inabox/InABox.Database/VersionNumber.cs

using System.Diagnostics.CodeAnalysis;
using System.Text.RegularExpressions;

namespace InABox.Database;

public class VersionNumber : IComparable
{
    public int MajorVersion { get; }
    public int MinorVersion { get; }
    public string Release { get; }
    
    public bool IsDevelopmentVersion { get; }
    public bool IsNewStyle { get; private set; }

    public VersionNumber()
    {
        IsDevelopmentVersion = true;
        MajorVersion = 0;
        MinorVersion = 0;
        Release = "0";
        IsNewStyle = true;
    }
    
    public VersionNumber(int majorVersion, int minorVersion)
    {
        IsDevelopmentVersion = false;
        MajorVersion = majorVersion;
        MinorVersion = minorVersion;
        Release = "0";
        IsNewStyle = true;
    }
    
    public VersionNumber(int majorVersion, int minorVersion, int release)
    {
        IsDevelopmentVersion = false;
        MajorVersion = majorVersion;
        MinorVersion = minorVersion;
        Release = release.ToString();
        IsNewStyle = true;
    }

    public VersionNumber(int majorVersion, int minorVersion, string release)
    {
        IsDevelopmentVersion = false;
        MajorVersion = majorVersion;
        MinorVersion = minorVersion;
        Release = release;
        IsNewStyle = false;
    }

    private static readonly Regex _format =
        new Regex(
            @"^(?<major>\d+)\.(?<minor>\d+)(?:(?<oldstyle>[A-Za-z]+)|\.(?<newstyle>\d+))?$",
            RegexOptions.Compiled);

    
    public static VersionNumber Parse(string versionStr)
    {
        if (!TryParse(versionStr, out var _result))
            throw new FormatException($"'{versionStr}' is not a valid version!");
        return _result;
    }
    
    public static bool TryParse(string versionStr, [NotNullWhen(true)] out VersionNumber? version)
    {
        if (versionStr == "???")
        {
            version = new();
            return true;
        }
        var match = _format.Match(versionStr);
        if (!match.Success)
        {
            version = null;
            return false;
        }
        
        if (match.Groups["oldstyle"].Success)
        {
            version = new(int.Parse(match.Groups["major"].Value),
                int.Parse(match.Groups["minor"].Value),
                match.Groups["release"].Value
            );
        }
        
        if (match.Groups["newstyle"].Success)
        {
            version = new(int.Parse(match.Groups["major"].Value),
                int.Parse(match.Groups["minor"].Value),
                int.Parse(match.Groups["newstyle"].Value)
            );
        }
        version = new(int.Parse(match.Groups["major"].Value),
            int.Parse(match.Groups["minor"].Value),
            0
        );
        
        return true;
    }
    
    public int CompareTo(object? obj)
    {
        if (obj is not VersionNumber other)
            throw new ArgumentException($"Object must be of type {nameof(VersionNumber)}");
        var _result = this < other ? -1 : this == other ? 0 : 1;
        return _result;
    }

    public static bool operator <(VersionNumber a, VersionNumber b)
    {
        if (a.IsDevelopmentVersion) return false;
        if (b.IsDevelopmentVersion) return true;

        if (a.MajorVersion != b.MajorVersion)
            return a.MajorVersion <  b.MajorVersion;
        if (a.MinorVersion != b.MinorVersion)
            return a.MinorVersion <  b.MinorVersion;
        if (a.IsNewStyle && b.IsNewStyle)
            return int.Parse(a.Release) < int.Parse(b.Release);
        return String.Compare(a.Release,b.Release, StringComparison.OrdinalIgnoreCase) < 0;
    }
    public static bool operator >(VersionNumber a, VersionNumber b)
    {
        return b < a;
    }

    public static bool operator <=(VersionNumber a, VersionNumber b)
    {
        return !(b < a);
    }

    public static bool operator >=(VersionNumber a, VersionNumber b)
    {
        return !(a < b);
    }

    public override bool Equals(object? obj)
    {
        if(obj is VersionNumber v)
        {
            return this == v;
        }
        return false;
    }

    public override int GetHashCode()
    {
        if (IsDevelopmentVersion)
            return 0;
        return MajorVersion ^ MinorVersion ^ Release.GetHashCode();
    }

    public static bool operator ==(VersionNumber a, VersionNumber b)
    {
        if (a.IsDevelopmentVersion)
            return b.IsDevelopmentVersion;
        if (b.IsDevelopmentVersion)
            return false;
        return a.MajorVersion == b.MajorVersion 
               && a.MinorVersion == b.MinorVersion 
               && String.Compare(a.Release,b.Release, StringComparison.OrdinalIgnoreCase) == 0;
    }
    public static bool operator !=(VersionNumber a, VersionNumber b)
    {
        if (a.IsDevelopmentVersion)
            return !b.IsDevelopmentVersion;
        if (b.IsDevelopmentVersion)
            return true;
        return a.MajorVersion != b.MajorVersion
               || a.MinorVersion != b.MinorVersion
               || String.Compare(a.Release, b.Release, StringComparison.OrdinalIgnoreCase) != 0;
    }

    public override string ToString()
    {
        return IsDevelopmentVersion
            ? "???"
            : IsNewStyle
                ? !Release.Equals("0")
                    ? $"{MajorVersion}.{MinorVersion:D2}.{Release}"
                    : $"{MajorVersion}.{MinorVersion:D2}"
                : $"{MajorVersion}.{MinorVersion:D2}{Release}";
    }


}