using AcDream.UI.Abstractions.Panels.Settings;

namespace AcDream.UI.Abstractions.Tests.Panels.Settings;

/// <summary>
/// Campaign CH slice CH6c: pins <see cref="ChatOpacityLink"/>'s port of retail's
/// linked default/active opacity invariant (<c>ChatInterface::SetDefaultOpacity
/// @0x004F3BC0</c> / <c>SetActiveOpacity @0x004F3C40</c>) — active &gt;= default,
/// ALWAYS, enforced by dragging the OTHER value rather than clamping the one
/// being set.
/// </summary>
public sealed class ChatOpacityLinkTests
{
    [Fact]
    public void SetDefault_BelowCurrentActive_LeavesActiveUnchanged()
    {
        // The ordinary case: lowering the background opacity while it's already
        // below the active value doesn't need to touch active at all.
        var (def, active) = ChatOpacityLink.SetDefault(currentActive: 1.0f, newDefault: 0.3f);
        Assert.Equal(0.3f, def);
        Assert.Equal(1.0f, active);
    }

    [Fact]
    public void SetDefault_AboveCurrentActive_DragsActiveUp_DoesNotClampDefault()
    {
        // The decomp-verified answer to "does raising default above active drag
        // active up, or clamp default?": ChatInterface::SetDefaultOpacity always
        // WRITES this->m_fDefaultOpacity = arg2 first, THEN calls SetActiveOpacity
        // when active < default. Default is never clamped down.
        var (def, active) = ChatOpacityLink.SetDefault(currentActive: 0.4f, newDefault: 0.9f);
        Assert.Equal(0.9f, def);
        Assert.Equal(0.9f, active);
    }

    [Fact]
    public void SetActive_AboveCurrentDefault_LeavesDefaultUnchanged()
    {
        var (def, active) = ChatOpacityLink.SetActive(currentDefault: 0.2f, newActive: 0.9f);
        Assert.Equal(0.2f, def);
        Assert.Equal(0.9f, active);
    }

    [Fact]
    public void SetActive_BelowCurrentDefault_DragsDefaultDown()
    {
        // Symmetric case: ChatInterface::SetActiveOpacity writes m_fActiveOpacity
        // first, then calls SetDefaultOpacity when default > active.
        var (def, active) = ChatOpacityLink.SetActive(currentDefault: 0.7f, newActive: 0.3f);
        Assert.Equal(0.3f, def);
        Assert.Equal(0.3f, active);
    }

    [Theory]
    [InlineData(-1f, 0f)]
    [InlineData(2f, 1f)]
    public void SetDefault_ClampsInputToUnitRange(float rawInput, float expectedDefault)
    {
        var (def, _) = ChatOpacityLink.SetDefault(currentActive: 1f, newDefault: rawInput);
        Assert.Equal(expectedDefault, def);
    }

    [Theory]
    [InlineData(-1f, 0f)]
    [InlineData(2f, 1f)]
    public void SetActive_ClampsInputToUnitRange(float rawInput, float expectedActive)
    {
        var (_, active) = ChatOpacityLink.SetActive(currentDefault: 0f, newActive: rawInput);
        Assert.Equal(expectedActive, active);
    }

    [Fact]
    public void SetDefault_ThenSetActive_NeverProducesActiveBelowDefault()
    {
        // A short sequence exercising the invariant through several moves, the
        // way a user dragging both sliders back and forth would.
        (float def, float active) = (0.5f, 1.0f);
        (def, active) = ChatOpacityLink.SetDefault(active, 0.9f);
        Assert.True(active >= def);
        (def, active) = ChatOpacityLink.SetActive(def, 0.1f);
        Assert.True(active >= def);
        (def, active) = ChatOpacityLink.SetDefault(active, 0.6f);
        Assert.True(active >= def);
        Assert.Equal(0.6f, def);
        Assert.Equal(0.6f, active);
    }
}