// Package notify is a package which provide common tcp/udp/unix socket service
package notify

import (
	"context"
	"net"
	"strings"
	"time"

	"b612.me/starainrt"
)

var builder *starainrt.StarQueue

func init() {
	builder = starainrt.NewQueue()
}

// StarNotifyS 为Server端
type StarNotifyS struct {
	// Queue 是用来处理收发信息的简单消息队列
	Queue *starainrt.StarQueue
	// FuncLists 记录了被通知项所记录的函数
	FuncLists   map[string]func(SMsg) string
	defaultFunc func(SMsg) string
	stopSign    context.Context
	cancel      context.CancelFunc
	connPool    map[string]net.Conn
	udpPool     map[string]*net.UDPAddr
	isUDP       bool
	// UDPConn UDP监听
	UDPConn *net.UDPConn
	// Online 当前链接是否处于活跃状态
	Online bool
	// ReadDeadline tcp/unix中读超时设置,udp请直接调用UDPConn
	ReadDeadline time.Time
	// WriteDeadline tcp/unix中写超时设置,udp请直接调用UDPConn
	WriteDeadline time.Time

	// Deadline tcp/unix中超时设置,udp请直接调用UDPConn
	Deadline time.Time
}

// SMsg 指明当前服务端被通知的关键字
type SMsg struct {
	Conn  net.Conn
	Key   string
	Value string
	UDP   *net.UDPAddr
	uconn *net.UDPConn
}

// Reply 用于向client端回复数据
func (nmsg *SMsg) Reply(msg string) error {
	var err error
	if nmsg.uconn == nil {
		_, err = nmsg.Conn.Write(builder.BuildMessage([]byte(nmsg.Key + "||" + msg)))
	} else {
		_, err = nmsg.uconn.WriteToUDP(builder.BuildMessage([]byte(nmsg.Key+"||"+msg)), nmsg.UDP)
	}
	return err
}

// Send 用于向client端发送key-value数据
func (nmsg *SMsg) Send(key, value string) error {
	var err error
	if nmsg.uconn == nil {
		_, err = nmsg.Conn.Write(builder.BuildMessage([]byte(key + "||" + value)))
	} else {
		_, err = nmsg.uconn.WriteToUDP(builder.BuildMessage([]byte(key+"||"+value)), nmsg.UDP)
	}
	return err
}

func (star *StarNotifyS) starinits() {
	star.stopSign, star.cancel = context.WithCancel(context.Background())
	star.Queue = starainrt.NewQueue()
	star.udpPool = make(map[string]*net.UDPAddr)
	star.FuncLists = make(map[string]func(SMsg) string)
	star.connPool = make(map[string]net.Conn)
	star.Online = false
	star.Queue.RestoreDuration(time.Second * 2)
}

// NewNotifyS 开启一个新的Server端通知
func NewNotifyS(netype, value string) (*StarNotifyS, error) {
	if netype[0:3] != "udp" {
		return notudps(netype, value)
	}
	return doudps(netype, value)
}

func doudps(netype, value string) (*StarNotifyS, error) {
	var star StarNotifyS
	star.starinits()
	star.isUDP = true
	udpaddr, err := net.ResolveUDPAddr(netype, value)
	if err != nil {
		return nil, err
	}
	star.UDPConn, err = net.ListenUDP(netype, udpaddr)
	if err != nil {
		return nil, err
	}
	go star.notify()
	go func() {
		<-star.stopSign.Done()
		for k, v := range star.udpPool {
			star.UDPConn.WriteToUDP(star.Queue.BuildMessage([]byte("b612ryzstop")), v)
			delete(star.connPool, k)
		}
		star.UDPConn.Close()
		star.Online = false
		return
	}()
	go func() {
		for {
			buf := make([]byte, 8192)
			n, addr, err := star.UDPConn.ReadFromUDP(buf)
			if n != 0 {
				star.Queue.ParseMessage(buf[0:n], addr)
				star.udpPool[addr.String()] = addr
			}
			if err != nil {
				continue
			}
		}
	}()
	star.Online = true
	return &star, nil
}

func notudps(netype, value string) (*StarNotifyS, error) {
	var star StarNotifyS
	star.starinits()
	star.isUDP = false
	listener, err := net.Listen(netype, value)
	if err != nil {
		return nil, err
	}
	go star.notify()
	go func() {
		<-star.stopSign.Done()
		for k, v := range star.connPool {
			v.Close()
			delete(star.connPool, k)
		}
		listener.Close()
		star.Online = false
		return
	}()
	go func() {
		for {
			conn, err := listener.Accept()
			if err != nil {
				select {
				case <-star.stopSign.Done():
					listener.Close()
					return
				default:
					continue
				}
			}
			if !star.ReadDeadline.IsZero() {
				conn.SetReadDeadline(star.ReadDeadline)
			}
			if !star.WriteDeadline.IsZero() {
				conn.SetWriteDeadline(star.WriteDeadline)
			}
			if !star.Deadline.IsZero() {
				conn.SetDeadline(star.Deadline)
			}
			go func(conn net.Conn) {
				for {
					buf := make([]byte, 8192)
					n, err := conn.Read(buf)
					if n != 0 {
						star.Queue.ParseMessage(buf[0:n], conn)
					}
					if err != nil {
						conn.Close()
						delete(star.connPool, conn.RemoteAddr().String())
						break
					}
				}
			}(conn)
			star.connPool[conn.RemoteAddr().String()] = conn
		}
	}()
	star.Online = true
	return &star, nil
}

// SetNotify 用于设置通知关键词的调用函数
func (star *StarNotifyS) SetNotify(name string, data func(SMsg) string) {
	star.FuncLists[name] = data
}

// SetDefaultNotify 用于设置默认关键词的调用函数
func (star *StarNotifyS) SetDefaultNotify(name string, data func(SMsg) string) {
	star.defaultFunc = data
}

func (star *StarNotifyS) notify() {
	for {
		select {
		case <-star.stopSign.Done():
			return
		default:
		}
		data, err := star.Queue.RestoreOne()
		if err != nil {
			time.Sleep(time.Millisecond * 20)
			continue
		}
		key, value := analyseData(string(data.Msg))
		var rmsg SMsg
		if !star.isUDP {
			rmsg = SMsg{data.Conn.(net.Conn), key, value, nil, nil}
		} else {
			rmsg = SMsg{nil, key, value, data.Conn.(*net.UDPAddr), star.UDPConn}
			if key == "b612ryzstop" {
				delete(star.udpPool, rmsg.UDP.String())
				continue
			}
		}
		go func() {
			if msg, ok := star.FuncLists[key]; ok {
				sdata := msg(rmsg)
				if sdata == "" {
					return
				}
				rmsg.Reply(sdata)
			} else {
				if star.defaultFunc != nil {
					sdata := star.defaultFunc(rmsg)
					if sdata == "" {
						return
					}
					rmsg.Reply(sdata)
				}
			}
		}()
	}
}

func analyseData(msg string) (key, value string) {
	slice := strings.SplitN(msg, "||", 2)
	if len(slice) == 1 {
		return msg, ""
	}
	return slice[0], slice[1]
}

// ServerStop 用于终止Server端运行
func (star *StarNotifyS) ServerStop() {
	star.cancel()
}