Merge Theater Mode (Phase 20) into dev

2026-06-20 22:12:23 -04:00
parent 835fb71337 2fc2d4eb6d
commit 011dbe8d81
14 changed files with 392 additions and 18 deletions
@@ -10,6 +10,15 @@ else
        <MudContainer MaxWidth="MaxWidth.Large" Class="player-inner-container">
            <MudPaper Elevation="8" Class="player-surface pa-3">

+                @* Theater Mode "now showing" band (Phase 20 §5/§7). Shown only when Theater is ON and a
+                   release is playing — keyed off the playing track's Release, not off any detail page
+                   (the bar reaches into no page; §6). The release page is hidden in Theater Mode, so the
+                   bar carries its identity: cover, linked title, release share. *@
+                @if (VisualizerControlState.TheaterMode && CurrentTrack?.Release is not null)
+                {
+                    <NowShowingPanel Release="CurrentTrack.Release" />
+                }
+
                <div class="player-layout">
                    <PlayerTransportZone IsLoaded="IsLoaded"
                                         CanPlay="CanPlay"
@@ -16,12 +16,18 @@ public partial class AudioPlayerBar : ComponentBase, IAsyncDisposable

    [Inject] private IJSRuntime JsRuntime { get; set; } = default!;

+    // Theater Mode (Phase 20). Property-injected (no constructor growth) so the bar can read
+    // TheaterMode to mount the "now showing" band and re-render when the flag flips. The toggle lives on
+    // the detail pages; the bar only observes — single source, multiple observers (§6).
+    [Inject] private WaveformVisualizerControlState VisualizerControlState { get; set; } = default!;
+
    private bool _isMinimized = true;
    private bool _isSeeking = false;
    private double _seekPosition = 0;
    private bool _queueOpen = false;
    private IStreamingPlayerService? _subscribedService;
    private IQueueService? _subscribedQueue;
+    private bool _subscribedToVisualizerState;

    // Spacer-height bridge: the expanded dock is position:fixed, so MainLayout's
    // spacer reserves its space. We mirror this element's live height into a CSS
@@ -143,8 +149,19 @@ public partial class AudioPlayerBar : ComponentBase, IAsyncDisposable
            QueueService.QueueChanged += OnQueueChanged;
            _subscribedQueue = QueueService;
        }
+
+        // Theater Mode (Phase 20 §7): re-render the bar when TheaterMode flips so the "now showing" band
+        // appears/disappears. VisualizerControlState is injected (one stable scoped instance per session),
+        // so the subscribe is once-only — same idempotent subscribe-here / unsubscribe-on-dispose shape.
+        if (!_subscribedToVisualizerState)
+        {
+            VisualizerControlState.Changed += OnVisualizerStateChanged;
+            _subscribedToVisualizerState = true;
+        }
    }

+    private void OnVisualizerStateChanged() => InvokeAsync(StateHasChanged);
+
    private void OnPlayerStateChanged() => InvokeAsync(StateHasChanged);

    private void OnQueueChanged()
@@ -402,6 +419,12 @@ public partial class AudioPlayerBar : ComponentBase, IAsyncDisposable
            _subscribedQueue = null;
        }

+        if (_subscribedToVisualizerState)
+        {
+            VisualizerControlState.Changed -= OnVisualizerStateChanged;
+            _subscribedToVisualizerState = false;
+        }
+
        if (_spacerModule is not null)
        {
            try
@@ -56,6 +56,54 @@
    color: var(--mud-palette-primary);
 }

