package hosts

import (
	"bufio"
	"bytes"
	"fmt"
	"io"
	"net"
	"os"
	"runtime"
	"strings"
	"sync"
)

var lineBreaker string

func init() {
	if runtime.GOOS == "windows" {
		lineBreaker = "\r\n"
	} else {
		lineBreaker = "\n"
	}
}
func SystemHostpath() string {
	if runtime.GOOS == "windows" {
		return `C:\Windows\System32\drivers\etc\hosts`
	}
	return `/etc/hosts`
}

var defaultParser = NewHosts()

func ParseHosts(hostPath string) error {
	return defaultParser.Parse(hostPath)
}

func Parse() error {
	return defaultParser.Parse(SystemHostpath())
}

func List() []*HostNode {
	return defaultParser.List()
}

func ListHosts() map[string][]string {
	return defaultParser.ListHosts()
}

func ListIPs() map[string][]string {
	return defaultParser.ListIPs()
}

func ListByHost(host string) []*HostNode {
	return defaultParser.ListByHost(host)
}

func ListIPsByHost(host string) []string {
	return defaultParser.ListIPsByHost(host)
}

func ListFirstIPByHost(host string) string {
	return defaultParser.ListFirstIPByHost(host)
}

func ListByIP(ip string) []*HostNode {
	return defaultParser.ListByIP(ip)
}

func ListHostsByIP(ip string) []string {
	return defaultParser.ListHostsByIP(ip)
}

func ListFirstHostByIP(ip string) string {
	return defaultParser.ListFirstHostByIP(ip)
}

func AddHosts(ip string, hosts ...string) error {
	return defaultParser.AddHosts(ip, hosts...)
}

func AddHostsComment(comment string, ip string, hosts ...string) error {
	return defaultParser.AddHostsComment(comment, ip, hosts...)
}

func RemoveIPHosts(ip string, hosts ...string) error {
	return defaultParser.RemoveIPHosts(ip, hosts...)
}

func RemoveIPs(ips ...string) error {
	return defaultParser.RemoveIPs(ips...)
}

func RemoveHosts(hosts ...string) error {
	return defaultParser.RemoveHosts(hosts...)
}

func SetIPHosts(ip string, hosts ...string) error {
	return defaultParser.SetIPHosts(ip, hosts...)
}

func SetHostIPs(host string, ips ...string) error {
	return defaultParser.SetHostIPs(host, ips...)
}

func InsertNodes(node *HostNode, before bool, comment string, ip string, hosts ...string) error {
	return defaultParser.InsertNodeByData(node, before, comment, ip, hosts...)
}

func SaveAs(path string) error {
	return defaultParser.SaveAs(path)
}

func Save() error {
	return defaultParser.Save()
}

func Build() ([]byte, error) {
	return defaultParser.Build()
}

func GetFirstNode() (*HostNode, error) {
	return defaultParser.GetFirstNode()
}

func GetNode(nodeID uint64) (*HostNode, error) {
	return defaultParser.GetNode(nodeID)
}

func GetNextNode(nodeID uint64) (*HostNode, error) {
	return defaultParser.GetNextNode(nodeID)
}

func GetLastNode(nodeID uint64) (*HostNode, error) {
	return defaultParser.GetLastNode(nodeID)
}

func GetLatestNode() (*HostNode, error) {
	return defaultParser.GetLatestNode()
}

func DeleteNode(node *HostNode) error {
	return defaultParser.DeleteNode(node)
}

func DeleteNodeByUID(uid uint64) error {
	return defaultParser.DeleteNodeByUID(uid)
}

func AddNode(node *HostNode) error {
	return defaultParser.AddNode(node)
}

func InsertNode(node *HostNode) error {
	return defaultParser.InsertNode(node)
}

func UpdateNode(node *HostNode) error {
	return defaultParser.UpdateNode(node)
}

type HostNode struct {
	uid         uint64
	nextuid     uint64
	lastuid     uint64
	ip          string
	host        []string
	comment     string
	original    string
	onlyComment bool
	valid       bool
}
type Host struct {
	idx      uint64
	hostPath string
	firstUid uint64
	lastUid  uint64
	fulldata map[uint64]*HostNode
	hostData map[string][]*HostNode
	ipData   map[string][]*HostNode
	sync.RWMutex
}

