refactor: stricter domain: attachments

toju-app/src/app/domains/attachment/application/services/attachment-transfer-transport.service.ts

@@ -0,0 +1,109 @@
+import { Injectable, inject } from '@angular/core';
+import { RealtimeSessionFacade } from '../../../../core/realtime';
+import { AttachmentStorageService } from '../../infrastructure/services/attachment-storage.service';
+import { FILE_CHUNK_SIZE_BYTES } from '../../domain/constants/attachment-transfer.constants';
+import { FileChunkEvent } from '../../domain/models/attachment-transfer.models';
+
+@Injectable({ providedIn: 'root' })
+export class AttachmentTransferTransportService {
+  private readonly webrtc = inject(RealtimeSessionFacade);
+  private readonly attachmentStorage = inject(AttachmentStorageService);
+
+  decodeBase64(base64: string): Uint8Array {
+    const binary = atob(base64);
+    const bytes = new Uint8Array(binary.length);
+
+    for (let index = 0; index < binary.length; index++) {
+      bytes[index] = binary.charCodeAt(index);
+    }
+
+    return bytes;
+  }
+
+  async streamFileToPeer(
+    targetPeerId: string,
+    messageId: string,
+    fileId: string,
+    file: File,
+    isCancelled: () => boolean
+  ): Promise<void> {
+    const totalChunks = Math.ceil(file.size / FILE_CHUNK_SIZE_BYTES);
+
+    let offset = 0;
+    let chunkIndex = 0;
+
+    while (offset < file.size) {
+      if (isCancelled())
+        break;
+
+      const slice = file.slice(offset, offset + FILE_CHUNK_SIZE_BYTES);
+      const arrayBuffer = await slice.arrayBuffer();
+      const base64 = this.arrayBufferToBase64(arrayBuffer);
+      const fileChunkEvent: FileChunkEvent = {
+        type: 'file-chunk',
+        messageId,
+        fileId,
+        index: chunkIndex,
+        total: totalChunks,
+        data: base64
+      };
+
+      await this.webrtc.sendToPeerBuffered(targetPeerId, fileChunkEvent);
+
+      offset += FILE_CHUNK_SIZE_BYTES;
+      chunkIndex++;
+    }
+  }
+
+  async streamFileFromDiskToPeer(
+    targetPeerId: string,
+    messageId: string,
+    fileId: string,
+    diskPath: string,
+    isCancelled: () => boolean
+  ): Promise<void> {
+    const base64Full = await this.attachmentStorage.readFile(diskPath);
+
+    if (!base64Full)
+      return;
+
+    const fileBytes = this.decodeBase64(base64Full);
+    const totalChunks = Math.ceil(fileBytes.byteLength / FILE_CHUNK_SIZE_BYTES);
+
+    for (let chunkIndex = 0; chunkIndex < totalChunks; chunkIndex++) {
+      if (isCancelled())
+        break;
+
+      const start = chunkIndex * FILE_CHUNK_SIZE_BYTES;
+      const end = Math.min(fileBytes.byteLength, start + FILE_CHUNK_SIZE_BYTES);
+      const slice = fileBytes.subarray(start, end);
+      const sliceBuffer = (slice.buffer as ArrayBuffer).slice(
+        slice.byteOffset,
+        slice.byteOffset + slice.byteLength
+      );
+      const base64Chunk = this.arrayBufferToBase64(sliceBuffer);
+      const fileChunkEvent: FileChunkEvent = {
+        type: 'file-chunk',
+        messageId,
+        fileId,
+        index: chunkIndex,
+        total: totalChunks,
+        data: base64Chunk
+      };
+
+      this.webrtc.sendToPeer(targetPeerId, fileChunkEvent);
+    }
+  }
+
+  private arrayBufferToBase64(buffer: ArrayBuffer): string {
+    let binary = '';
+
+    const bytes = new Uint8Array(buffer);
+
+    for (let index = 0; index < bytes.byteLength; index++) {
+      binary += String.fromCharCode(bytes[index]);
+    }
+
+    return btoa(binary);
+  }
+}