package dynamics

import (
	"container/list"
	"encoding/binary"
	"errors"
	"fmt"
	"math"
	"net"
	"sync"
	"time"

	"github.com/panjf2000/gnet/v2"
	"go.uber.org/zap"
	"joylink.club/bj-rtsts-server/config"
)

func init() {
	go func() {
		for {
			info := <-trainInfoChan
			for e := handlerList.Front(); e != nil; e = e.Next() {
				func() {
					defer func() {
						r := recover()
						if r != nil {
							zap.S().Errorf("列车信息处理函数报错", r)
						}
					}()
					handler := e.Value.(TrainInfoHandler)
					handler(info)
				}()
			}
		}
	}()
}

type TurnoutInfoFunc func() []*TurnoutInfo

var (
	running         bool
	mutex           sync.Mutex
	turnoutInfoFunc TurnoutInfoFunc
	//道岔消息生命信号
	turnoutLifeSignal uint16
	//列车消息生命信号
	trainLifeSignal uint16
	//列车生命信号是否初始化
	trainLifeSignalInit bool
	//用于处理生命信号循环使用产生的各种特殊处理
	limit uint16 = 10000
	//列车消息队列
	trainInfoChan chan *TrainInfo = make(chan *TrainInfo)
)

var handlerList list.List

type TrainInfoHandler func(info *TrainInfo)

type udpServer struct {
	gnet.BuiltinEventEngine

	eng       gnet.Engine
	addr      string
	multicore bool

	eventHandlers []gnet.EventHandler
}

func (server *udpServer) OnBoot(eng gnet.Engine) gnet.Action {
	server.eng = eng
	zap.S().Infof("udp server with multi-core=%t is listening on %s\n", server.multicore, server.addr)
	return gnet.None
}

// OnTraffic 接收到数据后的解析
func (server *udpServer) OnTraffic(c gnet.Conn) gnet.Action {
	defer func() {
		if r := recover(); r != nil {
			zap.L().Error("udp服务数据解析异常", zap.Any("panic", r))
		}
	}()
	buf, _ := c.Next(-1)
	lifeSignal := binary.BigEndian.Uint16(buf[0:2])
	if !trainLifeSignalInit {
		trainLifeSignalInit = true
	} else if trainLifeSignal < limit {
		if lifeSignal < trainLifeSignal || lifeSignal > trainLifeSignal-limit {
			zap.S().Debugf("丢弃列车信息[%d-%d]", lifeSignal, trainLifeSignal)
			return gnet.None
		}
	} else if trainLifeSignal < math.MaxUint16-10000 {
		if lifeSignal < trainLifeSignal {
			zap.S().Debugf("丢弃列车信息[%d-%d]", lifeSignal, trainLifeSignal)
			return gnet.None
		}
	} else {
		if lifeSignal < trainLifeSignal && lifeSignal > trainLifeSignal+10000 {
			zap.S().Debugf("丢弃列车信息[%d-%d]", lifeSignal, trainLifeSignal)
			return gnet.None
		}
	}
	trainLifeSignal = lifeSignal
	trainInfo := decoderDynamicsTrainInfo(buf)
	trainInfoChan <- trainInfo
	return gnet.None
}

func RunUdpServer() {
	server := &udpServer{addr: fmt.Sprintf("udp://:%d", config.Config.Dynamics.UdpLocalPort), multicore: false}
	err := gnet.Run(server, server.addr, gnet.WithMulticore(server.multicore))
	zap.L().Fatal("udp服务启动失败", zap.Error(err))
}

func Run(tiFunc TurnoutInfoFunc) error {
	mutex.Lock()
	defer mutex.Unlock()
	trainLifeSignalInit = false
	return runSendTurnoutStateTask(tiFunc)
}

// 注册数据操作
func RegisterTrainInfoHandler(handler TrainInfoHandler) {
	handlerList.PushBack(handler)
}

func Stop() {
	mutex.Lock()
	defer mutex.Unlock()
	turnoutInfoFunc = nil
}

// 动力学消息发送消息
func sendDynamicsMsg(buf []byte) error {
	defer func() {
		if r := recover(); r != nil {
			zap.S().Error("发送道岔信息失败", r)
		}
	}()
	addr := fmt.Sprintf("%v:%v", config.Config.Dynamics.Ip, config.Config.Dynamics.UdpRemotePort)
	remoteAddr, _ := net.ResolveUDPAddr("udp", addr)
	conn, err := net.DialUDP("udp", nil, remoteAddr)
	if err != nil {
		zap.S().Error("UDP通信失败", err)
		return err
	}
	defer func(conn *net.UDPConn) {
		err := conn.Close()
		if err != nil {
			zap.S().Error(err)
		}
	}(conn)
	_, err = conn.Write(buf)
	return err
}

