Run the title catch-up in its own YouTube lane

poc/public/media.js

@@ -40,6 +40,7 @@
         loadError: false,
         pageSize: 60,
         backfill: null,
+        titles: null,
         preferences: null,
         /** Scrapes that finished while this page was open, until the tab is reloaded. */
         completed: new Set()
@@ -75,6 +76,7 @@
                         </span>
                     </div>
                     <div id="backfill-summary" class="vk-bot-summary"></div>
+                    <div id="title-lane" class="vk-bot-lane"></div>
                     <div id="backfill-jobs" class="vk-bot-jobs"></div>
                 </div>
 
@@ -101,6 +103,7 @@
     const botLimited = overlay.querySelector("#bot-limited");
     const backfillSummary = overlay.querySelector("#backfill-summary");
     const backfillJobs = overlay.querySelector("#backfill-jobs");
+    const titleLane = overlay.querySelector("#title-lane");
     const tunablesHost = overlay.querySelector("#bot-tunables");
     const botErrors = overlay.querySelector("#bot-errors");
 
@@ -790,7 +793,6 @@
                         "vk-bot-job-member",
                         `${member.scrapeId} \u00b7 ${member.state} \u00b7 ${member.mode} \u00b7 ` +
                             `${member.backend} \u00b7 ${member.pending} pending` +
-                            (member.pendingTitles ? ` + ${member.pendingTitles} titles` : "") +
                             (kinds ? ` (${kinds})` : "")
                     )
                 );
@@ -826,6 +828,57 @@
         }
     }
 
+    function renderTitleLane(status) {
+        if (!status) return;
+        titleLane.replaceChildren();
+
+        const head = el("div", "vk-bot-job-head");
+        head.append(el("span", "vk-bot-job-title", "Titles (YouTube)"));
+        head.append(el("span", `vk-bot-state vk-bot-state-${status.state}`, status.state));
+
+        const parts = [`${status.pending} pending`, `${status.resolved} titles`];
+        if (status.failed) parts.push(`${status.failed} failed`);
+        if (status.perMinute) parts.push(`${status.perMinute}/min`);
+        if (status.pending > 0) parts.push(`ETA ${formatEta(status.etaMs)}`);
+        if (status.currentScrapeId) parts.push(`on ${channelLabel(status.currentScrapeId)}`);
+        head.append(el("span", "vk-bot-job-meta", parts.join(" \u00b7 ")));
+        titleLane.append(head);
+
+        const actions = el("div", "vk-bot-job-actions");
+        if (status.state === "running") {
+            actions.append(button("Pause", () => void titleAction("pause")));
+        } else if (status.pending > 0) {
+            actions.append(button("Start", () => void titleAction("start")));
+        }
+        titleLane.append(actions);
+
+        const note = el(
+            "div",
+            "vk-bot-job-member",
+            "One-time catch-up for rows indexed before titles were stored; talks to YouTube only, " +
+                "100 per batch, 10 s between batches."
+        );
+        titleLane.append(note);
+    }
+
+    async function titleAction(action) {
+        try {
+            state.titles = await window.VK.api.post(`/api/media/titles/${action}`, {});
+            renderTitleLane(state.titles);
+        } catch (error) {
+            setStatus(`titles ${action} failed: ${error.message}`);
+        }
+    }
+
+    async function refreshTitles() {
+        try {
+            state.titles = await window.VK.api.get("/api/media/titles");
+        } catch {
+            state.titles = null;
+        }
+        renderTitleLane(state.titles);
+    }
+
     async function refreshBackfill() {
         try {
             state.backfill = await window.VK.api.get("/api/media/backfill");
@@ -1765,6 +1818,7 @@
                 : "slopbot is disabled or not logged in (VESKSLOP_SLOPBOT_ENABLED=1 and a token)";
             if (!state.preferences) void refreshPreferences();
             void refreshBackfill();
+            void refreshTitles();
             void loadScrapes().then(renderScrapes);
             void refreshErrors();
         } else {
@@ -1782,7 +1836,10 @@
         state.completed.clear();
         void loadScrapes();
         if (state.view === "media") void loadMedia(true);
-        if (state.view === "bot") void refreshBackfill();
+        if (state.view === "bot") {
+            void refreshBackfill();
+            void refreshTitles();
+        }
     });
 
     overlay.querySelector("#backfill-start").addEventListener("click", () => void backfillAction("start"));
@@ -1812,7 +1869,10 @@
 
     // Backfill progress while the Bot tab is open.
     setInterval(() => {
-        if (state.view === "bot") void refreshBackfill();
+        if (state.view === "bot") {
+            void refreshBackfill();
+            void refreshTitles();
+        }
     }, 3000);
 
     // Infinite scroll: the buffer entering the viewport starts the next page.