package notify

import (
	"b612.me/stario"
	"b612.me/starnet"
	"context"
	"errors"
	"fmt"
	"math/rand"
	"net"
	"os"
	"strings"
	"sync"
	"sync/atomic"
	"time"
)

type ServerCommon struct {
	msgID                      uint64
	alive                      atomic.Value
	status                     Status
	listener                   net.Listener
	udpListener                *net.UDPConn
	queue                      *starnet.StarQueue
	stopFn                     context.CancelFunc
	stopCtx                    context.Context
	maxReadTimeout             time.Duration
	maxWriteTimeout            time.Duration
	parallelNum                int
	wg                         stario.WaitGroup
	clientPool                 map[string]*ClientConn
	mu                         sync.RWMutex
	handshakeRsaKey            []byte
	SecretKey                  []byte
	defaultMsgEn               func([]byte, []byte) []byte
	defaultMsgDe               func([]byte, []byte) []byte
	linkFns                    map[string]func(message *Message)
	defaultFns                 func(message *Message)
	noFinSyncMsgPool           sync.Map
	noFinSyncMsgMaxKeepSeconds int64
	maxHeartbeatLostSeconds    int64
	sequenceDe                 func([]byte) (interface{}, error)
	sequenceEn                 func(interface{}) ([]byte, error)
}

func NewServer() Server {
	var server ServerCommon
	server.wg = stario.NewWaitGroup(0)
	server.parallelNum = 0
	server.noFinSyncMsgMaxKeepSeconds = 0
	server.maxHeartbeatLostSeconds = 300
	server.stopCtx, server.stopFn = context.WithCancel(context.Background())
	server.SecretKey = defaultAesKey
	server.handshakeRsaKey = defaultRsaKey
	server.clientPool = make(map[string]*ClientConn)
	server.defaultMsgEn = defaultMsgEn
	server.defaultMsgDe = defaultMsgDe
	server.sequenceEn = encode
	server.sequenceDe = Decode
	server.alive.Store(false)
	server.linkFns = make(map[string]func(*Message))
	server.defaultFns = func(message *Message) {
		return
	}
	return &server
}

func (s *ServerCommon) Stop() error {
	if !s.alive.Load().(bool) {
		return nil
	}
	s.alive.Store(false)
	s.mu.Lock()
	s.status = Status{
		Alive:  false,
		Reason: "recv stop signal from user",
		Err:    nil,
	}
	s.mu.Unlock()
	s.stopFn()
	return nil
}
func (s *ServerCommon) Listen(network string, addr string) error {
	if s.alive.Load().(bool) {
		return errors.New("server already run")
	}
	s.stopCtx, s.stopFn = context.WithCancel(context.Background())
	s.queue = starnet.NewQueueCtx(s.stopCtx, 128)
	if strings.Contains(strings.ToLower(network), "udp") {
		return s.ListenUDP(network, addr)
	}
	return s.ListenTU(network, addr)
}

func (s *ServerCommon) ListenTU(network string, addr string) error {
	listener, err := net.Listen(network, addr)
	if err != nil {
		return err
	}
	s.alive.Store(true)
	s.status.Alive = true
	s.listener = listener
	go s.accept()
	go s.monitorPool()
	go s.loadMessage()
	return nil
}

func (s *ServerCommon) monitorPool() {
	for {
		select {
		case <-s.stopCtx.Done():
			s.noFinSyncMsgPool.Range(func(k, v interface{}) bool {
				data := v.(WaitMsg)
				close(data.Reply)
				s.noFinSyncMsgPool.Delete(k)
				return true
			})
			return
		case <-time.After(time.Second * 30):
		}
		now := time.Now()
		if s.noFinSyncMsgMaxKeepSeconds > 0 {
			s.noFinSyncMsgPool.Range(func(k, v interface{}) bool {
				data := v.(WaitMsg)
				if data.Time.Add(time.Duration(s.noFinSyncMsgMaxKeepSeconds) * time.Second).Before(now) {
					close(data.Reply)
					s.noFinSyncMsgPool.Delete(k)
				}
				return true
			})
		}
		if s.maxHeartbeatLostSeconds != 0 {
			for _, v := range s.clientPool {
				if now.Unix()-v.lastHeartBeat > s.maxHeartbeatLostSeconds {
					v.stopFn()
					s.removeClient(v)
				}
			}
		}
	}
}

