Improving all side of app

internal/datasource/synthetic/dsp_bridge.go

@@ -38,21 +38,32 @@ func stringParam(params map[string]any, key string) string {
 	return s
 }
 
-// BuildPipeline converts a []NodeDef (from JSON) into a []dsp.Node ready for
-// execution. JSON numbers are float64, so all numeric params are handled as
-// float64 regardless of the final type needed.
-func BuildPipeline(defs []NodeDef) ([]dsp.Node, error) {
-	nodes := make([]dsp.Node, 0, len(defs))
-	for i, d := range defs {
-		n, err := buildNode(d)
-		if err != nil {
-			return nil, fmt.Errorf("pipeline node %d (%q): %w", i, d.Type, err)
-		}
-		nodes = append(nodes, n)
+// stringSliceParam extracts a []string from params; JSON arrays decode to []any,
+// so each element is coerced via its string value. Returns nil if missing.
+func stringSliceParam(params map[string]any, key string) []string {
+	if params == nil {
+		return nil
 	}
-	return nodes, nil
+	v, ok := params[key]
+	if !ok {
+		return nil
+	}
+	arr, ok := v.([]any)
+	if !ok {
+		return nil
+	}
+	out := make([]string, 0, len(arr))
+	for _, e := range arr {
+		if s, ok := e.(string); ok && s != "" {
+			out = append(out, s)
+		}
+	}
+	return out
 }
 
+// buildNode converts a single NodeDef (from JSON) into a dsp.Node ready for
+// execution. JSON numbers are float64, so all numeric params are handled as
+// float64 regardless of the final type needed.
 func buildNode(d NodeDef) (dsp.Node, error) {
 	p := d.Params
 	switch d.Type {
@@ -100,7 +111,7 @@ func buildNode(d NodeDef) (dsp.Node, error) {
 		}, nil
 
 	case "expr":
-		return &dsp.ExprNode{Expr: stringParam(p, "expr")}, nil
+		return &dsp.ExprNode{Expr: stringParam(p, "expr"), Vars: stringSliceParam(p, "vars")}, nil
 
 	case "lowpass":
 		order := int(floatParam(p, "order"))
@@ -113,7 +124,7 @@ func buildNode(d NodeDef) (dsp.Node, error) {
 		}, nil
 
 	case "lua":
-		return &dsp.LuaNode{Script: stringParam(p, "script")}, nil
+		return &dsp.LuaNode{Script: stringParam(p, "script"), Vars: stringSliceParam(p, "vars")}, nil
 
 	default:
 		return nil, fmt.Errorf("unknown node type %q", d.Type)