arr-interconnect: declarative root folders for radarr/sonarr

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

services/arr-interconnect.nix

@@ -1,5 +1,15 @@
 { config, lib, pkgs, ... }:
 let
+  # Declarative root folders. The script reconciles against these: adds any
+  # that are missing, removes any that aren't listed. Removing a root folder
+  # only unregisters the path in Radarr/Sonarr — it never touches media files.
+  # Download-client staging dirs (/mnt/storage/usenet/downloads, the torrent
+  # downloads dir) must never appear here; the *arrs would import from library.
+  rootFolders = {
+    radarr = [ "/mnt/storage/torrents/movies" ];
+    sonarr = [ "/mnt/storage/torrents/shows" ];
+  };
+
   interconnectScript = pkgs.writeShellScript "arr-interconnect" ''
     set -euo pipefail
     PATH="${lib.makeBinPath [ pkgs.curl pkgs.jq pkgs.gnused pkgs.gnugrep pkgs.coreutils pkgs.systemd pkgs.sqlite pkgs.docker ]}:$PATH"
@@ -73,6 +83,59 @@ let
     wait_for "Radarr"   "$BASE:7878/api/v3/system/status" "$RADARR_KEY"   || true
     wait_for "Prowlarr" "$BASE:9696/api/v1/system/status" "$PROWLARR_KEY" || true
 
+    ##########################################################################
+    # Root folders — reconcile against the declarative list above.
+    #
+    # Runs before the Seerr blocks on purpose: they read rootfolder[0] to pick
+    # activeDirectory, which is only unambiguous once this has pruned the
+    # strays. Deleting a root folder unregisters the path only; existing
+    # movies/series keep their absolute paths and no files are touched.
+    ##########################################################################
+    reconcile_root_folders() {
+      local name="$1" port="$2" key="$3" desired="$4" current
+
+      [ -n "$key" ] || return 0
+
+      current=$(curl -sf -H "X-Api-Key: $key" "$BASE:$port/api/v3/rootfolder" || true)
+      if [ -z "$current" ]; then
+        echo "$name not reachable, skipping root folders"
+        return 0
+      fi
+
+      # Refuse to prune against an empty list — that would unregister every
+      # root folder the moment the Nix attrset is mistyped.
+      if [ "$(echo "$desired" | jq 'length')" = "0" ]; then
+        echo "$name has no declared root folders, skipping"
+        return 0
+      fi
+
+      echo "$desired" | jq -r '.[]' | while read -r path; do
+        if ! echo "$current" | jq -e --arg p "$path" 'any(.[]; .path == $p)' > /dev/null; then
+          echo "Adding root folder to $name: $path"
+          curl -sf -X POST \
+            -H "Content-Type: application/json" \
+            -H "X-Api-Key: $key" \
+            "$BASE:$port/api/v3/rootfolder" \
+            -d "$(jq -n --arg p "$path" '{path: $p}')" > /dev/null \
+            && echo "  done" || echo "  failed"
+        fi
+      done
+
+      # Tab-separated: root folder paths routinely contain spaces and brackets.
+      echo "$current" \
+        | jq -r --argjson d "$desired" \
+            '.[] | select(.path as $p | ($d | index($p)) == null) | "\(.id)\t\(.path)"' \
+        | while IFS=$'\t' read -r id path; do
+            echo "Removing stray root folder from $name: $path"
+            curl -sf -X DELETE -H "X-Api-Key: $key" \
+              "$BASE:$port/api/v3/rootfolder/$id" > /dev/null \
+              && echo "  done" || echo "  failed"
+          done
+    }
+
+    reconcile_root_folders "Radarr" 7878 "$RADARR_KEY" '${builtins.toJSON rootFolders.radarr}'
+    reconcile_root_folders "Sonarr" 8989 "$SONARR_KEY" '${builtins.toJSON rootFolders.sonarr}'
+
     ##########################################################################
     # Prowlarr → Sonarr (push indexers for TV)
     ##########################################################################
@@ -519,9 +582,10 @@ RUBY
         fi
 
         # --- Radarr. activeProfileId/activeDirectory are required and have no
-        # --- sane default, so pull them from Radarr itself.
+        # --- sane default, so pull them from Radarr itself. rootfolder[0] is
-        # ponytail: takes Radarr's first quality profile and root folder; pick
+        # --- unambiguous because reconcile_root_folders ran first.
-        # them explicitly here if you ever run more than one of either.
+        # ponytail: still takes the first quality profile; name it explicitly
+        # here if you ever run more than one.
         if [ -n "$RADARR_KEY" ] && [ "$(seerr_get /settings/radarr | jq 'length')" = "0" ]; then
           # || true on every assignment: set -e aborts the whole job on a bare
           # failing substitution, and Radarr being briefly down must not take