using MediaBrowser.Controller.Library;
using MediaBrowser.Model.Logging;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;

namespace MediaBrowser.Controller.IO
{
    /// <summary>
    /// Provides low level File access that is much faster than the File/Directory api's
    /// </summary>
    public static class FileData
    {
        /// <summary>
        /// Gets the filtered file system entries.
        /// </summary>
        /// <param name="path">The path.</param>
        /// <param name="logger">The logger.</param>
        /// <param name="searchPattern">The search pattern.</param>
        /// <param name="flattenFolderDepth">The flatten folder depth.</param>
        /// <param name="resolveShortcuts">if set to <c>true</c> [resolve shortcuts].</param>
        /// <param name="args">The args.</param>
        /// <returns>Dictionary{System.StringFileSystemInfo}.</returns>
        /// <exception cref="System.ArgumentNullException">path</exception>
        public static Dictionary<string, FileSystemInfo> GetFilteredFileSystemEntries(string path, ILogger logger, string searchPattern = "*", int flattenFolderDepth = 0, bool resolveShortcuts = true, ItemResolveArgs args = null)
        {
            if (string.IsNullOrEmpty(path))
            {
                throw new ArgumentNullException("path");
            }

            var dict = new Dictionary<string, FileSystemInfo>(StringComparer.OrdinalIgnoreCase);
            
            var entries = new DirectoryInfo(path).EnumerateFileSystemInfos(searchPattern, SearchOption.TopDirectoryOnly)
                .Where(i => !i.Attributes.HasFlag(FileAttributes.System) && !i.Name.Equals(".") && !i.Name.Equals(".."));

            foreach (var entry in entries)
            {
                var isDirectory = entry.Attributes.HasFlag(FileAttributes.Directory);

                if (resolveShortcuts && FileSystem.IsShortcut(entry.FullName))
                {
                    var newPath = FileSystem.ResolveShortcut(entry.FullName);
                    if (string.IsNullOrWhiteSpace(newPath))
                    {
                        //invalid shortcut - could be old or target could just be unavailable
                        logger.Warn("Encountered invalid shortuct: " + entry.FullName);
                        continue;
                    }
                    var data = FileSystem.GetFileSystemInfo(newPath);

                    if (data.Exists)
                    {
                        // Find out if the shortcut is pointing to a directory or file
                        if (data.Attributes.HasFlag(FileAttributes.Directory))
                        {
                            // add to our physical locations
                            if (args != null)
                            {
                                args.AddAdditionalLocation(newPath);
                            }
                        }

                        dict[data.FullName] = data;
                    }
                }
                else if (flattenFolderDepth > 0 && isDirectory)
                {
                    foreach (var child in GetFilteredFileSystemEntries(entry.FullName, logger, flattenFolderDepth: flattenFolderDepth - 1, resolveShortcuts: resolveShortcuts))
                    {
                        dict[child.Key] = child.Value;
                    }
                }
                else
                {
                    dict[entry.FullName] = entry;
                }
            }

            return dict;
        }

    }

}