Queue the smallest backfill jobs first and show queued state

media-scrape/src/backfill.ts

@@ -40,7 +40,8 @@ export interface BackfillMember {
 export interface BackfillJobStatus {
     chatId: string;
     guildId: string | null;
-    state: "idle" | "running" | "paused" | "done";
+    /** `queued` means started, but another job holds the queue. */
+    state: "idle" | "queued" | "running" | "paused" | "done";
     members: BackfillMember[];
     pending: number;
     cached: number;
@@ -188,6 +189,8 @@ export class BackfillQueue {
         const groups = this.plan();
         const jobs: BackfillJobStatus[] = [];
 
+        const anyClaimed = [...this.jobs.values()].some(candidate => candidate.claimed);
+
         for (const [chatId, group] of groups) {
             // Hide chats that are fully backfilled unless their job did work this session.
             const tracked = this.jobs.get(chatId);
@@ -196,11 +199,13 @@ export class BackfillQueue {
 
             const perMinute = tracked?.perMinute ?? this.estimatedPerMinute(settings, gaps);
             const etaMs = pending > 0 && perMinute > 0 ? Math.round((pending / perMinute) * 60_000) : null;
+            const state =
+                tracked?.state === "running" && anyClaimed && !tracked.claimed ? "queued" : (tracked?.state ?? "idle");
 
             jobs.push({
                 chatId,
                 guildId: group.guildId,
-                state: tracked?.state ?? "idle",
+                state,
                 members: group.members,
                 pending,
                 cached: group.members.reduce((sum, member) => sum + member.cached, 0),
@@ -280,11 +285,14 @@ export class BackfillQueue {
         return perRow > 0 ? 60_000 / perRow : 6000;
     }
 
-    /** Start every job with pending rows, or one chat's job. */
+    /** Start every job with pending rows, or one chat's job. Smallest jobs first: they finish. */
     start(chatId?: string): void {
         const status = this.list();
+        const order = chatId
+            ? status.jobs
+            : [...status.jobs].sort((a, b) => a.pending - b.pending);
 
-        for (const job of status.jobs) {
+        for (const job of order) {
             if (chatId && job.chatId !== chatId) continue;
             if (job.pending <= 0) continue;