/*
Copyright 2017 The Kubernetes 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 cmd

import (
	"fmt"
	"net"

	netutil "k8s.io/apimachinery/pkg/util/net"
	kubeadmapi "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm"
	kubeadmconstants "k8s.io/kubernetes/cmd/kubeadm/app/constants"
	kubeadmutil "k8s.io/kubernetes/cmd/kubeadm/app/util"
	tokenutil "k8s.io/kubernetes/cmd/kubeadm/app/util/token"

	"github.com/blang/semver"
)

var minK8sVersion = semver.MustParse(kubeadmconstants.MinimumControlPlaneVersion)

func setInitDynamicDefaults(cfg *kubeadmapi.MasterConfiguration) error {

	// Choose the right address for the API Server to advertise. If the advertise address is localhost or 0.0.0.0, the default interface's IP address is used
	// This is the same logic as the API Server uses
	ip, err := netutil.ChooseBindAddress(net.ParseIP(cfg.API.AdvertiseAddress))
	if err != nil {
		return err
	}
	cfg.API.AdvertiseAddress = ip.String()

	// Validate version argument
	ver, err := kubeadmutil.KubernetesReleaseVersion(cfg.KubernetesVersion)
	if err != nil {
		return err
	}
	cfg.KubernetesVersion = ver

	// Omit the "v" in the beginning, otherwise semver will fail
	k8sVersion, err := semver.Parse(cfg.KubernetesVersion[1:])
	if err != nil {
		return fmt.Errorf("couldn't parse kubernetes version %q: %v", cfg.KubernetesVersion, err)
	}
	if k8sVersion.LT(minK8sVersion) {
		return fmt.Errorf("this version of kubeadm only supports deploying clusters with the control plane version >= v%s. Current version: %s", kubeadmconstants.MinimumControlPlaneVersion, cfg.KubernetesVersion)
	}

	fmt.Printf("[init] Using Kubernetes version: %s\n", cfg.KubernetesVersion)
	fmt.Printf("[init] Using Authorization mode: %s\n", cfg.AuthorizationMode)

	// Warn about the limitations with the current cloudprovider solution.
	if cfg.CloudProvider != "" {
		fmt.Println("[init] WARNING: For cloudprovider integrations to work --cloud-provider must be set for all kubelets in the cluster.")
		fmt.Println("\t(/etc/systemd/system/kubelet.service.d/10-kubeadm.conf should be edited for this purpose)")
	}

	if cfg.Token == "" {
		var err error
		cfg.Token, err = tokenutil.GenerateToken()
		if err != nil {
			return fmt.Errorf("couldn't generate random token: %v", err)
		}
	}

	return nil
}