func (s *ServerCommon) SetDefaultCommEncode(fn func([]byte, []byte) []byte) {
	s.defaultMsgEn = fn
}

func (s *ServerCommon) SetDefaultCommDecode(fn func([]byte, []byte) []byte) {
	s.defaultMsgDe = fn
}

func (s *ServerCommon) SetDefaultLink(fn func(message *Message)) {
	s.defaultFns = fn
}

func (s *ServerCommon) SetLink(key string, fn func(*Message)) {
	s.mu.Lock()
	defer s.mu.Unlock()
	s.linkFns[key] = fn
}

func (s *ServerCommon) pushMessage(data []byte, source string) {
	s.queue.ParseMessage(data, source)
}

func (s *ServerCommon) removeClient(client *ClientConn) {
	s.mu.Lock()
	defer s.mu.Unlock()
	delete(s.clientPool, client.ClientID)
}

func (s *ServerCommon) accept() {
	if s.udpListener != nil {
		s.acceptUDP()
	}
	s.acceptTU()
}
func (s *ServerCommon) acceptTU() {
	for {
		select {
		case <-s.stopCtx.Done():
			return
		default:
		}
		conn, err := s.listener.Accept()
		if err != nil {
			fmt.Println("error accept:", err)
			continue
		}
		var id string
		for {
			id = fmt.Sprintf("%s%d%d", conn.RemoteAddr().String(), time.Now().UnixNano(), rand.Int63())
			s.mu.RLock()
			if _, ok := s.clientPool[id]; ok {
				s.mu.RUnlock()
				continue
			}
			s.mu.RUnlock()
			break
		}
		client := ClientConn{
			ClientID:        id,
			ClientAddr:      conn.RemoteAddr(),
			tuConn:          conn,
			server:          s,
			maxReadTimeout:  s.maxReadTimeout,
			maxWriteTimeout: s.maxWriteTimeout,
			SecretKey:       s.SecretKey,
			handshakeRsaKey: s.handshakeRsaKey,
			msgEn:           s.defaultMsgEn,
			msgDe:           s.defaultMsgDe,
			lastHeartBeat:   time.Now().Unix(),
		}
		client.alive.Store(true)
		client.status = Status{
			Alive:  true,
			Reason: "",
			Err:    nil,
		}
		client.stopCtx, client.stopFn = context.WithCancel(context.Background())
		s.mu.Lock()
		s.clientPool[id] = &client
		s.mu.Unlock()
		go client.readTUMessage()
	}
}

func (s *ServerCommon) loadMessage() {
	for {
		select {
		case <-s.stopCtx.Done():
			var wg sync.WaitGroup
			s.mu.RLock()
			for _, v := range s.clientPool {
				wg.Add(1)
				go func() {
					defer wg.Done()
					v.sayGoodByeForTU()
					v.alive.Store(false)
					v.status = Status{
						Alive:  false,
						Reason: "recv stop signal from server",
						Err:    nil,
					}
					v.stopFn()
					s.removeClient(v)
				}()
			}
			s.mu.RUnlock()
			select {
			case <-time.After(time.Second * 8):
			case <-stario.WaitUntilFinished(func() error {
				wg.Wait()
				return nil
			}):
			}
			if s.listener != nil {
				s.listener.Close()
			}
			s.wg.Wait()
			return
		case data, ok := <-s.queue.RestoreChan():
			if !ok {
				continue
			}
			s.wg.Add(1)
			go func(data starnet.MsgQueue) {
				s.mu.RLock()
				cc, ok := s.clientPool[data.Conn.(string)]
				s.mu.RUnlock()
				if !ok {
					return
				}
				//fmt.Println("received:", float64(time.Now().UnixNano()-nowd)/1000000)
				msg, err := s.sequenceDe(cc.msgDe(cc.SecretKey, data.Msg))
				if err != nil {
					fmt.Println("server decode data error", err)
					return
				}
				//fmt.Println("decoded:", float64(time.Now().UnixNano()-nowd)/1000000)
				message := Message{
					NetType:     NET_SERVER,
					ClientConn:  cc,
					TransferMsg: msg.(TransferMsg),
				}
				message.Time = time.Now()

