Fix review comments

2 files changed, 74 insertions, 4 deletions

diff --git a/MediaBrowser.Controller/Library/VersionPlaybackSelector.cs b/MediaBrowser.Controller/Library/VersionPlaybackSelector.cs
new file mode 100644
index 0000000000..1766c50141
--- /dev/null
+++ b/MediaBrowser.Controller/Library/VersionPlaybackSelector.cs
@@ -0,0 +1,59 @@
+using System;
+using System.Collections.Generic;
+using MediaBrowser.Controller.Entities;
+
+namespace MediaBrowser.Controller.Library
+{
+    /// <summary>
+    /// Single definition of "which alternate version was most recently played" shared by the resume tile
+    /// (<see cref="IUserDataManager.GetResumeUserData"/>), the media-source default ordering and Next Up.
+    /// Each call site declares its own eligibility rule so the intentional differences (resumable-only vs.
+    /// resumable-or-completed) are visible in one place instead of being re-implemented divergently.
+    /// The SQL resume query keeps its own translation of the same rule.
+    /// </summary>
+    public static class VersionPlaybackSelector
+    {
+        /// <summary>
+        /// Selects the entry whose user data has the greatest <see cref="UserItemData.LastPlayedDate"/>,
+        /// considering only entries that satisfy <paramref name="isEligible"/>. On an exact tie the first
+        /// encountered entry wins.
+        /// </summary>
+        /// <typeparam name="T">The candidate type (e.g. a version item or a media source).</typeparam>
+        /// <param name="items">The candidates to choose from.</param>
+        /// <param name="dataSelector">Resolves the user data for a candidate, or <c>null</c> when it has none.</param>
+        /// <param name="isEligible">Whether a candidate's user data makes it a valid winner.</param>
+        /// <returns>The most recently played eligible candidate, or <c>default</c> when none qualify.</returns>
+        public static T? SelectMostRecentlyPlayed<T>(
+            IEnumerable<T> items,
+            Func<T, UserItemData?> dataSelector,
+            Func<UserItemData, bool> isEligible)
+        {
+            ArgumentNullException.ThrowIfNull(items);
+            ArgumentNullException.ThrowIfNull(dataSelector);
+            ArgumentNullException.ThrowIfNull(isEligible);
+
+            T? winner = default;
+            var winnerDate = DateTime.MinValue;
+            var hasWinner = false;
+
+            foreach (var item in items)
+            {
+                var data = dataSelector(item);
+                if (data is null || !isEligible(data))
+                {
+                    continue;
+                }
+
+                var date = data.LastPlayedDate ?? DateTime.MinValue;
+                if (!hasWinner || date > winnerDate)
+                {
+                    winner = item;
+                    winnerDate = date;
+                    hasWinner = true;
+                }
+            }
+
+            return winner;
+        }
+    }
+}
diff --git a/MediaBrowser.Controller/Library/VersionResumeData.cs b/MediaBrowser.Controller/Library/VersionResumeData.cs
index 455fe739ce..772e2bf3a7 100644
--- a/MediaBrowser.Controller/Library/VersionResumeData.cs
+++ b/MediaBrowser.Controller/Library/VersionResumeData.cs
@@ -7,14 +7,17 @@ namespace MediaBrowser.Controller.Library
     /// <summary>
     /// The user data of the most recently played alternate version that should drive the completion state of a multi-version item.
     /// </summary>
+    /// <param name="VersionId">The id of the version that owns <paramref name="UserData"/>.</param>
     /// <param name="UserData">The resume version's user data.</param>
-    public record VersionResumeData(UserItemData UserData)
+    public record VersionResumeData(Guid VersionId, UserItemData UserData)
     {
         /// <summary>
         /// Merges the most recently played version's completion state into the supplied user data dto.
-        /// Only completion (played) propagates to the primary; the in-progress resume position stays on
-        /// the version that owns it, which is surfaced directly (e.g. in resume queries) so that playback
-        /// always targets the correct version rather than resuming the primary at another version's offset.
+        /// Completion (played) propagates to the primary. An in-progress resume position stays on the version
+        /// that owns it, which is surfaced directly (e.g. in resume queries) so that playback always targets
+        /// the correct version rather than resuming the primary at another version's offset. When the movie was
+        /// finished on a different version, the primary's own stale resume position is cleared so it does not
+        /// render as "watched and resumable" at the same time.
         /// </summary>
         /// <param name="dto">The user data dto to update.</param>
         public void ApplyTo(UserItemDataDto dto)
@@ -25,6 +28,14 @@ namespace MediaBrowser.Controller.Library
             {
                 dto.LastPlayedDate = UserData.LastPlayedDate;
             }
+
+            // A different version was finished (played, no resume position of its own) and is the most
+            // recently played: the whole movie is watched.
+            if (!VersionId.Equals(dto.ItemId) && UserData.Played && UserData.PlaybackPositionTicks <= 0)
+            {
+                dto.PlaybackPositionTicks = 0;
+                dto.PlayedPercentage = null;
+            }
         }
     }
 }