From d9059ad132395d9969479918b428cfa78530471f Mon Sep 17 00:00:00 2001
From: Your Name <you@example.com>
Date: Tue, 30 Jun 2026 11:21:33 -0400
Subject: [PATCH] fix: start video at deep-linked time via #t= media fragment
 (iOS)

The real iOS issue: it won't load the media until the first tap and ignores JS
currentTime until the element is seekable (populated very late), so every
load/seek hack started playback from 0. A #t=<seconds> media fragment on the
src is honoured by the media loader during the tap-triggered load itself, so it
starts at the right frame (and renders that frame instead of black). Bake the
deep-linked playhead into the src fragment, cached per clip so live playhead
changes don't reload the element; currentTime still drives in-session seeks.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
---
 tl/src/tl/views.cljs | 53 +++++++++++++++++++++++++++++++-------------
 1 file changed, 38 insertions(+), 15 deletions(-)

diff --git a/tl/src/tl/views.cljs b/tl/src/tl/views.cljs
index 0028b27..a4eaaaf 100644
--- a/tl/src/tl/views.cljs
+++ b/tl/src/tl/views.cljs
@@ -216,21 +216,44 @@
                             (scroll-to-seg-track! segs local)))))))
 
 (defn video-monitor []
-  [:video {:src @(rf/subscribe [::subs/clip-url]) :controls true :preload "auto"
-           :plays-inline true :webkit-playsinline "true"
-           ;; (Re)loading a clip resets the element to currentTime 0, so a restored
-           ;; / deep-linked playhead would show in the UI but play from 0. Seek the
-           ;; element to the current playhead once its metadata is ready.
-           :on-loaded-metadata
-           (fn [_]
-             (when-not @play
-               (let [segs @(rf/subscribe [::subs/segments])
-                     fps  @(rf/subscribe [::subs/fps])
-                     ph   @(rf/subscribe [::subs/playhead])]
-                 (seek-video! fps (scene/local->source segs ph)))))
-           :on-play  (fn [_] (engage-play!))
-           :on-pause (fn [_] (disengage!))
-           :ref (fn [n] (when n (reset! video-el n)))}])
+  ;; The src carries a #t= media fragment for the deep-linked playhead. That is
+  ;; the only thing that reliably starts iOS at the right time: iOS won't load
+  ;; the media until the first tap and ignores JS currentTime until the element
+  ;; is seekable (which happens very late), but it honours #t= during the media
+  ;; load itself — so the tap loads-and-starts at the right frame. (#t= also
+  ;; nudges iOS to render that frame instead of a black box.) currentTime still
+  ;; drives all in-session seeks once the element is loaded.
+  ;;
+  ;; Cache the src per clip so live playhead changes don't rewrite the fragment
+  ;; and reload the element — the fragment only matters at (re)load time.
+  (let [cache (atom nil)]                    ; {:clip url :src "url#t=secs"}
+    (fn []
+      (let [clip @(rf/subscribe [::subs/clip-url])
+            src  (cond
+                   (nil? clip)             nil
+                   (= clip (:clip @cache)) (:src @cache)
+                   :else
+                   (let [segs @(rf/subscribe [::subs/segments])
+                         fps  @(rf/subscribe [::subs/fps])
+                         ph   @(rf/subscribe [::subs/playhead])
+                         t    (max 0.001 (/ (scene/local->source segs ph) fps))
+                         s    (str clip "#t=" (.toFixed t 3))]
+                     (reset! cache {:clip clip :src s})
+                     s))]
+        [:video {:src src :controls true :preload "auto"
+                 :plays-inline true :webkit-playsinline "true"
+                 ;; desktop / once-loaded: align to the playhead when metadata is
+                 ;; ready (iOS already arrived there via the #t= fragment).
+                 :on-loaded-metadata
+                 (fn [_]
+                   (when-not @play
+                     (let [segs @(rf/subscribe [::subs/segments])
+                           fps  @(rf/subscribe [::subs/fps])
+                           ph   @(rf/subscribe [::subs/playhead])]
+                       (seek-video! fps (scene/local->source segs ph)))))
+                 :on-play  (fn [_] (engage-play!))
+                 :on-pause (fn [_] (disengage!))
+                 :ref (fn [n] (when n (reset! video-el n)))}]))))
 
 (defn- clip-label
   "Track-local clip label for the content segment whose :mark is `mid`."