/*
Copyright 2023 The Karmada Authors.

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,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package multiclient

import (
	"sync"

	corev1 "k8s.io/api/core/v1"
	"k8s.io/client-go/discovery"
	"k8s.io/client-go/informers"
	listcorev1 "k8s.io/client-go/listers/core/v1"

	clusterV1alpha1 "github.com/karmada-io/karmada/pkg/apis/cluster/v1alpha1"
	clusterlister "github.com/karmada-io/karmada/pkg/generated/listers/cluster/v1alpha1"
	"github.com/karmada-io/karmada/pkg/util"
)

// MultiClusterDiscoveryInterface provides DiscoveryClient for multiple clusters.
type MultiClusterDiscoveryInterface interface {
	Get(clusterName string) *discovery.DiscoveryClient
	Set(clusterName string) error
	Remove(clusterName string)
}

// MultiClusterDiscovery provides DiscoveryClient for multiple clusters.
type MultiClusterDiscovery struct {
	sync.RWMutex
	clients             map[string]*discovery.DiscoveryClient
	clusterClientOption *util.ClientOption
	secretLister        listcorev1.SecretLister
	clusterLister       clusterlister.ClusterLister
}

// NewMultiClusterDiscoveryClient returns a new MultiClusterDiscovery
func NewMultiClusterDiscoveryClient(clusterLister clusterlister.ClusterLister, KubeFactory informers.SharedInformerFactory, clusterClientOption *util.ClientOption) MultiClusterDiscoveryInterface {
	return &MultiClusterDiscovery{
		clusterLister:       clusterLister,
		secretLister:        KubeFactory.Core().V1().Secrets().Lister(),
		clients:             map[string]*discovery.DiscoveryClient{},
		clusterClientOption: clusterClientOption,
	}
}

// Get returns a DiscoveryClient for the provided clusterName.
func (m *MultiClusterDiscovery) Get(clusterName string) *discovery.DiscoveryClient {
	m.RLock()
	defer m.RUnlock()
	return m.clients[clusterName]
}

// Set a DiscoveryClient for the provided clusterName.
func (m *MultiClusterDiscovery) Set(clusterName string) error {
	clusterGetter := func(cluster string) (*clusterV1alpha1.Cluster, error) {
		return m.clusterLister.Get(cluster)
	}
	secretGetter := func(namespace string, name string) (*corev1.Secret, error) {
		return m.secretLister.Secrets(namespace).Get(name)
	}
	clusterConfig, err := util.BuildClusterConfig(clusterName, clusterGetter, secretGetter)
	if err != nil {
		return err
	}
	clusterConfig.QPS = m.clusterClientOption.QPS
	clusterConfig.Burst = m.clusterClientOption.Burst
	m.Lock()
	defer m.Unlock()
	m.clients[clusterName] = discovery.NewDiscoveryClientForConfigOrDie(clusterConfig)
	return nil
}

// Remove a DiscoveryClient for the provided clusterName.
func (m *MultiClusterDiscovery) Remove(clusterName string) {
	m.Lock()
	defer m.Unlock()
	delete(m.clients, clusterName)
}