using Cryville.Common;
using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.UI;

namespace Cryville.Crtr.Browsing.UI {
	[ExecuteAlways]
	internal class BrowserTabLayout : UIBehaviour, ILayoutElement {
		[SerializeField]
		float m_minWidth = 150;
		public float MinWidth {
			get { return m_minWidth; }
			set {
				if (m_minWidth == value) return;
				m_minWidth = value;
				UpdateTweener();
			}
		}

		float GetTargetLayoutMinWidth() {
			var width = MinWidth;
			if (Selected) {
				var preferredWidth = LayoutUtility.GetPreferredWidth(transform as RectTransform);
				if (preferredWidth > width) width = preferredWidth;
			}
			return width;
		}

		float m_layoutMinWidth = -1;
		float ILayoutElement.minWidth { get { return m_layoutMinWidth; } }
		void UpdateLayoutMinWidth(float value) {
			if (m_layoutMinWidth == value) return;
			m_layoutMinWidth = value;
			SetDirty();
		}

		public float preferredWidth { get { return -1; } }
		public float flexibleWidth { get { return -1; } }
		public float minHeight { get { return -1; } }
		public float preferredHeight { get { return -1; } }
		public float flexibleHeight { get { return -1; } }
		public int layoutPriority { get { return 1; } }

		bool m_selected;
		public bool Selected {
			get { return m_selected; }
			set {
				if (m_selected == value) return;
				m_selected = value;
				UpdateTweener();
			}
		}

		[SerializeField]
		float m_tweenDuration = 0.2f;

		float _lastWidth;
		bool _delayedUpdate;
		PropertyTweener<float> _tweener;
		void UpdateTweener() {
			var width = GetTargetLayoutMinWidth();
			_tweener.Start(width, m_tweenDuration);
			if (width != _lastWidth) {
				_lastWidth = width;
				_delayedUpdate = true;
			}
		}
		void Update() {
			if (_delayedUpdate) {
				_delayedUpdate = false;
				UpdateTweener();
			}
			_tweener.Advance(Time.deltaTime);
		}

		public void CalculateLayoutInputHorizontal() { }
		public void CalculateLayoutInputVertical() { }

		protected override void OnEnable() {
			base.OnEnable();
			m_layoutMinWidth = GetTargetLayoutMinWidth();
			_tweener ??= new PropertyTweener<float>(
					() => m_layoutMinWidth,
					v => UpdateLayoutMinWidth(v),
					Tweeners.Float.With(EasingFunctions.OutQuad)
				);
			SetDirty();
		}
		protected override void OnBeforeTransformParentChanged() {
			base.OnBeforeTransformParentChanged();
			SetDirty();
		}
		protected override void OnTransformParentChanged() {
			base.OnTransformParentChanged();
			SetDirty();
		}
		protected override void OnDidApplyAnimationProperties() {
			base.OnDidApplyAnimationProperties();
			SetDirty();
		}
#if UNITY_EDITOR
		protected override void OnValidate() {
			base.OnValidate();
			SetDirty();
		}
#endif
		protected override void OnDisable() {
			SetDirty();
			base.OnDisable();
		}
		void SetDirty() {
			if (!IsActive()) return;
			LayoutRebuilder.MarkLayoutForRebuild(transform as RectTransform);
		}
	}
}