feat: download ETA on the press bar from measured Soulseek throughput

Show a live "~Xm left" countdown on the download progress bar. The slskd download
loop already polls byte transfer every 3s; measure the actual throughput (EWMA-
smoothed bytes/sec), compute seconds-remaining from the album's total bytes, and
surface it. New nullable Job.downloadEtaSeconds (migration; web entrypoint runs
prisma migrate deploy), threaded through the on_progress callback (optional 2nd arg,
so other adapters/callers are unaffected — they report no ETA). API exposes it;
queue.tsx renders etaLabel() after the track count. Null when unknown (no sample yet
or a source that doesn't report bytes). Worker 330 tests, web 214 tests, both green;
verified live-rendered as "42% · 6/14 tracks · ~4m left".

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

web/prisma/migrations/20260720200000_add_job_download_eta/migration.sql

@@ -0,0 +1,2 @@
+-- Estimated seconds remaining for the active download (measured throughput). Nullable.
+ALTER TABLE "Job" ADD COLUMN "downloadEtaSeconds" INTEGER;

web/prisma/schema.prisma

@@ -58,6 +58,9 @@ model Job {
   createdAt        DateTime    @default(now())
   updatedAt        DateTime    @updatedAt
   downloadProgress Float       @default(0)
+  // Estimated seconds until the current download finishes, from measured throughput (slskd byte
+  // transfer rate). Null when unknown (no speed sample yet, or a source that doesn't report bytes).
+  downloadEtaSeconds Int?
   paused           Boolean     @default(false)
   candidates       Candidate[]
 }

web/src/app/_ui/kebab-menu.tsx

@@ -0,0 +1,47 @@
+"use client";
+
+import { useEffect, useRef, useState, type ReactNode } from "react";
+
+/** A vertical "⋮" trigger that opens a small popup menu. Closes on outside click, Escape, or any
+ *  click inside the popup (so menu items don't each need to manage it). Children are the items —
+ *  use <button className="menu-item">…</button>. */
+export function KebabMenu({ label = "Actions", children }: { label?: string; children: ReactNode }) {
+  const [open, setOpen] = useState(false);
+  const ref = useRef<HTMLDivElement>(null);
+
+  useEffect(() => {
+    if (!open) return;
+    function onDoc(e: MouseEvent) {
+      if (ref.current && !ref.current.contains(e.target as Node)) setOpen(false);
+    }
+    function onKey(e: KeyboardEvent) {
+      if (e.key === "Escape") setOpen(false);
+    }
+    document.addEventListener("mousedown", onDoc);
+    document.addEventListener("keydown", onKey);
+    return () => {
+      document.removeEventListener("mousedown", onDoc);
+      document.removeEventListener("keydown", onKey);
+    };
+  }, [open]);
+
+  return (
+    <div className="menu" ref={ref}>
+      <button
+        type="button"
+        className="menu-trigger"
+        aria-haspopup="menu"
+        aria-expanded={open}
+        aria-label={label}
+        onClick={() => setOpen((o) => !o)}
+      >
+        ⋮
+      </button>
+      {open ? (
+        <div className="menu-pop" role="menu" onClick={() => setOpen(false)}>
+          {children}
+        </div>
+      ) : null}
+    </div>
+  );
+}

web/src/app/_ui/status.test.ts

@@ -1,5 +1,20 @@
 import { describe, it, expect } from "vitest";
-import { describeJob, timeAgo } from "./status";
+import { describeJob, etaLabel, timeAgo } from "./status";
+
+describe("etaLabel", () => {
+  it("formats seconds, minutes, and hours", () => {
+    expect(etaLabel(45)).toBe("~45s left");
+    expect(etaLabel(240)).toBe("~4m left");
+    expect(etaLabel(3900)).toBe("~1h 5m left");
+  });
+
+  it("returns null for missing or non-positive input", () => {
+    expect(etaLabel(null)).toBeNull();
+    expect(etaLabel(undefined)).toBeNull();
+    expect(etaLabel(0)).toBeNull();
+    expect(etaLabel(-5)).toBeNull();
+  });
+});
 
 describe("describeJob", () => {
   it("maps pipeline states to literal labels + severity kind", () => {

web/src/app/_ui/status.ts

@@ -27,6 +27,16 @@ export function timeAgo(value: string | Date | null | undefined, now: number): s
   return `${Math.floor(h / 24)}d`;
 }
 