func NewHosts() *Host {
	return &Host{
		hostData: make(map[string][]*HostNode),
		ipData:   make(map[string][]*HostNode),
		fulldata: make(map[uint64]*HostNode),
	}
}

func (h *Host) Parse(hostPath string) error {
	h.Lock()
	defer h.Unlock()
	h.idx = 0
	h.firstUid = 0
	h.lastUid = 0
	h.hostPath = hostPath
	h.fulldata = make(map[uint64]*HostNode)
	h.hostData = make(map[string][]*HostNode)
	h.ipData = make(map[string][]*HostNode)
	return h.parse()
}

func (h *Host) parse() error {
	f, err := os.OpenFile(h.hostPath, os.O_RDONLY, 0666)
	if err != nil {
		return fmt.Errorf("open hosts file %s error: %s", h.hostPath, err)
	}
	defer f.Close()
	buf := bufio.NewReader(f)
	for {
		line, err := buf.ReadString('\n')
		if err == io.EOF {
			if h.idx-1 >= 0 {
				h.fulldata[h.idx].nextuid = 0
				h.lastUid = h.idx
			}
			break
		}
		if err != nil {
			return fmt.Errorf("read hosts file error: %s", err)
		}
		h.idx++
		line = strings.TrimSpace(line)
		data, _ := h.parseLine(line)
		data.uid = h.idx
		data.lastuid = h.idx - 1
		data.nextuid = h.idx + 1
		h.fulldata[data.uid] = &data
		if h.firstUid == 0 {
			h.firstUid = h.idx
		}
		if data.valid {
			for _, v := range data.host {
				h.hostData[v] = append(h.hostData[v], &data)
			}
			h.ipData[data.ip] = append(h.ipData[data.ip], &data)
		}
	}

	return nil
}

func (h *Host) parseLine(data string) (HostNode, error) {
	var res = HostNode{
		original: data,
	}
	if len(data) == 0 {
		return res, fmt.Errorf("empty line")
	}
	if data[0] == '#' {
		res.comment = data
		res.onlyComment = true
		res.valid = true
		return res, nil
	}
	var dataArr []string
	cache := ""
	for k, v := range data {
		if v == '#' {
			if len(cache) > 0 {
				dataArr = append(dataArr, cache)
				cache = ""
			}
			dataArr = append(dataArr, data[k:])
			break
		}
		if v == ' ' || v == '\t' {
			if len(cache) > 0 {
				dataArr = append(dataArr, cache)
				cache = ""
			}
			continue
		}
		cache += string(v)
	}
	if len(cache) > 0 {
		dataArr = append(dataArr, cache)
	}
	if len(dataArr) < 2 {
		return res, fmt.Errorf("invalid line")
	}
	if strings.HasPrefix(dataArr[1], "#") {
		return res, fmt.Errorf("invalid line")
	}
	if net.ParseIP(dataArr[0]) == nil {
		return res, fmt.Errorf("invalid ip address")
	}
	for k, v := range dataArr {
		switch k {
		case 0:
			res.ip = v
		default:
			if strings.HasPrefix(v, "#") {
				res.comment = v
			} else {
				res.host = append(res.host, v)
			}
		}
	}
	res.valid = true
	return res, nil
}

func (h *Host) List() []*HostNode {
	h.RLock()
	defer h.RUnlock()
	var res []*HostNode
	nextUid := h.firstUid
	for {
		if nextUid == 0 {
			break
		}
		res = append(res, h.fulldata[nextUid])
		nextUid = h.fulldata[nextUid].nextuid
	}
	return res
}

func (h *Host) ListHosts() map[string][]string {
	h.RLock()
	defer h.RUnlock()
	if h.hostData == nil {
		return nil
	}
	var res = make(map[string][]string)
	for k, v := range h.hostData {
		for _, vv := range v {
			res[k] = append(res[k], vv.ip)
		}
	}
	return res
}

func (h *Host) ListIPs() map[string][]string {
	h.RLock()
	defer h.RUnlock()
	if h.ipData == nil {
		return nil
	}
	var res = make(map[string][]string)
	for k, v := range h.ipData {
		for _, vv := range v {
			res[k] = append(res[k], vv.host...)
		}
	}
	return res
}

