using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using DiscImageChef.CommonTypes.Structs;

namespace DiscImageChef.Filesystems.ISO9660
{
    public partial class ISO9660
    {
        public Errno MapBlock(string path, long fileBlock, out long deviceBlock)
        {
            deviceBlock = 0;
            if(!mounted) return Errno.AccessDenied;

            Errno err = GetFileEntry(path, out DecodedDirectoryEntry entry);
            if(err != Errno.NoError) return err;

            if(entry.Flags.HasFlag(FileFlags.Directory) && !debug) return Errno.IsDirectory;

            deviceBlock = entry.Extent + fileBlock;

            return Errno.NoError;
        }

        public Errno GetAttributes(string path, out FileAttributes attributes)
        {
            attributes = new FileAttributes();
            if(!mounted) return Errno.AccessDenied;

            Errno err = Stat(path, out FileEntryInfo stat);

            if(err != Errno.NoError) return err;

            attributes = stat.Attributes;

            return Errno.NoError;
        }

        public Errno Read(string path, long offset, long size, ref byte[] buf) => throw new NotImplementedException();

        public Errno Stat(string path, out FileEntryInfo stat)
        {
            stat = null;
            if(!mounted) return Errno.AccessDenied;

            Errno err = GetFileEntry(path, out DecodedDirectoryEntry entry);
            if(err != Errno.NoError) return err;

            stat = new FileEntryInfo
            {
                Attributes       = new FileAttributes(),
                Blocks           = entry.Size / 2048, // TODO: XA
                BlockSize        = 2048,
                Length           = entry.Size,
                Inode            = entry.Extent,
                Links            = 1,
                LastWriteTimeUtc = entry.Timestamp
            };

            if(entry.Size % 2048 > 0) stat.Blocks++;

            if(entry.Flags.HasFlag(FileFlags.Directory)) stat.Attributes |= FileAttributes.Directory;
            if(entry.Flags.HasFlag(FileFlags.Hidden)) stat.Attributes    |= FileAttributes.Hidden;

            return Errno.NoError;
        }

        Errno GetFileEntry(string path, out DecodedDirectoryEntry entry)
        {
            entry = null;

            string cutPath = path.StartsWith("/")
                                 ? path.Substring(1).ToLower(CultureInfo.CurrentUICulture)
                                 : path.ToLower(CultureInfo.CurrentUICulture);
            string[] pieces = cutPath.Split(new[] {'/'}, StringSplitOptions.RemoveEmptyEntries);

            if(pieces.Length == 0) return Errno.InvalidArgument;

            string parentPath = string.Join("/", pieces, 0, pieces.Length - 1);

            if(!directoryCache.TryGetValue(parentPath, out _))
            {
                Errno err = ReadDir(parentPath, out _);

                if(err != Errno.NoError) return err;
            }

            Dictionary<string, DecodedDirectoryEntry> parent;

            if(pieces.Length == 1) parent = rootDirectoryCache;
            else if(!directoryCache.TryGetValue(parentPath, out parent)) return Errno.InvalidArgument;

            KeyValuePair<string, DecodedDirectoryEntry> dirent =
                parent.FirstOrDefault(t => t.Key.ToLower(CultureInfo.CurrentUICulture) == pieces[pieces.Length - 1]);

            if(string.IsNullOrEmpty(dirent.Key)) return Errno.NoSuchFile;

            entry = dirent.Value;
            return Errno.NoError;
        }
    }
}