				//fmt.Println("dispatch:", float64(time.Now().UnixNano()-nowd)/1000000)
				s.dispatchMsg(message)
			}(data)
		}
	}
}
func (s *ServerCommon) sysMsg(message Message) {
	switch message.Key {
	case "bye":
		fmt.Println("recv stop signal from client", message.ClientConn.ClientID)
		if message.TransferMsg.Type == MSG_SYS_WAIT {
			message.Reply(nil)
		}
		message.ClientConn.alive.Store(false)
		message.ClientConn.status = Status{
			Alive:  false,
			Reason: "recv stop signal from client",
			Err:    nil,
		}
		message.ClientConn.stopFn()
	case "heartbeat":
		message.ClientConn.lastHeartBeat = time.Now().Unix()
		message.Reply(nil)
	}
}

func (s *ServerCommon) dispatchMsg(message Message) {
	defer s.wg.Done()
	switch message.TransferMsg.Type {
	case MSG_SYS_WAIT:
		fallthrough
	case MSG_SYS:
		s.sysMsg(message)
		return
	case MSG_KEY_CHANGE:
		message.ClientConn.rsaDecode(message)
		return
	case MSG_SYS_REPLY:
		fallthrough
	case MSG_SYNC_REPLY:
		data, ok := s.noFinSyncMsgPool.Load(message.TransferMsg.ID)
		if ok {
			wait := data.(WaitMsg)
			wait.Reply <- message
			s.noFinSyncMsgPool.Delete(message.TransferMsg.ID)
			return
		}
		//just throw
		return
		//fallthrough
	default:
	}
	callFn := func(fn func(*Message)) {
		fn(&message)
	}
	fn, ok := s.linkFns[message.TransferMsg.Key]
	if ok {
		callFn(fn)
	}
	if s.defaultFns != nil {
		callFn(s.defaultFns)
	}
}
func (s *ServerCommon) send(c *ClientConn, msg TransferMsg) (WaitMsg, error) {
	if s.udpListener != nil {
		return s.sendUDP(c, msg)
	}
	return s.sendTU(c, msg)
}

func (s *ServerCommon) sendTU(c *ClientConn, msg TransferMsg) (WaitMsg, error) {
	var wait WaitMsg
	if msg.Type != MSG_SYNC_REPLY && msg.Type != MSG_KEY_CHANGE && msg.Type != MSG_SYS_REPLY || msg.ID == 0 {
		msg.ID = atomic.AddUint64(&s.msgID, 1)
	}
	data, err := s.sequenceEn(msg)
	if err != nil {
		return WaitMsg{}, err
	}
	data = c.msgEn(c.SecretKey, data)
	data = s.queue.BuildMessage(data)
	if c.maxWriteTimeout.Seconds() != 0 {
		c.tuConn.SetWriteDeadline(time.Now().Add(c.maxWriteTimeout))
	}
	_, err = c.tuConn.Write(data)
	//fmt.Println("resend:", float64(time.Now().UnixNano()-nowd)/1000000)
	if err == nil && (msg.Type == MSG_SYNC_ASK || msg.Type == MSG_SYS_WAIT) {
		wait.Time = time.Now()
		wait.TransferMsg = msg
		wait.Reply = make(chan Message, 1)
		s.noFinSyncMsgPool.Store(msg.ID, wait)
	}
	return wait, err
}

