Eliminate the one cross-engine reach-in in the scheduler: PlaylistEnumerator called
PlayoutBuilder.GetGroupedMediaItemsForShuffle / GetCollectionItemsForShuffleInOrder as
statics (one engine reaching into another engine's class). Move both helpers verbatim to
a new public static ShuffleSourceBuilder in ErsatzTV.Core/Scheduling (sibling to the
also-static MultiCollectionGrouper / MultiPartEpisodeGrouper; deps passed as parameters,
not DI). Classic (PlayoutBuilder) and Playlist (PlaylistEnumerator) now share this one
place to build shuffle sources.
One intentional signature change: GetGroupedMediaItemsForShuffle takes
(bool keepMultiPartEpisodesTogether, bool treatCollectionsAsShows) instead of a
ProgramSchedule (verified those are the only two properties it read). This deletes
PlaylistEnumerator's fake `new ProgramSchedule { KeepMultiPartEpisodesTogether = false }`
(its TODO becomes an honest false, false) and gives callers without a ProgramSchedule
(#176, #70) a schedule-entity-free entry point.
Scope is deliberately (a)-only: engine separation preserved, no god-factory. Block stays
its own family; the Scripted/YAML construction duplication is a separate follow-up gated
on #381. See docs/decisions.md 2026-07-17.
Behavior-preserving: the characterization net added in the previous commit (classic-shuffle
golden byte-identical, PlaylistEnumerator reach-in sequence unchanged) plus new direct
ShuffleSourceBuilder unit tests (multi-collection vs fake-multi-collection lookup;
multi-part grouping on/off) all green. Full Core.Tests: 546 passed. PlayoutBuilder.cs
also de-BOM'd + whitespace-normalized per the fix-as-you-touch convention (#311).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
timothyandClaude Opus 4.8
764cd3c31b