diff --git a/.eslintrc.js b/.eslintrc.js
index 09bac06f..765d14ac 100644
--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -6,9 +6,9 @@ module.exports = {
   extends: [],
   parser: '@typescript-eslint/parser',
   parserOptions: {
-    // 'ecmaVersion': 'latest',
-    // 'sourceType': 'module'
-    project: ['./tsconfig.json']
+    'ecmaVersion': 'latest',
+    'sourceType': 'module'
+    // project: ['./tsconfig.json']
   },
   plugins: [
     '@typescript-eslint'
diff --git a/src/components/chat/bubbles.ts b/src/components/chat/bubbles.ts
index ec595bdf..1cbcf858 100644
--- a/src/components/chat/bubbles.ts
+++ b/src/components/chat/bubbles.ts
@@ -522,6 +522,7 @@ export default class ChatBubbles {
               (element as any).onLoad(true);
             } else {
               element.dataset.docId = '' + doc.id;
+              (element as any).doc = doc;
             }
           }
         } else if(poll) {
diff --git a/src/components/wrappers/document.ts b/src/components/wrappers/document.ts
index 3ef9e59e..3b5e60b7 100644
--- a/src/components/wrappers/document.ts
+++ b/src/components/wrappers/document.ts
@@ -90,6 +90,7 @@ export default async function wrapDocument({message, withTime, fontWeight, voice
   const docDiv = document.createElement('div');
   docDiv.classList.add('document', `ext-${ext}`);
   docDiv.dataset.docId = '' + doc.id;
+  (docDiv as any).doc = doc;
 
   // return docDiv;
 
@@ -236,25 +237,28 @@ export default async function wrapDocument({message, withTime, fontWeight, voice
 
     // b && b.classList.add('hide');
 
-    let d = formatBytes(0);
+    const format = (bytes: number) => formatBytes(bytes);
+    let d = format(0);
     bytesContainer.style.visibility = 'hidden';
     // bytesContainer.replaceWith(sizeContainer);
     sizeContainer.append(d, bytesJoiner, _bytesContainer);
     bytesContainer.parentElement.append(sizeContainer);
     promise.addNotifyListener((progress: Progress) => {
-      const _d = formatBytes(progress.done);
+      const _d = format(progress.done);
       d.replaceWith(_d);
       d = _d;
     });
   };
 
-  const load = async(e?: Event) => {
+  // ! DO NOT USE ASYNC/AWAIT HERE ! SAFARI WON'T LET DOWNLOAD THE FILE BECAUSE OF ASYNC
+  const load = (e?: Event) => {
     const save = !e || e.isTrusted;
-    const doc = await managers.appDocsManager.getDoc(docDiv.dataset.docId);
+    const doc = (docDiv as any).doc;
+    // const doc = await managers.appDocsManager.getDoc(docDiv.dataset.docId);
     let download: CancellablePromise<any>;
     const queueId = appImManager.chat.bubbles ? appImManager.chat.bubbles.lazyLoadQueue.queueId : undefined;
     if(!save) {
-      download = appDownloadManager.downloadMediaVoid({media: doc, queueId});
+      download = appDownloadManager.downloadToDisc({media: doc, queueId}, true);
     } else if(doc.type === 'pdf') {
       const canOpenAfter = /* managers.appDocsManager.downloading.has(doc.id) ||  */!preloader || preloader.detached;
       download = appDownloadManager.downloadMediaURL({media: doc, queueId});
@@ -282,10 +286,10 @@ export default async function wrapDocument({message, withTime, fontWeight, voice
     }
   };
 
-  const {fileName: downloadFileName} = getDownloadMediaDetails({media: doc});
+  const {fileName: downloadFileName} = getDownloadMediaDetails({media: doc, downloadId: '1'});
   if(await managers.apiFileManager.isDownloading(downloadFileName)) {
     downloadDiv = docDiv.querySelector('.document-download') || icoDiv;
-    const promise = appDownloadManager.downloadMediaVoid({media: doc});
+    const promise = appDownloadManager.downloadToDisc({media: doc}, true);
 
     preloader = new ProgressivePreloader();
     preloader.attach(downloadDiv, false, promise);
diff --git a/src/global.d.ts b/src/global.d.ts
index e2744251..271540c0 100644
--- a/src/global.d.ts
+++ b/src/global.d.ts
@@ -30,7 +30,7 @@ declare global {
   type FiltersError = 'PINNED_DIALOGS_TOO_MUCH';
 
   type LocalFileError = ApiFileManagerError | ReferenceError | StorageError;
-  type LocalErrorType = LocalFileError | NetworkerError | FiltersError | 'UNKNOWN';
+  type LocalErrorType = LocalFileError | NetworkerError | FiltersError | 'UNKNOWN' | 'NO_DOC';
 
   type ServerErrorType = 'FILE_REFERENCE_EXPIRED' | 'SESSION_REVOKED' | 'AUTH_KEY_DUPLICATED' |
     'SESSION_PASSWORD_NEEDED' | 'CONNECTION_NOT_INITED' | 'ERROR_EMPTY' | 'MTPROTO_CLUSTER_INVALID' |
diff --git a/src/helpers/fileName.ts b/src/helpers/fileName.ts
index ef7d0b78..569d9064 100644
--- a/src/helpers/fileName.ts
+++ b/src/helpers/fileName.ts
@@ -58,7 +58,7 @@ export function getFileNameByLocation(location: InputFileLocation | InputWebFile
     }
   }
 
-  return str + (options.downloadId || '') + (ext ? '.' + ext : ext);
+  return str + (options.downloadId ? '_download' : '') + (ext ? '.' + ext : ext);
 }
 
 export type FileURLType = 'photo' | 'thumb' | 'document' | 'stream' | 'download';
diff --git a/src/helpers/formatBytes.ts b/src/helpers/formatBytes.ts
index d1f015d0..04db2cac 100644
--- a/src/helpers/formatBytes.ts
+++ b/src/helpers/formatBytes.ts
@@ -6,14 +6,18 @@
 
 import {i18n, LangPackKey} from '../lib/langPack';
 
-export default function formatBytes(bytes: number, decimals = 2) {
+export default function formatBytes(bytes: number, decimals: number | 'auto' = 'auto') {
   if(bytes === 0) return i18n('FileSize.B', [0]);
 
-  const k = 1024;
-  const dm = decimals < 0 ? 0 : decimals;
-  const sizes: LangPackKey[] = ['FileSize.B', 'FileSize.KB', 'FileSize.MB', 'FileSize.GB'];
+  const strictDecimals = decimals === 'auto';
 
+  const k = 1024;
   const i = Math.floor(Math.log(bytes) / Math.log(k));
+  const _decimals = decimals === 'auto' ? Math.max(0, i - 1) : decimals;
+
+  const dm = Math.max(0, _decimals);
+  const sizes: LangPackKey[] = ['FileSize.B', 'FileSize.KB', 'FileSize.MB', 'FileSize.GB'];
 
-  return i18n(sizes[i], [parseFloat((bytes / Math.pow(k, i)).toFixed(dm))]);
+  const fixed = (bytes / Math.pow(k, i)).toFixed(dm);
+  return i18n(sizes[i], [strictDecimals ? fixed : parseFloat(fixed)]);
 }
diff --git a/src/lib/appManagers/appDocsManager.ts b/src/lib/appManagers/appDocsManager.ts
index 5046dd20..524bbfbb 100644
--- a/src/lib/appManagers/appDocsManager.ts
+++ b/src/lib/appManagers/appDocsManager.ts
@@ -9,7 +9,7 @@
  * https://github.com/zhukov/webogram/blob/master/LICENSE
  */
 
-import {AccountWallPapers, Document, MessagesSavedGifs, PhotoSize, WallPaper} from '../../layer';
+import {AccountWallPapers, Document, DocumentAttribute, MessagesSavedGifs, PhotoSize, WallPaper} from '../../layer';
 import {ReferenceContext} from '../mtproto/referenceDatabase';
 import {getFullDate} from '../../helpers/date';
 import isObject from '../../helpers/object/isObject';
@@ -23,6 +23,7 @@ import MTProtoMessagePort from '../mtproto/mtprotoMessagePort';
 import getDocumentInput from './utils/docs/getDocumentInput';
 import getDocumentURL from './utils/docs/getDocumentURL';
 import type {ThumbCache} from '../storages/thumbs';
+import makeError from '../../helpers/makeError';
 
 export type MyDocument = Document.document;
 
