package net

import (
	"b612.me/stario"
	"b612.me/starlog"
	"context"
	"encoding/hex"
	"fmt"
	"net"
	"os"
	"path/filepath"
	"runtime"
	"strings"
	"sync"
	"time"
)

type TcpConn struct {
	*net.TCPConn
	f *os.File
}

type TcpServer struct {
	LocalAddr       string
	UsingKeepAlive  bool
	KeepAlivePeriod int
	KeepAliveIdel   int
	KeepAliveCount  int
	UseLinger       int
	sync.Mutex
	Clients      map[string]*TcpConn
	Interactive  bool
	UserTimeout  int
	ShowRecv     bool
	ShowAsHex    bool
	SaveToFolder string
	Listen       *net.TCPListener
	LogPath      string
	stopCtx      context.Context
	stopFn       context.CancelFunc
}

func (s *TcpServer) Close() error {
	return s.Listen.Close()
}

func (s *TcpServer) handleInteractive() {
	var conn *TcpConn
	var currentCmd string
	notifyMap := make(map[string]chan struct{})
	if !s.Interactive {
		return
	}
	starlog.Infoln("Interactive mode enabled")
	for {
		select {
		case <-s.stopCtx.Done():
			starlog.Infoln("Interactive mode stopped due to context done")
			return
		default:
		}
		cmd := stario.MessageBox("", "").MustString()
		if cmd == "" {
			continue
		}
		cmdf := strings.Fields(cmd)
		switch cmdf[0] {
		case "list":
			s.Lock()
			for k, v := range s.Clients {
				starlog.Green("Client %s: %s\n", k, v.RemoteAddr().String())
			}
			s.Unlock()
		case "use":
			if len(cmdf) < 2 {
				starlog.Errorln("use command need a client address")
				continue
			}
			conn = s.Clients[cmdf[1]]
			if conn == nil {
				starlog.Errorln("Client not found")
				continue
			}
			starlog.Infof("Using client %s\n", conn.RemoteAddr().String())
		case "hex":
			currentCmd = "hex"
			starlog.Infoln("Switch to hex mode,send hex to remote client")
		case "text":
			currentCmd = "text"
			starlog.Infoln("Switch to text mode,send text to remote client")
		case "close":
			if conn.TCPConn == nil {
				starlog.Errorln("No client selected")
				continue
			}
			conn.TCPConn.Close()
			starlog.Infof("Client %s closed\n", conn.RemoteAddr().String())
			conn = nil
			currentCmd = ""
		case "startauto":
			if conn == nil {
				starlog.Errorln("No client selected")
				continue
			}
			notifyMap[conn.RemoteAddr().String()] = make(chan struct{})
			go func(conn *TcpConn) {
				for {
					select {
					case <-notifyMap[conn.RemoteAddr().String()]:
						starlog.Infoln("Auto send stopped")
						return
					default:
					}
					_, err := conn.Write([]byte(strings.Repeat("B612", 256)))
					if err != nil {
						starlog.Errorln("Write error:", err)
						return
					}
				}
			}(conn)
			starlog.Infoln("Auto send started")
		case "closeauto":
			if conn == nil {
				starlog.Errorln("No client selected")
				continue
			}
			close(notifyMap[conn.RemoteAddr().String()])
		case "send":
			if conn == nil {
				starlog.Errorln("No client selected")
				continue
			}
			if currentCmd == "hex" {
				data, err := hex.DecodeString(strings.TrimSpace(strings.TrimPrefix(cmd, "send")))
				if err != nil {
					starlog.Errorln("Hex decode error:", err)
					continue
				}
				_, err = conn.Write(data)
				if err != nil {
					starlog.Errorln("Write error:", err)
				} else {
					if conn.f != nil {
						conn.f.Write([]byte(time.Now().String() + " send\n"))
						conn.f.Write(data)
						conn.f.Write([]byte("\n"))
					}
				}
			} else {
				_, err := conn.Write([]byte(strings.TrimSpace(strings.TrimPrefix(cmd, "send"))))
				if err != nil {
					starlog.Errorln("Write error:", err)
				} else {
					if conn.f != nil {
						conn.f.Write([]byte(time.Now().String() + " send\n"))
						conn.f.Write([]byte(cmdf[1]))
						conn.f.Write([]byte("\n"))
					}
				}
			}
			starlog.Infof("Send to %s success\n", conn.RemoteAddr().String())
		}
	}
}