+/* Theater Mode "now showing" band (Phase 20 §5/§7). Sits above the transport layout inside the
+   player surface and lets the bar grow taller to carry the hidden release's identity. The band only
+   renders when Theater is ON, so this geometry is gated by render-inclusion, not a CSS flag — when
+   Theater is OFF the player bar is byte-for-byte its non-Theater self.
+   Colour/surface come from the bar's themed --deepdrft-page-* aliases; no new token, no dark override. */
+::deep .now-showing {
+    display: flex;
+    align-items: center;
+    gap: 0.75rem;
+    padding-bottom: 0.5rem;
+    margin-bottom: 0.5rem;
+    border-bottom: 1px solid var(--deepdrft-page-text-muted);
+    min-width: 0;
+}
+
+/* Fixed cover box — the reused .deepdrft-track-detail-cover-art / -placeholder idioms are height:100%,
+   so the band supplies the square frame they fill. */
+::deep .now-showing-cover {
+    flex: 0 0 auto;
+    width: 44px;
+    height: 44px;
+    border-radius: 6px;
+    overflow: hidden;
+}
+
+::deep .now-showing-cover-art,
+::deep .now-showing-cover-placeholder {
+    width: 100%;
+}
+
+::deep .now-showing-cover-placeholder .mud-icon-root {
+    font-size: 24px;
+}
+
+::deep .now-showing-title-link {
+    flex: 1 1 auto;
+    min-width: 0;
+    text-decoration: none;
+}
+
+::deep .now-showing-title {
+    color: var(--deepdrft-page-text);
+}
+
+::deep .now-showing-share {
+    flex: 0 0 auto;
+}
+
 /* Minimized floating dock — positioning + hover only; colour from MudFab */
 .minimized-dock {
    position: fixed;
@@ -0,0 +1,46 @@
+@namespace DeepDrftPublic.Client.Controls.AudioPlayerBar
+@using DeepDrftModels.DTOs
+@using DeepDrftPublic.Client.Common
+@using DeepDrftPublic.Client.Controls
+
+@* "Now showing" block surfaced in the player bar when Theater Mode is ON (Phase 20 §5/§7). Theater
+   hides the release page, so the bar carries the release identity the page would have shown: cover art,
+   the release title linked to its detail page, and a release-mode share. Purely presentational — it owns
+   no player logic and no Theater state; AudioPlayerBar mounts it only when state.TheaterMode &&
+   CurrentTrack?.Release is not null, so Release is non-null here.
+
+   Theming is all reuse (§8, zero new CSS): the cover reuses the deepdrft-track-detail-cover-art /
+   -placeholder idiom; the share glyph goes green-accent in both themes via .dd-accent-icon; surface and
+   text come from the bar's own .player-surface and the .now-showing-* classes in the global sheet, which
+   bind the theme-aware --deepdrft-page-* aliases. *@
+
+<div class="now-showing">
+    <div class="now-showing-cover">
+        @if (!string.IsNullOrEmpty(Release.ImagePath))
+        {
+            <div class="deepdrft-track-detail-cover-art now-showing-cover-art"
+                 style="@($"background-image: url('api/image/{Uri.EscapeDataString(Release.ImagePath)}');")"></div>
+        }
+        else
+        {
+            <div class="deepdrft-track-detail-cover-placeholder deepdrft-gradient-soft-secondary now-showing-cover-placeholder">
+                <MudIcon Icon="@Icons.Material.Filled.Album" Color="Color.Primary" />
+            </div>
+        }
+    </div>
+
+    <a href="@ReleaseRoutes.DetailHref(Release)" class="now-showing-title-link">
+        <MudText Typo="Typo.subtitle2" Class="now-showing-title text-truncate">
+            @Release.Title
+        </MudText>
+    </a>
+
+    <div class="dd-accent-icon now-showing-share">
+        <SharePopover ReleaseEntryKey="@Release.EntryKey" ReleaseMedium="@Release.Medium" />
+    </div>
+</div>
+
+@code {
+    /// <summary>The current playing track's release. Non-null by the bar's mount gate.</summary>
+    [Parameter, EditorRequired] public ReleaseDto Release { get; set; } = default!;
+}
@@ -0,0 +1,49 @@
+@namespace DeepDrftPublic.Client.Controls
+@using DeepDrftPublic.Client.Services
+@implements IDisposable
+@inject WaveformVisualizerControlState State
+
+@* Theater-Mode toggle (Phase 20 §3). The single affordance placed identically on all three release
+   detail pages — immediately to the LEFT of the lava-lamp WaveformVisualizerControlPopover trigger.
+   It is purely a mutation surface: tapping it flips State.TheaterMode and raises Changed; the detail
+   pages observe that to gate their content @if, and the player bar observes it to grow. This component
+   reaches into no page and no bar — single source, multiple observers (§6).
+
+   Visible only when the lava OR waveform subsystem is on — there is nothing to go to theater FOR if both
+   are off (§3.2). Disabled until interactive (§3.4), the same prerender guard the lava/Play buttons use.
+   Active visual state when Theater is ON. .dd-accent-icon gives the green-accent glyph in both themes
+   with zero new CSS (§8) — same treatment as the lava-lamp trigger it sits beside. *@
+
+@if (State.LavaEnabled || State.WaveformEnabled)
+{
+    <div class="dd-accent-icon">
+        <MudTooltip Text="@(State.TheaterMode ? "Exit theater mode" : "Theater mode")">
+            <MudIconButton Icon="@Icons.Material.Filled.Theaters"
+                           Size="@IconSize"
+                           Color="Color.Secondary"
+                           Disabled="@(!RendererInfo.IsInteractive)"
+                           OnClick="@Toggle"
+                           aria-label="Theater mode"
+                           aria-pressed="@State.TheaterMode" />
+        </MudTooltip>
+    </div>
+}
+
+@code {
+    /// <summary>Trigger-icon size. Defaults Large to match the lava-lamp popover trigger it sits beside.</summary>
+    [Parameter] public Size IconSize { get; set; } = Size.Large;
+
+    protected override void OnInitialized() => State.Changed += OnStateChanged;
+
+    // The toggle's own visibility and active state both key off State, which another observer (or this
+    // button) may mutate, so re-render on every Changed — same idempotent posture the visualizer bridge uses.
+    private void OnStateChanged() => InvokeAsync(StateHasChanged);
+
+    private void Toggle()
+    {
+        State.TheaterMode = !State.TheaterMode;
+        State.NotifyChanged();
+    }
+
+    public void Dispose() => State.Changed -= OnStateChanged;
+}
@@ -226,12 +226,14 @@
    private void ToggleLava()
    {
        ControlState.LavaEnabled = !ControlState.LavaEnabled;
+        ControlState.CoerceTheaterMode();
        ControlState.NotifyChanged();
    }

