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("string")]
    public string en_combo = "COMBO";
    [Tooltip("COMBO 标签字形高度(像素)。宽度按各字母 sprite 宽高比自动计算。")]
    public int en_combo_fontSize = 20;
    public Color en_combo_color = Color.white;
    public float en_combo_yOffset= 0f;

    [Header("COMBO letter sprites")]
    [Tooltip("字母 C 的 sprite")]
    public Sprite letterC_sprite;
    [Tooltip("字母 O 的 sprite")]
    public Sprite letterO_sprite;
    [Tooltip("字母 M 的 sprite")]
    public Sprite letterM_sprite;
    [Tooltip("字母 B 的 sprite")]
    public Sprite letterB_sprite;

    [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;
    [Tooltip("Keep all visible glyphs at the configured height. Width is recalculated from each sprite aspect ratio.")]
    public bool forceUniformHeight = 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;

    // 数字上方用 sprite 拼接的 "COMBO" 标签所用的 glyph 池。
    private readonly List<Image> comboLabelImages = new List<Image>();

    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);

        // 编辑器中改动 combo 标签相关字段时,已生成的字母 glyph 实时更新(不新建,避免编辑期实例化)。
        if (comboLabelImages.Count > 0 && isActiveAndEnabled)
        {
            RefreshComboLabel();
        }
    }

    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, sprite);

            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;
        }

        RefreshComboLabel();
    }

    // 用字母 sprite(C/O/M/B)在数字上方拼接 "COMBO" 标签。字形高度、颜色、Y 偏移由 Inspector 字段控制。
    private void RefreshComboLabel()
    {
        string label = en_combo ?? string.Empty;

        // 计算总宽度并按需扩容 glyph 池。
        float height = Mathf.Max(1f, en_combo_fontSize);
        float totalWidth = 0f;
        int visibleCount = 0;
        for (int i = 0; i < label.Length; i++)
        {
            Sprite s = ResolveComboLetterSprite(label[i]);
            if (s == null) continue;
            totalWidth += ComboLetterWidth(s, height);
            visibleCount++;
        }
        if (visibleCount > 1) totalWidth += spacing * (visibleCount - 1);

        EnsureComboImageCount(label.Length);

        float x = centerAlign ? -totalWidth * 0.5f : 0f;
        for (int i = 0; i < comboLabelImages.Count; i++)
        {
            Image image = comboLabelImages[i];
            if (image == null) continue;

            Sprite sprite = i < label.Length ? ResolveComboLetterSprite(label[i]) : null;
            if (sprite == null)
            {
                image.gameObject.SetActive(false);
                continue;
            }

            float w = ComboLetterWidth(sprite, height);
            RectTransform rect = image.rectTransform;
            image.gameObject.SetActive(true);
            image.sprite = sprite;
            image.color = en_combo_color;
            image.preserveAspect = preserveAspect;
            ApplyCharacterSortingOrder(image);
            rect.sizeDelta = new Vector2(w, height);
            rect.anchorMin = new Vector2(0.5f, 0.5f);
            rect.anchorMax = new Vector2(0.5f, 0.5f);
            rect.pivot = new Vector2(0.5f, 0.5f);

            // 上方定位：数字 glyph 以 y=0 居中、高约 digitSize.y,标签放其上半高 + 半个字形高 + 偏移处。
            float baseY = digitSize.y * 0.5f + height * 0.5f;
            rect.anchoredPosition = new Vector2(x + w * 0.5f, baseY + en_combo_yOffset);

            x += w + spacing;
        }
    }

    private void EnsureComboImageCount(int count)
    {
        while (comboLabelImages.Count < count)
        {
            GameObject glyph = new GameObject("combo_letter_" + comboLabelImages.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;
            comboLabelImages.Add(image);
        }
    }

    private Sprite ResolveComboLetterSprite(char c)
    {
        switch (c)
        {
            case 'C': case 'c': return letterC_sprite;
            case 'O': case 'o': return letterO_sprite;
            case 'M': case 'm': return letterM_sprite;
            case 'B': case 'b': return letterB_sprite;
            default: return null;
        }
    }

    private float ComboLetterWidth(Sprite sprite, float height)
    {
        if (sprite == null || sprite.rect.height <= 0f) return height;
        float aspect = sprite.rect.width / sprite.rect.height;
        return height * aspect;
    }

    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], ResolveSprite(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, Sprite sprite)
    {
        Vector2 baseSize = digitSize;
        if (c == '.') baseSize = decimalPointSize;
        else if (c == '%') baseSize = percentSize;

        if (!forceUniformHeight || sprite == null || sprite.rect.height <= 0f)
        {
            return baseSize;
        }

        float height = Mathf.Max(0f, baseSize.y);
        float aspect = sprite.rect.width / sprite.rect.height;
        return new Vector2(height * aspect, height);
    }
}