using SWRIS.Enums;
using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Globalization;
using System.Windows.Data;
using System.Windows.Media;

namespace SWRIS.Converters
{
    public class RiskLevelToColorConverter : IValueConverter
    {
        // 预定义颜色（非冻结的Color结构，轻量）
        private static readonly Color NormalColor = Color.FromRgb(0x00, 0xFF, 0x78);
        private static readonly Color MildColor = Color.FromRgb(0x00, 0xFF, 0x78);
        private static readonly Color LightColor = Color.FromRgb(0xFF, 0xF0, 0x00);
        private static readonly Color ModerateColor = Color.FromRgb(0xFF, 0x94, 0x00);
        private static readonly Color SevereColor = Color.FromRgb(0xFF, 0x6C, 0x00);
        private static readonly Color CriticalColor = Color.FromRgb(0xFF, 0x00, 0x00);
        private static readonly Color ExceededLimitColor = Color.FromRgb(0xFF, 0x00, 0x8A);

        // 映射枚举到颜色
        private static readonly Dictionary<RiskLevel, Color> ColorMap = new Dictionary<RiskLevel, Color>
        {
            { RiskLevel.Normal, NormalColor },
            { RiskLevel.Mild, MildColor },
            { RiskLevel.Light, LightColor },
            { RiskLevel.Moderate, ModerateColor },
            { RiskLevel.Severe, SevereColor },
            { RiskLevel.Critical, CriticalColor },
            { RiskLevel.ExceededLimit, ExceededLimitColor }
        };

        // 缓存：键为 "risk_opacity"，值为冻结的SolidColorBrush
        private static readonly ConcurrentDictionary<string, SolidColorBrush> _brushCache = new ConcurrentDictionary<string, SolidColorBrush>();

        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
            if (value is RiskLevel risk)
            {
                double opacity = 1.0;
                if (parameter != null)
                {
                    // 尝试解析，若失败则使用默认1.0
                    double.TryParse(parameter.ToString(), NumberStyles.Any, CultureInfo.InvariantCulture, out opacity);
                }

                // 构建缓存键
                string cacheKey = $"{risk}_{opacity:F2}"; // 保留两位小数避免浮点数精度问题
                // 如果缓存中存在，直接返回
                if (_brushCache.TryGetValue(cacheKey, out var cachedBrush))
                {
                    return cachedBrush;
                }

                // 获取颜色
                if (!ColorMap.TryGetValue(risk, out var color))
                {
                    color = NormalColor; // 默认
                }

                // 创建新画笔并设置透明度
                var brush = new SolidColorBrush(color);
                brush.Opacity = opacity;
                brush.Freeze(); // 冻结以便跨线程使用

                // 缓存
                _brushCache[cacheKey] = brush;
                return brush;
            }

            return Brushes.Transparent;
        }

        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
        {
            throw new NotImplementedException();
        }
    }
}