    private void ToggleWaveform()
    {
        ControlState.WaveformEnabled = !ControlState.WaveformEnabled;
+        ControlState.CoerceTheaterMode();
        ControlState.NotifyChanged();
    }

@@ -54,11 +54,21 @@ else
                                TrackEntryKey="@firstTrack?.EntryKey" />
        </Ambient>
        <TopRightAction>
-            @* Lava-lamp icon → popover panel (full parity, §3d-revised). Sits top-right across from the
-               back link, clear of the header's own Play/Share affordances below. *@
-            <WaveformVisualizerControlPopover />
+            @* Theater toggle sits immediately LEFT of the lava-lamp popover (Phase 20 §3). Both are
+               controls over the experience, not release content, so both stay in Theater Mode (§4/OQ4).
+               Wrapped so they cluster on the right rather than spreading across the SpaceBetween row. *@
+            <div class="dd-detail-top-actions">
+                <TheaterModeToggle />
+                @* Lava-lamp icon → popover panel (full parity, §3d-revised). Sits top-right across from the
+                   back link, clear of the header's own Play/Share affordances below. *@
+                <WaveformVisualizerControlPopover />
+            </div>
        </TopRightAction>
        <Header>
+            @* Theater Mode (Phase 20 §4): the release content is removed from the render — not
+               CSS-hidden — so the visualizer fills the surface. OFF restores it byte-for-byte. *@
+            @if (!VisualizerControlState.TheaterMode)
+            {
            @* Header split: meta + Play/Share on the LEFT, bordered cover on the RIGHT (spec §3.1). *@
            <div class="cut-detail-header">
                <div class="cut-detail-meta">
@@ -117,8 +127,11 @@ else
                    }
                </div>
            </div>
+            }
        </Header>
        <BodyContent>
+            @if (!VisualizerControlState.TheaterMode)
+            {
            @* Blurb sits between the header and the track-list divider. *@
            <ReleaseDescription Description="@release.Description" />
            <MudDivider Class="cut-detail-divider" />
@@ -149,6 +162,7 @@ else
                    }
                </div>
            }
+            }
        </BodyContent>
    </ReleaseDetailScaffold>
 }
@@ -1,4 +1,5 @@
 using DeepDrftModels.DTOs;
+using DeepDrftPublic.Client.Services;
 using DeepDrftPublic.Client.ViewModels;
 using Microsoft.AspNetCore.Components;

