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

namespace Kreta.Core
{
    public sealed class KretaVersion
    {
        private KretaVersion()
        {
        }

        private static readonly Lazy<VersionInfo> VersionInfo = new Lazy<VersionInfo>(GetVersionInfo);

        public static VersionInfo Instance => VersionInfo.Value;

        private static VersionInfo GetVersionInfo()
        {
            var assembly = Assembly.GetExecutingAssembly();

            string assemblyLocation = assembly.Location;

            DateTime assemblyCreationDateTime = File.GetCreationTime(assemblyLocation);
            var result = new VersionInfo
            {
                AssemblyCreationDateTime = assemblyCreationDateTime
            };

            FileVersionInfo fileVersionInfo = FileVersionInfo.GetVersionInfo(assemblyLocation);

            string mainVersion = fileVersionInfo.FileVersion;
            if (!string.IsNullOrWhiteSpace(mainVersion))
            {
                result.MainVersion = mainVersion;
            }

            int fileMajorPart = fileVersionInfo.FileMajorPart;
            int fileMinorPart = fileVersionInfo.FileMinorPart;
            if (fileMajorPart > 0 && fileMinorPart >= 0)
            {
                result.ShortMainVersion = $"{fileMajorPart}.{fileMinorPart}";
            }

            List<AssemblyMetadataAttribute> customAttributes = assembly.GetCustomAttributes().OfType<AssemblyMetadataAttribute>().ToList();

            string branchName = customAttributes.SingleOrDefault(x => x.Key == Constants.Version.BranchName)?.Value;
            if (!string.IsNullOrWhiteSpace(branchName))
            {
                result.BranchName = branchName;
            }

            string commitNumber = customAttributes.SingleOrDefault(x => x.Key == Constants.Version.CommitNumber)?.Value;
            if (!string.IsNullOrWhiteSpace(commitNumber))
            {
                result.CommitNumber = commitNumber;
            }

            return result;
        }
    }
}