@@ -216,7 +217,10 @@ export class AppDocsManager extends AppManager {
 
     if(doc.type === 'voice' || doc.type === 'round') {
       // browser will identify extension
-      doc.file_name = doc.type + '_' + getFullDate(new Date(doc.date * 1000), {monthAsNumber: true, leadingZero: true}).replace(/[:\.]/g, '-').replace(', ', '_');
+      const attribute = doc.attributes.find((attribute) => attribute._ === 'documentAttributeFilename') as DocumentAttribute.documentAttributeFilename;
+      const ext = attribute && attribute.file_name.split('.').pop();
+      const date = getFullDate(new Date(doc.date * 1000), {monthAsNumber: true, leadingZero: true}).replace(/[:\.]/g, '-').replace(', ', '_');
+      doc.file_name = `${doc.type}_${date}${ext ? '.' + ext : ''}`;
     }
 
     if(isServiceWorkerOnline()) {
@@ -400,6 +404,7 @@ export class AppDocsManager extends AppManager {
 
   public requestDocPart(docId: DocId, dcId: number, offset: number, limit: number) {
     const doc = this.getDoc(docId);
+    if(!doc) return Promise.reject(makeError('NO_DOC'));
     return this.apiFileManager.requestFilePart(dcId, getDocumentInput(doc), offset, limit);
   }
 }
diff --git a/src/lib/appManagers/appDownloadManager.ts b/src/lib/appManagers/appDownloadManager.ts
index 0e055a3b..990d02d4 100644
--- a/src/lib/appManagers/appDownloadManager.ts
+++ b/src/lib/appManagers/appDownloadManager.ts
@@ -16,8 +16,7 @@ import noop from '../../helpers/noop';
 import getDownloadMediaDetails from './utils/download/getDownloadMediaDetails';
 import getDownloadFileNameFromOptions from './utils/download/getDownloadFileNameFromOptions';
 import indexOfAndSplice from '../../helpers/array/indexOfAndSplice';
-import {MAX_FILE_SAVE_SIZE} from '../mtproto/mtproto_config';
-import createDownloadAnchor from '../../helpers/dom/createDownloadAnchor';
+import makeError from '../../helpers/makeError';
 
 export type ResponseMethodBlob = 'blob';
 export type ResponseMethodJson = 'json';
@@ -38,6 +37,7 @@ type DownloadType = 'url' | 'blob' | 'void' | 'disc';
 
 export class AppDownloadManager {
   private downloads: {[fileName: string]: {main: Download} & {[type in DownloadType]?: Download}} = {};
+  // private downloadsToDisc: {[fileName: string]: Download} = {};
   private progress: {[fileName: string]: Progress} = {};
   // private progressCallbacks: {[fileName: string]: Array<ProgressCallback>} = {};
   private managers: AppManagers;
@@ -45,15 +45,14 @@ export class AppDownloadManager {
   public construct(managers: AppManagers) {
     this.managers = managers;
     rootScope.addEventListener('download_progress', (details) => {
-      this.progress[details.fileName] = details;
-
       // const callbacks = this.progressCallbacks[details.fileName];
       // if(callbacks) {
       //   callbacks.forEach((callback) => callback(details));
       // }
 
       const download = this.downloads[details.fileName];
-      if(download) {
+      if(download?.main?.notifyAll) {
+        this.progress[details.fileName] = details;
         download.main.notifyAll(details);
       }
     });
@@ -69,17 +68,12 @@ export class AppDownloadManager {
       };
 
       deferred.cancel = () => {
-        // try {
-        const error = new Error('Download canceled');
-        error.name = 'AbortError';
+        const error = makeError('DOWNLOAD_CANCELED');
 
         this.managers.apiFileManager.cancelDownload(fileName);
 
         deferred.reject(error);
-        deferred.cancel = () => {};
-        /* } catch(err) {
-
-        } */
+        deferred.cancel = noop;
       };
 
       deferred.catch(() => {
@@ -225,51 +219,93 @@ export class AppDownloadManager {
   //   }
   // }
 
-  public downloadToDisc(options: DownloadMediaOptions) {
+  public downloadToDisc(options: DownloadMediaOptions, justAttach?: boolean) {
     const media = options.media;
     const isDocument = media._ === 'document';
     if(!isDocument && !options.thumb) {
       options.thumb = (media as Photo.photo).sizes.slice().pop() as PhotoSize.photoSize;
     }
 
-    const {downloadOptions, fileName} = getDownloadMediaDetails(options);
-    if(downloadOptions.size && downloadOptions.size > MAX_FILE_SAVE_SIZE) {
-      const id = '' + (Math.random() * 0x7FFFFFFF | 0);
-      const url = `/download/${id}`;
-      options.downloadId = id;
-
-      const promise = this.downloadMedia(options, 'disc');
-
-      let iframe: HTMLIFrameElement;
-      const onProgress = () => {
-        iframe = document.createElement('iframe');
-        iframe.hidden = true;
-        // iframe.src = sw.scope + fileName;
-        iframe.src = url;
-        document.body.append(iframe);
-
-        indexOfAndSplice(promise.listeners, onProgress);
-      };
-
-      promise.addNotifyListener(onProgress);
-      promise.catch(noop).finally(() => {
-        setTimeout(() => {
-          iframe?.remove();
-        }, 1000);
-      });
-
-      return promise;
-    } else {
-      const promise = this.downloadMedia(options, 'blob');
-      promise.then((blob) => {
-        const url = URL.createObjectURL(blob);
-        createDownloadAnchor(url, downloadOptions.fileName || fileName, () => {
-          URL.revokeObjectURL(url);
-        });
-      });
+    // const {fileName: cacheFileName} = getDownloadMediaDetails(options);
+    // if(justAttach) {
+    //   const promise = this.downloadsToDisc[cacheFileName];
+    //   if(promise) {
+    //     return promise;
+    //   }
+    // }
+
+    // const {downloadOptions, fileName} = getDownloadMediaDetails(options);
+    // if(downloadOptions.size && downloadOptions.size > MAX_FILE_SAVE_SIZE) {
+    const id = '' + (Math.random() * 0x7FFFFFFF | 0);
+    // const id = 'test';
+    const url = `/download/${id}`;
+    options.downloadId = id;
+
+    const promise = this.downloadMedia(options, 'disc');
+    // this.downloadsToDisc[cacheFileName] = promise;
+
+    if(justAttach) {
       return promise;
     }
 
+    const iframe = document.createElement('iframe');
+    iframe.hidden = true;
+    iframe.src = url;
+    document.body.append(iframe);
+    // createDownloadAnchor(url, 'asd.txt');
+
+    // const events = [
+    //   'emptied',
+    //   'abort',
+    //   'suspend',
+    //   'reset',
+    //   'error',
+    //   'ended',
+    //   'load'
+    // ].forEach((event) => {
+    //   iframe.addEventListener(event, () => alert(event));
+    //   iframe.contentWindow.addEventListener(event, () => alert(event));
+    // });
+
+    let element: HTMLElement, hadProgress = false;
+    const onProgress = () => {
+      if(hadProgress) {
+        return;
+      }
+
+      hadProgress = true;
+      element = iframe;
+
+      indexOfAndSplice(promise.listeners, onProgress);
+    };
+
+    promise.addNotifyListener(onProgress);
+    promise.catch(noop).finally(() => {
+      if(!hadProgress) {
+        onProgress();
+      }
+
+      setTimeout(() => {
+        element?.remove();
+      }, 1000);
+
+      // if(this.downloadsToDisc[cacheFileName] === promise) {
+      //   delete this.downloadsToDisc[cacheFileName];
+      // }
+    });
+
+    return promise;
+    // } else {
+    //   const promise = this.downloadMedia(options, 'blob');
+    //   promise.then((blob) => {
+    //     const url = URL.createObjectURL(blob);
+    //     createDownloadAnchor(url, downloadOptions.fileName || fileName, () => {
+    //       URL.revokeObjectURL(url);
+    //     });
+    //   });
+    //   return promise;
+    // }
+
     // const promise = this.downloadMedia(options);
     // promise.then((blob) => {
     //   const url = URL.createObjectURL(blob);
diff --git a/src/lib/appManagers/utils/download/getDownloadFileNameFromOptions.ts b/src/lib/appManagers/utils/download/getDownloadFileNameFromOptions.ts
index 6770674c..84560e1c 100644
--- a/src/lib/appManagers/utils/download/getDownloadFileNameFromOptions.ts
+++ b/src/lib/appManagers/utils/download/getDownloadFileNameFromOptions.ts
@@ -8,5 +8,5 @@ import {getFileNameByLocation} from '../../../../helpers/fileName';
 import {DownloadOptions} from '../../../mtproto/apiFileManager';
 
 export default function getDownloadFileNameFromOptions(options: DownloadOptions) {
-  return getFileNameByLocation(options.location, {fileName: options.fileName});
+  return getFileNameByLocation(options.location, options);
 }
diff --git a/src/lib/appManagers/utils/webDocs/getWebDocumentDownloadOptions.ts b/src/lib/appManagers/utils/webDocs/getWebDocumentDownloadOptions.ts
index 674ac45e..664e5d16 100644
--- a/src/lib/appManagers/utils/webDocs/getWebDocumentDownloadOptions.ts
+++ b/src/lib/appManagers/utils/webDocs/getWebDocumentDownloadOptions.ts
@@ -3,7 +3,7 @@ import {DownloadOptions} from '../../../mtproto/apiFileManager';
 
 export default function getWebDocumentDownloadOptions(webDocument: WebDocument): DownloadOptions {
   return {
-    dcId: 4,
+    dcId: 0,
     location: {
       _: 'inputWebFileLocation',
       access_hash: (webDocument as WebDocument.webDocument).access_hash,
diff --git a/src/lib/files/cacheStorage.ts b/src/lib/files/cacheStorage.ts
index 07c045aa..c556fff8 100644
--- a/src/lib/files/cacheStorage.ts
+++ b/src/lib/files/cacheStorage.ts
@@ -10,6 +10,7 @@ import MemoryWriter from './memoryWriter';
 import FileManager from './memoryWriter';
 import FileStorage from './fileStorage';
 import makeError from '../../helpers/makeError';
+import deferredPromise from '../../helpers/cancellablePromise';
 
 export type CacheStorageDbName = 'cachedFiles' | 'cachedStreamChunks' | 'cachedAssets';
 
@@ -124,12 +125,17 @@ export default class CacheStorageController implements FileStorage {
     });
   }
 