@@ -19,6 +20,10 @@ public abstract class CutDetailBase : ComponentBase, IDisposable
    [Inject] public required CutDetailViewModel ViewModel { get; set; }
    [Inject] public required PersistentComponentState PersistentState { get; set; }

+    // Theater Mode (Phase 20). The page owns the @if (!VisualizerControlState.TheaterMode) content gate,
+    // so it must re-render when the flag flips on the toggle. Property-injected; no constructor growth.
+    [Inject] public required WaveformVisualizerControlState VisualizerControlState { get; set; }
+
    private PersistingComponentStateSubscription _persistingSubscription;

    // The release EntryKey the ViewModel currently holds — tracks param-only navigations (e.g.
@@ -28,7 +33,12 @@ public abstract class CutDetailBase : ComponentBase, IDisposable
    private bool _loaded;

    protected override void OnInitialized()
-        => _persistingSubscription = PersistentState.RegisterOnPersisting(Persist);
+    {
+        _persistingSubscription = PersistentState.RegisterOnPersisting(Persist);
+        VisualizerControlState.Changed += OnVisualizerStateChanged;
+    }
+
+    private void OnVisualizerStateChanged() => InvokeAsync(StateHasChanged);

    protected override async Task OnParametersSetAsync()
    {
@@ -61,7 +71,11 @@ public abstract class CutDetailBase : ComponentBase, IDisposable
        return Task.CompletedTask;
    }

-    public void Dispose() => _persistingSubscription.Dispose();
+    public void Dispose()
+    {
+        _persistingSubscription.Dispose();
+        VisualizerControlState.Changed -= OnVisualizerStateChanged;
+    }

