Add qbt-relink.sh to fix qBittorrent after a Sonarr import

Sonarr's hardlink-import removes files from their original
torrent-named folder, but qBittorrent's own records still point
there - the next recheck or peer request flips those downloads to
"missing files". qbt-relink.sh re-points a torrent's location and
per-file names at the Sonarr-organized destination and triggers a
recheck, so seeding continues against the same underlying data
(same inode) instead of erroring out or needing a re-download.

Documented as a required step in the sonarr skill's per-show
migration workflow.

Claude-Session: https://claude.ai/code/session_01HZQK6jHmdTpFjFZM8FUnqA

.claude/skills/sonarr/SKILL.md

@@ -37,7 +37,53 @@ once.
 5. **Clean up the empty source folder**:
    `docker exec jellyfin rmdir "<raw folder path>"` (any container with the
    `nas_media` mount works).
-6. **Verify Plex picks it up correctly** — this is not automatic, see below.
+6. **Re-point qBittorrent at the new location** — not automatic, see below.
+   Skip only if the show was never actually downloaded via qBittorrent (rare).
+7. **Verify Plex picks it up correctly** — also not automatic, see below.
+
+## Re-pointing qBittorrent after an import
+
+Sonarr's hardlink-import removes the file from its original torrent-named
+folder (only the new hardlinked copy remains) — qBittorrent's own record of
+that download doesn't know this happened and silently keeps pointing at the
+now-empty original path. It won't show an error immediately (a `stalledUP`
+torrent doesn't re-read its files until asked to), but the next recheck or
+peer request will flip it to a `missingFiles` error state.
+
+Fix it with `./qbt-relink.sh <torrent-hash> <new-season-folder>` (repo root):
+
+```bash
+./qbt-relink.sh 8601b9b9a7164ff5038aa1f8e678e3e708eea845 "/data/video/tv/Andor (2022)/Season 02"
+```
+
+Find the hash first:
+```bash
+source ~/.claude-homelab/.env
+bash ~/.claude/plugins/cache/claude-homelab/homelab-core/*/skills/qbittorrent/scripts/qbit-api.sh list \
+  | python3 -c "import sys,json; [print(t['hash'], t['name']) for t in json.load(sys.stdin)]" | grep -i "<show name>"
+```
+
+It sets the torrent's location to the season folder, renames each file to
+match Sonarr's output (paired by sorted order — always check the printed
+preview makes sense), then triggers a recheck. Since it's the same underlying
+data (hardlink, same inode), the hash check passes and the torrent goes back
+to seeding normally instead of erroring — no re-download. **The recheck reads
+the whole file over NFS and is slow** (minutes per multi-GB file) — kick off
+several in parallel rather than waiting on each one serially, and poll with:
+
+```bash
+bash ~/.claude/plugins/cache/claude-homelab/homelab-core/*/skills/qbittorrent/scripts/qbit-api.sh info <hash>
+```
+
+For a multi-season show downloaded as separate per-season torrents (e.g.
+Babylon 5), run `qbt-relink.sh` once per season/torrent, pointing each at its
+own `Season NN` folder — don't try to relink multiple torrents to one shared
+show-root folder, since the tool matches file counts 1:1 between the torrent
+and the destination folder.
+
+Credentials (`QBITTORRENT_URL`/`USERNAME`/`PASSWORD`) live in
+`~/.claude-homelab/.env` (the claude-homelab plugin's credential file), not
+this repo's `.credentials` — `qbt-relink.sh` sources that file directly.
 
