フォルダツリーの作成

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Dynamic;
using System.IO;
using System.Linq;
using System.Net;
using System.Net.Sockets;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;
using Box.V2;
using Box.V2.Auth;
using Box.V2.Config;
using Box.V2.Converter;
using Box.V2.Exceptions;
using Box.V2.JWTAuth;
using Box.V2.Models;
using Newtonsoft.Json;

namespace BoxPlayground
{
    public class Program4
    {
        static void Main(string[] args)
        {
            ExecuteMainAsync().Wait();
        }

        public class BoxFolderTreeBuilder
        {
            public BoxClient BoxClient { get; set; }
            public string RootFolderId { get; set; }
            public int MaxDepth { get; set; }

            public BoxFolderTreeBuilder(BoxClient boxClient, string rootFolderId = "0", int maxDepth = -1)
            {
                this.BoxClient = boxClient;
                this.RootFolderId = rootFolderId;
                this.MaxDepth = maxDepth;
            }

            public async Task<BoxFolderTree> BuildFolderTreeWithFlatLists()
            {
                var tree = new BoxFolderTree
                {
                    RootId = this.RootFolderId,
                    Files = new List<BoxFolderTreeItem>(),
                    Folders = new List<BoxFolderTreeFolder>()
                };
                var rootFolderItems = await this.BoxClient.FoldersManager.GetFolderItemsAsync(this.RootFolderId, limit: 1000, autoPaginate: true);
                var rootFolderChildren = new List<BoxFolderTreeFolder>();
                foreach (var item in rootFolderItems.Entries)
                {
                    var folderTreeItem = new BoxFolderTreeItem(item);
                    folderTreeItem.Path = $"{this.RootFolderId}";
                    if (item.Type == "file")
                    {
                        tree.Files.Add(folderTreeItem);
                    }
                    else if (item.Type == "folder")
                    {
                        var childFolder = new BoxFolderTreeFolder(folderTreeItem);
                        tree.Folders.Add(new BoxFolderTreeFolder(folderTreeItem));
                        rootFolderChildren.Add(childFolder);
                    }
                }
                tree = await Dive(tree, rootFolderChildren, 1);
                return tree;
            }

            private async Task<BoxFolderTree> Dive(BoxFolderTree tree,
                List<BoxFolderTreeFolder> children, int currentDepth)
            {
                if (InTooDeep(currentDepth))
                {
                    return tree;
                }
                else
                {
                    currentDepth++;
                    var additionalChildren = new List<BoxFolderTreeFolder>();
                    foreach (var child in children)
                    {
                        var folderItems = await this.BoxClient.FoldersManager.GetFolderItemsAsync(child.Item.Id, limit: 1000, autoPaginate: true);
                        var foundFolder = tree.Folders.FindIndex((f) =>
                        {
                            return f.Item.Id == child.Item.Id;
                        });
                        foreach (var item in folderItems.Entries)
                        {
                            if (foundFolder >= 0)
                            {
                                tree.Folders[foundFolder].Children.Add(item);
                            }
                            var folderTreeItem = new BoxFolderTreeItem(item);
                            folderTreeItem.Path = $"{child.Path}/{child.Item.Id}";
                            if (item.Type == "file")
                            {
                                tree.Files.Add(folderTreeItem);
                            }
                            else if (item.Type == "folder")
                            {
                                var childFolder = new BoxFolderTreeFolder(folderTreeItem);
                                tree.Folders.Add(new BoxFolderTreeFolder(folderTreeItem));
                                additionalChildren.Add(childFolder);
                            }
                        }
                    }
                    if (additionalChildren.Count == 0)
                    {
                        return tree;
                    }
                    else
                    {
                        return await Dive(tree, additionalChildren, currentDepth);
                    }
                }
            }

            private bool InTooDeep(int depthCount)
            {
                if (this.MaxDepth < 0)
                {
                    return false;
                }
                else
                {
                    return (depthCount >= this.MaxDepth);
                }
            }
            public class BoxFolderTreeItem
            {
                [JsonProperty(PropertyName = "item")]
                public BoxItem Item { get; set; }

                [JsonProperty(PropertyName = "path")]
                public string Path { get; set; }
                public BoxFolderTreeItem(BoxItem item)
                {
                    Item = item;
                }
            }
            public class BoxFolderTreeFolder : BoxFolderTreeItem
            {
                public BoxFolderTreeFolder(BoxFolderTreeItem item) : base(item.Item)
                {
                    this.Path = item.Path;
                }

                [JsonProperty(PropertyName = "children")]
                public List<BoxItem> Children { get; set; } = new List<BoxItem>();
            }
            public class BoxFolderTree
            {
                [JsonProperty(PropertyName = "rootId")]
                public string RootId { get; set; }
                [JsonProperty(PropertyName = "files")]
                public List<BoxFolderTreeItem> Files { get; set; }

                [JsonProperty(PropertyName = "folders")]
                public List<BoxFolderTreeFolder> Folders { get; set; }

                public string writeJSON()
                {
                    var converter = new Box.V2.Converter.BoxJsonConverter();
                    return converter.Serialize<BoxFolderTreeBuilder.BoxFolderTree>(this);
                }
            }
        }
        private static async Task ExecuteMainAsync()
        {
            using (FileStream fs = new FileStream($"./config.json", FileMode.Open))
            {
                var session = new BoxJWTAuth(BoxConfig.CreateFromJsonFile(fs));
                var serviceAccountClient = session.AdminClient(session.AdminToken());
                var folderTreeBuilder = new BoxFolderTreeBuilder(serviceAccountClient, rootFolderId: "37477903736");
                var tree = await folderTreeBuilder.BuildFolderTreeWithFlatLists();
                System.Console.WriteLine(tree.writeJSON());
            }
        }
    }
}