func (h *Host) ListByHost(host string) []*HostNode {
	h.RLock()
	defer h.RUnlock()
	if h.hostData == nil {
		return nil
	}
	return h.hostData[host]
}

func (h *Host) ListIPsByHost(host string) []string {
	h.RLock()
	defer h.RUnlock()
	if h.hostData == nil {
		return nil
	}
	var res []string
	for _, v := range h.hostData[host] {
		res = append(res, v.ip)
	}
	return res
}

func (h *Host) ListFirstIPByHost(host string) string {
	h.RLock()
	defer h.RUnlock()
	if h.hostData == nil {
		return ""
	}
	for _, v := range h.hostData[host] {
		return v.ip
	}
	return ""
}

func (h *Host) ListByIP(ip string) []*HostNode {
	h.RLock()
	defer h.RUnlock()
	if h.ipData == nil {
		return nil
	}
	return h.ipData[ip]
}

func (h *Host) ListHostsByIP(ip string) []string {
	h.RLock()
	defer h.RUnlock()
	return h.listHostsByIP(ip)
}

func (h *Host) listHostsByIP(ip string) []string {
	if h.ipData == nil {
		return nil
	}
	var res []string
	for _, v := range h.ipData[ip] {
		res = append(res, v.host...)
	}
	return res
}

func (h *Host) ListFirstHostByIP(ip string) string {
	h.RLock()
	defer h.RUnlock()
	if h.ipData == nil {
		return ""
	}
	for _, v := range h.ipData[ip] {
		if len(v.host) > 0 {
			return v.host[0]
		}
	}
	return ""
}

func (h *Host) AddHosts(ip string, hosts ...string) error {
	return h.addHosts("", ip, hosts...)
}

func (h *Host) AddHostsComment(comment string, ip string, hosts ...string) error {
	return h.addHosts(comment, ip, hosts...)
}

func (h *Host) RemoveIPHosts(ip string, hosts ...string) error {
	h.Lock()
	defer h.Unlock()
	if h.ipData == nil {
		return fmt.Errorf("hosts data not initialized")
	}
	ipInfo := h.ipData[ip]
	if len(ipInfo) == 0 {
		return nil
	}
cntfor:
	for _, v := range ipInfo {
		for _, host := range hosts {
			if len(v.host) == 1 && v.host[0] == host {
				delete(h.ipData, ip)
				if v.lastuid != 0 {
					h.fulldata[v.lastuid].nextuid = v.nextuid
				} else {
					h.firstUid = v.nextuid
				}
				if v.nextuid != 0 {
					h.fulldata[v.nextuid].lastuid = v.lastuid
				} else {
					h.lastUid = v.lastuid
				}
				var newHostData []*HostNode
				for _, vv := range h.hostData[v.host[0]] {
					if vv.uid != v.uid {
						newHostData = append(newHostData, vv)
					}
				}
				h.hostData[host] = newHostData
				delete(h.fulldata, v.uid)
				v = nil
				continue cntfor
			}
			if len(v.host) > 1 {
				var newHosts []string
				for _, vv := range v.host {
					if vv != host {
						newHosts = append(newHosts, vv)
					}
				}
				v.host = newHosts
				var newHostData []*HostNode
				for _, vv := range h.hostData[host] {
					if vv.uid != v.uid {
						newHostData = append(newHostData, vv)
					}
				}
				h.hostData[host] = newHostData
			}
		}
	}
	return nil
}

func (h *Host) RemoveIPs(ips ...string) error {
	h.Lock()
	defer h.Unlock()
	if h.ipData == nil {
		return fmt.Errorf("hosts data not initialized")
	}
	for _, ip := range ips {
		ipInfo := h.ipData[ip]
		if len(ipInfo) == 0 {
			continue
		}
		for _, v := range ipInfo {
			delete(h.ipData, ip)
			delete(h.fulldata, v.uid)
			if v.lastuid != 0 {
				h.fulldata[v.lastuid].nextuid = v.nextuid
			} else {
				h.firstUid = v.nextuid
			}
			if v.nextuid != 0 {
				h.fulldata[v.nextuid].lastuid = v.lastuid
			} else {
				h.lastUid = v.lastuid
			}
			for _, host := range v.host {
				var newHostData []*HostNode
				for _, vv := range h.hostData[host] {
					if vv.uid != v.uid {
						newHostData = append(newHostData, vv)
					}
				}
				h.hostData[host] = newHostData
			}
		}
	}
	return nil
}