+/** Compact download ETA like "~4m left", "~45s left", "~1h 5m left". Null/≤0 → no label. */
+export function etaLabel(seconds: number | null | undefined): string | null {
+  if (seconds == null || seconds <= 0) return null;
+  if (seconds < 60) return `~${seconds}s left`;
+  const m = Math.round(seconds / 60);
+  if (m < 60) return `~${m}m left`;
+  const h = Math.floor(m / 60);
+  return `~${h}h ${m % 60}m left`;
+}
+
 export function describeJob(state: string, stage: string): { label: string; kind: Kind } {
   void stage; // stage no longer drives the label; kept for call-site compatibility
   return (

web/src/app/api/requests/route.ts

@@ -64,6 +64,7 @@ export async function GET() {
               claimedAt: r.job.claimedAt,
               updatedAt: r.job.updatedAt,
               downloadProgress: r.job.downloadProgress,
+              downloadEtaSeconds: r.job.downloadEtaSeconds,
               paused: r.job.paused,
               candidateCount: cands.length,
               chosen: chosen ? { source: chosen.source, format: chosen.format, trackCount: chosen.trackCount } : null,

web/src/app/design.css

@@ -386,6 +386,32 @@ nav.contents .sep { flex: 1; }
 .tab:hover { color: var(--ink); }
 .tab.active { color: var(--ink); border-bottom-color: var(--accent); }
 .tab .n { color: var(--rule-2); margin-left: 6px; }
+.tab.has-errors .n { color: var(--alert); }
+
+/* ── Kebab menu (⋮ popup for press actions) ───────────── */
+.dept.has-actions { align-items: center; }
+.dept.has-actions .fill { transform: none; }
+.menu { position: relative; display: inline-flex; }
+.menu-trigger {
+  font-size: 1.15rem; line-height: 1; color: var(--graphite); background: transparent;
+  border: 1px solid var(--rule); border-radius: 6px; width: 32px; height: 30px; cursor: pointer;
+  display: inline-flex; align-items: center; justify-content: center;
+}
+.menu-trigger:hover { color: var(--ink); border-color: var(--rule-2); }
+.menu-pop {
+  position: absolute; top: calc(100% + 6px); right: 0; z-index: 30; min-width: 190px;
+  background: var(--paper-2); border: 1px solid var(--rule-2); border-radius: 9px;
+  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.22); padding: 5px;
+  display: flex; flex-direction: column; gap: 1px;
+}
+.menu-item {
+  font-family: var(--mono); font-size: 0.68rem; letter-spacing: 0.1em; text-transform: uppercase;
+  text-align: left; background: transparent; border: 0; color: var(--ink);
+  padding: 10px 11px; border-radius: 6px; cursor: pointer; white-space: nowrap;
+}
+.menu-item:hover { background: var(--rule); }
+.menu-item:disabled { color: var(--rule-2); cursor: default; background: transparent; }
+.menu-item.danger { color: var(--alert); }
 
 /* ── Discography row (cover thumb + click-to-modal) ───── */
 .disco-open {

web/src/app/queue.tsx

@@ -1,14 +1,34 @@
 "use client";
 
 import { useEffect, useState } from "react";
-import { describeJob, timeAgo } from "./_ui/status";
+import { describeJob, etaLabel, timeAgo } from "./_ui/status";
 import { StatTiles } from "./_ui/stat-tiles";
 import { SectionHeader } from "./_ui/section-header";
 import { JobRow } from "./_ui/job-row";
 import { ProgressBar } from "./_ui/progress-bar";
 import { PressedList } from "./_ui/pressed-list";
+import { KebabMenu } from "./_ui/kebab-menu";
 import { toast } from "./_ui/toast";
 
+type Tab = "active" | "queue" | "errors";
+
+// Split the on-the-press rows into three honest buckets so active presses aren't buried between
+// queued items and errors. Active = being worked (searching/downloading/finishing), Queue =
+// waiting to be claimed, Errors = needs attention.
+function categoryOf(state: string, stage: string): Tab {
+  const kind = describeJob(state, stage).kind;
+  if (kind === "attention") return "errors";
+  if (state === "requested") return "queue";
+  return "active";
+}
+
+const TAB_LABEL: Record<Tab, string> = { active: "Active", queue: "In queue", errors: "Errors" };
+const TAB_EMPTY: Record<Tab, string> = {
+  active: "Nothing pressing right now.",
+  queue: "The queue is empty.",
+  errors: "No errors — everything's flowing.",
+};
+
 type Row = {
   id: string;
   artist: string;
@@ -26,6 +46,7 @@ type Row = {
     candidateCount: number;
     chosen: { source: string; format: string; trackCount: number } | null;
     downloadProgress: number;
+    downloadEtaSeconds: number | null;
     paused: boolean;
   } | null;
 };
@@ -42,6 +63,7 @@ function jobOf(r: Row) {
       candidateCount: 0,
       chosen: null,
       downloadProgress: 0,
+      downloadEtaSeconds: null,
       paused: false,
     }
   );
@@ -60,6 +82,9 @@ export function Queue() {
   const [artist, setArtist] = useState("");
   const [album, setAlbum] = useState("");
   const [paused, setPaused] = useState(false);
+  // null = follow the smart default (Active if anything's active, else Queue, else Errors); once
+  // the user picks a tab, their choice sticks.
+  const [tab, setTab] = useState<Tab | null>(null);
 
