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

[DisallowMultipleComponent]
public class SpriteNumberDisplay : MonoBehaviour
{
    [Header("Sprites")]
    public Sprite[] digitSprites = new Sprite[10];
    public Sprite decimalPointSprite;
    public Sprite percentSprite;
    public Sprite plusSprite;
    public Sprite minusSprite;

    [Header("Layout")]
    public Vector2 digitSize = new Vector2(28f, 42f);
    public Vector2 decimalPointSize = new Vector2(12f, 42f);
    public Vector2 percentSize = new Vector2(28f, 42f);
    public float spacing = 2f;
    public bool centerAlign = true;
    public bool preserveAspect = true;
    public Color color = Color.white;
    [Tooltip("Canvas sorting order used by generated character sprites.")]
    public int characterSortingOrder = 0;

    private readonly List<Image> glyphImages = new List<Image>();
    private string currentText = string.Empty;

    private void OnEnable()
    {
        Refresh();
    }

    private void OnValidate()
    {
        digitSize.x = Mathf.Max(0f, digitSize.x);
        digitSize.y = Mathf.Max(0f, digitSize.y);
        decimalPointSize.x = Mathf.Max(0f, decimalPointSize.x);
        decimalPointSize.y = Mathf.Max(0f, decimalPointSize.y);
        percentSize.x = Mathf.Max(0f, percentSize.x);
        percentSize.y = Mathf.Max(0f, percentSize.y);
    }

    public void SetNumber(int value)
    {
        SetText(value.ToString());
    }

    public void SetText(string value)
    {
        string next = value ?? string.Empty;
        if (currentText == next && glyphImages.Count > 0)
        {
            return;
        }

        currentText = next;
        Refresh();
    }

    public void Clear()
    {
        SetText(string.Empty);
    }

    private void Refresh()
    {
        EnsureImageCount(currentText.Length);

        float totalWidth = CalculateTotalWidth(currentText);
        float x = centerAlign ? -totalWidth * 0.5f : 0f;

        for (int i = 0; i < glyphImages.Count; i++)
        {
            Image image = glyphImages[i];
            if (image == null) continue;

            if (i >= currentText.Length)
            {
                image.gameObject.SetActive(false);
                continue;
            }

            char c = currentText[i];
            Sprite sprite = ResolveSprite(c);
            Vector2 size = ResolveSize(c);

            if (sprite == null)
            {
                image.gameObject.SetActive(false);
                continue;
            }

            RectTransform rect = image.rectTransform;
            image.gameObject.SetActive(true);
            image.sprite = sprite;
            image.color = color;
            image.preserveAspect = preserveAspect;
            ApplyCharacterSortingOrder(image);
            rect.sizeDelta = size;
            rect.anchorMin = new Vector2(0.5f, 0.5f);
            rect.anchorMax = new Vector2(0.5f, 0.5f);
            rect.pivot = new Vector2(0.5f, 0.5f);
            rect.anchoredPosition = new Vector2(x + size.x * 0.5f, 0f);

            x += size.x + spacing;
        }
    }

    private void ApplyCharacterSortingOrder(Image image)
    {
        if (image == null)
        {
            return;
        }

        Canvas canvas = image.GetComponent<Canvas>();
        if (canvas == null)
        {
            canvas = image.gameObject.AddComponent<Canvas>();
        }

        canvas.overrideSorting = true;
        canvas.sortingOrder = characterSortingOrder;
    }

    private void EnsureImageCount(int count)
    {
        while (glyphImages.Count < count)
        {
            GameObject glyph = new GameObject("digit_" + glyphImages.Count, typeof(RectTransform), typeof(Canvas), typeof(Image));
            RectTransform rect = glyph.transform as RectTransform;
            rect.SetParent(transform, false);

            Image image = glyph.GetComponent<Image>();
            image.raycastTarget = false;
            glyphImages.Add(image);
        }
    }

    private float CalculateTotalWidth(string text)
    {
        if (string.IsNullOrEmpty(text))
        {
            return 0f;
        }

        float total = 0f;
        int visibleCount = 0;
        for (int i = 0; i < text.Length; i++)
        {
            if (ResolveSprite(text[i]) == null)
            {
                continue;
            }

            total += ResolveSize(text[i]).x;
            visibleCount++;
        }

        if (visibleCount > 1)
        {
            total += spacing * (visibleCount - 1);
        }

        return total;
    }

    private Sprite ResolveSprite(char c)
    {
        if (c >= '0' && c <= '9')
        {
            int index = c - '0';
            return digitSprites != null && index < digitSprites.Length ? digitSprites[index] : null;
        }

        if (c == '.') return decimalPointSprite;
        if (c == '%') return percentSprite;
        if (c == '+') return plusSprite;
        if (c == '-') return minusSprite;
        return null;
    }

    private Vector2 ResolveSize(char c)
    {
        if (c == '.') return decimalPointSize;
        if (c == '%') return percentSize;
        return digitSize;
    }
}