/*
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 util

import (
	"fmt"
	"net"
	"strconv"

	"k8s.io/klog"
)

// IPPart returns just the IP part of an IP or IP:port or endpoint string. If the IP
// part is an IPv6 address enclosed in brackets (e.g. "[fd00:1::5]:9999"),
// then the brackets are stripped as well.
func IPPart(s string) string {
	if ip := net.ParseIP(s); ip != nil {
		// IP address without port
		return s
	}
	// Must be IP:port
	host, _, err := net.SplitHostPort(s)
	if err != nil {
		klog.Errorf("Error parsing '%s': %v", s, err)
		return ""
	}
	// Check if host string is a valid IP address
	ip := net.ParseIP(host)
	if ip == nil {
		klog.Errorf("invalid IP part '%s'", host)
		return ""
	}
	return ip.String()
}

// PortPart returns just the port part of an endpoint string.
func PortPart(s string) (int, error) {
	// Must be IP:port
	_, port, err := net.SplitHostPort(s)
	if err != nil {
		klog.Errorf("Error parsing '%s': %v", s, err)
		return -1, err
	}
	portNumber, err := strconv.Atoi(port)
	if err != nil {
		klog.Errorf("Error parsing '%s': %v", port, err)
		return -1, err
	}
	return portNumber, nil
}

// ToCIDR returns a host address of the form <ip-address>/32 for
// IPv4 and <ip-address>/128 for IPv6
func ToCIDR(ip net.IP) string {
	len := 32
	if ip.To4() == nil {
		len = 128
	}
	return fmt.Sprintf("%s/%d", ip.String(), len)
}
