From f41c81eb56e5c4f7137fce887425d953471c37ea Mon Sep 17 00:00:00 2001
From: npeter83 <npeter83+claude@gmail.com>
Date: Sat, 29 Aug 2026 21:52:13 +0200
Subject: [PATCH] fix(downloads): media-library UI review fixes (E7)

Deep-review remediation on the frontend, all findings adversarially verified:

- LibraryPlayer picks audio vs video from the canonical media_kind (single source), not a
  hardcoded container whitelist, so an uploaded audio file with an uncommon/absent container
  renders in <audio> instead of a broken video box (legacy null media_kind keeps the heuristic).
- UploadDialog aborts the in-flight upload when the dialog is closed by X/ESC/backdrop/Back
  (not only the footer Cancel); drag highlight uses an enter/leave depth counter to stop the
  flicker; the progress bar gets a stable role=progressbar aria-label with the value on aria-valuenow.
- DownloadCenter's Shared tab renders honest loading/error states instead of a blank panel, and
  the library/shared row-action gating moves to a single tested helper (lib/downloadActions).

Tests: downloadActions gating matrix, the uploadReq XHR path (abort/401/422-localize/onerror),
and the media_kind-driven audio/video branch.

i18n: downloads.upload.uploadProgress (HU + EN).
---
 frontend/src/components/DownloadCenter.tsx    |  47 +++----
 .../src/components/LibraryPlayer.dom.test.tsx |  36 +++++-
 frontend/src/components/LibraryPlayer.tsx     |  21 ++--
 frontend/src/components/UploadDialog.tsx      |  31 ++++-
 frontend/src/i18n/locales/en/downloads.json   |   1 +
 frontend/src/i18n/locales/hu/downloads.json   |   1 +
 frontend/src/lib/api/core.test.ts             | 119 ++++++++++++++++++
 frontend/src/lib/downloadActions.test.ts      |  79 ++++++++++++
 frontend/src/lib/downloadActions.ts           |  43 +++++++
 9 files changed, 338 insertions(+), 40 deletions(-)
 create mode 100644 frontend/src/lib/api/core.test.ts
 create mode 100644 frontend/src/lib/downloadActions.test.ts
 create mode 100644 frontend/src/lib/downloadActions.ts

diff --git a/frontend/src/components/DownloadCenter.tsx b/frontend/src/components/DownloadCenter.tsx
index 0f2cb7b5..819890dd 100644
--- a/frontend/src/components/DownloadCenter.tsx
+++ b/frontend/src/components/DownloadCenter.tsx
@@ -35,6 +35,7 @@ import { useLiveQuery } from "../lib/useLiveQuery";
 import { useMe } from "../lib/useMe";
 import { api, type DownloadJob } from "../lib/api";
 import { invalidateDownloads, quickShareLink } from "../lib/downloads";
+import { libraryRowActions, sharedRowActions } from "../lib/downloadActions";
 import { inputCls } from "./ui/form";
 import { Button } from "./ui/Button";
 import { DownloadRow, IconBtn, UsageBar } from "./downloadRow";
@@ -280,28 +281,22 @@ export default function DownloadCenter() {
             <UsageBar />
             <div className="space-y-2">
               {library.map((job) => {
-                // E7·S5b — gate row actions on the stored media_kind. A generic uploaded file
-                // (media_kind='file') is download+share only: no player and no timeline to trim
-                // (Play/Edit are media-only), and no metadata/channel edit. Re-download needs a
-                // re-fetchable source, which an edit clip and an upload both lack (backend rejects
-                // both), so it's a true-download-only action.
-                const isFile = job.asset?.media_kind === "file";
-                const isMedia = !isFile;
-                const canRedownload = job.job_kind !== "edit" && job.job_kind !== "upload";
+                // Row actions gated on the stored media_kind + job_kind (see downloadActions).