func (h *Host) RemoveHosts(hosts ...string) error {
	h.Lock()
	defer h.Unlock()
	if h.hostData == nil {
		return fmt.Errorf("hosts data not initialized")
	}
	for _, host := range hosts {
		hostInfo := h.hostData[host]
		if len(hostInfo) == 0 {
			continue
		}
		delete(h.hostData, host)
		for _, v := range hostInfo {
			var newHosts []string
			for _, vv := range v.host {
				if vv != host {
					newHosts = append(newHosts, vv)
				}
			}
			v.host = newHosts
			if len(v.host) == 0 {
				delete(h.ipData, v.ip)
				if v.lastuid != 0 {
					h.fulldata[v.lastuid].nextuid = v.nextuid
				} else {
					h.firstUid = v.nextuid
				}
				if v.nextuid != 0 {
					h.fulldata[v.nextuid].lastuid = v.lastuid
				} else {
					h.lastUid = v.lastuid
				}
				delete(h.fulldata, v.uid)
			}
		}
	}
	return nil
}

func (h *Host) SetIPHosts(ip string, hosts ...string) error {
	info := h.ListByIP(ip)
	if len(info) == 0 {
		return h.AddHosts(ip, hosts...)
	} else if len(info) == 1 {
		info[0].host = hosts
		info[0].comment = ""
		return nil
	}
	err := h.RemoveIPs(ip)
	if err != nil {
		return err
	}
	return h.AddHosts(ip, hosts...)
}

func (h *Host) SetHostIPs(host string, ips ...string) error {
	info := h.ListByHost(host)
	if len(info) == 0 {
		return h.AddHosts(host, ips...)
	} else if len(info) == 1 {
		info[0].ip = ips[0]
		info[0].comment = ""
		return nil
	}
	err := h.RemoveHosts(host)
	if err != nil {
		return err
	}
	return h.AddHosts(ips[0], host)
}

func (h *Host) addHosts(comment string, ip string, hosts ...string) error {
	h.Lock()
	defer h.Unlock()
	if h.hostData == nil {
		return fmt.Errorf("hosts data not initialized")
	}
	ipInfo := h.listHostsByIP(ip)
	var needAddHosts []string
	for _, v := range hosts {
		if !inArray(ipInfo, v) {
			needAddHosts = append(needAddHosts, v)
		}
	}
	if len(needAddHosts) == 0 {
		return nil
	}
	if comment != "" && !strings.HasPrefix(strings.TrimSpace(comment), "#") {
		comment = "#" + comment
	}
	hostNode := HostNode{
		uid:     h.idx + 1,
		nextuid: 0,
		lastuid: h.lastUid,
		ip:      ip,
		host:    needAddHosts,
		valid:   true,
		comment: comment,
	}
	h.idx++
	h.fulldata[h.lastUid].nextuid = h.idx
	h.lastUid = h.idx
	h.fulldata[h.idx] = &hostNode
	h.ipData[ip] = append(h.ipData[ip], &hostNode)
	for _, v := range needAddHosts {
		h.hostData[v] = append(h.hostData[v], &hostNode)
	}
	return nil
}

func (h *Host) InsertNodeByData(node *HostNode, before bool, comment string, ip string, hosts ...string) error {
	h.Lock()
	defer h.Unlock()
	if h.hostData == nil {
		return fmt.Errorf("hosts data not initialized")
	}
	if _, ok := h.fulldata[node.uid]; !ok {
		return fmt.Errorf("node not exists")
	}
	if comment != "" && !strings.HasPrefix(strings.TrimSpace(comment), "#") {
		comment = "#" + comment
	}
	hostNode := HostNode{
		uid:     h.idx + 1,
		ip:      ip,
		host:    hosts,
		valid:   true,
		comment: comment,
	}
	if ip == "" && len(hosts) == 0 && comment != "" {
		hostNode.onlyComment = true
	}
	if before {
		hostNode.nextuid = node.uid
		hostNode.lastuid = node.lastuid
		if node.lastuid != 0 {
			h.fulldata[node.lastuid].nextuid = h.idx
		} else {
			h.firstUid = h.idx
		}
		node.lastuid = h.idx
	} else {
		hostNode.lastuid = node.uid
		hostNode.nextuid = node.nextuid
		if node.nextuid != 0 {
			h.fulldata[node.nextuid].lastuid = h.idx
		} else {
			h.lastUid = h.idx
		}
		node.nextuid = h.idx
	}
	return nil
}

