/*
Copyright 2020 The 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 util

import (
	"bytes"
	"encoding/binary"
	"github.com/pkg/errors"
	log "github.com/sirupsen/logrus"
	"net"
	"os"
	"os/exec"
	"os/user"
	"runtime"
	"strconv"
	"strings"
	"text/template"
)

func InitLogger(verbose bool) *log.Logger {
	logger := log.New()
	logger.Formatter = &log.TextFormatter{
		FullTimestamp:   true,
		TimestampFormat: "15:04:05 MST",
	}

	if verbose {
		logger.SetLevel(log.DebugLevel)
	}

	return logger
}

func IsExist(path string) bool {
	_, err := os.Stat(path)
	if err != nil {
		if os.IsExist(err) {
			return true
		}
		if os.IsNotExist(err) {
			return false
		}
		return false
	}
	return true
}

func CreateDir(path string) error {
	if IsExist(path) == false {
		err := os.MkdirAll(path, os.ModePerm)
		if err != nil {
			return err
		}
	}
	return nil
}

type Data map[string]interface{}

// Render text template with given `variables` Render-context
func Render(tmpl *template.Template, variables map[string]interface{}) (string, error) {

	var buf strings.Builder

	if err := tmpl.Execute(&buf, variables); err != nil {
		return "", errors.Wrap(err, "Failed to render template")
	}
	return buf.String(), nil
}

func ParseIp(ip string) []string {
	var availableIPs []string
	// if ip is "1.1.1.1/",trim /
	ip = strings.TrimRight(ip, "/")
	if strings.Contains(ip, "/") == true {
		if strings.Contains(ip, "/32") == true {
			aip := strings.Replace(ip, "/32", "", -1)
			availableIPs = append(availableIPs, aip)
		} else {
			availableIPs = GetAvailableIP(ip)
		}
	} else if strings.Contains(ip, "-") == true {
		ipRange := strings.SplitN(ip, "-", 2)
		availableIPs = GetAvailableIPRange(ipRange[0], ipRange[1])
	} else {
		availableIPs = append(availableIPs, ip)
	}
	return availableIPs
}

func GetAvailableIPRange(ipStart, ipEnd string) []string {
	var availableIPs []string

	firstIP := net.ParseIP(ipStart)
	endIP := net.ParseIP(ipEnd)
	if firstIP.To4() == nil || endIP.To4() == nil {
		return availableIPs
	}
	firstIPNum := ipToInt(firstIP.To4())
	EndIPNum := ipToInt(endIP.To4())
	pos := int32(1)

	newNum := firstIPNum

	for newNum <= EndIPNum {
		availableIPs = append(availableIPs, intToIP(newNum).String())
		newNum = newNum + pos
	}
	return availableIPs
}

func GetAvailableIP(ipAndMask string) []string {
	var availableIPs []string

	ipAndMask = strings.TrimSpace(ipAndMask)
	ipAndMask = IPAddressToCIDR(ipAndMask)
	_, ipnet, _ := net.ParseCIDR(ipAndMask)

	firstIP, _ := networkRange(ipnet)
	ipNum := ipToInt(firstIP)
	size := networkSize(ipnet.Mask)
	pos := int32(1)
	max := size - 2 // -1 for the broadcast address, -1 for the gateway address

	var newNum int32
	for attempt := int32(0); attempt < max; attempt++ {
		newNum = ipNum + pos
		pos = pos%max + 1
		availableIPs = append(availableIPs, intToIP(newNum).String())
	}
	return availableIPs
}

func IPAddressToCIDR(ipAdress string) string {
	if strings.Contains(ipAdress, "/") == true {
		ipAndMask := strings.Split(ipAdress, "/")
		ip := ipAndMask[0]
		mask := ipAndMask[1]
		if strings.Contains(mask, ".") == true {
			mask = IPMaskStringToCIDR(mask)
		}
		return ip + "/" + mask
	} else {
		return ipAdress
	}
}

func IPMaskStringToCIDR(netmask string) string {
	netmaskList := strings.Split(netmask, ".")
	var mint []int
	for _, v := range netmaskList {
		strv, _ := strconv.Atoi(v)
		mint = append(mint, strv)
	}
	myIPMask := net.IPv4Mask(byte(mint[0]), byte(mint[1]), byte(mint[2]), byte(mint[3]))
	ones, _ := myIPMask.Size()
	return strconv.Itoa(ones)
}

func networkRange(network *net.IPNet) (net.IP, net.IP) {
	netIP := network.IP.To4()
	firstIP := netIP.Mask(network.Mask)
	lastIP := net.IPv4(0, 0, 0, 0).To4()
	for i := 0; i < len(lastIP); i++ {
		lastIP[i] = netIP[i] | ^network.Mask[i]
	}
	return firstIP, lastIP
}

func networkSize(mask net.IPMask) int32 {
	m := net.IPv4Mask(0, 0, 0, 0)
	for i := 0; i < net.IPv4len; i++ {
		m[i] = ^mask[i]
	}
	return int32(binary.BigEndian.Uint32(m)) + 1
}

func ipToInt(ip net.IP) int32 {
	return int32(binary.BigEndian.Uint32(ip.To4()))
}

func intToIP(n int32) net.IP {
	b := make([]byte, 4)
	binary.BigEndian.PutUint32(b, uint32(n))
	return net.IP(b)
}

func GetLocalIP() (string, error) {
	addrs, err := net.InterfaceAddrs()
	if err != nil {
		return "", err
	}
	for _, addr := range addrs {
		if ipnet, ok := addr.(*net.IPNet); ok && !ipnet.IP.IsLoopback() {
			if ipnet.IP.To4() != nil && ipnet.IP.IsGlobalUnicast() {
				return ipnet.IP.String(), nil
			}
		}
	}
	return "", errors.New("valid local IP not found!")
}

func LocalIP() string {
	localIp, err := GetLocalIP()
	if err != nil {
		log.Fatalf("Failed to get Local IP: %v", err)
	}
	return localIp
}

// returns the home directory for the executing user.
func Home() (string, error) {
	user, err := user.Current()
	if nil == err {
		return user.HomeDir, nil
	}

	if "windows" == runtime.GOOS {
		return homeWindows()
	}

	return homeUnix()
}

func homeUnix() (string, error) {
	if home := os.Getenv("HOME"); home != "" {
		return home, nil
	}

	var stdout bytes.Buffer
	cmd := exec.Command("sh", "-c", "eval echo ~$USER")
	cmd.Stdout = &stdout
	if err := cmd.Run(); err != nil {
		return "", err
	}

	result := strings.TrimSpace(stdout.String())
	if result == "" {
		return "", errors.New("blank output when reading home directory")
	}

	return result, nil
}

func homeWindows() (string, error) {
	drive := os.Getenv("HOMEDRIVE")
	path := os.Getenv("HOMEPATH")
	home := drive + path
	if drive == "" || path == "" {
		home = os.Getenv("USERPROFILE")
	}
	if home == "" {
		return "", errors.New("HOMEDRIVE, HOMEPATH, and USERPROFILE are blank")
	}

	return home, nil
}