Refactoring decode/encode structure and logic

pkg/envoy/encoder.go

@@ -0,0 +1,46 @@
+package envoy
+
+import (
+	"context"
+)
+
+type (
+	Encoder interface {
+		Encode(context.Context, ...Node) error
+	}
+
+	Provider interface {
+		Next(context.Context) (node Node, parentNodes []Node, childNodes []Node, err error)
+	}
+)
+
+func Encode(ctx context.Context, p Provider, ee ...Encoder) error {
+	for {
+		node, pp, _, err := p.Next(ctx)
+
+		// If both node AND error are provided, that means its a dep. conflict
+		if node != nil && err != nil {
+			// @todo handle dep. conflicts
+			continue
+		} else if err != nil {
+			return err
+		}
+
+		if node == nil {
+			// No more nodes...
+			return nil
+		}
+
+		// Upgradable nodes need to be processed based on their parent nodes
+		if un, is := node.(NodeUpdater); is {
+			un.Update(pp...)
+		}
+
+		for _, e := range ee {
+			err = e.Encode(ctx, node)
+			if err != nil {
+				return err
+			}
+		}
+	}
+}