Refactors Accessor Logic for MCPServer Fields Into Specific Package (#1877)

* refactors accessor logic into specific package

Signed-off-by: ChrisJBurns <29541485+ChrisJBurns@users.noreply.github.com>

* lint

Signed-off-by: ChrisJBurns <29541485+ChrisJBurns@users.noreply.github.com>

---------

Signed-off-by: ChrisJBurns <29541485+ChrisJBurns@users.noreply.github.com>

Author: ChrisJBurns

pkg/operator/accessors/mcpserver_accessor.go

@@ -0,0 +1,103 @@
+// Package accessors provides accessor functions for the ToolHive operator
+package accessors
+
+import (
+	"maps"
+
+	mcpv1alpha1 "github.com/stacklok/toolhive/cmd/thv-operator/api/v1alpha1"
+)
+
+// MCPServerFieldAccessor provides accessor methods for handling labels and annotations
+type MCPServerFieldAccessor interface {
+	// GetProxyDeploymentLabelsAndAnnotations returns labels and annotations for the deployment
+	GetProxyDeploymentLabelsAndAnnotations(mcpServer *mcpv1alpha1.MCPServer) (labels, annotations map[string]string)
+
+	// GetProxyDeploymentTemplateLabelsAndAnnotations returns labels and annotations for the deployment pod template
+	GetProxyDeploymentTemplateLabelsAndAnnotations(mcpServer *mcpv1alpha1.MCPServer) (labels, annotations map[string]string)
+}
+
+// mcpServerFieldAccessor implements MCPServerFieldAccessor
+type mcpServerFieldAccessor struct{}
+
+// NewMCPServerFieldAccessor creates a new MCPServerFieldAccessor instance
+func NewMCPServerFieldAccessor() MCPServerFieldAccessor {
+	return &mcpServerFieldAccessor{}
+}
+
+// GetProxyDeploymentLabelsAndAnnotations returns labels and annotations for the deployment
+func (*mcpServerFieldAccessor) GetProxyDeploymentLabelsAndAnnotations(
+	mcpServer *mcpv1alpha1.MCPServer,
+) (map[string]string, map[string]string) {
+	baseAnnotations := make(map[string]string)
+	baseLabels := make(map[string]string)
+
+	if mcpServer.Spec.ResourceOverrides == nil ||
+		mcpServer.Spec.ResourceOverrides.ProxyDeployment == nil {
+		return baseLabels, baseAnnotations
+	}
+
+	deploymentLabels := baseLabels
+	deploymentAnnotations := baseAnnotations
+
+	if mcpServer.Spec.ResourceOverrides.ProxyDeployment.Labels != nil {
+		deploymentLabels = mergeLabels(baseLabels, mcpServer.Spec.ResourceOverrides.ProxyDeployment.Labels)
+	}
+	if mcpServer.Spec.ResourceOverrides.ProxyDeployment.Annotations != nil {
+		deploymentAnnotations = mergeAnnotations(baseAnnotations, mcpServer.Spec.ResourceOverrides.ProxyDeployment.Annotations)
+	}
+
+	return deploymentLabels, deploymentAnnotations
+}
+
+// GetProxyDeploymentTemplateLabelsAndAnnotations returns labels and annotations for the deployment pod template
+func (*mcpServerFieldAccessor) GetProxyDeploymentTemplateLabelsAndAnnotations(
+	mcpServer *mcpv1alpha1.MCPServer,
+) (map[string]string, map[string]string) {
+	baseAnnotations := make(map[string]string)
+	baseLabels := make(map[string]string)
+
+	if mcpServer.Spec.ResourceOverrides == nil ||
+		mcpServer.Spec.ResourceOverrides.ProxyDeployment == nil ||
+		mcpServer.Spec.ResourceOverrides.ProxyDeployment.PodTemplateMetadataOverrides == nil {
+		return baseLabels, baseAnnotations
+	}
+
+	deploymentLabels := baseLabels
+	deploymentAnnotations := baseAnnotations
+
+	if mcpServer.Spec.ResourceOverrides.ProxyDeployment.PodTemplateMetadataOverrides.Labels != nil {
+		deploymentLabels = mergeLabels(baseLabels, mcpServer.Spec.ResourceOverrides.ProxyDeployment.PodTemplateMetadataOverrides.Labels)
+	}
+	if mcpServer.Spec.ResourceOverrides.ProxyDeployment.PodTemplateMetadataOverrides.Annotations != nil {
+		overrides := mcpServer.Spec.ResourceOverrides.ProxyDeployment.PodTemplateMetadataOverrides.Annotations
+		deploymentAnnotations = mergeAnnotations(baseAnnotations, overrides)
+	}
+
+	return deploymentLabels, deploymentAnnotations
+}
+
+// mergeLabels merges override labels with default labels, with default labels taking precedence
+func mergeLabels(defaultLabels, overrideLabels map[string]string) map[string]string {
+	return mergeStringMaps(defaultLabels, overrideLabels)
+}
+
+// mergeAnnotations merges override annotations with default annotations, with default annotations taking precedence
+func mergeAnnotations(defaultAnnotations, overrideAnnotations map[string]string) map[string]string {
+	return mergeStringMaps(defaultAnnotations, overrideAnnotations)
+}
+
+// mergeStringMaps merges override map with default map, with default map taking precedence
+// This ensures that operator-required metadata is preserved for proper functionality
+func mergeStringMaps(defaultMap, overrideMap map[string]string) map[string]string {
+	if overrideMap == nil && defaultMap == nil {
+		return make(map[string]string)
+	}
+	if overrideMap == nil {
+		return maps.Clone(defaultMap)
+	}
+	result := maps.Clone(overrideMap)
+	if defaultMap != nil {
+		maps.Copy(result, defaultMap) // default map takes precedence
+	}
+	return result
+}