func (h *Host) DeleteNode(node *HostNode) error {
	h.Lock()
	defer h.Unlock()
	if h.hostData == nil {
		return fmt.Errorf("hosts data not initialized")
	}
	if _, ok := h.fulldata[node.uid]; !ok {
		return fmt.Errorf("node not exists")
	}
	if node.lastuid != 0 {
		h.fulldata[node.lastuid].nextuid = node.nextuid
	} else {
		h.firstUid = node.nextuid
	}
	if node.nextuid != 0 {
		h.fulldata[node.nextuid].lastuid = node.lastuid
	} else {
		h.lastUid = node.lastuid
	}
	for _, v := range node.host {
		var newHostData []*HostNode
		for _, vv := range h.hostData[v] {
			if vv.uid != node.uid {
				newHostData = append(newHostData, vv)
			}
		}
		h.hostData[v] = newHostData
	}
	ipInfo := h.ipData[node.ip]
	var newIPData []*HostNode
	for _, v := range ipInfo {
		if v.uid != node.uid {
			newIPData = append(newIPData, v)
		}
	}
	h.ipData[node.ip] = newIPData
	delete(h.fulldata, node.uid)
	return nil
}

func (h *Host) DeleteNodeByUID(uid uint64) error {
	h.RLock()
	node, ok := h.fulldata[uid]
	if !ok {
		h.RUnlock()
		return fmt.Errorf("node not exists")
	}
	h.RUnlock()
	return h.DeleteNode(node)
}

func (h *Host) AddNode(node *HostNode) error {
	h.Lock()
	defer h.Unlock()
	if h.hostData == nil {
		return fmt.Errorf("hosts data not initialized")
	}
	if node.comment != "" && !strings.HasPrefix(strings.TrimSpace(node.comment), "#") {
		node.comment = "#" + node.comment
	}
	if node.ip == "" && len(node.host) == 0 && node.comment != "" {
		node.onlyComment = true
	}
	h.idx++
	node.uid = h.idx
	node.lastuid = h.lastUid
	node.nextuid = 0
	h.fulldata[h.lastUid].nextuid = node.uid
	h.lastUid = node.uid
	h.fulldata[node.uid] = node
	node.valid = node.CheckValid()
	if node.valid {
		h.ipData[node.ip] = append(h.ipData[node.ip], node)
		for _, v := range node.host {
			h.hostData[v] = append(h.hostData[v], node)
		}
	}
	return nil
}

func (h *Host) InsertNode(node *HostNode) error {
	if node.lastuid == 0 && node.nextuid == 0 {
		return h.AddNode(node)
	}
	h.Lock()
	defer h.Unlock()
	if h.hostData == nil {
		return fmt.Errorf("hosts data not initialized")
	}
	if node.comment != "" && !strings.HasPrefix(strings.TrimSpace(node.comment), "#") {
		node.comment = "#" + node.comment
	}
	if node.ip == "" && len(node.host) == 0 && node.comment != "" {
		node.onlyComment = true
	}
	node.uid = h.idx + 1
	if h.fulldata[node.lastuid].nextuid != node.nextuid {
		return fmt.Errorf("node lastuid nextuid not match")
	}
	h.idx++
	h.fulldata[node.lastuid].nextuid = node.uid
	h.fulldata[node.nextuid].lastuid = node.uid
	h.fulldata[node.uid] = node
	node.valid = node.CheckValid()
	if node.valid {
		h.ipData[node.ip] = append(h.ipData[node.ip], node)
		for _, v := range node.host {
			h.hostData[v] = append(h.hostData[v], node)
		}
	}
	return nil
}

func inArray(arr []string, v string) bool {
	for _, vv := range arr {
		if v == vv {
			return true
		}
	}
	return false
}