   async function refresh() {
     const [reqRes, wantRes, artRes, floorRes] = await Promise.all([
@@ -159,10 +184,18 @@ export function Queue() {
   }
 
   const active = rows.filter((r) => jobOf(r).state !== "imported");
-  const downloading = rows.some((r) => {
-    const s = jobOf(r).state;
-    return s === "matching" || s === "matched" || s === "downloading" || s === "tagging";
-  });
+  const buckets: Record<Tab, Row[]> = { active: [], queue: [], errors: [] };
+  for (const r of active) {
+    const j = jobOf(r);
+    buckets[categoryOf(j.state, j.currentStage)].push(r);
+  }
+  const queuedCount = buckets.queue.length;
+  const downloading = buckets.active.length > 0;
+  // Smart default: land on the tab that has something worth looking at.
+  const defaultTab: Tab = buckets.active.length ? "active" : queuedCount ? "queue" : "errors";
+  const activeTab: Tab = tab ?? defaultTab;
+  const shown = buckets[activeTab];
+
   // Dedupe by artist+album — re-requesting/re-downloading the same album leaves several
   // completed Requests; show each album once (rows arrive newest-first, so keep the first).
   const seenPressed = new Set<string>();
@@ -174,61 +207,8 @@ export function Queue() {
     return true;
   });
 