+                const a = libraryRowActions(job);
                 return (
                   <DownloadRow key={job.id} job={job}>
-                    {isMedia && (
+                    {a.play && (
                       <IconBtn onClick={() => setPlayJob(job)} title={t("downloads.actions.play")}>
                         <PlayCircle className="w-4 h-4" />
                       </IconBtn>
                     )}
                     {saveBtn(job)}
-                    {isMedia && job.can_download && (job.asset?.duration_s ?? 0) > 0 && (
+                    {a.edit && (
                       <IconBtn onClick={() => setEditJob(job)} title={t("downloads.actions.edit")}>
                         <Scissors className="w-4 h-4" />
                       </IconBtn>
                     )}
-                    {isMedia && (
+                    {a.editDetails && (
                       <IconBtn
                         onClick={() => setMetaJob(job)}
                         title={t("downloads.actions.editDetails")}
@@ -318,7 +313,7 @@ export default function DownloadCenter() {
                     >
                       <Link2 className="w-4 h-4" />
                     </IconBtn>
-                    {canRedownload && (
+                    {a.redownload && (
                       <IconBtn
                         onClick={() =>
                           confirmThen(
@@ -367,18 +362,17 @@ export default function DownloadCenter() {
         {tab === "shared" && (
           <div className="space-y-2">
             {(sharedQ.data ?? []).map((job) => {
-              // Same media_kind gate as the library (S5b): a shared generic file is download-only —
-              // no player, no trim. Its owner set can_download, which still gates save/edit here.
-              const isMedia = job.asset?.media_kind !== "file";
+              // Same media_kind + can_download gate as the library, via the shared helper (S5b).
+              const a = sharedRowActions(job);
               return (
                 <DownloadRow key={job.id} job={job}>
-                  {isMedia && job.can_download && (
+                  {a.play && (
                     <IconBtn onClick={() => setPlayJob(job)} title={t("downloads.actions.play")}>
                       <PlayCircle className="w-4 h-4" />
                     </IconBtn>
                   )}
-                  {job.can_download && saveBtn(job)}
-                  {isMedia && job.can_download && (job.asset?.duration_s ?? 0) > 0 && (
+                  {a.save && saveBtn(job)}
+                  {a.edit && (
                     <IconBtn onClick={() => setEditJob(job)} title={t("downloads.actions.edit")}>
                       <Scissors className="w-4 h-4" />
                     </IconBtn>
@@ -399,11 +393,18 @@ export default function DownloadCenter() {
                 </DownloadRow>
               );
             })}
-            {sharedQ.data && sharedQ.data.length === 0 && (
-              <div className="text-sm text-muted py-10 text-center">
-                {t("downloads.empty.shared")}
-              </div>
-            )}
+            {(sharedQ.data ?? []).length === 0 &&
+              (sharedQ.isError && !sharedQ.data ? (
+                <StateMessage tone="error" onRetry={() => sharedQ.refetch()}>
+                  {t("common.loadError")}
+                </StateMessage>
+              ) : sharedQ.isLoading ? (
+                <LoadingState />
+              ) : (
+                <div className="text-sm text-muted py-10 text-center">
+                  {t("downloads.empty.shared")}
+                </div>
+              ))}
           </div>
         )}
 
diff --git a/frontend/src/components/LibraryPlayer.dom.test.tsx b/frontend/src/components/LibraryPlayer.dom.test.tsx
index 0ca2fc96..aaa05ede 100644
--- a/frontend/src/components/LibraryPlayer.dom.test.tsx
+++ b/frontend/src/components/LibraryPlayer.dom.test.tsx
@@ -1,9 +1,9 @@
 // @vitest-environment jsdom
 //
 // E7·S4b — the in-app library player streams the completed item's LOCAL file into a native media
-// element (no transcode; S4a guarantees a browser-native container). A video asset (has pixel dims)
-// renders <video src=/file>; an audio-only asset (m4a/mp3, no dims) renders <audio src=/file>. i18n is
-// key-passthrough here.