func (s *ServerCommon) Send(c *ClientConn, key string, value MsgVal) error {
	_, err := s.send(c, TransferMsg{
		Key:   key,
		Value: value,
		Type:  MSG_ASYNC,
	})
	return err
}
func (s *ServerCommon) sendWait(c *ClientConn, msg TransferMsg, timeout time.Duration) (Message, error) {
	data, err := s.send(c, msg)
	if err != nil {
		return Message{}, err
	}
	if timeout.Seconds() == 0 {
		msg, ok := <-data.Reply
		if !ok {
			return msg, os.ErrInvalid
		}
		return msg, nil
	}
	select {
	case <-time.After(timeout):
		close(data.Reply)
		s.noFinSyncMsgPool.Delete(data.TransferMsg.ID)
		return Message{}, os.ErrDeadlineExceeded
	case msg, ok := <-data.Reply:
		if !ok {
			return msg, os.ErrInvalid
		}
		return msg, nil
	}
}

func (s *ServerCommon) SendCtx(ctx context.Context, c *ClientConn, key string, value MsgVal) (Message, error) {
	return s.sendCtx(c, TransferMsg{
		Key:   key,
		Value: value,
		Type:  MSG_SYNC_ASK,
	}, ctx)
}

func (s *ServerCommon) sendCtx(c *ClientConn, msg TransferMsg, ctx context.Context) (Message, error) {
	data, err := s.send(c, msg)
	if err != nil {
		return Message{}, err
	}
	if ctx == nil {
		ctx = context.Background()
	}
	select {
	case <-ctx.Done():
		close(data.Reply)
		s.noFinSyncMsgPool.Delete(data.TransferMsg.ID)
		return Message{}, os.ErrClosed
	case msg, ok := <-data.Reply:
		if !ok {
			return msg, os.ErrInvalid
		}
		return msg, nil
	}
}
func (s *ServerCommon) SendWait(c *ClientConn, key string, value MsgVal, timeout time.Duration) (Message, error) {
	return s.sendWait(c, TransferMsg{
		Key:   key,
		Value: value,
		Type:  MSG_SYNC_ASK,
	}, timeout)
}

func (s *ServerCommon) SendObjCtx(ctx context.Context, c *ClientConn, key string, val interface{}) (Message, error) {
	data, err := s.sequenceEn(val)
	if err != nil {
		return Message{}, err
	}
	return s.sendCtx(c, TransferMsg{
		Key:   key,
		Value: data,
		Type:  MSG_SYNC_ASK,
	}, ctx)
}

func (s *ServerCommon) SendObj(c *ClientConn, key string, val interface{}) error {
	data, err := encode(val)
	if err != nil {
		return err
	}
	_, err = s.send(c, TransferMsg{
		Key:   key,
		Value: data,
		Type:  MSG_ASYNC,
	})
	return err
}

func (s *ServerCommon) Reply(m Message, value MsgVal) error {
	return m.Reply(value)
}

//for udp below

func (s *ServerCommon) ListenUDP(network string, addr string) error {
	udpAddr, err := net.ResolveUDPAddr(network, addr)
	if err != nil {
		return err
	}
	listener, err := net.ListenUDP(network, udpAddr)
	if err != nil {
		return err
	}
	s.alive.Store(true)
	s.status.Alive = true
	s.udpListener = listener
	go s.accept()
	go s.monitorPool()
	go s.loadMessage()
	return nil
}

func (s *ServerCommon) acceptUDP() {
	for {
		select {
		case <-s.stopCtx.Done():
			return
		default:
		}
		if s.maxReadTimeout.Seconds() > 0 {
			s.udpListener.SetReadDeadline(time.Now().Add(s.maxReadTimeout))
		}
		data := make([]byte, 4096)
		num, addr, err := s.udpListener.ReadFromUDP(data)
		id := addr.String()
		//fmt.Println("s recv udp:", float64(time.Now().UnixNano()-nowd)/1000000)
		s.mu.RLock()
		if _, ok := s.clientPool[id]; !ok {
			s.mu.RUnlock()
			client := ClientConn{
				ClientID:        id,
				ClientAddr:      addr,
				server:          s,
				maxReadTimeout:  s.maxReadTimeout,
				maxWriteTimeout: s.maxWriteTimeout,
				SecretKey:       s.SecretKey,
				handshakeRsaKey: s.handshakeRsaKey,
				msgEn:           s.defaultMsgEn,
				msgDe:           s.defaultMsgDe,
				lastHeartBeat:   time.Now().Unix(),
			}
			client.stopCtx, client.stopFn = context.WithCancel(context.Background())
			s.mu.Lock()
			s.clientPool[id] = &client
			s.mu.Unlock()
		} else {
			s.mu.RUnlock()
		}
		if err == os.ErrDeadlineExceeded {
			if num != 0 {
				s.pushMessage(data[:num], id)
			}
			continue
		}
		if err != nil {
			continue
		}
		s.pushMessage(data[:num], id)
	}
}