-  public getWriter(fileName: string, fileSize: number, mimeType: string) {
-    const writer = new MemoryWriter(mimeType, fileSize, (blob) => {
-      return this.saveFile(fileName, blob).catch(() => blob);
-    });
+  public prepareWriting(fileName: string, fileSize: number, mimeType: string) {
+    return {
+      deferred: deferredPromise<Blob>(),
+      getWriter: () => {
+        const writer = new MemoryWriter(mimeType, fileSize, (blob) => {
+          return this.saveFile(fileName, blob).catch(() => blob);
+        });
 
-    return Promise.resolve(writer);
+        return writer;
+      }
+    };
   }
 
   public static toggleStorage(enabled: boolean, clearWrite: boolean) {
diff --git a/src/lib/files/downloadStorage.ts b/src/lib/files/downloadStorage.ts
new file mode 100644
index 00000000..7fbf0f4a
--- /dev/null
+++ b/src/lib/files/downloadStorage.ts
@@ -0,0 +1,55 @@
+/*
+ * https://github.com/morethanwords/tweb
+ * Copyright (C) 2019-2021 Eduard Kuzmenko
+ * https://github.com/morethanwords/tweb/blob/master/LICENSE
+ */
+
+import deferredPromise from '../../helpers/cancellablePromise';
+import makeError from '../../helpers/makeError';
+import fileNameRFC from '../../helpers/string/fileNameRFC';
+import {getServiceMessagePort} from '../mtproto/mtproto.worker';
+import DownloadWriter from './downloadWriter';
+import FileStorage from './fileStorage';
+import StreamWriter from './streamWriter';
+
+export default class DownloadStorage implements FileStorage {
+  public getFile(fileName: string): Promise<any> {
+    return Promise.reject(makeError('NO_ENTRY_FOUND'));
+  }
+
+  public prepareWriting({fileName, downloadId, size}: {
+    fileName: string,
+    downloadId: string,
+    size: number
+  }) {
+    const headers = {
+      'Content-Type': 'application/octet-stream; charset=utf-8',
+      'Content-Disposition': 'attachment; filename*=UTF-8\'\'' + fileNameRFC(fileName),
+      ...(size ? {'Content-Length': size} : {})
+    };
+
+    const serviceMessagePort = getServiceMessagePort();
+    const promise = serviceMessagePort.invoke('download', {
+      headers,
+      id: downloadId
+    });
+
+    const deferred = deferredPromise<void>();
+    deferred.cancel = () => {
+      deferred.reject(makeError('DOWNLOAD_CANCELED'));
+    };
+
+    deferred.catch(() => {
+      getServiceMessagePort().invoke('downloadCancel', downloadId);
+    });
+
+    promise.then(deferred.resolve, deferred.reject);
+
+    return {
+      deferred,
+      getWriter: () => {
+        return new DownloadWriter(serviceMessagePort, downloadId);
+      }
+    };
+  }
+}
diff --git a/src/lib/files/downloadWriter.ts b/src/lib/files/downloadWriter.ts
new file mode 100644
index 00000000..f0a0c719
--- /dev/null
+++ b/src/lib/files/downloadWriter.ts
@@ -0,0 +1,29 @@
+/*
+ * https://github.com/morethanwords/tweb
+ * Copyright (C) 2019-2021 Eduard Kuzmenko
+ * https://github.com/morethanwords/tweb/blob/master/LICENSE
+ */
+
+import {getServiceMessagePort} from '../mtproto/mtproto.worker';
+import ServiceMessagePort from '../serviceWorker/serviceMessagePort';
+import StreamWriter from './streamWriter';
+
+export default class DownloadWriter implements StreamWriter {
+  constructor(
+    private serviceMessagePort: ServiceMessagePort<true>,
+    private downloadId: string
+  ) {
+    this.serviceMessagePort = getServiceMessagePort();
+  }
+
+  public async write(part: Uint8Array, offset?: number) {
+    return this.serviceMessagePort.invoke('downloadChunk', {
+      id: this.downloadId,
+      chunk: part
+    });
+  }
+
+  public finalize(saveToStorage?: boolean): Promise<Blob> {
+    return this.serviceMessagePort.invoke('downloadFinalize', this.downloadId).then(() => undefined);
+  }
+}
diff --git a/src/lib/files/fileStorage.ts b/src/lib/files/fileStorage.ts
index 69eff3a5..b882bf39 100644
--- a/src/lib/files/fileStorage.ts
+++ b/src/lib/files/fileStorage.ts
@@ -4,10 +4,10 @@
  * https://github.com/morethanwords/tweb/blob/master/LICENSE
  */
 
+import {CancellablePromise} from '../../helpers/cancellablePromise';
 import StreamWriter from './streamWriter';
 
 export default abstract class FileStorage {
   public abstract getFile(fileName: string): Promise<any>;
-
-  public abstract getWriter(fileName: string, fileSize: number, mimeType: string): Promise<StreamWriter>;
+  public abstract prepareWriting(...args: any[]): {deferred: CancellablePromise<any>, getWriter: () => StreamWriter};
 }
diff --git a/src/lib/mtproto/apiFileManager.ts b/src/lib/mtproto/apiFileManager.ts
index d2e2b7fb..d85b9930 100644
--- a/src/lib/mtproto/apiFileManager.ts
+++ b/src/lib/mtproto/apiFileManager.ts
@@ -18,7 +18,6 @@ import {DcId} from '../../types';
 import CacheStorageController from '../files/cacheStorage';
 import {logger, LogTypes} from '../logger';
 import assumeType from '../../helpers/assumeType';
-import ctx from '../../environment/ctx';
 import noop from '../../helpers/noop';
 import readBlobAsArrayBuffer from '../../helpers/blob/readBlobAsArrayBuffer';
 import bytesToHex from '../../helpers/bytes/bytesToHex';
@@ -32,13 +31,15 @@ import type {Progress} from '../appManagers/appDownloadManager';
 import getDownloadMediaDetails from '../appManagers/utils/download/getDownloadMediaDetails';
 import networkStats from './networkStats';
 import getDownloadFileNameFromOptions from '../appManagers/utils/download/getDownloadFileNameFromOptions';
-import {getServiceMessagePort} from './mtproto.worker';
 import StreamWriter from '../files/streamWriter';
 import FileStorage from '../files/fileStorage';
-import fileNameRFC from '../../helpers/string/fileNameRFC';
 import {MAX_FILE_SAVE_SIZE} from './mtproto_config';
 import throttle from '../../helpers/schedulers/throttle';
 import makeError from '../../helpers/makeError';
+import readBlobAsUint8Array from '../../helpers/blob/readBlobAsUint8Array';
+import DownloadStorage from '../files/downloadStorage';
+import copy from '../../helpers/object/copy';
+import indexOfAndSplice from '../../helpers/array/indexOfAndSplice';
 
 type Delayed = {
   offset: number,
@@ -82,10 +83,13 @@ export type MyUploadFile = UploadFile.uploadFile | UploadWebFile.uploadWebFile;
 //   originalPayload: ReferenceBytes
 // };
 
-const MAX_FILE_PART_SIZE = 1 * 1024 * 1024;
+const MAX_DOWNLOAD_FILE_PART_SIZE = 1 * 1024 * 1024;
+const MAX_UPLOAD_FILE_PART_SIZE = 512 * 1024;
+const MIN_PART_SIZE = 128 * 1024;
+const AVG_PART_SIZE = 512 * 1024;
 
-const REGULAR_DOWNLOAD_DELTA = 36;
-const PREMIUM_DOWNLOAD_DELTA = 72;
+const REGULAR_DOWNLOAD_DELTA = (9 * 512 * 1024) / MIN_PART_SIZE;
+const PREMIUM_DOWNLOAD_DELTA = REGULAR_DOWNLOAD_DELTA * 2;
 
 const IGNORE_ERRORS: Set<ErrorType> = new Set([
   'DOWNLOAD_CANCELED',
@@ -96,11 +100,16 @@ const IGNORE_ERRORS: Set<ErrorType> = new Set([
 
 export class ApiFileManager extends AppManager {
   private cacheStorage = new CacheStorageController('cachedFiles');
+  private downloadStorage = new DownloadStorage();
 
   private downloadPromises: {
     [fileName: string]: DownloadPromise
   } = {};
 
+  // private downloadToDiscPromises: {
+  //   [fileName: string]: DownloadPromise
+  // } = {};
+
   private uploadPromises: {
     [fileName: string]: CancellablePromise<InputFile>
   } = {};
@@ -133,6 +142,7 @@ export class ApiFileManager extends AppManager {
 
   private maxUploadParts = 4000;
   private maxDownloadParts = 8000;
+  private webFileDcId: DcId;
 
   protected after() {
     setInterval(() => { // clear old promises
@@ -144,6 +154,10 @@ export class ApiFileManager extends AppManager {
       }
     }, 1800e3);
 
