package node

import (
	"context"
	"fmt"
	"os"
	"strings"

	"k8s.io/client-go/tools/clientcmd"
	"k8s.io/klog/v2"

	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	kubernetes "k8s.io/client-go/kubernetes"
)

func ApplyLocalNodeMetadataIfPossible(ctx context.Context, nctx *NodeContext) error {
	spec := nctx.Config.Spec

	if len(spec.NodeAnnotations) == 0 && len(spec.NodeLabels) == 0 {
		return nil // nothing to do
	}

	nodeName := strings.TrimSpace(spec.NodeName)
	if nodeName == "" {
		return fmt.Errorf("spec.nodeName is required")
	}

	// Prefer admin kubeconfig (control-plane)
	kubeconfig := adminKubeconfigPath

	if _, err := os.Stat(kubeconfig); err != nil {
		klog.V(2).Infof("admin kubeconfig not found, skipping node metadata apply")
		return nil
	}

	restConfig, err := clientcmd.BuildConfigFromFlags("", kubeconfig)
	if err != nil {
		return fmt.Errorf("build kubeconfig: %w", err)
	}

	client, err := kubernetes.NewForConfig(restConfig)
	if err != nil {
		return fmt.Errorf("create kubernetes client: %w", err)
	}

	node, err := client.CoreV1().Nodes().Get(ctx, nodeName, metav1.GetOptions{})
	if err != nil {
		return fmt.Errorf("get node %q: %w", nodeName, err)
	}

	if node.Labels == nil {
		node.Labels = make(map[string]string)
	}
	if node.Annotations == nil {
		node.Annotations = make(map[string]string)
	}

	// Apply labels
	for k, v := range spec.NodeLabels {
		node.Labels[k] = v
	}

	// Apply annotations
	for k, v := range spec.NodeAnnotations {
		node.Annotations[k] = v
	}

	_, err = client.CoreV1().Nodes().Update(ctx, node, metav1.UpdateOptions{})
	if err != nil {
		return fmt.Errorf("update node metadata: %w", err)
	}

	klog.Infof("applied labels/annotations to node %q", nodeName)
	return nil
}