func (s *TcpServer) Run() error {
	s.stopCtx, s.stopFn = context.WithCancel(context.Background())
	if s.LogPath != "" {
		err := starlog.SetLogFile(s.LogPath, starlog.Std, true)
		if err != nil {
			starlog.Errorln("SetLogFile error:", err)
			return fmt.Errorf("SetLogFile error: %w", err)
		}
	}
	s.Clients = make(map[string]*TcpConn)
	tcpAddr, err := net.ResolveTCPAddr("tcp", s.LocalAddr)
	if err != nil {
		starlog.Errorln("ResolveTCPAddr error:", err)
		return fmt.Errorf("ResolveTCPAddr error: %w", err)
	}
	s.Listen, err = net.ListenTCP("tcp", tcpAddr)
	if err != nil {
		starlog.Errorln("ListenTCP error:", err)
		return fmt.Errorf("ListenTCP error: %w", err)
	}
	starlog.Infof("TcpServer listen on %s\n", s.LocalAddr)
	if s.Interactive {
		go s.handleInteractive()
	}
	for {
		select {
		case <-s.stopCtx.Done():
			starlog.Infoln("TcpServer stopped due to context done")
			return s.Listen.Close()
		default:
		}
		conn, err := s.Listen.AcceptTCP()
		if err != nil {
			starlog.Errorln("AcceptTCP error:", err)
			continue
		}
		starlog.Infof("Accept new connection from %s\n", conn.RemoteAddr().String())
		s.Lock()
		s.Clients[conn.RemoteAddr().String()] = s.getTcpConn(conn)
		s.Unlock()
		go s.handleConn(s.Clients[conn.RemoteAddr().String()])
	}
}

func (s *TcpServer) getTcpConn(conn *net.TCPConn) *TcpConn {
	var err error
	var f *os.File
	if s.SaveToFolder != "" {
		f, err = os.Create(filepath.Join(s.SaveToFolder, strings.ReplaceAll(conn.RemoteAddr().String(), ":", "_")))
		if err != nil {
			starlog.Errorf("Create file error for %s: %v\n", conn.RemoteAddr().String(), err)
		}
	}
	return &TcpConn{
		TCPConn: conn,
		f:       f,
	}
}

func (s *TcpServer) handleConn(conn *TcpConn) {
	var err error
	log := starlog.Std.NewFlag()
	err = SetTcpInfo(conn.TCPConn, s.UsingKeepAlive, s.KeepAliveIdel, s.KeepAlivePeriod, s.KeepAliveCount, s.UserTimeout)
	if err != nil {
		log.Errorf("SetTcpInfo error for %s: %v\n", conn.RemoteAddr().String(), err)
		s.Lock()
		delete(s.Clients, conn.RemoteAddr().String())
		s.Unlock()
		conn.Close()
		return
	}
	if s.UseLinger >= 0 {
		conn.SetLinger(s.UseLinger)
	}
	log.Infof("SetKeepAlive success for %s\n", conn.RemoteAddr().String())
	log.Infof("KeepAlivePeriod: %d, KeepAliveIdel: %d, KeepAliveCount: %d, UserTimeout: %d\n", s.KeepAlivePeriod, s.KeepAliveIdel, s.KeepAliveCount, s.UserTimeout)
	if runtime.GOOS != "linux" {
		log.Warningln("keepAliveCount and userTimeout only work on linux")
	}

	for {
		select {
		case <-s.stopCtx.Done():
			log.Infof("Connection from %s closed due to context done\n", conn.RemoteAddr().String())
			s.Lock()
			delete(s.Clients, conn.RemoteAddr().String())
			s.Unlock()
			conn.Close()
			return
		default:
		}
		buf := make([]byte, 8192)
		n, err := conn.Read(buf)
		if err != nil {
			log.Errorf("Read error for %s: %v\n", conn.RemoteAddr().String(), err)
			s.Lock()
			delete(s.Clients, conn.RemoteAddr().String())
			s.Unlock()
			conn.Close()
			return
		}
		if n > 0 {
			if s.ShowRecv {
				if s.ShowAsHex {
					log.Printf("Recv from %s: %x\n", conn.RemoteAddr().String(), buf[:n])
				} else {
					log.Printf("Recv from %s: %s\n", conn.RemoteAddr().String(), string(buf[:n]))
				}
			}
			if conn.f != nil {
				conn.f.Write([]byte(time.Now().String() + " recv\n"))
				conn.f.Write(buf[:n])
				conn.f.Write([]byte("\n"))
			}
		}
	}
}

func (s *TcpServer) Stop() {
	s.stopFn()
	if s.Listen != nil {
		s.Close()
	}
}