package main

import (
	"bufio"
	"fmt"
	"net"
	"sync"
)

type OpenVpnSrv struct {
	Remote   string `json:"active-vpn"`
	Status   string `json:"status"`
	hold     bool
	chanHold chan bool
	m        sync.RWMutex
	ret      chan []string
	buf      *bufio.ReadWriter
}

func (s *OpenVpnSrv) Lock() {
	s.m.Lock()
}

func (s *OpenVpnSrv) Unlock() {
	s.m.Unlock()
}

func NewOpenVpnSrv(conn net.Conn) *OpenVpnSrv {
	return &OpenVpnSrv{
		buf:      bufio.NewReadWriter(bufio.NewReader(conn), bufio.NewWriter(conn)),
		hold:     false,
		chanHold: make(chan bool),
		ret:      make(chan []string),
	}
}

// send a command to the server. Set the channel to receive the response
func (s *OpenVpnSrv) sendCommand(msg []string) (error, []string) {
	for _, line := range msg {
		if _, err := s.buf.WriteString(line + "\r\n"); err != nil {
			return err, nil
		}
	}

	if err := s.buf.Flush(); err != nil {
		return err, nil
	}

	// wait for the response
	ret := <-s.ret

	return nil, ret
}

func (s *OpenVpnSrv) Response(response []string) {
	s.Lock()
	s.ret <- response
	s.Unlock()
}

func (s *OpenVpnSrv) GetLine() (string, error) {
	return s.buf.ReadString('\n')
}

func (s *OpenVpnSrv) ValidRemote(server, port, proto string) {
	if s.Remote != "" {
		s.sendCommand([]string{fmt.Sprintf("remote MOD %s %s %s", s.Remote, port, proto)})
		s.Status = "Connected"
		return
	}
	s.Remote = server
	s.sendCommand([]string{"remote ACCEPT"})
}

func (s *OpenVpnSrv) Kill() {
}

func (s *OpenVpnSrv) Version() (error, []string) {
	return s.sendCommand([]string{"version"})
}

func (s *OpenVpnSrv) SetRemote(server string) error {
	// already the active server, do nothing
	if s.Remote == server {
		return nil
	}

	if s.Remote != "" {
		s.Kill()
	}

	s.Remote = server

	// release Hold if necessary
	s.ReleaseHold()
	return nil
}

func (s *OpenVpnSrv) waitForRelase() {
	s.hold = true
	s.Status = "Hold"
	<-s.chanHold
	s.sendCommand([]string{"hold release"})
}

func (s *OpenVpnSrv) ReleaseHold() {
	if !s.hold {
		return
	}
	s.hold = false
	s.chanHold <- true
	s.Status = "Waiting for connexion"
}