    // JSON-serializable bridge payload. Round-trips through PersistentComponentState's serializer.
    protected sealed record BridgedCut(ReleaseDto Release, IReadOnlyList<TrackDto> Tracks);
@@ -56,13 +56,23 @@ else
                               ShowMeta="false"
                               ShowShareRow="false">
            <TopRightAction>
-                @* Lava-lamp icon → popover panel, top-right across from the back link (Phase 12
-                   §3d-revised). Replaces the former inline TopContent knob-bar: the icon IS the toggle
-                   and the popover IS the panel. Mix takes the cleanest anchor case (§8e) — the popover's
-                   default bottom-right anchor opens down over the full-bleed field. *@
-                <WaveformVisualizerControlPopover />
+                @* Theater toggle sits immediately LEFT of the lava-lamp popover (Phase 20 §3). Both stay
+                   visible in Theater Mode — controls over the experience, not release content (§4/OQ4).
+                   Wrapped so they cluster on the right rather than spreading across the SpaceBetween row. *@
+                <div class="dd-detail-top-actions">
+                    <TheaterModeToggle />
+                    @* Lava-lamp icon → popover panel, top-right across from the back link (Phase 12
+                       §3d-revised). Replaces the former inline TopContent knob-bar: the icon IS the toggle
+                       and the popover IS the panel. Mix takes the cleanest anchor case (§8e) — the popover's
+                       default bottom-right anchor opens down over the full-bleed field. *@
+                    <WaveformVisualizerControlPopover />
+                </div>
            </TopRightAction>
            <Hero>
+                @* Theater Mode (Phase 20 §4): the hero overlay (Session/Mix release content) is removed
+                   from the render so the full-bleed visualizer fills the surface. OFF restores it. *@
+                @if (!VisualizerControlState.TheaterMode)
+                {
                @* Cover-as-background hero with all metadata overlaid, square `mix-hero` sizing. The
                   cover art IS the background, so no separate cover thumbnail (CoverThumbKey defaults
                   to null). Share and play ride in as slots, matching Sessions. *@
@@ -86,10 +96,14 @@ else
                        }
                    </PlayContent>
                </ReleaseHeroOverlay>
+                }
            </Hero>
            <BodyContent>
-                @* Blurb sits below the hero, inside the scaffold's foreground stacking context. *@
-                <ReleaseDescription Description="@release.Description" />
+                @if (!VisualizerControlState.TheaterMode)
+                {
+                    @* Blurb sits below the hero, inside the scaffold's foreground stacking context. *@
+                    <ReleaseDescription Description="@release.Description" />
+                }
            </BodyContent>
        </ReleaseDetailScaffold>
      </MudContainer>
@@ -1,4 +1,5 @@
 using DeepDrftModels.DTOs;
+using DeepDrftPublic.Client.Services;
 using DeepDrftPublic.Client.ViewModels;
 using Microsoft.AspNetCore.Components;

@@ -17,6 +18,10 @@ public abstract class ReleaseDetailBase : ComponentBase, IDisposable
    [Inject] public required ReleaseDetailViewModel ViewModel { get; set; }
    [Inject] public required PersistentComponentState PersistentState { get; set; }

+    // Theater Mode (Phase 20). The page owns the @if (!VisualizerControlState.TheaterMode) content gate,
+    // so it must re-render when the flag flips on the toggle. Property-injected; no constructor growth.
+    [Inject] public required WaveformVisualizerControlState VisualizerControlState { get; set; }
+
    private PersistingComponentStateSubscription _persistingSubscription;

    // The release EntryKey the ViewModel currently holds. Tracks param-only navigations (e.g.
@@ -30,7 +35,12 @@ public abstract class ReleaseDetailBase : ComponentBase, IDisposable
    protected abstract string PersistKey { get; }

    protected override void OnInitialized()
-        => _persistingSubscription = PersistentState.RegisterOnPersisting(Persist);
+    {
+        _persistingSubscription = PersistentState.RegisterOnPersisting(Persist);
+        VisualizerControlState.Changed += OnVisualizerStateChanged;
+    }
+
+    private void OnVisualizerStateChanged() => InvokeAsync(StateHasChanged);

    protected override async Task OnParametersSetAsync()
    {
@@ -69,7 +79,11 @@ public abstract class ReleaseDetailBase : ComponentBase, IDisposable
        return Task.CompletedTask;
    }

-    public void Dispose() => _persistingSubscription.Dispose();
+    public void Dispose()
+    {
+        _persistingSubscription.Dispose();
+        VisualizerControlState.Changed -= OnVisualizerStateChanged;
+    }

    // JSON-serializable bridge payload. Round-trips through PersistentComponentState's serializer.
    protected sealed record BridgedDetail(ReleaseDto Release, TrackDto? Track);
@@ -56,11 +56,21 @@ else
                &larr; All sessions
            </MudLink>

-            @* Lava-lamp icon → popover panel (full parity, §3e/§3d-revised). Anchored top-right, clear of
-               the hero overlay and the share/play affordances overlaid on the hero below. *@
-            <WaveformVisualizerControlPopover />
+            @* Theater toggle sits immediately LEFT of the lava-lamp popover (Phase 20 §3). The whole top
+               row (back + theater + lava) stays in Theater Mode — controls, not release content (§4/OQ4). *@
+            <div class="dd-detail-top-actions">
+                <TheaterModeToggle />
+                @* Lava-lamp icon → popover panel (full parity, §3e/§3d-revised). Anchored top-right, clear of
+                   the hero overlay and the share/play affordances overlaid on the hero below. *@
+                <WaveformVisualizerControlPopover />
+            </div>
        </div>

