Session 3: Radarr/Sonarr/Lidarr clients with add-on-search

Adds internal/arr with a shared HTTP layer and per-service clients that
look up candidates and POST the chosen one back with monitored=true and
search-on-add enabled. Lidarr requires metadata_profile_id, now part of
ArrConfig and validated when lidarr is set.

internal/arr/lidarr.go

@@ -0,0 +1,57 @@
+package arr
+
+import (
+	"context"
+	"fmt"
+
+	"bellhop/internal/config"
+)
+
+// Lidarr drives a Lidarr v1 instance.
+type Lidarr struct {
+	h                 *httpClient
+	qualityProfileID  int
+	metadataProfileID int
+	rootFolder        string
+}
+
+func NewLidarr(cfg *config.ArrConfig) *Lidarr {
+	return &Lidarr{
+		h:                 newHTTP(cfg.URL, cfg.APIKey),
+		qualityProfileID:  cfg.QualityProfileID,
+		metadataProfileID: cfg.MetadataProfileID,
+		rootFolder:        cfg.RootFolder,
+	}
+}
+
+func (l *Lidarr) Search(ctx context.Context, term string) ([]Result, error) {
+	body, err := l.h.get(ctx, "/api/v1/artist/lookup", map[string]string{"term": term})
+	if err != nil {
+		return nil, err
+	}
+	// Lidarr's lookup uses "artistName" instead of "title".
+	return parseLookup(body, "artistName")
+}
+
+func (l *Lidarr) Add(ctx context.Context, res Result) error {
+	if len(res.raw) == 0 {
+		return fmt.Errorf("lidarr: empty result")
+	}
+	body, err := buildAddBody(res.raw, map[string]any{
+		"qualityProfileId":  l.qualityProfileID,
+		"metadataProfileId": l.metadataProfileID,
+		"rootFolderPath":    l.rootFolder,
+		"monitored":         true,
+		"addOptions": map[string]any{
+			"monitor":                "all",
+			"searchForMissingAlbums": true,
+		},
+	})
+	if err != nil {
+		return err
+	}
+	_, err = l.h.post(ctx, "/api/v1/artist", body)
+	return err
+}
+
+var _ Client = (*Lidarr)(nil)