+    this.rootScope.addEventListener('config', (config) => {
+      this.webFileDcId = config.webfile_dc_id;
+    });
+
     this.rootScope.addEventListener('app_config', (appConfig) => {
       this.maxUploadParts = this.rootScope.premium ? appConfig.upload_max_fileparts_premium : appConfig.upload_max_fileparts_default;
       this.maxDownloadParts = appConfig.upload_max_fileparts_premium;
@@ -173,7 +187,7 @@ export class ApiFileManager extends AppManager {
 
   private downloadCheck(dcId: string | number) {
     const downloadPull = this.downloadPulls[dcId];
-    const downloadLimit = dcId === 'upload' ? 24 : (this.rootScope.premium ? PREMIUM_DOWNLOAD_DELTA : REGULAR_DOWNLOAD_DELTA);
+    const downloadLimit = /* dcId === 'upload' ? 24 :  */(this.rootScope.premium ? PREMIUM_DOWNLOAD_DELTA : REGULAR_DOWNLOAD_DELTA);
     // const downloadLimit = Infinity;
 
     if(this.downloadActives[dcId] >= downloadLimit || !downloadPull?.length) {
@@ -187,7 +201,7 @@ export class ApiFileManager extends AppManager {
     this.downloadActives[dcId] += activeDelta;
 
     const promise = data.cb();
-    const networkPromise = networkStats.waitForChunk(dcId as DcId, activeDelta * 1024 * 128);
+    const networkPromise = networkStats.waitForChunk(dcId as DcId, activeDelta * MIN_PART_SIZE);
     Promise.race([
       promise,
       networkPromise
@@ -235,7 +249,7 @@ export class ApiFileManager extends AppManager {
 
   public requestWebFilePart(dcId: DcId, location: InputWebFileLocation, offset: number, limit: number, id = 0, queueId = 0, checkCancel?: () => void) {
     return this.downloadRequest(dcId, id, async() => { // do not remove async, because checkCancel will throw an error
-      checkCancel && checkCancel();
+      checkCancel?.();
 
       return this.apiManager.invokeApi('upload.getWebFile', {
         location,
@@ -248,17 +262,26 @@ export class ApiFileManager extends AppManager {
     }, this.getDelta(limit), queueId);
   }
 
-  public requestFilePart(dcId: DcId, location: InputFileLocation, offset: number, limit: number, id = 0, queueId = 0, checkCancel?: () => void) {
+  public requestFilePart(
+    dcId: DcId,
+    location: InputFileLocation,
+    offset: number,
+    limit: number,
+    id = 0,
+    queueId = 0,
+    checkCancel?: () => void
+  ) {
     return this.downloadRequest(dcId, id, async() => { // do not remove async, because checkCancel will throw an error
-      checkCancel && checkCancel();
+      checkCancel?.();
 
       const invoke = async(): Promise<MyUploadFile> => {
-        checkCancel && checkCancel(); // do not remove async, because checkCancel will throw an error
+        checkCancel?.(); // do not remove async, because checkCancel will throw an error
 
         // * IMPORTANT: reference can be changed in previous request
         const reference = (location as InputFileLocation.inputDocumentFileLocation).file_reference?.slice();
 
-        const promise = /* pause(1000).then(() =>  */this.apiManager.invokeApi('upload.getFile', {
+        const promise = // pause(offset > (100 * 1024 * 1024) ? 10000000 : 0).then(() =>
+        this.apiManager.invokeApi('upload.getFile', {
           location,
           offset,
           limit
@@ -268,6 +291,8 @@ export class ApiFileManager extends AppManager {
         }) as Promise<MyUploadFile>/* ) */;
 
         return promise.catch((err: ApiError) => {
+          checkCancel?.();
+
           if(err.type === 'FILE_REFERENCE_EXPIRED') {
             return this.refreshReference(location as InputFileLocation.inputDocumentFileLocation, reference).then(invoke);
           }
@@ -295,19 +320,22 @@ export class ApiFileManager extends AppManager {
   } */
 
   private getDelta(bytes: number) {
-    return bytes / 1024 / 128;
+    return bytes / MIN_PART_SIZE;
   }
 
   private getLimitPart(size: number, isUpload: boolean): number {
     if(!size) { // * sometimes size can be 0 (e.g. avatars, webDocuments)
-      return 512 * 1024;
+      return AVG_PART_SIZE;
     }
 
-    let bytes = 128 * 1024;
+    // return 1 * 1024 * 1024;
+
+    let bytes = MIN_PART_SIZE;
 
     const maxParts = isUpload ? this.maxUploadParts : this.maxDownloadParts;
+    const maxPartSize = isUpload ? MAX_UPLOAD_FILE_PART_SIZE : MAX_DOWNLOAD_FILE_PART_SIZE;
     // usually it will stick to 512Kb size if the file is too big
-    while((size / bytes) > maxParts && bytes < MAX_FILE_PART_SIZE) {
+    while((size / bytes) > maxParts && bytes < maxPartSize) {
       bytes *= 2;
     }
     /* if(size < 1e6 || !size) bytes = 512;
@@ -399,201 +427,230 @@ export class ApiFileManager extends AppManager {
     return this.uploadPromises[fileName];
   }
 
-  public download(options: DownloadOptions): DownloadPromise {
-    const size = options.size ?? 0;
-    const {dcId, location, downloadId} = options;
-
+  private getConvertMethod(mimeType: string) {
     let process: ApiFileManager['uncompressTGS'] | ApiFileManager['convertWebp'];
-
-    if(downloadId) {
-
-    } else if(options.mimeType === 'application/x-tgwallpattern') {
+    if(mimeType === 'application/x-tgwallpattern') {
       process = this.uncompressTGV;
-      options.mimeType = 'image/svg+xml';
-    } else if(options.mimeType === 'image/webp' && !getEnvironment().IS_WEBP_SUPPORTED) {
+      mimeType = 'image/svg+xml';
+    } else if(mimeType === 'image/webp' && !getEnvironment().IS_WEBP_SUPPORTED) {
       process = this.convertWebp;
-      options.mimeType = 'image/png';
-    } else if(options.mimeType === 'application/x-tgsticker') {
+      mimeType = 'image/png';
+    } else if(mimeType === 'application/x-tgsticker') {
       process = this.uncompressTGS;
-      options.mimeType = 'application/json';
-    } else if(options.mimeType === 'audio/ogg' && !getEnvironment().IS_OPUS_SUPPORTED) {
+      mimeType = 'application/json';
+    } else if(mimeType === 'audio/ogg' && !getEnvironment().IS_OPUS_SUPPORTED) {
       process = this.convertOpus;
-      options.mimeType = 'audio/wav';
+      mimeType = 'audio/wav';
     }
 
-    const fileName = getDownloadFileNameFromOptions(options);
-    const cachedPromise = options.downloadId ? undefined : this.downloadPromises[fileName];
-    let fileStorage: FileStorage = this.getFileStorage();
+    return {mimeType, process};
+  }
 
-    this.debug && this.log('downloadFile', fileName, size, location, options.mimeType);
+  private allocateDeferredPromises(startOffset: number, size: number, limitPart: number) {
+    const delayed: Delayed[] = [];
+    let offset = startOffset;
+    let writePromise: CancellablePromise<void> = Promise.resolve(),
+      writeDeferred: CancellablePromise<void>;
+    do {
+      writeDeferred = deferredPromise<void>();
+      delayed.push({offset, writePromise, writeDeferred});
+      writePromise = writeDeferred;
+      offset += limitPart;
+    } while(offset < size);
+
+    return delayed;
+  }
 
-    /* if(options.queueId) {
-      this.log.error('downloadFile queueId:', fileName, options.queueId);
-    } */
+  public download(options: DownloadOptions): DownloadPromise {
+    const size = options.size ?? 0;
+    const {dcId, location, downloadId} = options;
 
-    if(cachedPromise) {
-      // this.log('downloadFile cachedPromise');
+    const originalMimeType = options.mimeType;
+    const convertMethod = this.getConvertMethod(originalMimeType);
+    const {process} = convertMethod;
+    options.mimeType = convertMethod.mimeType || 'image/jpeg';
 
-      if(size) {
-        return cachedPromise.then((blob) => {
-          if(blob instanceof Blob && blob.size < size) {
-            this.debug && this.log('downloadFile need to deleteFile, wrong size:', blob.size, size);
+    const fileName = getDownloadFileNameFromOptions(options);
+    const cacheFileName = downloadId ? getDownloadFileNameFromOptions({...copy(options), downloadId: undefined}) : fileName;
+    const cacheStorage: FileStorage = this.getFileStorage();
+    const downloadStorage: FileStorage = downloadId ? this.downloadStorage : undefined;
+    let deferred: DownloadPromise = downloadId ? undefined : this.downloadPromises[fileName];
 
-            return this.delete(fileName).then(() => {
-              return this.download(options);
-            }).catch(() => {
-              return this.download(options);
-            });
-          } else {
-            return blob;
-          }
-        });
-      } else {
-        return cachedPromise;
-      }
+    this.debug && this.log('downloadFile', fileName, options);
+
+    if(deferred) {
+      return deferred;
     }
 
-    const deferred: DownloadPromise = deferredPromise();
-    const mimeType = options.mimeType || 'image/jpeg';
+    // if(deferred) {
+    //   if(size) {
+    //     return deferred.then(async(blob) => {
+    //       if(blob instanceof Blob && blob.size < size) {
+    //         this.debug && this.log('downloadFile need to deleteFile, wrong size:', blob.size, size);
+
+    //         try {
+    //           await this.delete(fileName);
+    //         } finally {
+    //           return this.download(options);
+    //         }
+    //       } else {
+    //         return blob;
+    //       }
+    //     });
+    //   } else {
+    //     return deferred;
+    //   }
+    // }
+
+    const errorHandler = (item: typeof cachePrepared, error: ApiError) => {
+      if(item?.error) {
+        return;
+      }
 