+        @* Theater Mode (Phase 20 §4): the hero overlay + blurb (the session's release content) are removed
+           from the render so the ambient visualizer fills the surface. The top row above stays. OFF
+           restores this region byte-for-byte. *@
+        @if (!VisualizerControlState.TheaterMode)
+        {
        @* The overlay shows the cover thumbnail only when it differs from the resolved hero image —
           when there is no dedicated hero, heroImage already falls back to release.ImagePath, so the
           thumb would duplicate the background. That logic lives in ReleaseHeroOverlay. *@
@@ -86,6 +96,7 @@ else
        </ReleaseHeroOverlay>

        <ReleaseDescription Description="@release.Description" />
+        }

    </MudContainer>
 }
@@ -97,6 +97,13 @@ public sealed class WaveformVisualizerControlState
    /// </summary>
    public const bool DefaultWaveformEnabled = true;

+    /// <summary>
+    /// Default Theater-mode state. <c>false</c> so a fresh page load opens with the full release page,
+    /// not the bare visualizer (Phase 20 §4/OQ5). Has no TS-side anchor: Theater Mode is a page-chrome
+    /// presentation flag, not a visualizer dial — the bridge never reads it.
+    /// </summary>
+    public const bool DefaultTheaterMode = false;
+
    /// <summary>Apparent bottom-to-top scroll rate, normalized [0,1]. Bridge maps it to a visible
    /// time-span via <see cref="WaveformZoomMapping"/>; the standalone resolution/zoom control is gone.</summary>
    public double ScrollSpeed { get; set; } = DefaultScrollSpeed;
@@ -137,12 +144,35 @@ public sealed class WaveformVisualizerControlState
    /// </summary>
    public bool WaveformEnabled { get; set; } = DefaultWaveformEnabled;

+    /// <summary>
+    /// Whether Theater Mode is on (Phase 20). When <c>true</c> the three release-detail pages remove
+    /// their release content via <c>@if</c> so the visualizer fills the surface, and the player bar
+    /// grows to carry the playing release's identity. Distinct from the visualizer dials: the bridge
+    /// ignores it — the pages and the player bar observe it through the same <see cref="Changed"/> seam.
+    /// Gated for visibility on <see cref="LavaEnabled"/> || <see cref="WaveformEnabled"/> at the toggle.
+    /// </summary>
+    public bool TheaterMode { get; set; } = DefaultTheaterMode;
+
    /// <summary>
    /// Raised whenever any control value changes. The visualizer bridge subscribes to push the
-    /// affected dial(s). Mutators set the property then raise this; subscribers re-read the values.
+    /// affected dial(s); the Theater-Mode observers (detail pages, player bar) subscribe to react to
+    /// <see cref="TheaterMode"/>. Mutators set the property then raise this; subscribers re-read the values.
    /// </summary>
    public event Action? Changed;

+    /// <summary>
+    /// Enforces the Theater-Mode invariant: Theater Mode cannot remain on when both visualizer
+    /// subsystems are off (there is nothing to go to theater FOR). Call this after mutating
+    /// <see cref="LavaEnabled"/> or <see cref="WaveformEnabled"/> and before
+    /// <see cref="NotifyChanged"/> so all observers see a consistent, coerced state in the same
+    /// <see cref="Changed"/> cycle.
+    /// </summary>
+    public void CoerceTheaterMode()
+    {
+        if (TheaterMode && !LavaEnabled && !WaveformEnabled)
+            TheaterMode = false;
+    }
+
    /// <summary>Raise <see cref="Changed"/>. Called by the controls component after mutating a value.</summary>
    public void NotifyChanged() => Changed?.Invoke();
 }
@@ -351,6 +351,15 @@ h2, h3, h4, h5, h6,
    gap: 0.5rem;
 }

