refactor: centralize acquisition format helpers

src/__tests__/types/opds.test.ts

@@ -3,7 +3,9 @@ import type { Acquisition, Publication } from "@/types/opds";
 import {
   findAcquisitionLinkForFormat,
   getAcquisitionLinks,
+  getAcquisitionMediaType,
   getDownloadableFormats,
+  getMediaTypeDisplayLabel,
   hasDownloadableFormats,
   isAcquisitionLink,
 } from "@/types/opds";
@@ -112,3 +114,47 @@ describe("findAcquisitionLinkForFormat", () => {
     expect(findAcquisitionLinkForFormat(htmlOnly, "application/epub+zip")).toBeNull();
   });
 });
+
+describe("getMediaTypeDisplayLabel", () => {
+  it("maps EPUB and PDF to short labels", () => {
+    expect(getMediaTypeDisplayLabel("application/epub+zip")).toBe("EPUB");
+    expect(getMediaTypeDisplayLabel("application/pdf")).toBe("PDF");
+  });
+
+  it("maps the richer badge set for known non-EPUB/PDF types", () => {
+    expect(getMediaTypeDisplayLabel("application/pdf+aes")).toBe("PDF (Encrypted)");
+    expect(getMediaTypeDisplayLabel("application/zip")).toBe("ZIP");
+    expect(getMediaTypeDisplayLabel("application/x-mobipocket-ebook")).toBe("MOBI");
+    expect(getMediaTypeDisplayLabel("image/jpeg")).toBe("JPEG");
+  });
+
+  it("matches case-insensitively", () => {
+    expect(getMediaTypeDisplayLabel("Application/EPUB+ZIP")).toBe("EPUB");
+  });
+
+  it("falls back to the raw media type for unknown formats", () => {
+    expect(getMediaTypeDisplayLabel("application/x-custom-format")).toBe(
+      "application/x-custom-format",
+    );
+  });
+});
+
+describe("getAcquisitionMediaType", () => {
+  it("prefers media_type over type", () => {
+    expect(
+      getAcquisitionMediaType(
+        link({ href: "/x", media_type: "application/pdf", type: "application/epub+zip" }),
+      ),
+    ).toBe("application/pdf");
+  });
+
+  it("falls back to the type when media_type is absent", () => {
+    expect(getAcquisitionMediaType(link({ href: "/x", type: "application/epub+zip" }))).toBe(
+      "application/epub+zip",
+    );
+  });
+
+  it("defaults to EPUB when neither media_type nor type is present", () => {
+    expect(getAcquisitionMediaType(link({ href: "/x" }))).toBe("application/epub+zip");
+  });
+});

src/features/opds/OpdsPublicationCard.tsx

@@ -10,8 +10,9 @@ import type React from "react";
 import { Button } from "@/components/ui/Button";
 import type { CategorizedLibraryRecord, PublicationLibraryInfo } from "@/types/offline";
 import type { DownloadStatus, MediaType, Publication } from "@/types/opds";
+import { getMediaTypeDisplayLabel } from "@/types/opds";
 import { LibraryStateBadge } from "./LibraryStateBadge";
-import { getMediaTypeLabel, PublicationFormatMenu } from "./PublicationFormatMenu";
+import { PublicationFormatMenu } from "./PublicationFormatMenu";
 import { usePublicationState } from "./usePublicationState";
 
 interface OpdsPublicationCardProps {
@@ -41,24 +42,6 @@ interface OpdsPublicationCardProps {
   onViewDetails?: (publication: Publication) => void;
 }
 