// 给动力学发送列车信息
func SendDynamicsTrainMsg(buf []byte) error {
	defer func() {
		if r := recover(); r != nil {
			zap.S().Error("发送道岔信息失败", r)
		}
	}()
	addr := fmt.Sprintf("%v:%v", config.Config.Dynamics.Ip, config.Config.Dynamics.UdpRemoteTrainPort)
	remoteAddr, _ := net.ResolveUDPAddr("udp", addr)
	conn, err := net.DialUDP("udp", nil, remoteAddr)
	if err != nil {
		zap.S().Error("UDP通信失败", err)
		return err
	}
	defer func(conn *net.UDPConn) {
		err := conn.Close()
		if err != nil {
			zap.S().Error(err)
		}
	}(conn)
	_, err = conn.Write(buf)
	return err
}

// 发送道岔状态任务
func runSendTurnoutStateTask(tiFunc TurnoutInfoFunc) error {
	if running {
		return nil
	}
	if tiFunc == nil {
		return errors.New("tiFunc不能为空")
	}
	turnoutInfoFunc = tiFunc
	go func() {
		defer func() {
			if r := recover(); r != nil {
				fmt.Println("Recovered from panic:", r)
			}
		}()
		tick := time.Tick(50 * time.Millisecond)
		for range tick {
			if turnoutInfoFunc == nil {
				continue
			}
			slice := turnoutInfoFunc()
			for _, turnoutInfo := range slice {
				turnoutInfo.lifeSignal = turnoutLifeSignal
				// sendTurnoutInfo 发送道岔信息
				err := sendDynamicsMsg(encoderDynamicsTurnout(turnoutInfo))
				if err != nil {
					zap.S().Error(err)
				}
			}
			turnoutLifeSignal++
		}
	}()
	return nil
}

// 解析动力学的列车信息
func decoderDynamicsTrainInfo(buf []byte) *TrainInfo {
	trainInfo := &TrainInfo{}
	trainInfo.LifeSignal = binary.BigEndian.Uint16(buf[0:2])
	trainInfo.Number = buf[2]
	trainInfo.Len = binary.BigEndian.Uint16(buf[3:5])
	trainInfo.Link = buf[5]
	trainInfo.LinkOffset = binary.BigEndian.Uint32(buf[6:10])
	trainInfo.Slope = binary.BigEndian.Uint16(buf[10:12])
	b := buf[12]
	trainInfo.UpSlope = (b & (1 << 7)) != 0
	trainInfo.Up = (b & (1 << 6)) != 0
	trainInfo.TotalResistance = binary.BigEndian.Uint32(buf[14:18])
	trainInfo.AirResistance = binary.BigEndian.Uint32(buf[18:22])
	trainInfo.SlopeResistance = binary.BigEndian.Uint32(buf[22:26])
	trainInfo.CurveResistance = binary.BigEndian.Uint32(buf[26:30])
	trainInfo.Speed = math.Float32frombits(binary.BigEndian.Uint32(buf[30:34]))
	trainInfo.HeadSpeed1 = math.Float32frombits(binary.BigEndian.Uint32(buf[34:38]))
	trainInfo.HeadSpeed2 = math.Float32frombits(binary.BigEndian.Uint32(buf[38:42]))
	trainInfo.TailSpeed1 = math.Float32frombits(binary.BigEndian.Uint32(buf[42:46]))
	trainInfo.TailSpeed2 = math.Float32frombits(binary.BigEndian.Uint32(buf[46:50]))
	trainInfo.HeadRadarSpeed = math.Float32frombits(binary.BigEndian.Uint32(buf[50:54]))
	trainInfo.TailRadarSpeed = math.Float32frombits(binary.BigEndian.Uint32(buf[54:58]))
	return trainInfo
}

// 将道岔转为动力学的消息
func encoderDynamicsTurnout(info *TurnoutInfo) []byte {
	var data []byte
	data = binary.BigEndian.AppendUint16(data, info.lifeSignal)
	data = binary.BigEndian.AppendUint16(data, info.Code)
	var b byte
	if info.NPosition {
		b |= 1 << 7
	}
	if info.RPosition {
		b |= 1 << 6
	}
	data = append(data, b)
	return data
}