using AcDream.App.UI;

namespace AcDream.App.Tests.UI;

/// <summary>
/// Campaign CH slice CH6c: <see cref="RetailWindowOpacityController"/> — the live
/// per-window opacity mechanism ported from <c>ChatInterface::SetOpacity/
/// SetDefaultOpacity/SetActiveOpacity</c> (<c>0x004F3120</c>/<c>0x004F3BC0</c>/
/// <c>0x004F3C40</c>), extended to every <see cref="RetailWindowManager"/>-registered
/// window rather than retail's ChatInterface-only scope (register row AP-190).
/// </summary>
public sealed class RetailWindowOpacityControllerTests
{
    private static UiRoot NewRoot() => new() { Width = 800f, Height = 600f };

    /// <summary>Registers a bare window ("outer frame" + one focusable child) and
    /// returns both — mirrors how a real window has a content descendant the
    /// chat entry / any input field could take focus on.</summary>
    private static (RetailWindowHandle handle, UiElement child) RegisterWindow(UiRoot root, string name)
    {
        var frame = new UiPanel { Width = 100f, Height = 100f };
        var child = new UiPanel { Width = 10f, Height = 10f, AcceptsFocus = true };
        frame.AddChild(child);
        root.AddChild(frame);
        RetailWindowHandle handle = root.WindowManager.Register(name, frame);
        return (handle, child);
    }

    [Fact]
    public void Construction_AttachesToAlreadyRegisteredWindows_AtDefaultOpacity()
    {
        UiRoot root = NewRoot();
        (RetailWindowHandle handle, _) = RegisterWindow(root, "Vitals");

        var controller = new RetailWindowOpacityController(
            root.WindowManager, defaultOpacity: 0.5f, activeOpacity: 1.0f);

        // No descendant has focus yet — every window starts at the DEFAULT
        // (unfocused) opacity, matching retail's unfocused ChatInterface state.
        Assert.Equal(0.5f, handle.Opacity);
        Assert.Equal(0.5f, controller.DefaultOpacity);
        Assert.Equal(1.0f, controller.ActiveOpacity);
    }

    [Fact]
    public void WindowRegisteredAfterConstruction_PicksUpLiveOpacityImmediately()
    {
        UiRoot root = NewRoot();
        var controller = new RetailWindowOpacityController(
            root.WindowManager, defaultOpacity: 0.3f, activeOpacity: 0.9f);

        // The window is mounted AFTER the controller exists — proves the
        // RetailWindowManager.WindowRegistered subscription (not just the ctor's
        // catch-up loop over already-registered windows) is what applies retail's
        // GLOBAL opacity scope to every future Mount* call too.
        (RetailWindowHandle handle, _) = RegisterWindow(root, "Toolbar");

        Assert.Equal(0.3f, handle.Opacity);
    }

    [Fact]
    public void FocusEnteringAWindow_SwitchesToActiveOpacity_LeavingSwitchesBack()
    {
        UiRoot root = NewRoot();
        (RetailWindowHandle handle, UiElement child) = RegisterWindow(root, "Chat");
        var controller = new RetailWindowOpacityController(
            root.WindowManager, defaultOpacity: 0.5f, activeOpacity: 1.0f);
        Assert.Equal(0.5f, handle.Opacity);

        root.SetKeyboardFocus(child);
        Assert.Equal(1.0f, handle.Opacity);

        root.SetKeyboardFocus(null);
        Assert.Equal(0.5f, handle.Opacity);
        GC.KeepAlive(controller);
    }

    [Fact]
    public void OpacityFade_AppliesToEveryRegisteredWindow_NotJustChat()
    {
        // The CH6c scope extension: retail's ChatInterface::SetOpacity only ever
        // runs on chat-derived windows. acdream applies the SAME mechanism to
        // every RetailWindowManager window — vitals, toolbar, whatever else is
        // mounted — matching the task's GLOBAL-option framing.
        UiRoot root = NewRoot();
        (RetailWindowHandle vitals, _) = RegisterWindow(root, "Vitals");
        (RetailWindowHandle toolbar, UiElement toolbarChild) = RegisterWindow(root, "Toolbar");
        var controller = new RetailWindowOpacityController(
            root.WindowManager, defaultOpacity: 0.4f, activeOpacity: 1.0f);

        Assert.Equal(0.4f, vitals.Opacity);
        Assert.Equal(0.4f, toolbar.Opacity);

        root.SetKeyboardFocus(toolbarChild);

        Assert.Equal(0.4f, vitals.Opacity);   // unrelated window: still unfocused
        Assert.Equal(1.0f, toolbar.Opacity);  // the focused one: active
    }

    [Fact]
    public void SetDefaultOpacity_AboveCurrentActive_DragsActiveUp_AndReappliesEverywhere()
    {
        // Decomp-verified linking (ChatInterface::SetDefaultOpacity @0x004F3BC0):
        // raising DEFAULT above the current ACTIVE value drags active UP to
        // match — it never clamps the default down instead.
        UiRoot root = NewRoot();
        (RetailWindowHandle unfocused, _) = RegisterWindow(root, "A");
        (RetailWindowHandle focused, UiElement focusedChild) = RegisterWindow(root, "B");
        var controller = new RetailWindowOpacityController(
            root.WindowManager, defaultOpacity: 0.3f, activeOpacity: 0.5f);
        root.SetKeyboardFocus(focusedChild);
        Assert.Equal(0.3f, unfocused.Opacity);
        Assert.Equal(0.5f, focused.Opacity);

        controller.SetDefaultOpacity(0.9f);

        Assert.Equal(0.9f, controller.DefaultOpacity);
        Assert.Equal(0.9f, controller.ActiveOpacity);
        Assert.Equal(0.9f, unfocused.Opacity);
        Assert.Equal(0.9f, focused.Opacity);
    }

