using UnityEngine;
using UnityEngine.UI;

[ExecuteAlways]
[DisallowMultipleComponent]
[RequireComponent(typeof(Text))]
[RequireComponent(typeof(LayoutElement))]
public sealed class BubbleTextWidthLimiter : MonoBehaviour
{
    [Min(1f)]
    public float maxPreferredWidth = 224f;

    private Text textComponent;
    private LayoutElement layoutElement;
    private string lastText;
    private Font lastFont;
    private int lastFontSize;
    private FontStyle lastFontStyle;
    private float lastMaxPreferredWidth = -1f;

    private void Awake()
    {
        CacheComponents();
        Apply();
    }

    private void OnEnable()
    {
        CacheComponents();
        Apply();
    }

    private void OnValidate()
    {
        CacheComponents();
        Apply();
    }

    private void LateUpdate()
    {
        if (NeedsRefresh())
        {
            Apply();
        }
    }

    private void CacheComponents()
    {
        if (textComponent == null)
        {
            textComponent = GetComponent<Text>();
        }

        if (layoutElement == null)
        {
            layoutElement = GetComponent<LayoutElement>();
        }
    }

    private bool NeedsRefresh()
    {
        if (textComponent == null || layoutElement == null)
        {
            return false;
        }

        return lastText != textComponent.text
            || lastFont != textComponent.font
            || lastFontSize != textComponent.fontSize
            || lastFontStyle != textComponent.fontStyle
            || !Mathf.Approximately(lastMaxPreferredWidth, maxPreferredWidth);
    }

    private void Apply()
    {
        if (textComponent == null || layoutElement == null)
        {
            return;
        }

        textComponent.horizontalOverflow = HorizontalWrapMode.Wrap;
        textComponent.verticalOverflow = VerticalWrapMode.Overflow;

        var generationSettings = textComponent.GetGenerationSettings(new Vector2(10000f, 0f));
        var rawPreferredWidth = textComponent.cachedTextGeneratorForLayout.GetPreferredWidth(textComponent.text ?? string.Empty, generationSettings)
            / textComponent.pixelsPerUnit;

        layoutElement.minWidth = 0f;
        layoutElement.preferredWidth = Mathf.Min(rawPreferredWidth, Mathf.Max(1f, maxPreferredWidth));
        layoutElement.flexibleWidth = -1f;
        layoutElement.minHeight = -1f;
        layoutElement.preferredHeight = -1f;
        layoutElement.flexibleHeight = -1f;

        var rectTransform = transform as RectTransform;
        if (rectTransform != null)
        {
            LayoutRebuilder.MarkLayoutForRebuild(rectTransform);
            if (rectTransform.parent is RectTransform parentRect)
            {
                LayoutRebuilder.MarkLayoutForRebuild(parentRect);
            }
        }

        lastText = textComponent.text;
        lastFont = textComponent.font;
        lastFontSize = textComponent.fontSize;
        lastFontStyle = textComponent.fontStyle;
        lastMaxPreferredWidth = maxPreferredWidth;
    }
}