using System;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.Events;
using UnityEngine.EventSystems;
using UnityEngine.UI;

[RequireComponent(typeof(RectTransform))]
public class SelectableButton : MonoBehaviour, IPointerClickHandler, IPointerEnterHandler, IPointerExitHandler
{
    public enum Colors 
    {
        NormalColor,
        HighlightedColor,
        PressedColor,
        SelectedColor,
        DisabledColor
    }

    [SerializeField] private List<GraphicNode> graphics;
    [SerializeField] private bool selectedOnStart;
    [SerializeField, ReadOnly] private bool isSelected;
    [SerializeField] private UnityEvent onSelect;
    [SerializeField] private UnityEvent onDeselect;

    private GameObject parent => transform.parent.gameObject;
    [SerializeField] private bool interactable = true;

    public UnityEvent OnSelect => onSelect;
    public UnityEvent OnDeselect => onDeselect;
    public bool IsSelected => isSelected;
    private void Awake()
    {
        foreach (GraphicNode graphic in graphics)
        {
            graphic.targetGraphic.gameObject.SetActive(true);
        }

        if (selectedOnStart)
        {
            isSelected = true;
        }
        else
        {
            CrossFadeColor(Colors.NormalColor, true);
        }
    }

    private void OnEnable()
    {
        if (isSelected) CrossFadeColor(Colors.SelectedColor, true);
    }

    public void OnPointerClick(PointerEventData eventData)
    {
        Select();
    }

    private void CrossFadeColor(Colors colors, bool instant)
    {
        foreach (GraphicNode graphic in graphics)
        {
            Color color = colors switch
            {
                Colors.NormalColor => graphic.colors.normalColor,
                Colors.HighlightedColor => graphic.colors.highlightedColor,
                Colors.PressedColor => graphic.colors.pressedColor,
                Colors.SelectedColor => graphic.colors.selectedColor,
                Colors.DisabledColor => graphic.colors.disabledColor,
                _ => graphic.colors.normalColor,
            };

            graphic.targetGraphic.CrossFadeColor(color, instant ? 0f : graphic.colors.fadeDuration, true, true);
        }
    }

    public void Select(bool instant = false)
    {
        if (isSelected || !interactable) return;
        isSelected = true;
        CrossFadeColor(Colors.SelectedColor, instant);

        foreach (SelectableButton button in parent.GetComponentsInChildren<SelectableButton>())
        {
            if(button != this && button.isSelected)
            {
                button.Deselect();
            }
        }
        onSelect?.Invoke();
    }

    public void InvokeSelectEvent()
    {
        if (isSelected) onSelect?.Invoke();
    }

    public void Deselect(bool instant = false)
    {
        isSelected = false;
        CrossFadeColor(Colors.NormalColor, instant);
        onDeselect?.Invoke();
    }

    public void SetIteractable(bool value)
    {
        interactable = value;

        if (interactable)
        {
            CrossFadeColor(isSelected ? Colors.SelectedColor : Colors.NormalColor, true);
        }
        else
        {
            CrossFadeColor(Colors.DisabledColor, true);
        }
    }

    public void OnPointerEnter(PointerEventData eventData)
    {
        if (isSelected || !interactable) return;

        CrossFadeColor(Colors.HighlightedColor, false);
    }

    public void OnPointerExit(PointerEventData eventData)
    {
        if (isSelected || !interactable) return;

        CrossFadeColor(Colors.NormalColor, false);
    }

}