-    let error: ApiError;
-    let resolved = false;
-    let cacheWriter: StreamWriter;
-    let errorHandler = (_error: typeof error) => {
-      error = _error;
-      delete this.downloadPromises[fileName];
-      deferred.reject(error);
-      errorHandler = () => {};
+      for(const p of prepared) {
+        if(item && item !== p) {
+          continue;
+        }
 
-      if(cacheWriter && (!error || error.type !== 'DOWNLOAD_CANCELED')) {
-        cacheWriter.truncate?.();
+        p.error = error;
+        p.deferred.reject(error);
       }
     };
 
     const id = this.tempId++;
+    const limitPart = options.limitPart || this.getLimitPart(size, false);
 
-    if(downloadId) {
-      const headers = {
-        'Content-Type': 'application/octet-stream; charset=utf-8',
-        'Content-Disposition': 'attachment; filename*=UTF-8\'\'' + fileNameRFC(options.fileName),
-        // 'Content-Disposition': `attachment; filename="${options.fileName}"`,
-        // 'Content-Type': 'application/octet-stream; charset=utf-8',
-        ...(size ? {'Content-Length': size} : {})
-      };
+    let getFile: FileStorage['getFile'] = cacheStorage.getFile.bind(cacheStorage);
 
-      const serviceMessagePort = getServiceMessagePort();
-      const promise = serviceMessagePort.invoke('download', {
-        fileName,
-        headers,
-        id: downloadId
-      });
+    let cachePrepared: ReturnType<FileStorage['prepareWriting']> & {writer?: StreamWriter, error?: ApiError},
+      downloadPrepared: typeof cachePrepared;
+    const prepared: (typeof cachePrepared)[] = [];
+    const possibleSize = size || limitPart;
 
-      promise.catch(errorHandler);
-      deferred.catch(() => {
-        getServiceMessagePort().invoke('downloadCancel', downloadId);
-      });
+    const getErrorsCount = () => prepared.reduce((acc, item) => acc + +!!item.error, 0);
 
-      class f implements StreamWriter {
-        constructor() {
+    const attach = (item: typeof cachePrepared, fileName: string) => {
+      const {deferred} = item;
+      const _errorHandler = errorHandler.bind(null, item);
 
+      deferred.cancel = () => deferred.reject(makeError('DOWNLOAD_CANCELED'));
+      deferred.catch((error) => {
+        _errorHandler(error);
+        item.writer?.truncate?.();
+      }).finally(() => {
+        if(this.downloadPromises[fileName] === deferred) {
+          delete this.downloadPromises[fileName];
         }
 
-        public async write(part: Uint8Array, offset?: number) {
-          return serviceMessagePort.invoke('downloadChunk', {
-            id: downloadId,
-            chunk: part
-          });
-        }
+        delete item.writer;
+        indexOfAndSplice(prepared, item);
+      });
 
-        public finalize(saveToStorage?: boolean): Promise<Blob> {
-          return serviceMessagePort.invoke('downloadFinalize', downloadId).then(() => null);
-        }
-      }
+      this.downloadPromises[fileName] = deferred;
 
-      class d implements FileStorage {
-        public getFile(fileName: string): Promise<any> {
-          return Promise.reject();
-        }
+      prepared.push(item);
+    };
 
-        public getWriter(fileName: string, fileSize: number, mimeType: string): Promise<StreamWriter> {
-          return Promise.resolve(new f());
-        }
+    if(cacheStorage && (!downloadStorage || possibleSize <= MAX_FILE_SAVE_SIZE)) {
+      cachePrepared = cacheStorage.prepareWriting(cacheFileName, possibleSize, options.mimeType)
+      attach(cachePrepared, cacheFileName);
+    }
+
+    if(downloadStorage) {
+      downloadPrepared = downloadStorage.prepareWriting({
+        fileName: options.fileName, // it's doc file_name
+        downloadId,
+        size: possibleSize
+      });
+      attach(downloadPrepared, fileName);
+
+      if(cachePrepared) { // cancel cache too
+        downloadPrepared.deferred.catch((err) => cachePrepared.deferred.reject(err));
       }
 
-      fileStorage = new d();
+      // this.downloadToDiscPromises[cacheFileName] = deferred;
+      // deferred.catch(noop).finally(() => {
+      //   if(this.downloadToDiscPromises[cacheFileName] === deferred) {
+      //     delete this.downloadToDiscPromises[cacheFileName];
+      //   }
+      // });
     }
 
-    fileStorage.getFile(fileName).then(async(blob: Blob) => {
-      // throw '';
+    deferred = downloadPrepared?.deferred ?? cachePrepared.deferred;
 
-      if(blob.size < size) {
-        if(!options.onlyCache) {
-          await this.delete(fileName);
-        }
+    if(downloadStorage && process) { // then have to load file again
+      getFile = downloadStorage.getFile.bind(downloadStorage);
+    }
+
+    getFile(cacheFileName).then(async(blob: Blob) => {
+      checkCancel();
+
+      // if(blob.size < size) {
+      //   if(!options.onlyCache) {
+      //     await this.delete(cacheFileName);
+      //     checkCancel();
+      //   }
 
-        throw false;
+      //   throw makeError('NO_ENTRY_FOUND');
+      // }
+
+      if(downloadPrepared) {
+        const writer = downloadPrepared.writer = downloadPrepared.getWriter();
+        checkCancel();
+
+        const arr = await readBlobAsUint8Array(blob);
+        checkCancel();
+        await writer.write(arr);
+        checkCancel();
+
+        downloadPrepared.deferred.resolve(await writer.finalize());
       }
 
-      deferred.resolve(blob);
+      if(cachePrepared) {
+        cachePrepared.deferred.resolve(blob);
+      }
     }).catch(async(err: ApiError) => {
       if(options.onlyCache) {
-        errorHandler(err);
+        errorHandler(null, err);
         return;
       }
 
-      // this.log('not cached', fileName);
-      const limit = options.limitPart || this.getLimitPart(size, false);
-      const writerPromise = fileStorage.getWriter(fileName, size || limit, mimeType);
-
-      const writer = cacheWriter = await writerPromise;
+      prepared.forEach((p) => {
+        p.writer = p.getWriter();
+      });
 
-      let offset: number;
-      const startOffset = 0;
-      let writePromise: CancellablePromise<void> = Promise.resolve(),
-        writeDeferred: CancellablePromise<void>;
-      // const maxRequests = 13107200 / limit; // * 100 Mb speed
       const maxRequests = Infinity;
 
-      const processDownloaded = async(bytes: Uint8Array) => {
-        if(process) {
-          // const perf = performance.now();
-          const processed = await process(bytes, fileName);
-          // this.log('downloadFile process downloaded time', performance.now() - perf, mimeType, process);
-          return processed;
-        }
+      const isWebFile = location._ === 'inputWebFileLocation';
+      const requestPart = (isWebFile ? this.requestWebFilePart : this.requestFilePart).bind(this);
 
-        return bytes;
-      };
-
-      const r = location._ === 'inputWebFileLocation' ? this.requestWebFilePart.bind(this) : this.requestFilePart.bind(this);
+      if(isWebFile && this.webFileDcId === undefined) {
+        await this.apiManager.getConfig();
+        checkCancel();
+      }
 
-      const delayed: Delayed[] = [];
-      offset = startOffset;
-      do {
-        writeDeferred = deferredPromise<void>();
-        delayed.push({offset, writePromise, writeDeferred});
-        writePromise = writeDeferred;
-        offset += limit;
-      } while(offset < size);
+      const delayed = this.allocateDeferredPromises(0, size, limitPart);
 
-      const progress: Progress = {done: 0, offset, total: size, fileName};
+      const progress: Progress = {done: 0, offset: 0, total: size, fileName};
       const dispatchProgress = () => {
-        progress.done = done;
-        deferred.notify?.(progress);
+        try {
+          checkCancel();
+          progress.done = done;
+          this.rootScope.dispatchEvent('download_progress', progress);
+        } catch(err) {}
       };
 
       const throttledDispatchProgress = throttle(dispatchProgress, 50, true);
 
       let done = 0;
       const superpuper = async() => {
-        // if(!delayed.length) return;
-
         const {offset, writePromise, writeDeferred} = delayed.shift();
         try {
           checkCancel();
 
-          // @ts-ignore
-          const result = await r(dcId, location as any, offset, limit, id, options.queueId, checkCancel);
+          const requestPerf = performance.now();
+          const result = await requestPart(dcId, location as any, offset, limitPart, id, options.queueId, checkCancel);
+          const requestTime = performance.now() - requestPerf;
 
           const bytes = result.bytes;
 
@@ -603,7 +660,7 @@ export class ApiFileManager extends AppManager {
 
           const byteLength = bytes.byteLength;
           this.debug && this.log('downloadFile requestFilePart result:', fileName, result);
-          const isFinal = (offset + limit) >= size || !byteLength;
+          const isFinal = (offset + limitPart) >= size || !byteLength;
           if(byteLength) {
             done += byteLength;
 
@@ -613,68 +670,65 @@ export class ApiFileManager extends AppManager {
               throttledDispatchProgress();
             }
 
+            const writeQueuePerf = performance.now();
             await writePromise;
             checkCancel();
+            const writeQueueTime = performance.now() - writeQueuePerf;
 
