using System;
using System.Linq;
using System.Runtime.InteropServices;
using System.Threading.Tasks;
using RomRepoMgr.Database;

namespace RomRepoMgr.Core.Filesystem
{
    public class Vfs : IDisposable
    {
        Fuse   _fuse;
        Winfsp _winfsp;

        public static bool IsAvailable => Winfsp.IsAvailable || Fuse.IsAvailable;

        public void Dispose() => _fuse?.Dispose();

        public event EventHandler<System.EventArgs> Umounted;

        public void MountTo(string mountPoint)
        {
            if(Fuse.IsAvailable)
            {
                _fuse = new Fuse(this)
                {
                    MountPoint = mountPoint
                };

                Task.Run(() =>
                {
                    _fuse.Start();

                    Umounted?.Invoke(this, System.EventArgs.Empty);
                });
            }
            else if(Winfsp.IsAvailable)
            {
                _winfsp = new Winfsp(this);
                bool ret = _winfsp.Mount(mountPoint);

                if(ret)
                    return;

                _winfsp = null;
                Umounted?.Invoke(this, System.EventArgs.Empty);
            }
            else
                Umounted?.Invoke(this, System.EventArgs.Empty);
        }

        public void Umount()
        {
            _fuse?.Umount();
            _fuse = null;
            _winfsp?.Umount();
            _winfsp = null;

            Umounted?.Invoke(this, System.EventArgs.Empty);
        }

        internal void GetInfo(out ulong files, out ulong totalSize)
        {
            using var ctx = Context.Create(Settings.Settings.Current.DatabasePath);

            totalSize = (ulong)ctx.Files.Where(f => f.IsInRepo).Sum(f => (double)f.Size);
            files     = (ulong)ctx.Files.Count(f => f.IsInRepo);
        }

        internal string[] SplitPath(string path) =>
            path.Split(RuntimeInformation.IsOSPlatform(OSPlatform.Windows) ? "\\" : "/",
                       StringSplitOptions.RemoveEmptyEntries);
    }
}