func (s *ServerCommon) sendUDP(c *ClientConn, msg TransferMsg) (WaitMsg, error) {
	var wait WaitMsg
	if msg.Type != MSG_SYNC_REPLY && msg.Type != MSG_KEY_CHANGE && msg.Type != MSG_SYS_REPLY || msg.ID == 0 {
		msg.ID = uint64(time.Now().UnixNano()) + rand.Uint64() + rand.Uint64()
	}
	data, err := s.sequenceEn(msg)
	if err != nil {
		return WaitMsg{}, err
	}
	data = c.msgEn(c.SecretKey, data)
	data = s.queue.BuildMessage(data)
	if c.maxWriteTimeout.Seconds() != 0 {
		s.udpListener.SetWriteDeadline(time.Now().Add(c.maxWriteTimeout))
	}
	_, err = s.udpListener.WriteTo(data, c.ClientAddr)
	if err == nil && (msg.Type == MSG_SYNC_ASK || msg.Type == MSG_SYS_WAIT) {
		wait.Time = time.Now()
		wait.TransferMsg = msg
		wait.Reply = make(chan Message, 1)
		s.noFinSyncMsgPool.Store(msg.ID, wait)
	}
	return wait, err
}

func (s *ServerCommon) StopMonitorChan() <-chan struct{} {
	return s.stopCtx.Done()
}

func (s *ServerCommon) Status() Status {
	return s.status
}

func (s *ServerCommon) GetSecretKey() []byte {
	return s.SecretKey
}
func (s *ServerCommon) SetSecretKey(key []byte) {
	s.SecretKey = key
}
func (s *ServerCommon) RsaPrivKey() []byte {
	return s.handshakeRsaKey
}
func (s *ServerCommon) SetRsaPrivKey(key []byte) {
	s.handshakeRsaKey = key
}

func (s *ServerCommon) GetClient(id string) *ClientConn {
	s.mu.RLock()
	defer s.mu.RUnlock()
	c, ok := s.clientPool[id]
	if !ok {
		return nil
	}
	return c
}
func (s *ServerCommon) GetClientLists() []*ClientConn {
	s.mu.RLock()
	defer s.mu.RUnlock()
	var list []*ClientConn = make([]*ClientConn, 0, len(s.clientPool))
	for _, v := range s.clientPool {
		list = append(list, v)
	}
	return list
}

func (s *ServerCommon) GetClientAddrs() []net.Addr {
	s.mu.RLock()
	defer s.mu.RUnlock()
	var list = make([]net.Addr, 0, len(s.clientPool))
	for _, v := range s.clientPool {
		list = append(list, v.ClientAddr)
	}
	return list
}

func (s *ServerCommon) GetSequenceEn() func(interface{}) ([]byte, error) {
	return s.sequenceEn
}
func (s *ServerCommon) SetSequenceEn(fn func(interface{}) ([]byte, error)) {
	s.sequenceEn = fn
}
func (s *ServerCommon) GetSequenceDe() func([]byte) (interface{}, error) {
	return s.sequenceDe
}
func (s *ServerCommon) SetSequenceDe(fn func([]byte) (interface{}, error)) {
	s.sequenceDe = fn
}

func (s *ServerCommon) HeartbeatTimeoutSec() int64 {
	return s.maxHeartbeatLostSeconds
}

func (s *ServerCommon) SetHeartbeatTimeoutSec(sec int64) {
	s.maxHeartbeatLostSeconds = sec
}