-            // const perf = performance.now();
-            await writer.write(bytes, offset);
+            const perf = performance.now();
+            await Promise.all(prepared.map(({writer}) => writer?.write(bytes, offset)));
             checkCancel();
-            // downloadId && this.log('write time', performance.now() - perf);
+            // downloadId && this.log('write time', performance.now() - perf, 'request time', requestTime, 'queue time', writeQueueTime);
           }
 
           if(isFinal && process) {
-            const bytes = writer.getParts();
-            const processedResult = await processDownloaded(bytes);
-            checkCancel();
+            const promises = prepared
+            .filter(({writer}) => writer?.getParts && writer.replaceParts)
+            .map(async({writer}) => {
+              const bytes = writer.getParts();
+              const processedResult = await process(bytes, cacheFileName);
+              writer.replaceParts(processedResult);
+            });
 
-            writer.replaceParts(processedResult);
+            await Promise.all(promises);
+            checkCancel();
           }
 
           writeDeferred.resolve();
 
           if(isFinal) {
-            resolved = true;
-
             const realSize = size || byteLength;
-            if(!size) {
-              writer.trim(realSize);
+            if(!size || byteLength < size) {
+              prepared.forEach(({writer}) => writer?.trim?.(realSize));
             }
 
-            deferred.resolve(await writer.finalize(realSize <= MAX_FILE_SAVE_SIZE));
+            const saveToStorage = realSize <= MAX_FILE_SAVE_SIZE;
+            prepared.forEach((item) => {
+              const {deferred, writer} = item;
+              if(deferred.isFulfilled || deferred.isRejected || !writer) {
+                return;
+              }
+
+              const result = writer.finalize(saveToStorage);
+              deferred.resolve(result);
+            });
           }
         } catch(err) {
-          errorHandler(err as ApiError);
+          errorHandler(null, err as ApiError);
         }
       };
 
       for(let i = 0, length = Math.min(maxRequests, delayed.length); i < length; ++i) {
         superpuper();
       }
-    });
+    }).catch(noop);
 
     const checkCancel = () => {
-      if(error) {
-        throw error;
+      if(getErrorsCount() === prepared.length) {
+        throw prepared[0].error;
       }
     };
 
-    deferred.cancel = () => {
-      if(!error && !resolved) {
-        const error = makeError('DOWNLOAD_CANCELED');
-        errorHandler(error);
-      }
-    };
-
-    deferred.notify = (progress: Progress) => {
-      this.rootScope.dispatchEvent('download_progress', progress);
-    };
-
-    this.downloadPromises[fileName] = deferred;
-
-    deferred.catch(noop).finally(() => {
-      delete this.downloadPromises[fileName];
-    });
-
     return deferred;
   }
 
@@ -736,23 +790,14 @@ export class ApiFileManager extends AppManager {
   }
 
   public upload({file, fileName}: {file: Blob | File, fileName?: string}) {
-    const fileSize = file.size,
-      isBigFile = fileSize >= 10485760;
-
-    let canceled = false,
-      resolved = false,
-      doneParts = 0;
-    const partSize = this.getLimitPart(fileSize, true);
-
     fileName ||= getFileNameForUpload(file);
 
+    const fileSize = file.size;
+    const isBigFile = fileSize >= 10485760;
+    const partSize = this.getLimitPart(fileSize, true);
     const activeDelta = this.getDelta(partSize);
-
     const totalParts = Math.ceil(fileSize / partSize);
     const fileId = randomLong();
-
-    let _part = 0;
-
     const resultInputFile: InputFile = {
       _: isBigFile ? 'inputFileBig' : 'inputFile',
       id: fileId as any,
@@ -767,6 +812,7 @@ export class ApiFileManager extends AppManager {
       return deferred;
     }
 
+    let canceled = false, resolved = false;
     let errorHandler = (error: ApiError) => {
       if(error?.type !== 'UPLOAD_CANCELED') {
         this.log.error('Up Error', error);
@@ -774,74 +820,47 @@ export class ApiFileManager extends AppManager {
 
       deferred.reject(error);
       canceled = true;
-      errorHandler = () => {};
+      errorHandler = noop;
     };
 
     const method = isBigFile ? 'upload.saveBigFilePart' : 'upload.saveFilePart';
-
     const id = this.tempId++;
 
     const self = this;
     function* generator() {
+      let _part = 0, doneParts = 0;
       for(let offset = 0; offset < fileSize; offset += partSize) {
         const part = _part++; // 0, 1
-        yield self.downloadRequest('upload', id, () => {
+        yield self.downloadRequest('upload', id, async() => {
+          checkCancel();
+
           const blob = file.slice(offset, offset + partSize);
+          const buffer = await readBlobAsArrayBuffer(blob);
+          checkCancel();
 
-          return readBlobAsArrayBuffer(blob).then((buffer) => {
+          self.debug && self.log('Upload file part, isBig:', isBigFile, part, buffer.byteLength, new Uint8Array(buffer).length, new Uint8Array(buffer).slice().length);
+
+          return self.apiManager.invokeApi(method, {
+            file_id: fileId,
+            file_part: part,
+            file_total_parts: totalParts,
+            bytes: buffer
+          } as any, {
+            fileUpload: true
+          }).then(() => {
             if(canceled) {
-              throw makeError('UPLOAD_CANCELED');
+              return;
             }
 
-            self.debug && self.log('Upload file part, isBig:', isBigFile, part, buffer.byteLength, new Uint8Array(buffer).length, new Uint8Array(buffer).slice().length);
+            ++doneParts;
+            const progress: Progress = {done: doneParts * partSize, offset, total: fileSize, fileName};
+            deferred.notify(progress);
 
-            /* const u = new Uint8Array(buffer.byteLength);
-            for(let i = 0; i < u.length; ++i) {
-              //u[i] = Math.random() * 255 | 0;
-              u[i] = 0;
+            if(doneParts >= totalParts) {
+              deferred.resolve(resultInputFile);
+              resolved = true;
             }
-            buffer = u.buffer; */
-
-            /* setTimeout(() => {
-              doneParts++;
-              uploadResolve();
-
-              //////this.log('Progress', doneParts * partSize / fileSize);
-
-              self.log('done part', part, doneParts);
-
-              deferred.notify({done: doneParts * partSize, total: fileSize});
-
-              if(doneParts >= totalParts) {
-                deferred.resolve(resultInputFile);
-                resolved = true;
-              }
-            }, 1250);
-            return; */
-
-            return self.apiManager.invokeApi(method, {
-              file_id: fileId,
-              file_part: part,
-              file_total_parts: totalParts,
-              bytes: buffer/* new Uint8Array(buffer) */
-            } as any, {
-              // startMaxLength: partSize + 256,
-              fileUpload: true
-            }).then(() => {
-              if(canceled) {
-                return;
-              }
-
-              ++doneParts;
-              const progress: Progress = {done: doneParts * partSize, offset, total: fileSize, fileName};
-              deferred.notify(progress);
-
-              if(doneParts >= totalParts) {
-                deferred.resolve(resultInputFile);
-                resolved = true;
-              }
-            }, errorHandler);
-          });
+          }, errorHandler);
         }, activeDelta).catch(errorHandler);
       }
     }
@@ -855,14 +874,16 @@ export class ApiFileManager extends AppManager {
     };
 
     const maxRequests = Infinity;
-    // const maxRequests = 10;
-    /* for(let i = 0; i < 10; ++i) {
-      process();
-    } */
     for(let i = 0, length = Math.min(maxRequests, totalParts); i < length; ++i) {
       process();
     }
 
+    const checkCancel = () => {
+      if(canceled) {
+        throw makeError('UPLOAD_CANCELED');
+      }
+    };
+
     deferred.cancel = () => {
       if(!canceled && !resolved) {
         canceled = true;
@@ -875,7 +896,9 @@ export class ApiFileManager extends AppManager {
     };
 
     deferred.finally(() => {
-      delete this.uploadPromises[fileName];
+      if(this.uploadPromises[fileName] === deferred) {
+        delete this.uploadPromises[fileName];
+      }
     });
 
     return this.uploadPromises[fileName] = deferred;
diff --git a/src/lib/mtproto/api_methods.ts b/src/lib/mtproto/api_methods.ts
index 75f016a1..697aed0c 100644
--- a/src/lib/mtproto/api_methods.ts
+++ b/src/lib/mtproto/api_methods.ts
@@ -6,7 +6,7 @@
 
 import ctx from '../../environment/ctx';
 import {ignoreRestrictionReasons} from '../../helpers/restrictions';
-import {MethodDeclMap, User} from '../../layer';
+import {Config, MethodDeclMap, User} from '../../layer';
 import {InvokeApiOptions} from '../../types';
 import {AppManager} from '../appManagers/manager';
 import {MTAppConfig} from './appConfig';
@@ -43,8 +43,8 @@ export default abstract class ApiManagerMethods extends AppManager {
     }
   } = {};
 
+  private config: Config;
   private appConfig: MTAppConfig;
-  private getAppConfigPromise: Promise<MTAppConfig>;
 
   constructor() {
     super();
@@ -140,7 +140,7 @@ export default abstract class ApiManagerMethods extends AppManager {
     processResult: (response: MethodDeclMap[T]['res']) => R,
     processError?: (error: ApiError) => any,
     params?: MethodDeclMap[T]['req'],
-    options?: InvokeApiOptions & {cacheKey?: string}
+    options?: InvokeApiOptions & {cacheKey?: string, overwrite?: boolean}
   }): Promise<Awaited<R>> {
     o.params ??= {};
     o.options ??= {};
@@ -154,10 +154,32 @@ export default abstract class ApiManagerMethods extends AppManager {
       return oldPromise;
     }
 
