using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;

namespace JSMachine.DCS.Infrastructure
{
    /// <summary>
    /// 基础参数守卫工具，在进入业务流程前校验空值、路径和条件状态。
    /// </summary>
    public static class Guards
    {
        /// <summary>当任意参数为空时抛出参数异常。</summary>
        /// <param name="parameters">待检查的参数集合。</param>
        public static void ThrowIfNull(params object[] parameters)
        {
            if (parameters.Any(item => item == null))
                throw new ArgumentNullException();
        }

        /// <summary>当任意字符串为空或空字符串时抛出参数异常。</summary>
        /// <param name="strings">待检查的字符串集合。</param>
        public static void ThrowIfNullOrEmpty(params string[] strings)
        {
            if (strings.Any(string.IsNullOrEmpty))
                throw new ArgumentNullException();
        }

        /// <summary>检查字符串序列及其中的每一项是否为空。</summary>
        /// <param name="strings">待检查的字符串序列。</param>
        public static void ThrowIfNullOrEmpty(IEnumerable<string> strings)
        {
            ThrowIfNull(strings);
            ThrowIfNullOrEmpty(strings.ToArray());
        }

        /// <summary>当指定文件不存在时抛出文件未找到异常。</summary>
        /// <param name="path">文件路径。</param>
        public static void ThrowIfFileNotFound(string path)
        {
            if (!File.Exists(path))
                throw new FileNotFoundException("Can not found the specified file path. ", path);
        }

        /// <summary>当指定目录不存在时抛出目录未找到异常。</summary>
        /// <param name="path">目录路径。</param>
        public static void ThrowIfFolderNotFount(string path)
        {
            if (!Directory.Exists(path))
                throw new DirectoryNotFoundException($"Can not found the specified path {path}. ");
        }

        /// <summary>当路径既不是文件也不是目录时抛出目录异常。</summary>
        /// <param name="path">待检查的路径。</param>
        public static void ThrowIfInvalidPath(string path)
        {
            if (!File.Exists(path) && !Directory.Exists(path))
                throw new DirectoryNotFoundException($"The specified path is not a valid file or directory.  ({path})");
        }

        /// <summary>当条件不成立时抛出无效操作异常。</summary>
        /// <param name="condition">必须成立的条件。</param>
        public static void ThrowIfNot(bool condition)
        {
            if (!condition)
                throw new InvalidOperationException();
        }

        /// <summary>计算条件并在结果不成立时抛出无效操作异常。</summary>
        /// <param name="condition">返回校验结果的委托。</param>
        public static void ThrowIfNot(Func<bool> condition)
        {
            ThrowIfNull(condition);
            ThrowIfNot(condition());
        }
    }
}