using System;
using Godot;

namespace TBL.GodotSharp.Ui.AutoAdaption
{
    /// <summary>
    /// 自动自适应控制器
    /// <para>控制所有的 <see cref="AutoAdaptionUiRoot"/></para>
    /// </summary>
    public class AutoAdaptionController : Node
    {
        /// <summary>
        /// 设计 Ui 尺寸
        /// </summary>
        [Export] public Vector2 DesignSize;

        /// <summary>
        /// 自动缩放 Ui 开关
        /// </summary>
        [Export] private bool _autoScaleUi;

        /// <summary>
        /// 世界视图缩放值
        /// </summary>
        private int _worldViewScale = 1;

        /// <summary>
        /// 自动 Ui 缩放值
        /// </summary>
        private float _autoScaleShrink = 1.0f;

        /// <summary>
        /// 是否启用自动 Ui 调节
        /// </summary>
        public bool AutoScaleUi
        {
            get => _autoScaleUi;
            set
            {
                _autoScaleUi = value;
                var winSize = OS.WindowSize;
                var minSize = DesignSize;
                if (winSize.x < winSize.y)
                {
                    minSize.y = minSize.x;
                }
                else
                {
                    minSize.x = minSize.y;
                }

                if (_autoScaleUi)
                {
                    var d = 1;
                    if (winSize.x < winSize.y) d = 0;
                    _autoScaleShrink = Mathf.Max(1.0f, Mathf.Floor(winSize[d] / minSize[d]));
                }
                else
                {
                    _autoScaleShrink = 1.0f;
                }

                GetTree().SetScreenStretch(SceneTree.StretchMode.Disabled, SceneTree.StretchAspect.Expand, minSize);
                AutoAdaptionUiRoot.AdaptionShrink = _autoScaleShrink;

                if (_autoScaleUi)
                {
                    WorldViewScale = Mathf.RoundToInt(_autoScaleShrink);
                }
                else
                {
                    WorldViewScale = 1;
                }
            }
        }

        /// <summary>
        /// 世界视图缩放率
        /// </summary>
        public int WorldViewScale
        {
            get => Mathf.Max(1, _worldViewScale);
            set
            {
                _worldViewScale = value;
                // TODO: 世界视图
                // WorldViewContainer.WorldViewShrink = WorldViewScale;
            }
        }

        /// <summary>
        /// 自动 Ui 缩放率
        /// </summary>
        public float AutoScaleShrink => _autoScaleShrink;

        /// <summary>
        /// 屏幕尺寸变化事件
        /// </summary>
        protected void _OnScreenResized()
        {
            AutoScaleUi = _autoScaleUi;
            WorldViewScale = _worldViewScale;
        }

        #region Node

        public override async void _EnterTree()
        {
            var tree = GetTree();
            if (DesignSize == Vector2.Zero)
                DesignSize = new Vector2(
                    Convert.ToSingle(ProjectSettings.GetSetting("display/window/size/width")),
                    Convert.ToSingle(ProjectSettings.GetSetting("display/window/size/height"))
                );
            AutoScaleUi = _autoScaleUi;
            WorldViewScale = _worldViewScale;
            Name = nameof(AutoAdaptionController);
            tree.Connect("screen_resized", this, nameof(_OnScreenResized));
            await ToSignal(tree, "idle_frame");
            tree.EmitSignal("screen_resized");
        }

        public override void _ExitTree()
        {
            AutoScaleUi = _autoScaleUi;
            WorldViewScale = _worldViewScale;
        }

        #endregion

        /// <summary>
        /// 设置控件为填满设计尺寸
        /// </summary>
        public void SetFullParentDesignSize(Control target)
        {
            target.AnchorLeft = target.AnchorTop = 0.5f;
            target.AnchorRight = target.AnchorBottom = 0.5f;
            target.MarginLeft = DesignSize.x * -0.5f;
            target.MarginRight = DesignSize.x * 0.5f;
            target.MarginTop = DesignSize.x * -0.5f;
            target.MarginBottom = DesignSize.x * 0.5f;
        }
    }
}