/*
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 util

import (
	"context"
	"fmt"
	"net"
	"net/url"

	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/labels"
	clientset "k8s.io/client-go/kubernetes"
	netutils "k8s.io/utils/net"
)

// GetControlplaneEndpoint parses an Endpoint and returns it as a string,
// or returns an error in case it cannot be parsed.
func GetControlplaneEndpoint(address, port string) (string, error) {
	var ip = netutils.ParseIPSloppy(address)
	if ip == nil {
		return "", fmt.Errorf("invalid value `%s` given for address", address)
	}
	return formatURL(ip.String(), port).String(), nil
}

// formatURL takes a host and a port string and creates a net.URL using https scheme
func formatURL(host, port string) *url.URL {
	return &url.URL{
		Scheme: "https",
		Host:   net.JoinHostPort(host, port),
	}
}

// GetAPIServiceIP returns a valid node IP address.
func GetAPIServiceIP(clientset clientset.Interface) (string, error) {
	nodes, err := clientset.CoreV1().Nodes().List(context.TODO(), metav1.ListOptions{})
	if err != nil || len(nodes.Items) == 0 {
		return "", fmt.Errorf("there are no nodes in cluster, err: %w", err)
	}

	var (
		masterLabel       = labels.Set{"node-role.kubernetes.io/master": ""}
		controlplaneLabel = labels.Set{"node-role.kubernetes.io/control-plane": ""}
	)
	// first, select the master node as the IP of APIServer. if there is
	// no master nodes, randomly select a worker node.
	for _, node := range nodes.Items {
		ls := labels.Set(node.GetLabels())

		if masterLabel.AsSelector().Matches(ls) || controlplaneLabel.AsSelector().Matches(ls) {
			if ip := netutils.ParseIPSloppy(node.Status.Addresses[0].Address); ip != nil {
				return ip.String(), nil
			}
		}
	}
	return nodes.Items[0].Status.Addresses[0].Address, nil
}