-function getMediaTypeLabelForBadge(mediaType: string): string {
-  const labels: Record<string, string> = {
-    "application/epub+zip": "EPUB",
-    "application/pdf": "PDF",
-    "application/pdf+aes": "PDF (Encrypted)",
-    "application/zip": "ZIP",
-    "chemical/x-mdldrum": "MDL",
-    "chemical/x-mol": "MOL",
-    "text/html": "HTML",
-    "application/rtf": "RTF",
-    "application/x-mobipocket-ebook": "MOBI",
-    "application/x-kindle": "Kindle",
-    "image/jpeg": "JPEG",
-    "image/png": "PNG",
-  };
-  return labels[mediaType.toLowerCase()] || mediaType;
-}
-
 export const OpdsPublicationCard: React.FC<OpdsPublicationCardProps> = ({
   publication,
   showFormats = true,
@@ -192,7 +175,7 @@ export const OpdsPublicationCard: React.FC<OpdsPublicationCardProps> = ({
             {formatLabels.map((fmt) => (
               <li key={fmt}>
                 <span className="badge badge-xs badge-outline badge-info">
-                  {getMediaTypeLabelForBadge(fmt)}
+                  {getMediaTypeDisplayLabel(fmt)}
                 </span>
               </li>
             ))}
@@ -260,7 +243,7 @@ export const OpdsPublicationCard: React.FC<OpdsPublicationCardProps> = ({
                 size="sm"
                 onClick={handleDownload}
                 className="w-full outline-none focus-visible:ring-2 focus-visible:ring-primary"
-                aria-label={`Download ${publication.title} as ${getMediaTypeLabel(selectedFormat)}`}
+                aria-label={`Download ${publication.title} as ${getMediaTypeDisplayLabel(selectedFormat)}`}
               >
                 <DownloadIcon className="w-4 h-4 mr-1" aria-hidden="true" />
                 Download
@@ -289,15 +272,15 @@ export const OpdsPublicationCard: React.FC<OpdsPublicationCardProps> = ({
                 className="text-error justify-start gap-2 px-2 outline-none focus-visible:ring-2 focus-visible:ring-primary"
                 aria-label={
                   record.section === "superseded"
-                    ? `Delete older ${getMediaTypeLabelForBadge(record.media_type)} copy of ${publication.title}`
+                    ? `Delete older ${getMediaTypeDisplayLabel(record.media_type)} copy of ${publication.title}`
                     : `Delete local copy of ${publication.title}`
                 }
               >
                 <TrashIcon className="w-3.5 h-3.5" aria-hidden="true" />
                 {deletingRevisionId === record.revision_id
                   ? "Deleting..."
                   : record.section === "superseded"
-                    ? `Delete older ${getMediaTypeLabelForBadge(record.media_type)} copy`
+                    ? `Delete older ${getMediaTypeDisplayLabel(record.media_type)} copy`
                     : "Delete local copy"}
               </Button>
             ))}

src/features/opds/PublicationDetailModal.tsx

@@ -3,7 +3,11 @@ import type React from "react";
 import { Button } from "@/components/ui/Button";
 import type { CategorizedLibraryRecord, PublicationLibraryInfo } from "@/types/offline";
 import type { DownloadStatus, MediaType, Publication } from "@/types/opds";
-import { getAcquisitionLinks } from "@/types/opds";
+import {
+  getAcquisitionLinks,
+  getAcquisitionMediaType,
+  getMediaTypeDisplayLabel,
+} from "@/types/opds";
 import { LibraryStateBadge } from "./LibraryStateBadge";
 
 interface PublicationDetailModalProps {
@@ -210,13 +214,8 @@ export const PublicationDetailModal: React.FC<PublicationDetailModalProps> = ({
               {downloadStatus !== "downloading" && (
                 <div className="flex flex-wrap gap-2">
                   {acquisitionLinks.map((link) => {
-                    const format = link.media_type ?? link.type ?? "application/epub+zip";
-                    const label =
-                      format === "application/epub+zip"
-                        ? "EPUB"
-                        : format === "application/pdf"
-                          ? "PDF"
-                          : format;
+                    const format = getAcquisitionMediaType(link);
+                    const label = getMediaTypeDisplayLabel(format);
                     return (
                       <Button
                         key={`${link.href}-${format}`}

src/features/opds/PublicationFormatMenu.tsx

@@ -3,13 +3,10 @@ import type React from "react";
 import { useEffect, useId, useRef } from "react";
 import { Button } from "@/components/ui/Button";
 import type { MediaType } from "@/types/opds";
+import { getMediaTypeDisplayLabel } from "@/types/opds";
 
 function getMediaTypeLabel(mediaType: MediaType): string {
-  const labels: Record<MediaType, string> = {
-    "application/epub+zip": "EPUB",
-    "application/pdf": "PDF",
-  };
-  return labels[mediaType] || mediaType;
+  return getMediaTypeDisplayLabel(mediaType);
 }
 
 interface PublicationFormatMenuProps {

src/types/opds.ts

@@ -159,3 +159,35 @@ export function findAcquisitionLinkForFormat(
     ) ?? null
   );
 }
+
+const MEDIA_TYPE_LABELS: Record<string, string> = {
+  "application/epub+zip": "EPUB",
+  "application/pdf": "PDF",
+  "application/pdf+aes": "PDF (Encrypted)",
+  "application/zip": "ZIP",
+  "chemical/x-mdldrum": "MDL",
+  "chemical/x-mol": "MOL",
+  "text/html": "HTML",
+  "application/rtf": "RTF",
+  "application/x-mobipocket-ebook": "MOBI",
+  "application/x-kindle": "Kindle",
+  "image/jpeg": "JPEG",
+  "image/png": "PNG",
+};
+
+/**
+ * Single source for display labels shown next to media types (badges, format
+ * menus, download buttons). Falls back to the raw media type for unknown
+ * formats and matches case-insensitively.
+ */
+export function getMediaTypeDisplayLabel(mediaType: string): string {
+  return MEDIA_TYPE_LABELS[mediaType.toLowerCase()] || mediaType;
+}
+
+/**
+ * Normalize an acquisition link into its download format, preferring
+ * `media_type` over `type` and defaulting to EPUB when neither is present.
+ */
+export function getAcquisitionMediaType(link: Acquisition): MediaType {
+  return link.media_type ?? link.type ?? EPUB_MEDIA_TYPE;
+}