/*
Copyright 2020 KubeSphere 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 k8s

import (
	"os"
	"os/user"
	"path"

	"k8s.io/client-go/util/homedir"

	"github.com/spf13/pflag"

	"kubesphere.io/kubesphere/pkg/utils/reflectutils"
)

type KubernetesOptions struct {
	// kubeconfig path, if not specified, will use
	// in cluster way to create clientset
	KubeConfig string `json:"kubeconfig" yaml:"kubeconfig"`

	// kubernetes apiserver public address, used to generate kubeconfig
	// for downloading, default to host defined in kubeconfig
	// +optional
	Master string `json:"master,omitempty" yaml:"master"`

	// kubernetes clientset qps
	// +optional
	QPS float32 `json:"qps,omitempty" yaml:"qps"`

	// kubernetes clientset burst
	// +optional
	Burst int `json:"burst,omitempty" yaml:"burst"`
}

// NewKubernetesOptions returns a `zero` instance
func NewKubernetesOptions() (option *KubernetesOptions) {
	option = &KubernetesOptions{
		QPS:   1e6,
		Burst: 1e6,
	}

	// make it be easier for those who wants to run api-server locally
	homePath := homedir.HomeDir()
	if homePath == "" {
		// try os/user.HomeDir when $HOME is unset.
		if u, err := user.Current(); err == nil {
			homePath = u.HomeDir
		}
	}

	userHomeConfig := path.Join(homePath, ".kube/config")
	if _, err := os.Stat(userHomeConfig); err == nil {
		option.KubeConfig = userHomeConfig
	}
	return
}

func (k *KubernetesOptions) Validate() []error {
	errors := []error{}

	if k.KubeConfig != "" {
		if _, err := os.Stat(k.KubeConfig); err != nil {
			errors = append(errors, err)
		}
	}
	return errors
}

func (k *KubernetesOptions) ApplyTo(options *KubernetesOptions) {
	reflectutils.Override(options, k)
}

func (k *KubernetesOptions) AddFlags(fs *pflag.FlagSet, c *KubernetesOptions) {
	fs.StringVar(&k.KubeConfig, "kubeconfig", c.KubeConfig, ""+
		"Path for kubernetes kubeconfig file, if left blank, will use "+
		"in cluster way.")

	fs.StringVar(&k.Master, "master", c.Master, ""+
		"Used to generate kubeconfig for downloading, if not specified, will use host in kubeconfig.")
}