+    const getNewPromise = () => {
+      const promise = map.get(cacheKey);
+      return promise === p ? undefined : promise;
+    }
+
     const originalPromise = this.invokeApi(method, params, options);
-    const newPromise: Promise<Awaited<R>> = originalPromise.then(processResult, processError);
+    const newPromise: Promise<Awaited<R>> = originalPromise.then((result) => {
+      return getNewPromise() || processResult(result);
+    }, (error) => {
+      const promise = getNewPromise();
+      if(promise) {
+        return promise;
+      }
+
+      if(!processError) {
+        throw error;
+      }
+
+      return processError(error);
+    });
 
     const p = newPromise.finally(() => {
+      if(map.get(cacheKey) !== p) {
+        return;
+      }
+
       map.delete(cacheKey);
       if(!map.size) {
         delete cache[method];
@@ -226,24 +248,38 @@ export default abstract class ApiManagerMethods extends AppManager {
     }
   }
 
-  public getConfig() {
-    return this.invokeApiCacheable('help.getConfig');
+  public getConfig(overwrite?: boolean) {
+    if(this.config && !overwrite) {
+      return this.config;
+    }
+
+    return this.invokeApiSingleProcess({
+      method: 'help.getConfig',
+      params: {},
+      processResult: (config) => {
+        this.config = config;
+        this.rootScope.dispatchEvent('config', config);
+        return config;
+      },
+      options: {overwrite}
+    });
   }
 
   public getAppConfig(overwrite?: boolean) {
-    if(this.appConfig && !overwrite) return this.appConfig;
-    if(this.getAppConfigPromise && !overwrite) return this.getAppConfigPromise;
-    const promise: Promise<MTAppConfig> = this.getAppConfigPromise = this.invokeApi('help.getAppConfig').then((config: MTAppConfig) => {
-      if(this.getAppConfigPromise !== promise) {
-        return this.getAppConfigPromise;
-      }
+    if(this.appConfig && !overwrite) {
+      return this.appConfig;
+    }
 
-      this.appConfig = config;
-      ignoreRestrictionReasons(config.ignore_restriction_reasons ?? []);
-      this.rootScope.dispatchEvent('app_config', config);
-      return config;
+    return this.invokeApiSingleProcess({
+      method: 'help.getAppConfig',
+      params: {},
+      processResult: (config: MTAppConfig) => {
+        this.appConfig = config;
+        ignoreRestrictionReasons(config.ignore_restriction_reasons ?? []);
+        this.rootScope.dispatchEvent('app_config', config);
+        return config;
+      },
+      options: {overwrite}
     });
-
-    return promise;
   }
 }
diff --git a/src/lib/mtproto/dcConfigurator.ts b/src/lib/mtproto/dcConfigurator.ts
index b76c9a45..2bb7e1f7 100644
--- a/src/lib/mtproto/dcConfigurator.ts
+++ b/src/lib/mtproto/dcConfigurator.ts
@@ -51,7 +51,7 @@ export function getTelegramConnectionSuffix(connectionType: ConnectionType) {
 // #if MTPROTO_HAS_WS
 export function constructTelegramWebSocketUrl(dcId: DcId, connectionType: ConnectionType, premium?: boolean) {
   const suffix = getTelegramConnectionSuffix(connectionType);
-  const path = connectionType !== 'client' ? 'apiws' + (premium ? PREMIUM_SUFFIX : TEST_SUFFIX) : ('apiws' + TEST_SUFFIX);
+  const path = connectionType !== 'client' ? 'apiws' + TEST_SUFFIX + (premium ? PREMIUM_SUFFIX : '') : ('apiws' + TEST_SUFFIX);
   const chosenServer = `wss://${App.suffix.toLowerCase()}ws${dcId}${suffix}.web.telegram.org/${path}`;
 
   return chosenServer;
diff --git a/src/lib/mtproto/transports/websocket.ts b/src/lib/mtproto/transports/websocket.ts
index 72b2538b..e0a8c8f8 100644
--- a/src/lib/mtproto/transports/websocket.ts
+++ b/src/lib/mtproto/transports/websocket.ts
@@ -86,8 +86,8 @@ export default class Socket extends EventListenerBase<{
     this.close();
   };
 
-  private handleClose = () => {
-    this.log('closed'/* , event, this.pending, this.ws.bufferedAmount */);
+  private handleClose = (e?: CloseEvent) => {
+    this.log('closed', e/* , this.pending, this.ws.bufferedAmount */);
 
     this.removeListeners();
     this.dispatchEvent('close');
diff --git a/src/lib/rootScope.ts b/src/lib/rootScope.ts
index fe02ee4f..9c755f9f 100644
--- a/src/lib/rootScope.ts
+++ b/src/lib/rootScope.ts
@@ -4,7 +4,7 @@
  * https://github.com/morethanwords/tweb/blob/master/LICENSE
  */
 
-import type {Message, StickerSet, Update, NotifyPeer, PeerNotifySettings, PollResults, Poll, WebPage, GroupCall, GroupCallParticipant, ReactionCount, MessagePeerReaction, PhoneCall} from '../layer';
+import type {Message, StickerSet, Update, NotifyPeer, PeerNotifySettings, PollResults, Poll, WebPage, GroupCall, GroupCallParticipant, ReactionCount, MessagePeerReaction, PhoneCall, Config} from '../layer';
 import type {AppMessagesManager, Dialog, MessagesStorageKey, MyMessage} from './appManagers/appMessagesManager';
 import type {MyDialogFilter} from './storages/filters';
 import type {Folder} from './storages/dialogs';
@@ -143,6 +143,7 @@ export type BroadcastEvents = {
 
   'premium_toggle': boolean,
 
+  'config': Config,
   'app_config': MTAppConfig
 };
 
diff --git a/src/lib/serviceWorker/download.ts b/src/lib/serviceWorker/download.ts
new file mode 100644
index 00000000..f7d8fba2
--- /dev/null
+++ b/src/lib/serviceWorker/download.ts
@@ -0,0 +1,162 @@
+/*
+ * https://github.com/morethanwords/tweb
+ * Copyright (C) 2019-2021 Eduard Kuzmenko
+ * https://github.com/morethanwords/tweb/blob/master/LICENSE
+ */
+
+import type {ServiceDownloadTaskPayload} from './serviceMessagePort';
+import type ServiceMessagePort from './serviceMessagePort';
+import deferredPromise, {CancellablePromise} from '../../helpers/cancellablePromise';
+import makeError from '../../helpers/makeError';
+import pause from '../../helpers/schedulers/pause';
+
+type DownloadType = Uint8Array;
+type DownloadItem = ServiceDownloadTaskPayload & {
+  // transformStream: TransformStream<DownloadType, DownloadType>,
+  readableStream: ReadableStream<DownloadType>,
+  // writableStream: WritableStream<DownloadType>,
+  // writer: WritableStreamDefaultWriter<DownloadType>,
+  // controller: TransformStreamDefaultController<DownloadType>,
+  controller: ReadableStreamController<Uint8Array>,
+  promise: CancellablePromise<void>,
+  // downloadPromise: Promise<void>,
+  used?: boolean
+};
+const downloadMap: Map<string, DownloadItem> = new Map();
+const DOWNLOAD_ERROR = makeError('UNKNOWN');
+const DOWNLOAD_TEST = false;
+
+type A = Parameters<ServiceMessagePort<false>['addMultipleEventsListeners']>[0];
+
+const events: A = {
+  download: (payload) => {
+    const {id} = payload;
+    if(downloadMap.has(id)) {
+      return Promise.reject(DOWNLOAD_ERROR);
+    }
+
+    // const y = (20 * 1024 * 1024) / payload.limitPart;
+    // const strategy = new ByteLengthQueuingStrategy({highWaterMark: y});
+    // let controller: TransformStreamDefaultController<DownloadType>;
+    const strategy = new CountQueuingStrategy({highWaterMark: 1});
+    // const transformStream = new TransformStream<DownloadType, DownloadType>(/* {
+    //   start: (_controller) => controller = _controller,
+    // },  */undefined, strategy, strategy);
+
+    // const {readable, writable} = transformStream;
+    // const writer = writable.getWriter();
+
+    const promise = deferredPromise<void>();
+    promise.then(() => {
+      setTimeout(() => {
+        downloadMap.delete(id);
+      }, 5e3);
+    }, () => {
+      downloadMap.delete(id);
+    });
+
+    // writer.closed.then(promise.resolve, promise.reject);
+
+    let controller: ReadableStreamController<any>;
+    const readable = new ReadableStream({
+      start: (_controller) => {
+        controller = _controller;
+      },
+
+      cancel: (reason) => {
+        promise.reject(DOWNLOAD_ERROR);
+      }
+    }, strategy);
+
+    // writer.closed.catch(noop).finally(() => {
+    //   log.error('closed writer');
+    //   onEnd();
+    // });
+
+    // const downloadPromise = writer.closed.catch(() => {throw DOWNLOAD_ERROR;});
+    const item: DownloadItem = {
+      ...payload,
+      // transformStream,
+      readableStream: readable,
+      // writableStream: writable,
+      // writer,
+      // downloadPromise,
+      promise,
+      controller
+    };
+
+    downloadMap.set(id, item);
+
+    // return downloadPromise;
+    return promise.catch(() => {throw DOWNLOAD_ERROR});
+  },
+
+  downloadChunk: ({id, chunk}) => {
+    const item = downloadMap.get(id);
+    if(!item) {
+      return Promise.reject();
+    }
+
+    // return item.controller.enqueue(chunk);
+    // return item.writer.write(chunk);
+    return item.controller.enqueue(chunk);
+  },
+
+  downloadFinalize: (id) => {
+    const item = downloadMap.get(id);
+    if(!item) {
+      return Promise.reject();
+    }
+
+    item.promise.resolve();
+    // return item.controller.terminate();
+    // return item.writer.close();
+    return item.controller.close();
+  },
+
+  downloadCancel: (id) => {
+    const item = downloadMap.get(id);
+    if(!item) {
+      return;
+    }
+
+    item.promise.reject();
+    // return item.controller.error();
+    // return item.writer.abort();
+    return item.controller.error();
+  }
+};
+
+export default function handleDownload(serviceMessagePort: ServiceMessagePort<false>) {
+  serviceMessagePort.addMultipleEventsListeners(events);
+
+  return {
+    onDownloadFetch,
+    onClosedWindows: cancelAllDownloads
+  };
+}
+
+function onDownloadFetch(event: FetchEvent, params: string) {
+  event.respondWith(pause(100).then(() => {
+    const item = downloadMap.get(params);
+    if(!item || (item.used && !DOWNLOAD_TEST)) {
+      return;
+    }
+
+    item.used = true;
+    const stream = item.readableStream;
+    const response = new Response(stream, {headers: item.headers});
+    return response;
+  }));
+
+  // event.respondWith(response);
+}
+
+function cancelAllDownloads() {
+  if(downloadMap.size) {
+    for(const [id, item] of downloadMap) {
+      // item.writer.abort().catch(noop);
+      item.controller.error();
+    }
+  }
+}
diff --git a/src/lib/serviceWorker/index.service.ts b/src/lib/serviceWorker/index.service.ts
index 1d8b0a9f..3602b636 100644
--- a/src/lib/serviceWorker/index.service.ts
+++ b/src/lib/serviceWorker/index.service.ts
@@ -14,12 +14,11 @@ import onStreamFetch from './stream';
 import {closeAllNotifications, onPing} from './push';
 import CacheStorageController from '../files/cacheStorage';
 import {IS_SAFARI} from '../../environment/userAgent';
-import ServiceMessagePort, {ServiceDownloadTaskPayload} from './serviceMessagePort';
+import ServiceMessagePort from './serviceMessagePort';
 import listenMessagePort from '../../helpers/listenMessagePort';
 import {getWindowClients} from '../../helpers/context';
 import {MessageSendPort} from '../mtproto/superMessagePort';
-import noop from '../../helpers/noop';
-import makeError from '../../helpers/makeError';
+import handleDownload from './download';
 
