using System;
using TMPro;
using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.UI;

namespace Cryville.Crtr.Config.UI {
	public abstract class PVPNumberBase : PropertyValuePanel {
		[SerializeField]
		GameObject m_slider;
		[SerializeField]
		RectTransform m_handleArea;
		[SerializeField]
		Image m_handle;
		[SerializeField]
		TMP_InputField m_text;
		[SerializeField]
		Button m_textActivationButton;
		protected void Start() {
			m_slider.AddComponent<SliderBehaviour>().parent = this;

			m_text.interactable = SetMapped;
			m_text.onValueChanged.AddListener(OnTextEdited);
			m_text.onDeselect.AddListener(OnTextDeselected);

			m_textActivationButton.interactable = SetMapped;

			OnIdle();
		}

		void OnTextEdited(string value) {
			if (!m_text.isFocused) return;
			if (double.TryParse(value, out var result)) {
				try { MappedValue = result; }
				catch (Exception) { }
			}
		}
		void OnTextDeselected(string value) {
			OnValueUpdated();
			m_text.enabled = false;
		}

		protected override void OnValueUpdated() {
			if (Range != null && Range.Length == 2) {
				var min = (double)Range[0];
				var max = (double)Range[1];
				var value = Convert.ToDouble(RawValue);
				if (value < min) {
					value = min;
					RawValue = value;
				}
				else if (value > max) {
					value = max;
					RawValue = value;
				}
			}
			if (!m_text.isFocused) {
				m_text.text = MappedValue.ToString();
			}
		}

		protected virtual void OnIdle() { }

		class SliderBehaviour : UIBehaviour, IInitializePotentialDragHandler, IDragHandler, IEndDragHandler, IPointerClickHandler {
			public PVPNumberBase parent;

			Camera cam;
			Vector2 pp;
			bool use, nouse;

			void Update() {
				if (use) {
					parent.SetRatio(GetRatioFromPos(pp));
					SetValueFromPos(pp);
				}
			}

			public void OnInitializePotentialDrag(PointerEventData eventData) {
				// eventData.useDragThreshold = false;
				pp = eventData.position;
			}

			public void OnDrag(PointerEventData eventData) {
				if (nouse) return;
				cam = eventData.pressEventCamera;
				if (!use) {
					var delta = eventData.position - pp;
					float dx = Mathf.Abs(delta.x), dy = Mathf.Abs(delta.y);
					if (dx > dy) use = true;
					else if (dx < dy) nouse = true;
				}
				if (use) {
					pp = eventData.position;
					eventData.Use();
				}
			}

			public void OnEndDrag(PointerEventData eventData) {
				if (!nouse) {
					SetValueFromPos(eventData.position);
					parent.OnIdle();
					eventData.Use();
					use = false;
				}
				nouse = false;
			}

			public void OnPointerClick(PointerEventData eventData) {
				SetValueFromPos(eventData.position);
				eventData.Use();
			}

			float GetRatioFromPos(Vector2 pos) {
				RectTransform handleArea = parent.m_handleArea;
				if (RectTransformUtility.ScreenPointToLocalPointInRectangle(handleArea, pos, cam, out Vector2 lp)) {
					lp -= handleArea.rect.position;
					return Mathf.Clamp01(lp.x / handleArea.rect.width);
				}
				return float.NegativeInfinity;
			}

			void SetValueFromPos(Vector2 pos) {
				parent.GetRange(out double min, out double max);
				double ratio = GetRatioFromPos(pos);
				double result = parent.GetValue(ratio, Time.deltaTime, min, max);
				if (result < min) result = min;
				else if (result > max) result = max;
				parent.RawValue = result;
			}
		}

		void GetRange(out double min, out double max) {
			min = double.NegativeInfinity;
			max = double.PositiveInfinity;
			if (Range != null && Range.Length == 2) {
				min = (double)Range[0];
				max = (double)Range[1];
			}
		}

		protected void SetRatio(float ratio) {
			RectTransform handle = m_handle.rectTransform;
			handle.anchorMin = new Vector2(ratio, handle.anchorMin.y);
			handle.anchorMax = new Vector2(ratio, handle.anchorMax.y);
			handle.anchoredPosition = Vector2.zero;
		}

		protected abstract double GetValue(double ratio, float deltaTime, double min, double max);
	}
}