cleanup category handling

module.nix

@@ -112,7 +112,13 @@ let
       syncCategories = lib.mkOption {
         type = lib.types.listOf lib.types.int;
         default = [ ];
-        description = "List of sync category IDs for the application.";
+        description = ''
+          List of Newznab category IDs to sync for this application.
+          When empty (default), categories are auto-detected at runtime
+          by querying Prowlarr's indexer/categories API endpoint and
+          collecting all IDs under the parent category matching the
+          implementation type (e.g. Sonarr -> TV, Radarr -> Movies).
+        '';
         example = [
           5000
           5010
@@ -291,6 +297,44 @@ let
     };
   };
 
+  # Map Servarr implementation names to their Newznab parent category names.
+  # Used to auto-detect syncCategories from the Prowlarr API when not explicitly set.
+  implementationCategoryMap = {
+    Sonarr = "TV";
+    Radarr = "Movies";
+    Lidarr = "Audio";
+    Readarr = "Books";
+    Whisparr = "XXX";
+  };
+
+  # Emit shell code that sets SYNC_CATEGORIES to a JSON array of category IDs.
+  # When the user provides explicit IDs, use those. Otherwise, query the Prowlarr
+  # /indexer/categories endpoint and collect the parent + all subcategory IDs for
+  # the implementation's Newznab category.
+  mkResolveSyncCategories =
+    app:
+    let
+      hasExplicit = app.syncCategories != [ ];
+      categoryName = implementationCategoryMap.${app.implementation} or null;
+    in
+    if hasExplicit then
+      "SYNC_CATEGORIES=${lib.escapeShellArg (builtins.toJSON app.syncCategories)}"
+    else if categoryName != null then
+      ''
+        echo "Auto-detecting sync categories for ${app.implementation}..."
+        ALL_CATEGORIES=$(${curl} -sf "$BASE_URL/indexer/categories" -H "X-Api-Key: $API_KEY")
+        SYNC_CATEGORIES=$(echo "$ALL_CATEGORIES" | ${jq} --arg name ${lib.escapeShellArg categoryName} \
+          '[.[] | select(.name == $name) | .id, .subCategories[].id]')
+        if [ "$SYNC_CATEGORIES" = "[]" ] || [ -z "$SYNC_CATEGORIES" ]; then
+          echo "Warning: could not auto-detect categories for '${categoryName}', using empty list" >&2
+          SYNC_CATEGORIES='[]'
+        else
+          echo "Resolved sync categories: $SYNC_CATEGORIES"
+        fi
+      ''
+    else
+      "SYNC_CATEGORIES='[]' ";
+
   curl = "${pkgs.curl}/bin/curl";
   jq = "${pkgs.jq}/bin/jq";
   grep = "${pkgs.gnugrep}/bin/grep";
@@ -353,6 +397,7 @@ let
       echo "Synced app '${app.name}' already exists, skipping"
     else
       echo "Adding synced app '${app.name}'..."
+      ${mkResolveSyncCategories app}
       PAYLOAD=$(${jq} -n \
         --arg name ${lib.escapeShellArg app.name} \
         --arg implementation ${lib.escapeShellArg app.implementation} \
@@ -361,7 +406,7 @@ let
         --arg prowlarrUrl ${lib.escapeShellArg app.prowlarrUrl} \
         --arg baseUrl ${lib.escapeShellArg app.baseUrl} \
         --arg apiKey "$TARGET_API_KEY" \
-        --argjson syncCategories ${builtins.toJSON app.syncCategories} \
+        --argjson syncCategories "$SYNC_CATEGORIES" \
         '{
           name: $name,
           implementation: $implementation,