using System;
using Sandbox;
using Sandbox.UI;

namespace Goo.Internal;

internal sealed class StatefulShapePanel : Panel, IStatefulEventHost
{
    internal Action<MousePanelEvent>? _onClick;
    internal Action<MousePanelEvent>? _onMouseEnter;
    internal Action<MousePanelEvent>? _onMouseLeave;
    internal Action<MousePanelEvent>? _onMouseDown;
    internal Action<MousePanelEvent>? _onMouseUp;
    internal Action<MousePanelEvent>? _onMouseMove;
    internal bool    _userSetPointerEvents;
    internal Action? _requestRebuild;
    public Action? RequestRebuild { set => _requestRebuild = value; }

    public void ApplyEvents(in BlobEvents events)
    {
        _onClick      = events.OnClick;
        _onMouseEnter = events.OnMouseEnter;
        _onMouseLeave = events.OnMouseLeave;
        _onMouseDown  = events.OnMouseDown;
        _onMouseUp    = events.OnMouseUp;
        _onMouseMove  = events.OnMouseMove;
    }

    public bool HasEventHandlers =>
        _onClick != null || _onMouseEnter != null || _onMouseLeave != null ||
        _onMouseDown != null || _onMouseUp != null || _onMouseMove != null;

    public bool UserSetPointerEvents
    {
        get => _userSetPointerEvents;
        set => _userSetPointerEvents = value;
    }

    // Apply a baked alpha texture as BackgroundImage. The shape color comes from
    // BackgroundColor flowing through the engine's BgTint multiplier; this method
    // is only responsible for the alpha mask.
    public void ApplyShape(BlobKind kind, in ShapeParams shape)
    {
        Style.BackgroundImage = ShapeTextureCache.GetOrBake(kind, in shape);
        Style.BackgroundSizeX = Length.Percent(100);
        Style.BackgroundSizeY = Length.Percent(100);
    }

    public void ApplyPolygon(Vector2[] points)
    {
        Style.BackgroundImage = ShapeTextureCache.GetOrBakePolygon(points);
        Style.BackgroundSizeX = Length.Percent(100);
        Style.BackgroundSizeY = Length.Percent(100);
    }

    protected override void OnClick(MousePanelEvent e)       { base.OnClick(e);       EventDispatch.Fire(_onClick, e, _requestRebuild); }
    protected override void OnRightClick(MousePanelEvent e)  { base.OnRightClick(e);  EventDispatch.Fire(_onClick, e, _requestRebuild); }
    protected override void OnMiddleClick(MousePanelEvent e) { base.OnMiddleClick(e); EventDispatch.Fire(_onClick, e, _requestRebuild); }
    protected override void OnMouseOver(MousePanelEvent e)   { base.OnMouseOver(e);   EventDispatch.Fire(_onMouseEnter, e, _requestRebuild); }
    protected override void OnMouseOut(MousePanelEvent e)    { base.OnMouseOut(e);    EventDispatch.Fire(_onMouseLeave, e, _requestRebuild); }
    protected override void OnMouseDown(MousePanelEvent e)   { base.OnMouseDown(e);   EventDispatch.Fire(_onMouseDown, e, _requestRebuild); }
    protected override void OnMouseUp(MousePanelEvent e)     { base.OnMouseUp(e);     EventDispatch.Fire(_onMouseUp, e, _requestRebuild); }
    protected override void OnMouseMove(MousePanelEvent e)   { base.OnMouseMove(e);   EventDispatch.Fire(_onMouseMove, e, _requestRebuild); }
}