+// element. video/audio is chosen from the stored media_kind (the single source), NOT a container
+// list — so an audio upload with an uncommon/absent container still renders <audio src=/file>. i18n
+// is key-passthrough here.
 import { describe, it, expect, afterEach, vi } from "vitest";
 import { render, cleanup } from "@testing-library/react";
 
@@ -89,11 +89,37 @@ describe("LibraryPlayer", () => {
     expect(document.body.querySelector("audio")).toBeNull();
   });
 
-  it("plays an audio-only asset (no dims, m4a) in an <audio> element", () => {
-    render(<LibraryPlayer job={withAsset({ container: "m4a" })} onClose={() => {}} />);
+  it("plays an audio-only asset (media_kind='audio') in an <audio> element", () => {
+    render(
+      <LibraryPlayer
+        job={withAsset({ media_kind: "audio", container: "m4a" })}
+        onClose={() => {}}
+      />,
+    );
     const audio = document.body.querySelector("audio");
     expect(audio).not.toBeNull();
     expect(audio!.getAttribute("src")).toBe("/api/downloads/7/file");
     expect(document.body.querySelector("video")).toBeNull();
   });
+
+  it("uses media_kind — an audio upload with an uncommon container still renders <audio>", () => {
+    // The exact bug the fix targets: the old container whitelist (m4a/mp3/…) would drop an .m4b/.weba
+    // audio upload into a <video> box. media_kind='audio' is authoritative regardless of container.
+    render(
+      <LibraryPlayer
+        job={withAsset({ media_kind: "audio", container: "m4b" })}
+        onClose={() => {}}
+      />,
+    );
+    expect(document.body.querySelector("audio")).not.toBeNull();
+    expect(document.body.querySelector("video")).toBeNull();
+  });
+
+  it("falls back to the container heuristic for a legacy null media_kind", () => {
+    // A pre-discriminator asset (media_kind null) still resolves audio vs video from dims+container.
+    render(
+      <LibraryPlayer job={withAsset({ media_kind: null, container: "mp3" })} onClose={() => {}} />,
+    );
+    expect(document.body.querySelector("audio")).not.toBeNull();
+  });
 });
diff --git a/frontend/src/components/LibraryPlayer.tsx b/frontend/src/components/LibraryPlayer.tsx
index 9c296d6d..0b8caa4c 100644
--- a/frontend/src/components/LibraryPlayer.tsx
+++ b/frontend/src/components/LibraryPlayer.tsx
@@ -8,19 +8,24 @@ import { jobTitle } from "./downloadRow";
 // YouTube IFrame shell) or PlexPlayer (a Plex HLS/session shell): both are bound to their own domain
 // APIs and can't point at a local file. Instead we reuse the shared a11y shell (`Modal`: focus-trap,
 // ESC/back-to-close, scroll-lock, layer-stack, portal) and stream the local file into a NATIVE
-// <video>/<audio controls> — the same element VideoEditor already plays this URL in. S4a guarantees
-// every download is a browser-native container (mp4/H.264/AAC + m4a/mp3), so native playback (seek via
-// the range-aware /file endpoint, volume, fullscreen, speed) always works with zero transcode.
+// <video>/<audio controls> — the same element VideoEditor already plays this URL in. Downloads are a
+// browser-native container (mp4/H.264/AAC + m4a/mp3), so native playback (seek via the range-aware
+// /file endpoint, volume, fullscreen, speed) works with zero transcode; an uploaded media item may be
+// any codec (best-effort playback).
 export default function LibraryPlayer({ job, onClose }: { job: DownloadJob; onClose: () => void }) {
   const { t } = useTranslation();
   const fileUrl = useMemo(() => api.downloadFileUrl(job.id), [job.id]);
-  // Video vs audio-only: a video asset carries real pixel dimensions; audio (m4a/mp3) has none. Fall
-  // back to the container kind so a dimension-less-but-video asset still gets the <video> element.