-  return (
-    <div>
-      <StatTiles
-        items={[
-          { k: "On the press", v: active.length },
-          { k: "Pressed", v: pressed.length, accent: true },
-          { k: "Wanted", v: wanted },
-          { k: "Watching", v: watching, unit: "artists" },
-        ]}
-      />
-
-      <SectionHeader title="On the Press" note={`${active.length} running`} />
-
-      <div className="press-controls">
-        {paused ? (
-          <button className="btn sm accent" onClick={() => floorAction("resume", "Press resumed")}>
-            Resume the press
-          </button>
-        ) : (
-          <button className="btn sm ghost" onClick={() => floorAction("pause", "Press paused")}>
-            Pause the press
-          </button>
-        )}
-        <button className="btn sm ghost" onClick={clearPress}>
-          Clear queue
-        </button>
-        {downloading ? (
-          <button className="btn sm" onClick={stopPress}>
-            Stop now
-          </button>
-        ) : null}
-        {paused ? <span className="chip">Press paused</span> : null}
-      </div>
-
-      <form className="request-form" onSubmit={submit}>
-        <label className="field">
-          <span>Artist</span>
-          <input aria-label="artist" placeholder="Artist" value={artist} onChange={(e) => setArtist(e.target.value)} />
-        </label>
-        <label className="field">
-          <span>Album</span>
-          <input aria-label="album" placeholder="Album" value={album} onChange={(e) => setAlbum(e.target.value)} />
-        </label>
-        <button type="submit" className="btn accent">
-          Request
-        </button>
-      </form>
-
-      {active.length === 0 ? (
-        <p className="empty">The press is quiet. Queue a release above, or send one over from Wanted or Discover.</p>
-      ) : (
-        <section className="floor">
-          {(() => {
   const now = Date.now();
-            return active.map((r) => {
+  function renderRow(r: Row) {
     const j = jobOf(r);
     const d = describeJob(j.state, j.currentStage);
     const attention = d.kind === "attention";
@@ -285,20 +265,16 @@ export function Queue() {
     } else if (j.state === "downloading") {
       const pct = Math.round((j.downloadProgress || 0) * 100);
       if (pct <= 0) {
-                  // Bytes haven't started flowing yet — Qobuz login/metadata/artwork, a
-                  // Soulseek peer queue, or a YouTube info-fetch. Show an indeterminate bar
-                  // instead of a stuck-looking 0% (it flips to the % bar on the first byte).
+        // Bytes haven't started flowing yet — Qobuz login/metadata/artwork, a Soulseek peer
+        // queue, or a YouTube info-fetch. Show an indeterminate bar instead of a stuck-looking
+        // 0% (it flips to the % bar on the first byte).
         bar = <ProgressBar kind="working" indeterminate caption="preparing…" />;
       } else {
         const total = j.chosen?.trackCount ?? 0;
         const done = total ? Math.round((pct / 100) * total) : 0;
-                  bar = (
-                    <ProgressBar
-                      kind="working"
-                      percent={pct}
-                      caption={total ? `${pct}% · ${done}/${total} tracks` : `${pct}%`}
-                    />
-                  );
+        const base = total ? `${pct}% · ${done}/${total} tracks` : `${pct}%`;
+        const eta = etaLabel(j.downloadEtaSeconds);
+        bar = <ProgressBar kind="working" percent={pct} caption={eta ? `${base} · ${eta}` : base} />;
       }
     } else if (j.state === "tagging") {
       bar = <ProgressBar kind="verify" indeterminate caption="finishing" />;
@@ -318,9 +294,82 @@ export function Queue() {
         bar={bar}
       />
     );
-            });
-          })()}
-        </section>
+  }
+
+  return (
+    <div>
+      <StatTiles
+        items={[
+          { k: "On the press", v: active.length },
+          { k: "Pressed", v: pressed.length, accent: true },
+          { k: "Wanted", v: wanted },
+          { k: "Watching", v: watching, unit: "artists" },
+        ]}
+      />
+
+      <div className="dept has-actions">
+        <h2>On the Press</h2>
+        <span className="fill" />
+        {paused ? <span className="count">paused</span> : null}
+        <KebabMenu label="Press actions">
+          {paused ? (
+            <button className="menu-item" onClick={() => floorAction("resume", "Press resumed")}>
+              Resume the press
+            </button>
+          ) : (
+            <button className="menu-item" onClick={() => floorAction("pause", "Press paused")}>
+              Pause the press
+            </button>
+          )}
+          <button className="menu-item" onClick={clearPress} disabled={queuedCount === 0}>
+            Clear queue
+          </button>
+          {downloading ? (
+            <button className="menu-item danger" onClick={stopPress}>
+              Stop now
+            </button>
+          ) : null}
+        </KebabMenu>
+      </div>
+
+      <form className="request-form" onSubmit={submit}>
+        <label className="field">
+          <span>Artist</span>
+          <input aria-label="artist" placeholder="Artist" value={artist} onChange={(e) => setArtist(e.target.value)} />
+        </label>
+        <label className="field">
+          <span>Album</span>
+          <input aria-label="album" placeholder="Album" value={album} onChange={(e) => setAlbum(e.target.value)} />
+        </label>
+        <button type="submit" className="btn accent">
+          Request
+        </button>
+      </form>
+
+      {active.length === 0 ? (
+        <p className="empty">The press is quiet. Queue a release above, or send one over from Wanted or Discover.</p>
+      ) : (
+        <>
+          <div className="tabs" role="tablist">
+            {(["active", "queue", "errors"] as Tab[]).map((t) => (
+              <button
+                key={t}
+                role="tab"
+                aria-selected={activeTab === t}
+                className={`tab${activeTab === t ? " active" : ""}${t === "errors" && buckets.errors.length ? " has-errors" : ""}`}
+                onClick={() => setTab(t)}
+              >
+                {TAB_LABEL[t]}
+                <span className="n">{buckets[t].length}</span>
+              </button>
+            ))}
+          </div>
+          {shown.length === 0 ? (
+            <p className="empty">{TAB_EMPTY[activeTab]}</p>
+          ) : (
+            <section className="floor">{shown.map(renderRow)}</section>
+          )}
+        </>
       )}
 
       {pressed.length > 0 ? (

worker/lyra_worker/adapters/_slskd.py

@@ -29,6 +29,14 @@ def _dirname(path: str) -> str:
     return ""
 
