namespace MrGameEng.Core;

/// <summary>Phase of a scene transition.</summary>
public enum TransitionPhase
{
    /// <summary>The old scene is being covered (coverage grows 0 → 1).</summary>
    Out,

    /// <summary>The new scene is being revealed (coverage shrinks 1 → 0).</summary>
    In,
}

/// <summary>
/// Timing of a visual transition between scenes. The scene switch itself happens at full
/// coverage, so a slow <c>OnLoad</c> of the next scene is hidden behind the overlay.
/// Progress is tracked by <see cref="SceneManager"/> on unscaled time, so transitions work
/// while gameplay is paused. The core only times the phases — how the overlay looks is
/// defined by the host (the MonoGame host's <c>OverlayTransition</c> and the
/// <c>Transitions</c> factories); headless hosts simply let transitions pass invisibly.
/// </summary>
public abstract class Transition
{
    /// <summary>Seconds the covering phase takes.</summary>
    public float OutDuration { get; }

    /// <summary>Seconds the revealing phase takes.</summary>
    public float InDuration { get; }

    /// <summary>Creates a transition with explicit phase durations.</summary>
    protected Transition(float outDuration, float inDuration)
    {
        OutDuration = Math.Max(0f, outDuration);
        InDuration = Math.Max(0f, inDuration);
    }
}