+  // Video vs audio-only comes from the stored media_kind (the single source every sibling reads —
+  // WatchPage/downloadRow/DownloadCenter) — NOT a re-derived container list, which would misclassify
+  // an uploaded audio file whose container is outside a hardcoded set (uploads accept any container).
+  // Only fall back to the old dimension+container heuristic for a legacy asset with a null media_kind.
   const asset = job.asset;
   const isAudio =
-    !(asset?.width && asset?.height) &&
-    !!asset?.container &&
-    ["m4a", "mp3", "opus", "ogg", "wav", "flac", "aac"].includes(asset.container.toLowerCase());
+    asset?.media_kind === "audio" ||
+    (asset?.media_kind == null &&
+      !(asset?.width && asset?.height) &&
+      !!asset?.container &&
+      ["m4a", "mp3", "opus", "ogg", "wav", "flac", "aac"].includes(asset.container.toLowerCase()));
   // Our self-hosted poster (always same-origin, never expires) is the primary; the source thumbnail is
   // the fallback. Same precedence as the library-row thumbnail.
   const poster = job.poster_url ? api.posterImageUrl(job.id) : (asset?.thumbnail_url ?? undefined);
diff --git a/frontend/src/components/UploadDialog.tsx b/frontend/src/components/UploadDialog.tsx
index 4edbdd85..c5eeebca 100644
--- a/frontend/src/components/UploadDialog.tsx
+++ b/frontend/src/components/UploadDialog.tsx
@@ -1,4 +1,4 @@
-import { useRef, useState } from "react";
+import { useEffect, useRef, useState } from "react";
 import { useTranslation } from "react-i18next";
 import { useQueryClient } from "@tanstack/react-query";
 import { UploadCloud, File as FileIcon } from "lucide-react";
@@ -24,8 +24,16 @@ export default function UploadDialog({ onClose }: { onClose: () => void }) {
   const [pct, setPct] = useState<number | null>(null); // null = idle; 0–100 while uploading
   const inputRef = useRef<HTMLInputElement>(null);
   const abortRef = useRef<AbortController | null>(null);
+  // dragenter/dragleave fire as the cursor crosses the drop zone's OWN children (icon/text), so a
+  // plain boolean flickers. Count enter vs leave and only clear the highlight at depth 0.
+  const dragDepth = useRef(0);
   const busy = pct !== null;
 
+  // Closing the dialog mid-upload (X / ESC / backdrop / browser Back all unmount us) must abort the
+  // in-flight XHR — otherwise it keeps streaming in the background and still toasts success. Only the
+  // footer Cancel wired the abort; this covers every other dismissal.
+  useEffect(() => () => abortRef.current?.abort(), []);
+
   const pick = () => inputRef.current?.click();
 
   const submit = async () => {
@@ -62,13 +70,19 @@ export default function UploadDialog({ onClose }: { onClose: () => void }) {
       <button
         type="button"
         onClick={pick}
-        onDragOver={(e) => {
+        onDragEnter={(e) => {
           e.preventDefault();
+          dragDepth.current += 1;
           setDragOver(true);
         }}
-        onDragLeave={() => setDragOver(false)}
+        onDragOver={(e) => e.preventDefault()}
+        onDragLeave={() => {
+          dragDepth.current = Math.max(0, dragDepth.current - 1);
+          if (dragDepth.current === 0) setDragOver(false);
+        }}
         onDrop={(e) => {
           e.preventDefault();
+          dragDepth.current = 0;
           setDragOver(false);
           const f = e.dataTransfer.files?.[0];
           if (f) {
@@ -123,7 +137,16 @@ export default function UploadDialog({ onClose }: { onClose: () => void }) {
 
       {busy && (
         <div className="mb-5" aria-live="polite">
-          <div className="h-2 rounded-full bg-surface overflow-hidden">
+          <div
+            className="h-2 rounded-full bg-surface overflow-hidden"
+            role="progressbar"
+            aria-valuenow={pct ?? 0}
+            aria-valuemin={0}
+            aria-valuemax={100}
+            // A STABLE descriptor as the name; the live percentage rides aria-valuenow (and the visible
+            // <p> below re-announces it via the aria-live wrapper) — don't bake the value into the name.
