Enable more specific AttachmentDownload prioritization

ts/types/Attachment.ts

@@ -70,7 +70,6 @@ export type AttachmentType = {
   flags?: number;
   thumbnail?: ThumbnailType;
   isCorrupted?: boolean;
-  downloadJobId?: string;
   cdnNumber?: number;
   cdnId?: string;
   cdnKey?: string;
@@ -696,7 +695,7 @@ export function hasNotResolved(attachment?: AttachmentType): boolean {
 
 export function isDownloading(attachment?: AttachmentType): boolean {
   const resolved = resolveNestedAttachment(attachment);
-  return Boolean(resolved && resolved.downloadJobId && resolved.pending);
+  return Boolean(resolved && resolved.pending);
 }
 
 export function hasFailed(attachment?: AttachmentType): boolean {

ts/types/AttachmentDownload.ts

@@ -0,0 +1,56 @@
+// Copyright 2024 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+import { z } from 'zod';
+import { MIMETypeSchema, type MIMEType } from './MIME';
+import type { AttachmentType } from './Attachment';
+
+export const attachmentDownloadTypeSchema = z.enum([
+  'long-message',
+  'attachment',
+  'preview',
+  'contact',
+  'quote',
+  'sticker',
+]);
+
+export type AttachmentDownloadJobTypeType = z.infer<
+  typeof attachmentDownloadTypeSchema
+>;
+
+export type AttachmentDownloadJobType = {
+  messageId: string;
+  receivedAt: number;
+  sentAt: number;
+  attachmentType: AttachmentDownloadJobTypeType;
+  attachment: AttachmentType;
+  attempts: number;
+  active: boolean;
+  retryAfter: number | null;
+  lastAttemptTimestamp: number | null;
+  digest: string;
+  contentType: MIMEType;
+  size: number;
+};
+
+export const attachmentDownloadJobSchema = z.object({
+  messageId: z.string(),
+  receivedAt: z.number(),
+  sentAt: z.number(),
+  attachmentType: attachmentDownloadTypeSchema,
+  attachment: z
+    .object({ size: z.number(), contentType: MIMETypeSchema })
+    .passthrough(),
+  attempts: z.number(),
+  active: z.boolean(),
+  retryAfter: z.number().nullable(),
+  lastAttemptTimestamp: z.number().nullable(),
+  digest: z.string(),
+  contentType: MIMETypeSchema,
+  size: z.number(),
+  messageIdForLogging: z.string().optional(),
+}) satisfies z.ZodType<
+  Omit<AttachmentDownloadJobType, 'attachment' | 'contentType'> & {
+    contentType: string;
+    attachment: Record<string, unknown>;
+  }
+>;

ts/types/MIME.ts

@@ -1,7 +1,9 @@
 // Copyright 2018 Signal Messenger, LLC
 // SPDX-License-Identifier: AGPL-3.0-only
+import { z } from 'zod';
 
-export type MIMEType = string & { _mimeTypeBrand: never };
+export const MIMETypeSchema = z.string().brand('mimeType');
+export type MIMEType = z.infer<typeof MIMETypeSchema>;
 
 export const stringToMIMEType = (value: string): MIMEType => {
   return value as MIMEType;