[GoPro] Support playlists.

Which results in a couple of changes in the naming:
- Use the ID of the video, rather than ID of the playlist in the name.
- If creation time of the video is available, prefer it to the creation
  time of the playlist.
- Combine the titles of the playlist and the video itself, if available.

Signed-off-by: Alexey Neyman <stilor@att.net>

yt_dlp/extractor/gopro.py

@@ -1,5 +1,6 @@
 from .common import InfoExtractor
 from ..utils import (
+    ExtractorError,
     int_or_none,
     remove_end,
     str_or_none,
@@ -10,16 +11,16 @@ from ..utils import (
 
 
 class GoProIE(InfoExtractor):
-    _VALID_URL = r'https?://(www\.)?gopro\.com/v/(?P<id>[A-Za-z0-9]+)'
+    _VALID_URL = r'https?://(www\.)?gopro\.com/v(/(?P<plid>[A-Za-z0-9]+))?(/(?P<id>[A-Za-z0-9]+))?'
 
     _TESTS = [{
         'url': 'https://gopro.com/v/ZNVvED8QDzR5V',
         'info_dict': {
-            'id': 'ZNVvED8QDzR5V',
+            'id': 'LvV9MVbapDqKy',
             'title': 'My GoPro Adventure - 9/19/21',
             'thumbnail': r're:https?://.+',
             'ext': 'mp4',
-            'timestamp': 1632072947,
+            'timestamp': 1632070674,
             'upload_date': '20210919',
             'uploader_id': 'fireydive30018',
             'duration': 396062,
@@ -27,11 +28,25 @@ class GoProIE(InfoExtractor):
     }, {
         'url': 'https://gopro.com/v/KRm6Vgp2peg4e',
         'info_dict': {
-            'id': 'KRm6Vgp2peg4e',
+            'id': '0rl3J2y2l5N3v',
             'title': 'じゃがいも カリカリ オーブン焼き',
             'thumbnail': r're:https?://.+',
             'ext': 'mp4',
-            'timestamp': 1607231125,
+            'timestamp': 1607231111,
+            'upload_date': '20201206',
+            'uploader_id': 'dc9bcb8b-47d2-47c6-afbc-4c48f9a3769e',
+            'duration': 45187,
+            'track': 'The Sky Machine',
+        },
+    }, {
+        'url': 'https://gopro.com/v/KRm6Vgp2peg4e/0rl3J2y2l5N3v',
+        'note': 'Same video as above, but full link (playlist+video)',
+        'info_dict': {
+            'id': '0rl3J2y2l5N3v',
+            'title': 'じゃがいも カリカリ オーブン焼き',
+            'thumbnail': r're:https?://.+',
+            'ext': 'mp4',
+            'timestamp': 1607231111,
             'upload_date': '20201206',
             'uploader_id': 'dc9bcb8b-47d2-47c6-afbc-4c48f9a3769e',
             'duration': 45187,
@@ -40,29 +55,49 @@ class GoProIE(InfoExtractor):
     }, {
         'url': 'https://gopro.com/v/kVrK9wlJvBMwn',
         'info_dict': {
-            'id': 'kVrK9wlJvBMwn',
-            'title': 'DARKNESS',
+            'id': 'pJzDM128KQ8wG',
+            'title': 'DARKNESS (DARKNESS)',
             'thumbnail': r're:https?://.+',
             'ext': 'mp4',
-            'timestamp': 1594183735,
+            'timestamp': 1594181304,
             'upload_date': '20200708',
             'uploader_id': '闇夜乃皇帝',
             'duration': 313075,
             'track': 'Battery (Live)',
-            'artist': 'Metallica',
+            'artists': ['Metallica'],
         },
     }]
 
     def _real_extract(self, url):
         video_id = self._match_id(url)
-        webpage = self._download_webpage(url, video_id)
+        playlist_id = self._match_valid_url(url).group('plid')
+        if playlist_id is None and video_id is None:
+            raise ExtractorError('Invalid URL: neither video ID nor playlist ID is present')
 
+        webpage = self._download_webpage(url, video_id or playlist_id)
         metadata = self._search_json(
-            r'window\.__reflectData\s*=', webpage, 'metadata', video_id)
+            r'window\.__reflectData\s*=', webpage, 'metadata', video_id or playlist_id)
+        collection_title = str_or_none(
+            try_get(metadata, lambda x: x['collection']['title'])
+            or self._html_search_meta(['og:title', 'twitter:title'], webpage)
+            or remove_end(self._html_search_regex(
+                r'<title[^>]*>([^<]+)</title>', webpage, 'title', fatal=False), ' | GoPro'))
+        if collection_title:
+            collection_title = collection_title.replace('\n', ' ')
+        entries = []
+        for video_info in metadata['collectionMedia']:
+            # If video_id is none, downloading the whole playlist.
+            if video_id is None or video_id == video_info['id']:
+                entries.append(self.ExtractOneEntry(webpage, metadata, collection_title, video_info))
+        if not entries:
+            raise ExtractorError(f'{url}: No videos found')
+        return self.playlist_result(entries, playlist_id=playlist_id,
+                                    playlist_title=collection_title)
 
-        video_info = metadata['collectionMedia'][0]
+    def ExtractOneEntry(self, webpage, metadata, collection_title, video_info):
+        video_id = video_info['id']
         media_data = self._download_json(
-            'https://api.gopro.com/media/{}/download'.format(video_info['id']), video_id)
+            f'https://api.gopro.com/media/{video_id}/download', video_id)
 
         formats = []
         for fmt in try_get(media_data, lambda x: x['_embedded']['variations']) or []:
@@ -78,13 +113,14 @@ class GoProIE(InfoExtractor):
                 'height': int_or_none(fmt.get('height')),
             })
 
-        title = str_or_none(
-            try_get(metadata, lambda x: x['collection']['title'])
-            or self._html_search_meta(['og:title', 'twitter:title'], webpage)
-            or remove_end(self._html_search_regex(
-                r'<title[^>]*>([^<]+)</title>', webpage, 'title', fatal=False), ' | GoPro'))
-        if title:
-            title = title.replace('\n', ' ')
+        title = collection_title
+        content_title = video_info.get('content_title')
+        if content_title:
+            content_title = content_title.replace('\n', ' ')
+            if title:
+                title += f' ({content_title})'
+            else:
+                title = content_title
 
         return {
             'id': video_id,
@@ -93,7 +129,8 @@ class GoProIE(InfoExtractor):
             'thumbnail': url_or_none(
                 self._html_search_meta(['og:image', 'twitter:image'], webpage)),
             'timestamp': unified_timestamp(
-                try_get(metadata, lambda x: x['collection']['created_at'])),
+                video_info.get('created_at')
+                or try_get(metadata, lambda x: x['collection']['created_at'])),
             'uploader_id': str_or_none(
                 try_get(metadata, lambda x: x['account']['nickname'])),
             'duration': int_or_none(