func (h *Host) SaveAs(path string) error {
	return h.save(path)
}

func (h *Host) Save() error {
	return h.save(h.hostPath)
}

func (h *Host) save(path string) error {
	h.Lock()
	defer h.Unlock()
	if h.firstUid == 0 || h.fulldata == nil {
		return fmt.Errorf("no data")
	}
	f, err := os.OpenFile(path, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0666)
	if err != nil {
		return fmt.Errorf("open hosts file %s error: %s", h.hostPath, err)
	}
	defer f.Close()
	node := h.fulldata[h.firstUid]
	if node == nil {
		return fmt.Errorf("no data")
	}
	for {
		if node.onlyComment {
			if _, err := f.WriteString(node.comment + "\n"); err != nil {
				return fmt.Errorf("write hosts file error: %s", err)
			}
			if node.nextuid == 0 {
				break
			}
			node = h.fulldata[node.nextuid]
			continue
		}
		if _, err := f.WriteString(node.ip + " "); err != nil {
			return fmt.Errorf("write hosts file error: %s", err)
		}
		if _, err := f.WriteString(strings.Join(node.host, " ")); err != nil {
			return fmt.Errorf("write hosts file error: %s", err)
		}
		if len(node.comment) > 0 {
			if _, err := f.WriteString(" " + node.comment); err != nil {
				return fmt.Errorf("write hosts file error: %s", err)
			}
		}
		if _, err := f.WriteString(lineBreaker); err != nil {
			return fmt.Errorf("write hosts file error: %s", err)
		}
		if node.nextuid == 0 {
			break
		}
		node = h.fulldata[node.nextuid]
	}
	return nil
}

func (h *Host) Build() ([]byte, error) {
	if h.firstUid == 0 || h.fulldata == nil {
		return nil, fmt.Errorf("no data")
	}
	h.Lock()
	defer h.Unlock()
	var f bytes.Buffer
	node := h.fulldata[h.firstUid]
	if node == nil {
		return nil, fmt.Errorf("no data")
	}
	for {
		if node.onlyComment {
			if _, err := f.WriteString(node.comment + "\n"); err != nil {
				return nil, fmt.Errorf("write hosts file error: %s", err)
			}
			if node.nextuid == 0 {
				break
			}
			node = h.fulldata[node.nextuid]
			continue
		}
		if _, err := f.WriteString(node.ip + " "); err != nil {
			return nil, fmt.Errorf("write hosts file error: %s", err)
		}
		if _, err := f.WriteString(strings.Join(node.host, " ")); err != nil {
			return nil, fmt.Errorf("write hosts file error: %s", err)
		}
		if len(node.comment) > 0 {
			if _, err := f.WriteString(" " + node.comment); err != nil {
				return nil, fmt.Errorf("write hosts file error: %s", err)
			}
		}
		if _, err := f.WriteString(lineBreaker); err != nil {
			return nil, fmt.Errorf("write hosts file error: %s", err)
		}
		if node.nextuid == 0 {
			break
		}
		node = h.fulldata[node.nextuid]
	}
	return f.Bytes(), nil
}

func (h *Host) GetFirstNode() (*HostNode, error) {
	h.RLock()
	defer h.RUnlock()
	if h.firstUid == 0 {
		return nil, fmt.Errorf("no data")
	}
	if h.fulldata == nil {
		return nil, fmt.Errorf("no data")
	}
	return h.fulldata[h.firstUid], nil
}

func (h *Host) GetNode(nodeID uint64) (*HostNode, error) {
	h.RLock()
	defer h.RUnlock()
	if h.fulldata == nil {
		return nil, fmt.Errorf("no data")
	}
	if node, ok := h.fulldata[nodeID]; ok {
		return node, nil
	}
	return nil, fmt.Errorf("node not exists")
}

func (h *Host) GetNextNode(nodeID uint64) (*HostNode, error) {
	h.RLock()
	defer h.RUnlock()
	if h.fulldata == nil {
		return nil, fmt.Errorf("no data")
	}
	if node, ok := h.fulldata[nodeID]; ok {
		if node.nextuid == 0 {
			return nil, fmt.Errorf("no next node")
		}
		return h.fulldata[node.nextuid], nil
	}
	return nil, fmt.Errorf("node not exists")
}

func (h *Host) GetLastNode(nodeID uint64) (*HostNode, error) {
	h.RLock()
	defer h.RUnlock()
	if h.fulldata == nil {
		return nil, fmt.Errorf("no data")
	}
	if node, ok := h.fulldata[nodeID]; ok {
		if node.lastuid == 0 {
			return nil, fmt.Errorf("no last node")
		}
		return h.fulldata[node.lastuid], nil
	}
	return nil, fmt.Errorf("node not exists")
}

