#pragma warning disable CS1591

using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using MediaBrowser.Model.IO;

namespace MediaBrowser.Controller.Providers
{
    public class DirectoryService : IDirectoryService
    {
        // TODO make static and switch to FastConcurrentLru.
        private readonly ConcurrentDictionary<string, FileSystemMetadata[]> _cache = new(StringComparer.Ordinal);

        private readonly ConcurrentDictionary<string, FileSystemMetadata> _fileCache = new(StringComparer.Ordinal);

        private readonly ConcurrentDictionary<string, List<string>> _filePathCache = new(StringComparer.Ordinal);

        private readonly IFileSystem _fileSystem;

        public DirectoryService(IFileSystem fileSystem)
        {
            _fileSystem = fileSystem;
        }

        public FileSystemMetadata[] GetFileSystemEntries(string path)
        {
            return _cache.GetOrAdd(
                path,
                static (p, fileSystem) =>
                {
                    try
                    {
                        return fileSystem.GetFileSystemEntries(p).ToArray();
                    }
                    catch (DirectoryNotFoundException)
                    {
                        return [];
                    }
                },
                _fileSystem);
        }

        public List<FileSystemMetadata> GetDirectories(string path)
        {
            var list = new List<FileSystemMetadata>();
            var items = GetFileSystemEntries(path);
            for (var i = 0; i < items.Length; i++)
            {
                var item = items[i];
                if (item.IsDirectory)
                {
                    list.Add(item);
                }
            }

            return list;
        }

        public List<FileSystemMetadata> GetFiles(string path)
        {
            var list = new List<FileSystemMetadata>();
            var items = GetFileSystemEntries(path);
            for (var i = 0; i < items.Length; i++)
            {
                var item = items[i];
                if (!item.IsDirectory)
                {
                    list.Add(item);
                }
            }

            return list;
        }

        public FileSystemMetadata? GetFile(string path)
        {
            var entry = GetFileSystemEntry(path);
            return entry is not null && !entry.IsDirectory ? entry : null;
        }

        public FileSystemMetadata? GetDirectory(string path)
        {
            var entry = GetFileSystemEntry(path);
            return entry is not null && entry.IsDirectory ? entry : null;
        }

        public FileSystemMetadata? GetFileSystemEntry(string path)
        {
            if (!_fileCache.TryGetValue(path, out var result))
            {
                var file = _fileSystem.GetFileSystemInfo(path);
                if (file?.Exists ?? false)
                {
                    result = file;
                    _fileCache.TryAdd(path, result);
                }
            }

            return result;
        }

        public IReadOnlyList<string> GetFilePaths(string path)
            => GetFilePaths(path, false);

        public IReadOnlyList<string> GetFilePaths(string path, bool clearCache)
        {
            if (clearCache)
            {
                _filePathCache.TryRemove(path, out _);
            }

            var filePaths = _filePathCache.GetOrAdd(
                path,
                static (p, fileSystem) =>
                {
                    try
                    {
                        return fileSystem.GetFilePaths(p).OrderBy(x => x).ToList();
                    }
                    catch (DirectoryNotFoundException)
                    {
                        return [];
                    }
                },
                _fileSystem);

            return filePaths;
        }

        public bool IsAccessible(string path)
        {
            return _fileSystem.GetFileSystemEntryPaths(path).Any();
        }
    }
}