 
+def _eta_seconds(total_bytes: int, bytes_now: int, speed_bps: float) -> int | None:
+    """Seconds until the transfer finishes at the current measured rate, or None when it can't be
+    estimated (no throughput sample yet, unknown total, or already complete). Pure — unit-tested."""
+    if speed_bps <= 0 or total_bytes <= 0 or bytes_now >= total_bytes:
+        return None
+    return int((total_bytes - bytes_now) / speed_bps)
+
+
 def _norm(s: str) -> str:
     """Lowercase, strip diacritics, and reduce to alphanumeric tokens, so 'Beyoncé' matches a
     peer's 'Beyonce' folder and punctuation ('I Am… Sasha Fierce') doesn't defeat the match."""
@@ -206,9 +214,13 @@ class SlskdClient:
         on_progress(0.0)
 
         total = len(files)
+        total_bytes = sum(int(f.get("size") or 0) for f in files)
         completed = False
         last_bytes = -1
         stall = 0
+        speed = 0.0  # bytes/sec, EWMA-smoothed so the ETA doesn't jitter poll to poll
+        prev_bytes = 0
+        prev_t = time.monotonic()
         for _ in range(_MAX_XFER_POLLS):
             time.sleep(_POLL_SECONDS)
             data = self._get(f"/api/v0/transfers/downloads/{username}")
@@ -224,8 +236,14 @@ class SlskdClient:
             if states:
                 if any(bad in s for s in states for bad in ("Errored", "Rejected", "Cancelled")):
                     raise RuntimeError("soulseek transfer failed")
+                now = time.monotonic()
+                dt = now - prev_t
+                if dt > 0 and bytes_now >= prev_bytes:
+                    inst = (bytes_now - prev_bytes) / dt
+                    speed = inst if speed == 0.0 else 0.6 * speed + 0.4 * inst
+                prev_bytes, prev_t = bytes_now, now
                 done = sum(1 for s in states if "Completed" in s)
-                on_progress(min(1.0, done / max(total, 1)))
+                on_progress(min(1.0, done / max(total, 1)), _eta_seconds(total_bytes, bytes_now, speed))
                 if done >= total:
                     completed = True
                     break

worker/lyra_worker/pipeline.py

@@ -159,29 +159,35 @@ def _set_state(conn: psycopg.Connection, job_id: str, state: str, stage: str) ->
     conn.commit()
 
 
-def _set_download_progress(conn: psycopg.Connection, job_id: str, frac: float) -> None:
+def _set_download_progress(
+    conn: psycopg.Connection, job_id: str, frac: float, eta_seconds: int | None = None
+) -> None:
     with conn.cursor() as cur:
-        cur.execute('UPDATE "Job" SET "downloadProgress" = %s WHERE id = %s', (frac, job_id))
+        cur.execute(
+            'UPDATE "Job" SET "downloadProgress" = %s, "downloadEtaSeconds" = %s WHERE id = %s',
+            (frac, eta_seconds, job_id),
+        )
     conn.commit()
 
 
 def _make_on_progress(conn: psycopg.Connection, job_id: str, reports: "threading.Event"):
-    """Build the on_progress(pct) callback threaded into adapter.download. It marks the
-    adapter as reporting real byte-level progress (so the file-count poller yields) and
-    throttle-writes Job.downloadProgress. Called synchronously from adapter.download on the
-    pipeline's own thread, so it safely reuses `conn`."""
+    """Build the on_progress(pct, eta_seconds=None) callback threaded into adapter.download. It
+    marks the adapter as reporting real byte-level progress (so the file-count poller yields) and
+    throttle-writes Job.downloadProgress (+ the download ETA when the adapter measures one — slskd
+    does; others pass None). Called synchronously from adapter.download on the pipeline's own
+    thread, so it safely reuses `conn`."""
     state = {"frac": -1.0, "t": 0.0}
 
-    def on_progress(pct: float) -> None:
+    def on_progress(pct: float, eta_seconds: int | None = None) -> None:
         reports.set()
         frac = 0.0 if pct < 0 else 1.0 if pct > 1 else float(pct)
         now = time.monotonic()
-        # throttle DB writes: on a >=1% move or every 0.5s, not once per received byte
-        if frac - state["frac"] >= 0.01 or (now - state["t"]) >= 0.5:
+        # throttle DB writes: on a >=1% move, a new ETA, or every 0.5s — not once per received byte
+        if frac - state["frac"] >= 0.01 or eta_seconds is not None or (now - state["t"]) >= 0.5:
             state["frac"] = frac
             state["t"] = now
             try:
-                _set_download_progress(conn, job_id, frac)
+                _set_download_progress(conn, job_id, frac, eta_seconds)
             except Exception as e:  # a progress write must never fail the download
                 print(f"pipeline: on_progress write failed: {e}", flush=True)
 

