using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Threading.Tasks;
using Box.V2.Config;
using Box.V2.JWTAuth;

namespace BoxDownloadAllFiles {
    class Program {
        static void Main (string[] args) {
            ExecuteMainAsync ().Wait ();
        }

        private static async Task ExecuteMainAsync () {
            using (FileStream fs = new FileStream ($"./config.json", FileMode.Open)) {
                var session = new BoxJWTAuth (BoxConfig.CreateFromJsonFile (fs));
                var client = session.AdminClient (session.AdminToken ());
                var folderId = "987654321";
                var folder = await client.FoldersManager.GetInformationAsync (folderId);
                var folderName = folder.Name;
                var localFolderPath = Path.Combine (Directory.GetCurrentDirectory (), folderName);
                ResetLocalFolder (localFolderPath);

                var items = await client.FoldersManager.GetFolderItemsAsync (folderId, 1000, autoPaginate : true);
                var fileDownloadTasks = new List<Task> ();
                var files = items.Entries.Where (i => i.Type == "file");
                foreach (var file in files) {
                    fileDownloadTasks.Add (client.FilesManager.DownloadStreamAsync (file.Id).ContinueWith ((t) => {
                        var localFile = File.Create (Path.Combine (localFolderPath, file.Name));
                        return t.Result.CopyToAsync (localFile);
                    }));
                }
                await Task.WhenAll (fileDownloadTasks);
            }
        }

        private static void ResetLocalFolder (string localFolderPath) {
            if (!Directory.Exists (localFolderPath)) {
                Directory.CreateDirectory (localFolderPath);
            } else {
                foreach (var file in Directory.EnumerateFiles (localFolderPath)) {
                    File.Delete (Path.Combine (localFolderPath, file));
                }
                Directory.Delete (localFolderPath);
                Directory.CreateDirectory (localFolderPath);
            }
        }
    }
}