From 63c92e0c4ef4652e67fb7a3eca427f26f782e2e2 Mon Sep 17 00:00:00 2001
From: zrose584 <57181548+zrose584@users.noreply.github.com>
Date: Sun, 9 Jan 2022 16:13:00 +0100
Subject: add preview thumbnails
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Signed-off-by: Jesús <heckyel@hyperbola.info>
---
 youtube/static/js/plyr-start.js             |  4 ++
 youtube/templates/watch.html                |  1 +
 youtube/watch.py                            | 64 +++++++++++++++++++++++++++++
 youtube/yt_data_extract/watch_extraction.py |  2 +
 4 files changed, 71 insertions(+)

diff --git a/youtube/static/js/plyr-start.js b/youtube/static/js/plyr-start.js
index 86840e9..7b67185 100644
--- a/youtube/static/js/plyr-start.js
+++ b/youtube/static/js/plyr-start.js
@@ -116,6 +116,10 @@
         }
       },
     },
+    previewThumbnails: {
+        enabled: true,
+        src: [storyboard_url],
+    },
     settings: ['captions', 'quality', 'speed', 'loop'],
   });
 }());
diff --git a/youtube/templates/watch.html b/youtube/templates/watch.html
index 7c8f5cf..b4f9adf 100644
--- a/youtube/templates/watch.html
+++ b/youtube/templates/watch.html
@@ -239,6 +239,7 @@
 
     <script src="/youtube.com/static/js/av-merge.js"></script>
     <script src="/youtube.com/static/js/watch.js"></script>
+    <script> let storyboard_url = {{ storyboard_url | tojson }} </script>
     <script src="/youtube.com/static/js/common.js"></script>
     <script src="/youtube.com/static/js/transcript-table.js"></script>
     {% if settings.use_video_player == 2 %}
diff --git a/youtube/watch.py b/youtube/watch.py
index 85b4bd9..a592385 100644
--- a/youtube/watch.py
+++ b/youtube/watch.py
@@ -15,6 +15,9 @@ import traceback
 import urllib
 import re
 import urllib3.exceptions
+from urllib.parse import parse_qs, urlencode
+from types import SimpleNamespace
+from math import ceil
 
 try:
     with open(os.path.join(settings.data_dir, 'decrypt_function_cache.json'), 'r') as f:
@@ -507,6 +510,65 @@ def format_bytes(bytes):
     return '%.2f%s' % (converted, suffix)
 
 
+@yt_app.route('/ytl-api/storyboard.vtt')
+def get_storyboard_vtt():
+    """
+    See:
+        https://github.com/iv-org/invidious/blob/9a8b81fcbe49ff8d88f197b7f731d6bf79fc8087/src/invidious.cr#L3603
+        https://github.com/iv-org/invidious/blob/3bb7fbb2f119790ee6675076b31cd990f75f64bb/src/invidious/videos.cr#L623
+    """
+
+    spec_url = request.args.get('spec_url')
+    url, *l = spec_url.split('|')
+    url1, q = url.split('?')
+    q = parse_qs(q)
+
+    storyboard = None
+    wanted_height = 90
+
+    for i, board in enumerate(l):
+        *t, _, sigh = board.split("#")
+        width, height, count, width_cnt, height_cnt, interval = map(int, t)
+        if height != wanted_height: continue
+        q['sigh'] = [sigh]
+        url = f"{url1}?{urlencode(q, doseq=True)}"
+        storyboard = SimpleNamespace(
+            url               = url.replace("$L", str(i)).replace("$N", "M$M"),
+            width             = width,
+            height            = height,
+            interval          = interval,
+            width_cnt         = width_cnt,
+            height_cnt        = height_cnt,
+            storyboard_count  = ceil(count / (width_cnt * height_cnt))
+        )
+
+    if not storyboard:
+        flask.abort(404)
+
+    def to_ts(ms):
+        s, ms = divmod(ms, 1000)
+        h, s = divmod(s, 3600)
+        m, s = divmod(s, 60)
+        return f"{h:02}:{m:02}:{s:02}.{ms:03}"
+
+    r = "WEBVTT"
+    ts = 0
+
+    for i in range(storyboard.storyboard_count):
+        url = '/' + storyboard.url.replace("$M", str(i))
+        interval = storyboard.interval
+        w, h = storyboard.width, storyboard.height
+        w_cnt, h_cnt = storyboard.width_cnt, storyboard.height_cnt
+
+        for j in range(h_cnt):
+            for k in range(w_cnt):
+                r += f"{to_ts(ts)} --> {to_ts(ts+interval)}\n"
+                r += f"{url}#xywh={w * k},{h * j},{w},{h}\n\n"
+                ts += interval
+
+    return flask.Response(r, mimetype='text/vtt')
+
+
 time_table = {'h': 3600, 'm': 60, 's': 1}
 
 
@@ -726,6 +788,8 @@ def get_watch_page(video_id=None):
         invidious_reload_button = info['invidious_reload_button'],
         video_url = util.URL_ORIGIN + '/watch?v=' + video_id,
         video_id = video_id,
+        storyboard_url = (util.URL_ORIGIN + '/ytl-api/storyboard.vtt?' +
+            urlencode([('spec_url', info['storyboard_spec_url'])])),
 
         js_data = {
             'video_id': info['id'],
diff --git a/youtube/yt_data_extract/watch_extraction.py b/youtube/yt_data_extract/watch_extraction.py
index e7e0d74..309c85c 100644
--- a/youtube/yt_data_extract/watch_extraction.py
+++ b/youtube/yt_data_extract/watch_extraction.py
@@ -650,6 +650,8 @@ def extract_watch_info(polymer_json):
 
     # other stuff
     info['author_url'] = 'https://www.youtube.com/channel/' + info['author_id'] if info['author_id'] else None
+    info['storyboard_spec_url'] = player_response['storyboards']['playerStoryboardSpecRenderer']['spec']
+
     return info
 
 single_char_codes = {
-- 
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