func (h *Host) GetLatestNode() (*HostNode, error) {
	h.RLock()
	defer h.RUnlock()
	if h.lastUid == 0 {
		return nil, fmt.Errorf("no data")
	}
	if h.fulldata == nil {
		return nil, fmt.Errorf("no data")
	}
	return h.fulldata[h.lastUid], nil
}

func (h *Host) UpdateNode(node *HostNode) error {
	h.Lock()
	defer h.Unlock()
	if h.fulldata == nil {
		return fmt.Errorf("no data")
	}
	if _, ok := h.fulldata[node.uid]; !ok {
		return fmt.Errorf("node not exists")
	}
	if node.comment != "" && !strings.HasPrefix(strings.TrimSpace(node.comment), "#") {
		node.comment = "#" + node.comment
	}
	if node.ip == "" && len(node.host) == 0 && node.comment != "" {
		node.onlyComment = true
	}
	h.fulldata[node.uid] = node
	node.valid = node.CheckValid()
	for k, v := range h.ipData {
		var newIPData []*HostNode
		for _, vv := range v {
			if vv.uid != node.uid {
				newIPData = append(newIPData, vv)
			}
		}
		h.ipData[k] = newIPData
	}
	for k, v := range h.hostData {
		var newHostData []*HostNode
		for _, vv := range v {
			if vv.uid != node.uid {
				newHostData = append(newHostData, vv)
			}
		}
		h.hostData[k] = newHostData
	}
	if node.valid {
		h.ipData[node.ip] = append(h.ipData[node.ip], node)
		for _, v := range node.host {
			h.hostData[v] = append(h.hostData[v], node)
		}
	}
	return nil
}

func (n *HostNode) String() string {
	if n.onlyComment {
		return n.comment
	}
	return fmt.Sprintf("%s %s %s", n.ip, strings.Join(n.host, " "), n.comment)
}

func (n *HostNode) Bytes() []byte {
	return []byte(n.String())
}

func (n *HostNode) Hosts() []string {
	return n.host
}

func (n *HostNode) IP() string {
	return n.ip
}

func (n *HostNode) Comment() string {
	return n.comment
}

func (n *HostNode) UID() uint64 {
	return n.uid
}

func (n *HostNode) NextUID() uint64 {
	return n.nextuid
}

func (n *HostNode) LastUID() uint64 {
	return n.lastuid
}

func (n *HostNode) Valid() bool {
	return n.valid
}

func (n *HostNode) OnlyComment() bool {
	return n.onlyComment
}

func (n *HostNode) Original() string {
	return n.original
}

func (n *HostNode) SetHosts(hosts ...string) {
	n.host = hosts
}

func (n *HostNode) SetIP(ip string) {
	n.ip = ip
}

func (n *HostNode) SetComment(comment string) {
	if comment == "" {
		return
	}
	if !strings.HasPrefix(strings.TrimSpace(comment), "#") {
		n.comment = "#" + comment
		return
	}
	n.comment = comment
}

func (n *HostNode) SetValid(valid bool) {
	n.valid = valid
}

func (n *HostNode) SetOnlyComment(onlyComment bool) {
	n.onlyComment = onlyComment
}

func (n *HostNode) SetOriginal(original string) {
	n.original = original
}

func (n *HostNode) AddHosts(hosts ...string) {
	n.host = append(n.host, hosts...)
}

func (n *HostNode) SetLastUID(uid uint64) error {
	if n.uid != 0 {
		return fmt.Errorf("uid already set,you cannot change the existing node")
	}
	n.lastuid = uid
	return nil
}

func (n *HostNode) SetNextUID(uid uint64) error {
	if n.uid != 0 {
		return fmt.Errorf("uid already set,you cannot change the existing node")
	}
	n.nextuid = uid
	return nil
}

func (n *HostNode) CheckValid() bool {
	if n.ip == "" && len(n.host) == 0 && n.comment == "" {
		return true
	}
	if n.ip == "" && len(n.host) == 0 && n.comment != "" {
		return true
	}
	if n.ip == "" && len(n.host) > 0 {
		return false
	}
	if net.ParseIP(n.ip) == nil {
		return false
	}
	return true
}