channelPage.channelTitle,
-        channelPage.channelLogoUrl);
+        channelPage.channelLogoUrl, channelPage.subscribersCount);
   }
 
   /// Gets the info found on a YouTube Channel About page.
diff --git a/lib/src/reverse_engineering/responses/channel_page.dart b/lib/src/reverse_engineering/responses/channel_page.dart
index e1b6e9e..16f0184 100644
--- a/lib/src/reverse_engineering/responses/channel_page.dart
+++ b/lib/src/reverse_engineering/responses/channel_page.dart
@@ -31,6 +31,22 @@ class ChannelPage {
       _root.querySelector('meta[property="og:image"]')?.attributes['content'] ??
       '';
 
+  int? get subscribersCount => initialData.subscribersCount;
+
+  ///
+  late final _InitialData initialData = _getInitialData();
+
+  _InitialData _getInitialData() {
+    final scriptText = _root
+        .querySelectorAll('script')
+        .map((e) => e.text)
+        .toList(growable: false);
+    return scriptText.extractGenericData(
+        (obj) => _InitialData(obj),
+        () => TransientFailureException(
+            'Failed to retrieve initial data from the channel about page, please report this to the project GitHub page.'));
+  }
+
   ///
   ChannelPage(this._root);
 
@@ -68,3 +84,50 @@ class ChannelPage {
     });
   }
 }
+
+class _InitialData {
+  static final RegExp _subCountExp = RegExp(r'(\d+(?:\.\d+)?)(K|M|\s)');
+
+  // Json parsed map
+  final Map<String, dynamic> root;
+
+  _InitialData(this.root);
+
+  int? get subscribersCount {
+    final renderer = root.get('header')?.get('c4TabbedHeaderRenderer');
+    if (renderer?['subscriberCountText'] == null) {
+      return null;
+    }
+    final subText =
+        renderer?.get('subscriberCountText')?.getT<String>('simpleText');
+    if (subText == null) {
+      return null;
+    }
+    final match = _subCountExp.firstMatch(subText);
+    if (match == null) {
+      return null;
+    }
+    if (match.groupCount != 2) {
+      return null;
+    }
+
+    final count = double.tryParse(match.group(1) ?? '');
+    if (count == null) {
+      return null;
+    }
+
+    final multiplierText = match.group(2);
+    if (multiplierText == null) {
+      return null;
+    }
+
+    var multiplier = 1;
+    if (multiplierText == 'K') {
+      multiplier = 1000;
+    } else if (multiplierText == 'M') {
+      multiplier = 1000000;
+    }
+
+    return (count * multiplier).toInt();
+  }
+}
diff --git a/pubspec.yaml b/pubspec.yaml
index 45b681e..e4b270e 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,6 +1,6 @@
 name: youtube_explode_dart
 description: A port in dart of the youtube explode library. Supports several API functions without the need of Youtube API Key.
-version: 1.9.9
+version: 1.9.10
 
 homepage: https://github.com/Hexer10/youtube_explode_dart
 
diff --git a/test/channel_test.dart b/test/channel_test.dart
index 9571997..eb1d5ae 100644
--- a/test/channel_test.dart
+++ b/test/channel_test.dart
@@ -18,6 +18,7 @@ void main() {
     expect(channel.title, 'Tyrrrz');
     expect(channel.logoUrl, isNotEmpty);
     expect(channel.logoUrl, isNot(equalsIgnoringWhitespace('')));
+    expect(channel.subscribersCount, greaterThanOrEqualTo(190));
   });
 
   group('Get metadata of any channel', () {