 export const log = logger('SW', LogTypes.Error | LogTypes.Debug | LogTypes.Log | LogTypes.Warn);
 const ctx = self as any as ServiceWorkerGlobalScope;
@@ -52,19 +51,6 @@ const onWindowConnected = (source: WindowClient) => {
   connectedWindows.add(source.id);
 };
 
-type DownloadType = Uint8Array;
-type DownloadItem = ServiceDownloadTaskPayload & {
-  transformStream: TransformStream<DownloadType, DownloadType>,
-  readableStream: ReadableStream<DownloadType>,
-  writableStream: WritableStream<DownloadType>,
-  writer: WritableStreamDefaultWriter<DownloadType>,
-  // controller: TransformStreamDefaultController<DownloadType>,
-  // promise: CancellablePromise<void>,
-  used?: boolean
-};
-const downloadMap: Map<string, DownloadItem> = new Map();
-const DOWNLOAD_ERROR = makeError('UNKNOWN');
-
 export const serviceMessagePort = new ServiceMessagePort<false>();
 serviceMessagePort.addMultipleEventsListeners({
   notificationsClear: closeAllNotifications,
@@ -79,86 +65,14 @@ serviceMessagePort.addMultipleEventsListeners({
 
   hello: (payload, source) => {
     onWindowConnected(source as any as WindowClient);
-  },
-
-  download: (payload) => {
-    const {id} = payload;
-    if(downloadMap.has(id)) {
-      return;
-    }
-
-    // const writableStrategy = new ByteLengthQueuingStrategy({highWaterMark: 1024 * 1024});
-    // let controller: TransformStreamDefaultController<DownloadType>;
-    const transformStream = new TransformStream<DownloadType, DownloadType>(/* {
-      start: (_controller) => controller = _controller,
-    }, {
-      highWaterMark: 1,
-      size: (chunk) => chunk.byteLength
-    }, new CountQueuingStrategy({highWaterMark: 4}) */);
-
-    const {readable, writable} = transformStream;
-    const writer = writable.getWriter();
-    // const promise = deferredPromise<void>();
-    // promise.catch(noop).finally(() => {
-    //   downloadMap.delete(id);
-    // });
-
-    // writer.closed.then(promise.resolve, promise.reject);
-
-    writer.closed.catch(noop).finally(() => {
-      log.error('closed writer');
-      downloadMap.delete(id);
-    });
-
-    const item: DownloadItem = {
-      ...payload,
-      transformStream,
-      readableStream: readable,
-      writableStream: writable,
-      writer
-      // promise,
-      // controller
-    };
-
-    downloadMap.set(id, item);
-
-    return writer.closed.catch(() => {throw DOWNLOAD_ERROR;});
-    // return promise;
-  },
-
-  downloadChunk: ({id, chunk}) => {
-    const item = downloadMap.get(id);
-    if(!item) {
-      return Promise.reject();
-    }
-
-    // return item.controller.enqueue(chunk);
-    return item.writer.write(chunk);
-  },
-
-  downloadFinalize: (id) => {
-    const item = downloadMap.get(id);
-    if(!item) {
-      return Promise.reject();
-    }
-
-    // item.promise.resolve();
-    // return item.controller.terminate();
-    return item.writer.close();
-  },
-
-  downloadCancel: (id) => {
-    const item = downloadMap.get(id);
-    if(!item) {
-      return;
-    }
-
-    // item.promise.reject();
-    // return item.controller.error();
-    return item.writer.abort();
   }
 });
 
+const {
+  onDownloadFetch,
+  onClosedWindows: onDownloadClosedWindows
+} = handleDownload(serviceMessagePort);
+
 // * service worker can be killed, so won't get 'hello' event
 getWindowClients().then((windowClients) => {
   log(`got ${windowClients.length} windows from the start`);
@@ -184,11 +98,7 @@ listenMessagePort(serviceMessagePort, undefined, (source) => {
       _mtprotoMessagePort = undefined;
     }
 
-    if(downloadMap.size) {
-      for(const [id, item] of downloadMap) {
-        item.writer.abort().catch(noop);
-      }
-    }
+    onDownloadClosedWindows();
   }
 });
 // #endif
@@ -216,14 +126,7 @@ const onFetch = (event: FetchEvent): void => {
       }
 
       case 'download': {
-        const item = downloadMap.get(params);
-        if(!item || item.used) {
-          break;
-        }
-
-        item.used = true;
-        const response = new Response(item.transformStream.readable, {headers: item.headers});
-        event.respondWith(response);
+        onDownloadFetch(event, params);
         break;
       }
     }
@@ -231,7 +134,8 @@ const onFetch = (event: FetchEvent): void => {
     log.error('fetch error', err);
     event.respondWith(new Response('', {
       status: 500,
-      statusText: 'Internal Server Error'
+      statusText: 'Internal Server Error',
+      headers: {'Cache-Control': 'no-cache'}
     }));
   }
 };
@@ -242,13 +146,13 @@ const onChangeState = () => {
 
 ctx.addEventListener('install', (event) => {
   log('installing');
-  event.waitUntil(ctx.skipWaiting()); // Activate worker immediately
+  event.waitUntil(ctx.skipWaiting().then(() => log('skipped waiting'))); // Activate worker immediately
 });
 
 ctx.addEventListener('activate', (event) => {
   log('activating', ctx);
-  event.waitUntil(ctx.caches.delete(CACHE_ASSETS_NAME));
-  event.waitUntil(ctx.clients.claim());
+  event.waitUntil(ctx.caches.delete(CACHE_ASSETS_NAME).then(() => log('cleared assets cache')));
+  event.waitUntil(ctx.clients.claim().then(() => log('claimed clients')));
 });
 
 // ctx.onerror = (error) => {
diff --git a/src/lib/serviceWorker/serviceMessagePort.ts b/src/lib/serviceWorker/serviceMessagePort.ts
index 290ea2c5..c4a2975c 100644
--- a/src/lib/serviceWorker/serviceMessagePort.ts
+++ b/src/lib/serviceWorker/serviceMessagePort.ts
@@ -28,9 +28,8 @@ export type ServiceRequestFilePartTaskPayload = {
 };
 
 export type ServiceDownloadTaskPayload = {
-  fileName: string,
   headers: any,
-  id: string,
+  id: string
 };
 
 export type ServiceEvent = {
diff --git a/src/scss/partials/_document.scss b/src/scss/partials/_document.scss
index 4f0d9aee..870f4750 100644
--- a/src/scss/partials/_document.scss
+++ b/src/scss/partials/_document.scss
@@ -23,6 +23,10 @@
     line-height: 1;
     text-align: center;
 
+    html.is-safari & {
+      -webkit-mask-image: -webkit-radial-gradient(circle, white 100%, black 100%); // fix safari overflow
+    }
+
     &-text {
       opacity: 0;