/// <summary>
/// Base class for a high-level game mode (state) handled by
/// <see cref="GameModeManager"/>. A mode configures the relevant scene systems
/// when it becomes active (<see cref="Enter"/>), can clean up when it is left
/// (<see cref="Exit"/>) and may run per-frame logic in <see cref="Tick"/>.
///
/// Modes are plain C# classes (not MonoBehaviours). To add a new mode, derive
/// from this class and register an instance in GameModeManager.BuildModes().
/// </summary>
public abstract class GameMode
{
    /// <summary>The owning manager, providing access to the controlled systems.</summary>
    protected GameModeManager Manager { get; private set; }

    /// <summary>Human-readable name (shown in logs / debug UI).</summary>
    public abstract string DisplayName { get; }

    /// <summary>Wires the mode to its manager. Called once during registration.</summary>
    internal void Bind(GameModeManager manager) => Manager = manager;

    /// <summary>Called once when this mode becomes the active mode.</summary>
    public virtual void Enter() { }

    /// <summary>Called once when this mode stops being the active mode.</summary>
    public virtual void Exit() { }

    /// <summary>Called every frame while this mode is the active mode.</summary>
    public virtual void Tick() { }
}