TBL.CSharp/Utilities/Random/Random.cs

using System;

namespace TBL.CSharp.Utilities.Random
{
    /// <summary>
    /// 随机数扩展工具类
    /// </summary>
    public static class Random
    {
        /// <summary>
        /// 生成非负随机数
        /// </summary>
        public static int Next(this IRandom random) => Math.Abs(Math.Max(random.NextRaw(), int.MinValue + 1));

        /// <summary>
        /// 生成随机数，并将结果取余到范围内
        /// </summary>
        /// <param name="random">随机数发生器</param>
        /// <param name="minValue">随机最小值(结果包含)</param>
        /// <param name="maxValue">随机最大值(结果不包含)</param>
        /// <returns>生成结果</returns>
        /// <exception cref="ArgumentOutOfRangeException">范围上下界不正确</exception>
        public static int Next(this IRandom random, int minValue, int maxValue)
        {
            if (minValue >= maxValue)
                throw new ArgumentOutOfRangeException(nameof(minValue),
                    $"{nameof(minValue)}({minValue}) >= {nameof(maxValue)}({maxValue})");
            return minValue + random.Next() % (maxValue - minValue);
        }

        /// <summary>
        /// 生成 <c>0</c> ~ <paramref name="maxValue"/> 内随机数
        /// </summary>
        /// <param name="random">随机数发生器</param>
        /// <param name="maxValue">随机最大值(结果不包含)</param>
        /// <returns>生成结果</returns>
        /// <exception cref="ArgumentOutOfRangeException">范围上下界不正确</exception>
        public static int Next(this IRandom random, int maxValue) => random.Next(0, maxValue);

        /// <summary>
        /// 进行概率取模检定
        /// </summary>
        /// <param name="random">随机数发生器</param>
        /// <param name="minValue">随机最小值(结果包含)</param>
        /// <param name="maxValue">随机最大值(结果不包含)</param>
        /// <param name="line">检定分界线</param>
        /// <returns>随机结果对 <paramref name="line"/> 的取模值</returns>
        public static int CheckModule(this IRandom random, int minValue, int maxValue, int line) =>
            random.Next(minValue, maxValue) % line;

        /// <summary>
        /// 以百分比进行概率取模检定
        /// </summary>
        /// <param name="random">随机数发生器</param>
        /// <param name="line">检定分界线</param>
        /// <returns>在范围 <c>0</c> ~ <c>100</c> 中生成的随机结果对 <paramref name="line"/> 的取模值</returns>
        public static int CheckModulePercent(this IRandom random, int line) =>
            random.CheckModule(0, 100, line);

        /// <summary>
        /// 进行概率检定
        /// </summary>
        /// <param name="random">随机数发生器</param>
        /// <param name="minValue">随机最小值(结果包含)</param>
        /// <param name="maxValue">随机最大值(结果不包含)</param>
        /// <param name="line">检定分界线</param>
        /// <returns>随机结果是否小于 <paramref name="line"/></returns>
        public static bool Check(this IRandom random, int minValue, int maxValue, int line) =>
            random.Next(minValue, maxValue) < line;

        /// <summary>
        /// 以百分比进行概率检定
        /// </summary>
        /// <param name="random">随机数发生器</param>
        /// <param name="line">检定分界百分比</param>
        /// <returns>在范围 <c>0</c> ~ <c>100</c> 中生成的随机结果是否小于 <paramref name="line"/></returns>
        public static bool CheckPercent(this IRandom random, int line) => random.Check(0, 100, line);
    }
}