 ## Verifying the Plex side (do this every time, not just once)
 

qbt-relink.sh

@@ -0,0 +1,121 @@
+#!/usr/bin/env bash
+# Re-point a qBittorrent torrent at files Sonarr has since renamed/moved.
+#
+# When Sonarr imports an existing download via hardlink, it removes the file
+# from its original torrent-named folder (only the new hardlinked copy
+# remains) - so qBittorrent's record of that torrent silently starts
+# pointing at nothing. This re-links the torrent to the new location so it
+# keeps seeding the same underlying data (same inode, so the hash check
+# passes) instead of erroring out as "missing files".
+#
+# Usage:
+#   ./qbt-relink.sh <torrent-hash> <new-folder>
+#
+# <new-folder> should be the Sonarr season folder (or show folder, for a
+# single-season show) containing the renamed files - e.g.
+#   ./qbt-relink.sh 8601b9b9... "/data/video/tv/Andor (2022)/Season 02"
+#
+# Pairs the torrent's files with the files in <new-folder> by sorted order
+# (both sort into episode order for every case seen so far: qBittorrent's
+# torrent file listing and Sonarr's SxxExx-prefixed renamed files). Always
+# prints the proposed pairing before applying - check it makes sense,
+# especially for anything with specials/extras where sort order could
+# mismatch episode order.
+
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+ENV_FILE="$HOME/.claude-homelab/.env"
+
+if [[ ! -f "$ENV_FILE" ]]; then
+    echo "Error: $ENV_FILE not found (qBittorrent creds live there, not this repo's .credentials)" >&2
+    exit 1
+fi
+# shellcheck source=/dev/null
+source "$ENV_FILE"
+
+if [[ -z "${QBITTORRENT_URL:-}" || -z "${QBITTORRENT_USERNAME:-}" || -z "${QBITTORRENT_PASSWORD:-}" ]]; then
+    echo "Error: QBITTORRENT_URL/USERNAME/PASSWORD not set in $ENV_FILE" >&2
+    exit 1
+fi
+
+HASH="${1:-}"
+NEW_FOLDER="${2:-}"
+if [[ -z "$HASH" || -z "$NEW_FOLDER" ]]; then
+    echo "Usage: $0 <torrent-hash> <new-folder>" >&2
+    exit 1
+fi
+
+COOKIE_JAR=$(mktemp)
+trap 'rm -f "$COOKIE_JAR"' EXIT
+
+login_status=$(curl -s -o /dev/null -w "%{http_code}" -c "$COOKIE_JAR" -X POST "$QBITTORRENT_URL/api/v2/auth/login" \
+    --data-urlencode "username=$QBITTORRENT_USERNAME" \
+    --data-urlencode "password=$QBITTORRENT_PASSWORD")
+if [[ "$login_status" != "200" ]]; then
+    echo "Error: qBittorrent login failed (http $login_status)" >&2
+    exit 1
+fi
+
+# Current files inside the torrent (relative paths, in qBittorrent's index order)
+old_files_json=$(curl -s -b "$COOKIE_JAR" -G "$QBITTORRENT_URL/api/v2/torrents/files" --data-urlencode "hash=$HASH")
+
+torrent_name=$(python3 -c "
+import json,sys
+files = json.loads(sys.argv[1])
+if not files:
+    print('ERROR: no files returned for this hash - check the hash is correct', file=sys.stderr)
+    sys.exit(1)
+print(files[0]['name'].split('/')[0])
+" "$old_files_json")
+
+echo "Torrent folder: $torrent_name"
+echo "New folder:     $NEW_FOLDER"
+echo
+
+# New files actually on disk at the destination (via any container with the nas_media mount)
+new_files=$(docker exec jellyfin sh -c "ls -1 \"$NEW_FOLDER\"" | sort)
+
+# Build the old->new pairing (sorted-order match), print it for review, and
+# save it as a TSV for the rename loop below.
+python3 -c "
+import json, sys
+old_files = sorted(json.loads(sys.argv[1]), key=lambda f: f['name'])
+new_files = sys.argv[2].strip().split(chr(10)) if sys.argv[2].strip() else []
+
+if len(old_files) != len(new_files):
+    print(f'ERROR: file count mismatch - torrent has {len(old_files)} files, destination has {len(new_files)}', file=sys.stderr)
+    sys.exit(1)
+
+with open('/tmp/qbt_relink_flat.tsv', 'w') as f:
+    for old, new in zip(old_files, new_files):
+        print(f\"  {old['name']}\")
+        print(f\"    -> {new}\")
+        f.write(f\"{old['name']}\t{new}\n\")
+" "$old_files_json" "$new_files"
+
+echo
+echo "--- Applying ---"
+
+echo "setLocation -> $NEW_FOLDER"
+curl -s -b "$COOKIE_JAR" -X POST "$QBITTORRENT_URL/api/v2/torrents/setLocation" \
+    --data-urlencode "hashes=$HASH" \
+    --data-urlencode "location=$NEW_FOLDER" > /dev/null
+
+# setLocation above already moved the torrent's root to $NEW_FOLDER itself
+# (the season folder) - so new paths here are bare filenames, not prefixed
+# with the season folder name again.
+while IFS=$'\t' read -r old new; do
+    curl -s -b "$COOKIE_JAR" -X POST "$QBITTORRENT_URL/api/v2/torrents/renameFile" \
+        --data-urlencode "hash=$HASH" \
+        --data-urlencode "oldPath=$old" \
+        --data-urlencode "newPath=$new" > /dev/null
+    echo "  renamed: $old -> $new"
+done < /tmp/qbt_relink_flat.tsv
+
+echo "recheck..."
+curl -s -b "$COOKIE_JAR" -X POST "$QBITTORRENT_URL/api/v2/torrents/recheck" \
+    --data-urlencode "hashes=$HASH" > /dev/null
+
+echo "Done. Recheck is running in the background - poll with:"
+echo "  bash ~/.claude/plugins/cache/claude-homelab/homelab-core/*/skills/qbittorrent/scripts/qbit-api.sh info $HASH"