fix(downloads): fix cancel, dismiss, speed, and retry bugs

- Speed indicator: only set prevBytesRef on first observation to prevent
  intermediate re-renders from inflating the calculated speed
- Cancel: throw UnrecoverableError on abort to prevent BullMQ retries
- Dismiss: remove stale BullMQ lock before job.remove() so cancelled
  jobs can actually be dismissed
- Retry: add getActiveByUrl() helper that checks job state before
  blocking re-download, auto-cleans terminal jobs
- Wikipedia: reset selection status to failed on cancel so the
  "downloading" state doesn't persist

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

admin/app/jobs/run_download_job.ts

@@ -1,4 +1,4 @@
-import { Job } from 'bullmq'
+import { Job, UnrecoverableError } from 'bullmq'
 import { RunDownloadJobParams, DownloadProgressData } from '../../types/downloads.js'
 import { QueueService } from '#services/queue_service'
 import { doResumableDownload } from '../utils/downloads.js'
@@ -161,6 +161,12 @@ export class RunDownloadJob {
         url,
         filepath,
       }
+    } catch (error: any) {
+      // If this was a cancellation abort, don't let BullMQ retry
+      if (error?.message?.includes('aborted') || error?.message?.includes('cancelled')) {
+        throw new UnrecoverableError(`Download cancelled: ${error.message}`)
+      }
+      throw error
     } finally {
       // Clean up abort controller
       RunDownloadJob.abortControllers.delete(job.id!)
@@ -174,6 +180,29 @@ export class RunDownloadJob {
     return await queue.getJob(jobId)
   }
 
+  /**
+   * Check if a download is actively in progress for the given URL.
+   * Returns the job only if it's in an active state (active, waiting, delayed).
+   * If the job exists in a terminal state (failed, completed), removes it and returns undefined.
+   */
+  static async getActiveByUrl(url: string): Promise<Job | undefined> {
+    const job = await this.getByUrl(url)
+    if (!job) return undefined
+
+    const state = await job.getState()
+    if (state === 'active' || state === 'waiting' || state === 'delayed') {
+      return job
+    }
+
+    // Terminal state -- clean up stale job so it doesn't block re-download
+    try {
+      await job.remove()
+    } catch {
+      // May already be gone
+    }
+    return undefined
+  }
+
   static async dispatch(params: RunDownloadJobParams) {
     const queueService = new QueueService()
     const queue = queueService.getQueue(this.queue)

admin/app/services/download_service.ts

@@ -78,7 +78,18 @@ export class DownloadService {
       const queue = this.queueService.getQueue(queueName)
       const job = await queue.getJob(jobId)
       if (job) {
-        await job.remove()
+        try {
+          await job.remove()
+        } catch {
+          // Job may be locked by the worker after cancel. Remove the stale lock and retry.
+          try {
+            const client = await queue.client
+            await client.del(`bull:${queueName}:${jobId}:lock`)
+            await job.remove()
+          } catch {
+            // Last resort: already removed or truly stuck
+          }
+        }
         return
       }
     }
@@ -109,7 +120,18 @@ export class DownloadService {
     try {
       await job.remove()
     } catch {
-      // Job may still be locked by worker - it will fail on next progress check
+      // Job may still be locked by worker - try again after it reaches terminal state
+      try {
+        const updatedJob = await queue.getJob(jobId)
+        if (updatedJob) {
+          const state = await updatedJob.getState()
+          if (state === 'failed' || state === 'completed') {
+            await updatedJob.remove()
+          }
+        }
+      } catch {
+        // Best effort - job will be cleaned up on next dismiss attempt
+      }
     }
 
     // Delete the partial file from disk
@@ -123,6 +145,20 @@ export class DownloadService {
       }
     }
 
+    // If this was a Wikipedia download, update selection status to failed
+    // (the worker's failed event may not fire if we removed the job first)
+    if (job.data.filetype === 'zim' && job.data.url?.includes('wikipedia_en_')) {
+      try {
+        const { DockerService } = await import('#services/docker_service')
+        const { ZimService } = await import('#services/zim_service')
+        const dockerService = new DockerService()
+        const zimService = new ZimService(dockerService)
+        await zimService.onWikipediaDownloadComplete(job.data.url, false)
+      } catch {
+        // Best effort
+      }
+    }
+
     return { success: true, message: 'Download cancelled and partial file deleted' }
   }
 }

admin/app/services/map_service.ts

@@ -109,7 +109,7 @@ export class MapService implements IMapService {
     const downloadFilenames: string[] = []
 
     for (const resource of toDownload) {
-      const existing = await RunDownloadJob.getByUrl(resource.url)
+      const existing = await RunDownloadJob.getActiveByUrl(resource.url)
       if (existing) {
         logger.warn(`[MapService] Download already in progress for URL ${resource.url}, skipping.`)
         continue
@@ -180,7 +180,7 @@ export class MapService implements IMapService {
       throw new Error(`Invalid PMTiles file URL: ${url}. URL must end with .pmtiles`)
     }
 
-    const existing = await RunDownloadJob.getByUrl(url)
+    const existing = await RunDownloadJob.getActiveByUrl(url)
     if (existing) {
       throw new Error(`Download already in progress for URL ${url}`)
     }

admin/app/services/zim_service.ts

@@ -143,7 +143,7 @@ export class ZimService {
       throw new Error(`Invalid ZIM file URL: ${url}. URL must end with .zim`)
     }
 
-    const existing = await RunDownloadJob.getByUrl(url)
+    const existing = await RunDownloadJob.getActiveByUrl(url)
     if (existing) {
       throw new Error('A download for this URL is already in progress')
     }
@@ -221,7 +221,7 @@ export class ZimService {
     const downloadFilenames: string[] = []
 
     for (const resource of toDownload) {
-      const existingJob = await RunDownloadJob.getByUrl(resource.url)
+      const existingJob = await RunDownloadJob.getActiveByUrl(resource.url)
       if (existingJob) {
         logger.warn(`[ZimService] Download already in progress for ${resource.url}, skipping.`)
         continue
@@ -464,7 +464,7 @@ export class ZimService {
     }
 
     // Check if already downloading
-    const existingJob = await RunDownloadJob.getByUrl(selectedOption.url)
+    const existingJob = await RunDownloadJob.getActiveByUrl(selectedOption.url)
     if (existingJob) {
       return { success: false, message: 'Download already in progress' }
     }

admin/inertia/components/ActiveDownloads.tsx

@@ -67,7 +67,10 @@ const ActiveDownloads = ({ filetype, withHeader = false }: ActiveDownloadProps)
         }
       }
 
-      prevBytesRef.current.set(jobId, { bytes: currentBytes, time: now })
+      // Only set initial observation; never advance timestamp when bytes unchanged
+      if (!prev) {
+        prevBytesRef.current.set(jobId, { bytes: currentBytes, time: now })
+      }
       return speedRef.current.get(jobId)?.at(-1) || 0
     },
     []