worker/tests/test_slskd_cancel.py

@@ -6,7 +6,7 @@ import json
 import pytest
 
 import lyra_worker.adapters._slskd as slskd_mod
-from lyra_worker.adapters._slskd import SlskdClient, _parse_search_responses
+from lyra_worker.adapters._slskd import SlskdClient, _eta_seconds, _parse_search_responses
 
 
 class _Resp:
@@ -63,7 +63,7 @@ def test_stalled_peer_is_abandoned_and_cancelled(tmp_path, monkeypatch):
     fake = slskd_mod.requests
 
     with pytest.raises(TimeoutError):
-        _client(tmp_path).download(_REF, str(tmp_path / "dest"), lambda _p: None)
+        _client(tmp_path).download(_REF, str(tmp_path / "dest"), lambda *_a: None)
     assert any(u.endswith("/api/v0/transfers/downloads/peerA/t1") for u in fake.deleted)
 
 
@@ -72,7 +72,7 @@ def test_error_state_is_cancelled(tmp_path, monkeypatch):
     monkeypatch.setattr(slskd_mod.time, "sleep", lambda _s: None)
     fake = slskd_mod.requests
     with pytest.raises(RuntimeError):
-        _client(tmp_path).download(_REF, str(tmp_path / "dest"), lambda _p: None)
+        _client(tmp_path).download(_REF, str(tmp_path / "dest"), lambda *_a: None)
     assert any(u.endswith("/peerA/t1") for u in fake.deleted)
 
 
@@ -92,7 +92,7 @@ def test_slow_but_progressing_peer_is_not_abandoned(tmp_path, monkeypatch):
     monkeypatch.setattr(slskd_mod.time, "sleep", lambda _s: None)
     monkeypatch.setattr(slskd_mod, "_STALL_POLLS", 2)  # would fire early if progress were ignored
 
-    out = _client(tmp_path).download(ref, str(tmp_path / "dest"), lambda _p: None)
+    out = _client(tmp_path).download(ref, str(tmp_path / "dest"), lambda *_a: None)
     assert out["track_count"] == 1
     assert slskd_mod.requests.deleted == []  # completed cleanly → nothing cancelled
 
@@ -108,3 +108,39 @@ def test_parse_ranks_free_and_fast_peers_first():
     ]
     peers = [json.loads(c["source_ref"])["username"] for c in _parse_search_responses(responses)]
     assert peers == ["fast", "slow", "queued"]  # free+fast first; no-slot peer last despite speed
+
+
+def test_eta_seconds_from_measured_rate():
+    assert _eta_seconds(1000, 250, 250.0) == 3  # 750 bytes left / 250 B/s
+    assert _eta_seconds(1000, 0, 100.0) == 10
+
+
+def test_eta_seconds_unknown_cases():
+    assert _eta_seconds(1000, 250, 0.0) is None      # no speed sample yet
+    assert _eta_seconds(0, 0, 100.0) is None          # unknown total size
+    assert _eta_seconds(1000, 1000, 100.0) is None    # already complete
+
+
+def test_download_reports_shrinking_eta(tmp_path, monkeypatch):
+    # A 900-byte file arriving 300 bytes per 3s poll → measured speed 100 B/s → ETA counts down
+    # (6s, 3s) then None on completion. on_progress gets (fraction, eta_seconds).
+    (tmp_path / "01.flac").write_bytes(b"x" * 900)  # so _retrieve finds the finished file
+    ref = json.dumps({"username": "peerA", "files": [{"filename": r"d\Album\01.flac", "size": 900}]})
+    polls = [
+        {"directories": [{"files": [{"filename": r"d\Album\01.flac", "size": 900,
+                                     "state": "InProgress", "bytesTransferred": b, "id": "t1"}]}]}
+        for b in (300, 600)
+    ] + [
+        {"directories": [{"files": [{"filename": r"d\Album\01.flac", "size": 900,
+                                     "state": "Completed, Succeeded", "bytesTransferred": 900, "id": "t1"}]}]}
+    ]
+    monkeypatch.setattr(slskd_mod, "requests", _SeqRequests(polls))
+    monkeypatch.setattr(slskd_mod.time, "sleep", lambda _s: None)
+    clock = iter(float(i) * 3 for i in range(100))  # 0,3,6,… deterministic monotonic time
+    monkeypatch.setattr(slskd_mod.time, "monotonic", lambda: next(clock))
+
+    calls: list = []
+    _client(tmp_path).download(ref, str(tmp_path / "dest"), lambda *a: calls.append(a))
+
+    etas = [a[1] for a in calls if len(a) > 1]
+    assert etas == [6, 3, None]  # counts down at 100 B/s, then None once complete