using System;

using System.Text.RegularExpressions;

namespace FastGithub.Configuration

{

/// <summary>

/// 表示域名表达式

/// *表示除.之外任意0到多个字符

/// </summary>

public class DomainPattern : IComparable<DomainPattern>

{

private readonly Regex regex;

private readonly string domainPattern;

/// <summary>

/// 域名表达式

/// *表示除.之外任意0到多个字符

/// </summary>

/// <param name="domainPattern">域名表达式</param>

public DomainPattern(string domainPattern)

{

this.domainPattern = domainPattern;

var regexPattern = Regex.Escape(domainPattern).Replace(@"\*", @"[^\.]*");

this.regex = new Regex($"^{regexPattern}$", RegexOptions.IgnoreCase);

}

/// <summary>

/// 与目标比较

/// </summary>

/// <param name="other"></param>

/// <returns></returns>

public int CompareTo(DomainPattern? other)

{

if (other is null)

{

return 1;

}

var segmentsX = this.domainPattern.Split('.');

var segmentsY = other.domainPattern.Split('.');

var value = segmentsX.Length - segmentsY.Length;

if (value != 0)

{

return value;

}

for (var i = segmentsX.Length - 1; i >= 0; i--)

{

var x = segmentsX[i];

var y = segmentsY[i];

value = Compare(x, y);

if (value == 0)

{

continue;

}

return value;

}

return 0;

}

/// <summary>

/// 比较两个分段

/// </summary>

/// <param name="x">abc</param>

/// <param name="y">abc*</param>

/// <returns></returns>

private static int Compare(string x, string y)

{

var valueX = x.Replace('*', char.MaxValue);

var valueY = y.Replace('*', char.MaxValue);

return valueX.CompareTo(valueY);

}

/// <summary>

/// 是否与指定域名匹配

/// </summary>

/// <param name="domain"></param>

/// <returns></returns>

public bool IsMatch(string domain)

{

return this.regex.IsMatch(domain);

}

/// <summary>

/// 转换为文本

/// </summary>

/// <returns></returns>

public override string ToString()

{

return this.domainPattern;

}

}

}