+/* Theater toggle + lava-lamp popover cluster on the detail-page top action row (Phase 20 §3). Keeps
+   the two icon affordances adjacent on the right edge rather than letting the SpaceBetween row spread
+   them apart. Shared by Cut/Mix (scaffold TopRightAction) and Session (its own top row). */
+.dd-detail-top-actions {
+    display: flex;
+    align-items: center;
+    gap: 0.25rem;
+}
+
 .deepdrft-track-detail-meta {
    display: flex;
    flex-direction: row;
@@ -0,0 +1,91 @@
+using DeepDrftPublic.Client.Services;
+
+namespace DeepDrftTests;
+
+/// <summary>
+/// Unit tests for the Theater-Mode auto-exit invariant on <see cref="WaveformVisualizerControlState"/>
+/// (Phase 20 bug fix): when both subsystems are disabled, <see cref="WaveformVisualizerControlState.CoerceTheaterMode"/>
+/// must force <c>TheaterMode = false</c> so observers never see a stranded-theater state.
+/// </summary>
+[TestFixture]
+public class WaveformVisualizerControlStateTests
+{
+    private WaveformVisualizerControlState _state = null!;
+
+    [SetUp]
+    public void SetUp() => _state = new WaveformVisualizerControlState();
+
+    // ── CoerceTheaterMode guard ──
+
+    // Both off + Theater on → coerce exits theater.
+    [Test]
+    public void CoerceTheaterMode_BothOff_TheaterBecomesFalse()
+    {
+        _state.TheaterMode = true;
+        _state.LavaEnabled = false;
+        _state.WaveformEnabled = false;
+
+        _state.CoerceTheaterMode();
+
+        Assert.That(_state.TheaterMode, Is.False);
+    }
+
+    // Lava still on → theater is left alone even if waveform is off.
+    [Test]
+    public void CoerceTheaterMode_LavaOnWaveformOff_TheaterPreserved()
+    {
+        _state.TheaterMode = true;
+        _state.LavaEnabled = true;
+        _state.WaveformEnabled = false;
+
+        _state.CoerceTheaterMode();
+
+        Assert.That(_state.TheaterMode, Is.True);
+    }
+
+    // Waveform still on → theater is left alone even if lava is off.
+    [Test]
+    public void CoerceTheaterMode_WaveformOnLavaOff_TheaterPreserved()
+    {
+        _state.TheaterMode = true;
+        _state.LavaEnabled = false;
+        _state.WaveformEnabled = true;
+
+        _state.CoerceTheaterMode();
+
+        Assert.That(_state.TheaterMode, Is.True);
+    }
+
+    // Theater already false + both off → no change (no false-positive write).
+    [Test]
+    public void CoerceTheaterMode_TheaterAlreadyFalse_NoChange()
+    {
+        _state.TheaterMode = false;
+        _state.LavaEnabled = false;
+        _state.WaveformEnabled = false;
+
+        _state.CoerceTheaterMode();
+
+        Assert.That(_state.TheaterMode, Is.False);
+    }
+
+    // ── Changed event fires once with coerced state visible ──
+
+    // Verify that after coercion, the Changed notification carries the already-corrected TheaterMode
+    // value — all observers see a consistent state in the single Changed cycle.
+    [Test]
+    public void NotifyChanged_AfterCoerce_ObserverSeesTheaterFalse()
+    {
+        _state.TheaterMode = true;
+        _state.LavaEnabled = false;
+        _state.WaveformEnabled = false;
+
+        bool? observedTheaterMode = null;
+        _state.Changed += () => observedTheaterMode = _state.TheaterMode;
+
+        _state.CoerceTheaterMode();
+        _state.NotifyChanged();
+
+        Assert.That(observedTheaterMode, Is.False);
+    }
+}