+            aria-label={t("downloads.upload.uploadProgress")}
+          >
             <div
               className="h-full bg-accent transition-[width] duration-150"
               style={{ width: `${pct ?? 0}%` }}
diff --git a/frontend/src/i18n/locales/en/downloads.json b/frontend/src/i18n/locales/en/downloads.json
index 06c7cd21..6bd6082f 100644
--- a/frontend/src/i18n/locales/en/downloads.json
+++ b/frontend/src/i18n/locales/en/downloads.json
@@ -33,6 +33,7 @@
     "namePlaceholder": "Leave blank to use the file name",
     "submit": "Upload",
     "uploading": "Uploading… {{pct}}%",
+    "uploadProgress": "Upload progress",
     "added": "File uploaded"
   },
   "tabs": {
diff --git a/frontend/src/i18n/locales/hu/downloads.json b/frontend/src/i18n/locales/hu/downloads.json
index c4e03813..56ab3e54 100644
--- a/frontend/src/i18n/locales/hu/downloads.json
+++ b/frontend/src/i18n/locales/hu/downloads.json
@@ -33,6 +33,7 @@
     "namePlaceholder": "Hagyd üresen a fájlnév használatához",
     "submit": "Feltöltés",
     "uploading": "Feltöltés… {{pct}}%",
+    "uploadProgress": "Feltöltés folyamata",
     "added": "Fájl feltöltve"
   },
   "tabs": {
diff --git a/frontend/src/lib/api/core.test.ts b/frontend/src/lib/api/core.test.ts
new file mode 100644
index 00000000..73e3b365
--- /dev/null
+++ b/frontend/src/lib/api/core.test.ts
@@ -0,0 +1,119 @@
+// @vitest-environment jsdom
+//
+// uploadReq is the XHR upload path (progress/abort/error/401/4xx-localize) that `fetch`/`req` can't
+// cover. UploadDialog's DOM test mocks api.uploadDownload wholesale, so without this the abort, 401,
+// and structured-detail-localize branches ship untested. A controllable fake XMLHttpRequest drives
+// each lifecycle branch.
+import { describe, it, expect, beforeEach, vi } from "vitest";
+
+const { reportError, notify, remove } = vi.hoisted(() => ({
+  reportError: vi.fn(),
+  notify: vi.fn(() => 1),
+  remove: vi.fn(),
+}));
+
+vi.mock("../errorDialog", () => ({ reportError }));
+vi.mock("../notifications", () => ({ notify, remove }));
+vi.mock("../../i18n", () => ({ default: { t: (k: string) => k, language: "en" } }));
+vi.mock("../activeAccount", () => ({
+  activeAccountId: () => null,
+  ACTIVE_ACCOUNT_KEY: "k",
+  notifyActiveAccountChange: vi.fn(),
+}));
+
+import { uploadReq, setUnauthorizedHandler, HttpError } from "./core";
+
+// A fake XHR whose lifecycle the test drives: capture the instance, set status/responseText, then
+// invoke onload/onerror/abort by hand.
