package util

import (
	"context"
	"fmt"

	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/cli-runtime/pkg/genericclioptions"
	cmdutil "k8s.io/kubectl/pkg/cmd/util"

	karmadaclientset "github.com/karmada-io/karmada/pkg/generated/clientset/versioned"
)

const proxyURL = "/apis/cluster.karmada.io/v1alpha1/clusters/%s/proxy/"

// The Factory interface provides 2 major features compared to the cmdutil.Factory:
// 1. provides a method to get a karmada clientset
// 2. provides a method to get a cmdutil.Factory for the member cluster
type Factory interface {
	cmdutil.Factory

	// KarmadaClientSet returns a karmada clientset
	KarmadaClientSet() (karmadaclientset.Interface, error)

	// FactoryForMemberCluster returns a cmdutil.Factory for the member cluster
	FactoryForMemberCluster(clusterName string) (cmdutil.Factory, error)
}

var _ Factory = &factoryImpl{}

// factoryImpl is the implementation of Factory
type factoryImpl struct {
	cmdutil.Factory

	// kubeConfigFlags holds all the flags specificed by user.
	// These flags will be inherited by the member cluster's client.
	kubeConfigFlags *genericclioptions.ConfigFlags
}

// NewFactory returns a new factory
func NewFactory(kubeConfigFlags *genericclioptions.ConfigFlags) Factory {
	matchVersionKubeConfigFlags := cmdutil.NewMatchVersionFlags(kubeConfigFlags)
	f := &factoryImpl{
		kubeConfigFlags: kubeConfigFlags,
		Factory:         cmdutil.NewFactory(matchVersionKubeConfigFlags),
	}
	return f
}

// KarmadaClientSet returns a karmada clientset
func (f *factoryImpl) KarmadaClientSet() (karmadaclientset.Interface, error) {
	clientConfig, err := f.ToRESTConfig()
	if err != nil {
		return nil, err
	}
	return karmadaclientset.NewForConfig(clientConfig)
}

// FactoryForMemberCluster returns a cmdutil.Factory for the member cluster
func (f *factoryImpl) FactoryForMemberCluster(clusterName string) (cmdutil.Factory, error) {
	// Get client config of the karmada, and use it to create a cmdutil.Factory for the member cluster later.
	clientConfig, err := f.ToRESTConfig()
	if err != nil {
		return nil, err
	}
	karmadaAPIServer := clientConfig.Host

	// Check if the given cluster is joined to karmada
	client, err := karmadaclientset.NewForConfig(clientConfig)
	if err != nil {
		return nil, err
	}
	_, err = client.ClusterV1alpha1().Clusters().Get(context.TODO(), clusterName, metav1.GetOptions{})
	if err != nil {
		return nil, err
	}

	// Inherit all properties from the original flags specified by user except for the kube-apiserver address.
	kubeConfigFlags := &genericclioptions.ConfigFlags{
		CacheDir:         f.kubeConfigFlags.CacheDir,
		KubeConfig:       f.kubeConfigFlags.KubeConfig,
		ClusterName:      f.kubeConfigFlags.ClusterName,
		AuthInfoName:     f.kubeConfigFlags.AuthInfoName,
		Context:          f.kubeConfigFlags.Context,
		Namespace:        f.kubeConfigFlags.Namespace,
		Insecure:         f.kubeConfigFlags.Insecure,
		CertFile:         f.kubeConfigFlags.CertFile,
		KeyFile:          f.kubeConfigFlags.KeyFile,
		CAFile:           f.kubeConfigFlags.CAFile,
		BearerToken:      f.kubeConfigFlags.BearerToken,
		Impersonate:      f.kubeConfigFlags.Impersonate,
		ImpersonateUID:   f.kubeConfigFlags.ImpersonateUID,
		ImpersonateGroup: f.kubeConfigFlags.ImpersonateGroup,
		Username:         f.kubeConfigFlags.Username,
		Password:         f.kubeConfigFlags.Password,
		Timeout:          f.kubeConfigFlags.Timeout,
		WrapConfigFn:     f.kubeConfigFlags.WrapConfigFn,
	}
	// Override the kube-apiserver address.
	memberAPIserver := karmadaAPIServer + fmt.Sprintf(proxyURL, clusterName)
	kubeConfigFlags.APIServer = &memberAPIserver
	matchVersionKubeConfigFlags := cmdutil.NewMatchVersionFlags(kubeConfigFlags)
	return cmdutil.NewFactory(matchVersionKubeConfigFlags), nil
}