using System;
using System.IO;
using System.Text;
using System.Text.RegularExpressions;
using ln.build.semver;
using Microsoft.VisualBasic;

namespace ln.build.semver
{

    public class SemVersion
    {
        public int Major { get; set; }
        public int Minor { get; set; }
        public int Patch { get; set; }
        public string PreRelease { get; set; } = String.Empty;

        public bool IsPreRelease => !PreRelease?.Equals(string.Empty) ?? false;
        public bool IsRelease => PreRelease?.Equals(string.Empty) ?? true;

        public SemVersion(int major,int minor,int patch,string prerelease)
        {
            Major = major;
            Minor = minor;
            Patch = patch;
            PreRelease = prerelease;
        }
        private SemVersion(){}
        public SemVersion(SemVersion source)
        :this(source.Major, source.Minor, source.Patch, source.PreRelease)
        { }


        public void Increment(SemVerLevels level){
            switch (level)
            {
                case SemVerLevels.MAJOR:
                    Major++;
                    Minor = 0;
                    Patch = 0;
                    break;
                case SemVerLevels.MINOR:
                    Minor++;
                    Patch = 0;
                    break;
                case SemVerLevels.PATCH:
                    Patch++;
                    break;
            }
        }

        public override string ToString()
        {
            StringBuilder stringBuilder = new StringBuilder();
            stringBuilder.AppendFormat("{0}.{1}.{2}", Major, Minor, Patch);
            if (!PreRelease?.Equals(string.Empty) ?? false)
                stringBuilder.AppendFormat("-{0}", PreRelease);
            return stringBuilder.ToString();
        }


        public static Regex rexVersion = new Regex("^(?<major>\\d+).(?<minor>\\d+).(?<patch>\\d+)(-(?<prerelease>.+))?$");
        public static SemVersion Parse(string versionString)
        {
            Match match = rexVersion.Match(versionString);
            if (!match.Success)
                throw new FormatException(String.Format("{0} is no valid SemVer", versionString));
            
            SemVersion version = new SemVersion();
            version.Major = int.Parse(match.Groups["major"].Value);
            version.Minor = int.Parse(match.Groups["minor"].Value);
            version.Patch = int.Parse(match.Groups["patch"].Value);
            if (match.Groups["prerelease"].Success)
                version.PreRelease = match.Groups["prerelease"].Value;

            return version;
        }


    }

}