+class FakeXHR {
+  static last: FakeXHR;
+  status = 0;
+  responseText = "";
+  withCredentials = false;
+  headers: Record<string, string> = {};
+  upload: { onprogress: ((e: ProgressEvent) => void) | null } = { onprogress: null };
+  onload: (() => void) | null = null;
+  onerror: (() => void) | null = null;
+  onabort: (() => void) | null = null;
+  sent = false;
+  constructor() {
+    FakeXHR.last = this;
+  }
+  open() {}
+  setRequestHeader(k: string, v: string) {
+    this.headers[k] = v;
+  }
+  send() {
+    this.sent = true;
+  }
+  abort() {
+    this.onabort?.();
+  }
+}
+
+beforeEach(() => {
+  reportError.mockReset();
+  notify.mockReset();
+  setUnauthorizedHandler(null);
+  vi.stubGlobal("XMLHttpRequest", FakeXHR as unknown as typeof XMLHttpRequest);
+});
+
+const form = () => new FormData();
+
+describe("uploadReq", () => {
+  it("resolves with the parsed JSON on a 2xx", async () => {
+    const p = uploadReq<{ id: number }>("/u", form());
+    const x = FakeXHR.last;
+    x.status = 200;
+    x.responseText = '{"id":7}';
+    x.onload!();
+    await expect(p).resolves.toEqual({ id: 7 });
+  });
+
+  it("rejects immediately if the signal is already aborted (never sends)", async () => {
+    const ac = new AbortController();
+    ac.abort();
+    const p = uploadReq("/u", form(), { signal: ac.signal });
+    await expect(p).rejects.toBeInstanceOf(HttpError);
+    expect(FakeXHR.last?.sent).not.toBe(true);
+  });
+
+  it("aborts the XHR and rejects when the signal fires", async () => {
+    const ac = new AbortController();
+    const p = uploadReq("/u", form(), { signal: ac.signal });
+    ac.abort(); // → our abort listener calls xhr.abort() → onabort → reject
+    await expect(p).rejects.toMatchObject({ status: 0 });
+  });
+
+  it("calls the unauthorized handler on 401", async () => {
+    const onUnauth = vi.fn();
+    setUnauthorizedHandler(onUnauth);
+    const p = uploadReq("/u", form());
+    const x = FakeXHR.last;
+    x.status = 401;
+    x.onload!();
+    await expect(p).rejects.toBeInstanceOf(HttpError);
+    expect(onUnauth).toHaveBeenCalledOnce();
+    expect(reportError).not.toHaveBeenCalled();
+  });
+
+  it("localizes a structured 422 upload_too_large and surfaces the error", async () => {
+    const p = uploadReq("/u", form());
+    const x = FakeXHR.last;
+    x.status = 422;
+    x.responseText = '{"detail":{"code":"upload_too_large","limit":5}}';
+    x.onload!();
+    await expect(p).rejects.toMatchObject({ status: 422 });
+    // localizeDetail routes upload_too_large → the tooLarge key (t is passthrough in the mock).
+    expect(reportError).toHaveBeenCalledWith("downloads.errors.upload.tooLarge");
+  });
+
+  it("reports a connectivity failure on a network error", async () => {
+    const p = uploadReq("/u", form());
+    FakeXHR.last.onerror!();
+    await expect(p).rejects.toMatchObject({ status: 0 });
+    // The soft self-clearing "connection lost" toast (via notify), not a blocking modal.
+    expect(notify).toHaveBeenCalled();
+    expect(reportError).not.toHaveBeenCalled();
+  });
+});
diff --git a/frontend/src/lib/downloadActions.test.ts b/frontend/src/lib/downloadActions.test.ts
new file mode 100644
index 00000000..4b3fc85a
--- /dev/null
+++ b/frontend/src/lib/downloadActions.test.ts
@@ -0,0 +1,79 @@
+// E7·S5b — the Library/Shared row-action gate. A generic uploaded file (media_kind='file') is
+// download+share only (no Play/Edit/Details); an edit clip and an upload can't be re-downloaded.
+// These pin the gate so a regression that shows Play/Edit on a file, or re-download on an upload,
+// is caught (the affordance itself, not just the backend guard behind it).
