// Copyright 2024 PingCAP, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// See the License for the specific language governing permissions and
// limitations under the License.

package controller

import (
	"context"
	"fmt"

	corev1 "k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/runtime"
	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
	"k8s.io/client-go/kubernetes"
	corelisters "k8s.io/client-go/listers/core/v1"
	"k8s.io/client-go/util/retry"
	"k8s.io/klog/v2"
)

// NodeControlInterface manages Nodes used in TidbCluster
type NodeControlInterface interface {
	GetNode(name string) (*corev1.Node, error)
	UpdateNode(runtime.Object, *corev1.Node) (*corev1.Node, error)
	UpdateAnnotations(obj runtime.Object, node *corev1.Node, new map[string]string, remove []string) (*corev1.Node, error)
}

type realNodeControl struct {
	kubeCli    kubernetes.Interface
	nodeLister corelisters.NodeLister
}

// NewRealNodeControl creates a new NodeControlInterface
func NewRealNodeControl(
	kubeCli kubernetes.Interface,
	nodeLister corelisters.NodeLister,
) NodeControlInterface {
	return &realNodeControl{
		kubeCli:    kubeCli,
		nodeLister: nodeLister,
	}
}

func (c *realNodeControl) GetNode(name string) (*corev1.Node, error) {
	return c.nodeLister.Get(name)
}

func (c *realNodeControl) UpdateNode(obj runtime.Object, node *corev1.Node) (*corev1.Node, error) {
	metaObj, ok := obj.(metav1.Object)
	if !ok {
		return nil, fmt.Errorf("%+v is not a runtime.Object, cannot get controller from it", obj)
	}

	kind := obj.GetObjectKind().GroupVersionKind().Kind
	ns := metaObj.GetNamespace()
	name := metaObj.GetName()

	nodeName := node.GetName()

	labels := node.GetLabels()
	ann := node.GetAnnotations()

	var updateNode *corev1.Node
	// don't wait due to limited number of clients, but backoff after the default number of steps
	err := retry.RetryOnConflict(retry.DefaultRetry, func() error {
		var updateErr error
		updateNode, updateErr = c.kubeCli.CoreV1().Nodes().Update(context.TODO(), node, metav1.UpdateOptions{})
		if updateErr == nil {
			klog.Infof("Node: [%s] updated successfully, %s: [%s/%s]", nodeName, kind, ns, name)
			return nil
		}
		klog.Errorf("failed to update Node: [%s], error: %v", nodeName, updateErr)

		if updated, err := c.nodeLister.Get(nodeName); err == nil {
			// make a copy so we don't mutate the shared cache
			node = updated.DeepCopy()
			node.Labels = labels
			node.Annotations = ann
		} else {
			utilruntime.HandleError(fmt.Errorf("error getting updated Node %s from lister: %v", nodeName, err))
		}

		return updateErr
	})
	return updateNode, err
}

func (c *realNodeControl) UpdateAnnotations(obj runtime.Object, node *corev1.Node, new map[string]string, remove []string) (*corev1.Node, error) {
	metaObj, ok := obj.(metav1.Object)
	if !ok {
		return nil, fmt.Errorf("%+v is not a runtime.Object, cannot get controller from it", obj)
	}

	ns := metaObj.GetNamespace()
	name := metaObj.GetName()
	kind := obj.GetObjectKind().GroupVersionKind().Kind

	if node.Annotations == nil {
		node.Annotations = make(map[string]string)
	}
	nodeName := node.GetName()

	var changes int
	for key, value := range new {
		if node.Annotations[key] != value {
			changes++
			node.Annotations[key] = value
		}
	}
	for _, annotation := range remove {
		if _, ok := node.Annotations[annotation]; ok {
			changes++
			delete(node.Annotations, annotation)
		}
	}
	if changes == 0 {
		klog.V(4).Infof("node %s already has annotations synced, skipping. %s: %s/%s", nodeName, kind, ns, name)
		return node, nil
	}
	return c.UpdateNode(obj, node)
}

var _ NodeControlInterface = &realNodeControl{}