    [Fact]
    public void SetActiveOpacity_BelowCurrentDefault_DragsDefaultDown_AndReappliesEverywhere()
    {
        // Symmetric case (ChatInterface::SetActiveOpacity @0x004F3C40).
        UiRoot root = NewRoot();
        (RetailWindowHandle unfocused, _) = RegisterWindow(root, "A");
        (RetailWindowHandle focused, UiElement focusedChild) = RegisterWindow(root, "B");
        var controller = new RetailWindowOpacityController(
            root.WindowManager, defaultOpacity: 0.5f, activeOpacity: 0.7f);
        root.SetKeyboardFocus(focusedChild);

        controller.SetActiveOpacity(0.1f);

        Assert.Equal(0.1f, controller.DefaultOpacity);
        Assert.Equal(0.1f, controller.ActiveOpacity);
        Assert.Equal(0.1f, unfocused.Opacity);
        Assert.Equal(0.1f, focused.Opacity);
    }

    [Fact]
    public void SetOpacity_AppliesBothInRetailsUpdateFromPlayerModuleOrder()
    {
        // UpdateFromPlayerModule (0x004CE3F0) reads/applies Default first, then
        // Active — the shape used to push a freshly loaded ChatSettings pair.
        UiRoot root = NewRoot();
        (RetailWindowHandle handle, _) = RegisterWindow(root, "Chat");
        var controller = new RetailWindowOpacityController(
            root.WindowManager, defaultOpacity: 0.5f, activeOpacity: 1.0f);

        controller.SetOpacity(defaultOpacity: 0.2f, activeOpacity: 0.6f);

        Assert.Equal(0.2f, controller.DefaultOpacity);
        Assert.Equal(0.6f, controller.ActiveOpacity);
        Assert.Equal(0.2f, handle.Opacity);
    }

    [Fact]
    public void ConstructorSeed_EnforcesTheActiveGreaterThanOrEqualDefaultInvariant()
    {
        // A corrupt/hand-edited settings.json could carry active < default.
        // The seed collapses through the SAME link the live setters use.
        UiRoot root = NewRoot();
        var controller = new RetailWindowOpacityController(
            root.WindowManager, defaultOpacity: 0.8f, activeOpacity: 0.2f);

        Assert.True(controller.ActiveOpacity >= controller.DefaultOpacity);
        Assert.Equal(0.2f, controller.DefaultOpacity);
        Assert.Equal(0.2f, controller.ActiveOpacity);
    }

    [Fact]
    public void Dispose_UnsubscribesFromFocusChanges()
    {
        UiRoot root = NewRoot();
        (RetailWindowHandle handle, UiElement child) = RegisterWindow(root, "Chat");
        var controller = new RetailWindowOpacityController(
            root.WindowManager, defaultOpacity: 0.5f, activeOpacity: 1.0f);

        controller.Dispose();
        root.SetKeyboardFocus(child);

        // Still at the last value the controller applied before disposal — a
        // focus change after Dispose is not observed anymore.
        Assert.Equal(0.5f, handle.Opacity);
    }

    [Fact]
    public void WindowUnregistered_DetachesSubscription_AndForgetsFocusedState()
    {
        // CH6c review NIT: before this fix, the only detach point for a
        // handle's DescendantFocusChanged subscription (and its membership in
        // _focused) was the CONTROLLER's own Dispose — a window unregistered
        // while it held focus stayed subscribed and pinned in _focused for
        // the rest of the session. Prove the RetailWindowManager.WindowUnregistered
        // wiring actually detaches: a stray post-unregister notification (the
        // kind a lingering external reference to the handle could still fire)
        // must not reach the controller anymore.
        UiRoot root = NewRoot();
        (RetailWindowHandle handle, UiElement child) = RegisterWindow(root, "Chat");
        var controller = new RetailWindowOpacityController(
            root.WindowManager, defaultOpacity: 0.5f, activeOpacity: 1.0f);

        root.SetKeyboardFocus(child);
        Assert.Equal(1.0f, handle.Opacity);

        root.WindowManager.Unregister("Chat");

        // Unregister hides the outer frame, which drops keyboard focus off
        // the now-invisible child — the manager's (still-live at that point)
        // focus-change plumbing reapplies DefaultOpacity naturally. Expected
        // either way; not itself the thing this test pins.
        Assert.Equal(0.5f, handle.Opacity);

        controller.SetActiveOpacity(0.7f);

        // A stray post-unregister focus-gain notification (the kind a
        // lingering external reference to the handle could still fire). If
        // the controller were STILL subscribed, this would re-add the stale
        // handle to _focused and apply the NEW active opacity (0.7).
        handle.NotifyDescendantFocusChanged(child);

        Assert.Equal(0.5f, handle.Opacity);
    }

    [Fact]
    public void SetMutators_AfterDispose_AreNoOps()
    {
        UiRoot root = NewRoot();
        (RetailWindowHandle handle, _) = RegisterWindow(root, "Chat");
        var controller = new RetailWindowOpacityController(
            root.WindowManager, defaultOpacity: 0.5f, activeOpacity: 1.0f);

        controller.Dispose();
        controller.SetDefaultOpacity(0.9f);
        controller.SetActiveOpacity(0.9f);
        controller.SetOpacity(0.2f, 0.3f);

        // None of the three post-Dispose calls changed anything — no
        // ObjectDisposedException either, matching Dispose's own idempotent
        // shape.
        Assert.Equal(0.5f, controller.DefaultOpacity);
        Assert.Equal(1.0f, controller.ActiveOpacity);
        Assert.Equal(0.5f, handle.Opacity);
    }
}