+import { describe, it, expect } from "vitest";
+import { libraryRowActions, sharedRowActions } from "./downloadActions";
+import type { DownloadJob } from "./api";
+
+const job = (
+  over: Partial<DownloadJob>,
+  asset: Partial<NonNullable<DownloadJob["asset"]>> | null,
+) =>
+  ({
+    id: 1,
+    status: "done",
+    job_kind: "download",
+    can_download: true,
+    asset: asset && {
+      id: 1,
+      status: "ready",
+      title: "x",
+      duration_s: 90,
+      media_kind: "video",
+      container: "mp4",
+      ...asset,
+    },
+    ...over,
+  }) as unknown as DownloadJob;
+
+describe("libraryRowActions", () => {
+  it("a media (video) item gets play, edit, details, redownload", () => {
+    expect(libraryRowActions(job({}, {}))).toEqual({
+      play: true,
+      edit: true,
+      editDetails: true,
+      redownload: true,
+    });
+  });
+
+  it("a generic file gets NO play/edit/details (download+share only)", () => {
+    const a = libraryRowActions(job({}, { media_kind: "file", duration_s: null }));
+    expect(a.play).toBe(false);
+    expect(a.edit).toBe(false);
+    expect(a.editDetails).toBe(false);
+  });
+
+  it("an upload cannot be re-downloaded (no re-fetchable source)", () => {
+    expect(libraryRowActions(job({ job_kind: "upload" }, { media_kind: "file" })).redownload).toBe(
+      false,
+    );
+  });
+
+  it("an edit clip cannot be re-downloaded", () => {
+    expect(libraryRowActions(job({ job_kind: "edit" }, {})).redownload).toBe(false);
+  });
+
+  it("edit is hidden when the media has no duration", () => {
+    expect(libraryRowActions(job({}, { duration_s: 0 })).edit).toBe(false);
+  });
+});
+
+describe("sharedRowActions", () => {
+  it("a downloadable media item gets play, save, edit", () => {
+    expect(sharedRowActions(job({}, {}))).toEqual({ play: true, save: true, edit: true });
+  });
+
+  it("nothing is offered when the owner disabled download", () => {
+    expect(sharedRowActions(job({ can_download: false }, {}))).toEqual({
+      play: false,
+      save: false,
+      edit: false,
+    });
+  });
+
+  it("a shared generic file gets only save (no player/trim)", () => {
+    const a = sharedRowActions(job({}, { media_kind: "file", duration_s: null }));
+    expect(a).toEqual({ play: false, save: true, edit: false });
+  });
+});
diff --git a/frontend/src/lib/downloadActions.ts b/frontend/src/lib/downloadActions.ts
new file mode 100644
index 00000000..c89d53da
--- /dev/null
+++ b/frontend/src/lib/downloadActions.ts
@@ -0,0 +1,43 @@
+import type { DownloadJob } from "./api";
+
+// Which row actions apply to a completed library / shared item — gated on the stored media_kind and
+// job_kind (E7·S5b). A generic uploaded file (media_kind='file') is download + share only: no player,
+// no trim, no details edit. Re-download needs a re-fetchable source, which an edit clip and an upload
+// both lack (the backend 409s both). A single source for the gate the Library + Shared rows render,
+// so it's unit-testable instead of buried in JSX conditionals — and the two tabs can't drift apart.
+
+const isMediaKind = (job: DownloadJob): boolean => job.asset?.media_kind !== "file";
+const hasDuration = (job: DownloadJob): boolean => (job.asset?.duration_s ?? 0) > 0;
+
+export interface LibraryRowActions {
+  play: boolean;
+  edit: boolean;
+  editDetails: boolean;
+  redownload: boolean;
+}
+
+export function libraryRowActions(job: DownloadJob): LibraryRowActions {
+  const media = isMediaKind(job);
+  return {
+    play: media,
+    edit: media && job.can_download && hasDuration(job),
+    editDetails: media,
+    redownload: job.job_kind !== "edit" && job.job_kind !== "upload",
+  };
+}
+
+export interface SharedRowActions {
+  play: boolean;
+  save: boolean;
+  edit: boolean;
+}
+
+export function sharedRowActions(job: DownloadJob): SharedRowActions {
+  const media = isMediaKind(job);
+  // The owner's `can_download` gates save/play/edit on a shared item (it reflects their link ACL).
+  return {
+    play: media && job.can_download,
+    save: job.can_download,
+    edit: media && job.can_download && hasDuration(job),
+  };
+}