// +build !windows

/* SPDX-License-Identifier: MIT
 *
 * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
 */

package main

import (
	"crypto/md5"
	"encoding/base64"
	"encoding/hex"
	"encoding/json"
	"errors"
	"fmt"
	"net"
	"os"
	"os/signal"
	"strconv"
	"syscall"

	"github.com/KusakabeSi/EtherGuardVPN/config"
	"github.com/KusakabeSi/EtherGuardVPN/conn"
	"github.com/KusakabeSi/EtherGuardVPN/device"
	"github.com/KusakabeSi/EtherGuardVPN/ipc"
	"github.com/KusakabeSi/EtherGuardVPN/path"
	"github.com/KusakabeSi/EtherGuardVPN/tap"
	yaml "gopkg.in/yaml.v2"
)

func printExampleSuperConf() {
	sconfig := config.SuperConfig{
		NodeName:   "NodeSuper",
		PrivKeyV4:  "SM8pGjT0r8njy1/7ffN4wMwF7nnJ8UYSjGRWpCqo3ng=",
		PrivKeyV6:  "SM8pGjT0r8njy1/7ffN4wMwF7nnJ8UYSjGRWpCqo3ng=",
		ListenPort: 3000,
		LogLevel: config.LoggerInfo{
			LogLevel:   "normal",
			LogTransit: true,
		},
		Peers: []config.PeerInfo{
			{
				NodeID:   2,
				PubKey:   "NuYJ/3Ght+C4HovFq5Te/BrIazo6zwDJ8Bdu4rQCz0o=",
				EndPoint: "127.0.0.1:3002",
				Static:   true,
			},
		},
		GraphRecalculateSetting: config.GraphRecalculateSetting{
			JitterTolerance:           20,
			JitterToleranceMultiplier: 1.1,
			NodeReportTimeout:         40,
			RecalculateCoolDown:       5,
		},
	}

	soprint, _ := yaml.Marshal(sconfig)
	fmt.Print(string(soprint))
	return
}

func Super(configPath string, useUAPI bool, printExample bool) (err error) {
	if printExample {
		printExampleSuperConf()
		return nil
	}
	var sconfig config.SuperConfig
	err = readYaml(configPath, &sconfig)
	if err != nil {
		fmt.Printf("Error read config: %s :", configPath)
		fmt.Print(err)
		return err
	}
	interfaceName := sconfig.NodeName
	var logLevel int
	switch sconfig.LogLevel.LogLevel {
	case "verbose", "debug":
		logLevel = device.LogLevelVerbose
	case "error":
		logLevel = device.LogLevelError
	case "silent":
		logLevel = device.LogLevelSilent
	}

	logger4 := device.NewLogger(
		logLevel,
		fmt.Sprintf("(%s) ", interfaceName+"_v4"),
	)
	logger6 := device.NewLogger(
		logLevel,
		fmt.Sprintf("(%s) ", interfaceName+"_v6"),
	)

	super_chains := path.SUPER_Events{
		Event_server_pong:            make(chan path.PongMsg, 1<<5),
		Event_server_register:        make(chan path.RegisterMsg, 1<<5),
		Event_server_NhTable_changed: make(chan struct{}, 1<<4),
	}

	thetap, _ := tap.CreateDummyTAP()
	graph := path.NewGraph(3, true, sconfig.GraphRecalculateSetting)
	device_v4 := device.NewDevice(thetap, path.SuperNodeMessage, conn.NewCustomBind(true, false), logger4, &graph, true, "", nil, &super_chains)
	device_v6 := device.NewDevice(thetap, path.SuperNodeMessage, conn.NewCustomBind(false, true), logger6, &graph, true, "", nil, &super_chains)
	defer device_v4.Close()
	defer device_v6.Close()
	var sk [32]byte
	sk_slice, _ := base64.StdEncoding.DecodeString(sconfig.PrivKeyV4)
	copy(sk[:], sk_slice)
	device_v4.SetPrivateKey(sk)
	sk_slice, _ = base64.StdEncoding.DecodeString(sconfig.PrivKeyV6)
	copy(sk[:], sk_slice)
	device_v6.SetPrivateKey(sk)
	device_v4.IpcSet("listen_port=" + strconv.Itoa(sconfig.ListenPort) + "\n")
	device_v6.IpcSet("listen_port=" + strconv.Itoa(sconfig.ListenPort) + "\n")
	device_v4.IpcSet("replace_peers=true\n")
	device_v6.IpcSet("listen_port=" + strconv.Itoa(sconfig.ListenPort) + "\n")

	for _, peerconf := range sconfig.Peers {
		sk_slice, _ = base64.StdEncoding.DecodeString(peerconf.PubKey)
		copy(sk[:], sk_slice)
		if peerconf.NodeID >= path.SuperNodeMessage {
			return errors.New(fmt.Sprintf("Invalid Node_id at peer %s\n", peerconf.PubKey))
		}
		device_v4.NewPeer(sk, peerconf.NodeID)
		device_v6.NewPeer(sk, peerconf.NodeID)
		http_PeerState[peerconf.PubKey] = &PeerState{}
	}
	logger4.Verbosef("Device started")

	errs := make(chan error, 1<<3)
	term := make(chan os.Signal, 1)
	if useUAPI {
		uapi4, err := startUAPI(interfaceName+"_v4", logger4, device_v4, errs)
		if err != nil {
			return err
		}
		defer uapi4.Close()
		uapi6, err := startUAPI(interfaceName+"_v6", logger6, device_v6, errs)
		if err != nil {
			return err
		}
		defer uapi6.Close()
	}
	signal.Notify(term, syscall.SIGTERM)
	signal.Notify(term, os.Interrupt)

	select {
	case <-term:
	case <-errs:
	case <-device_v4.Wait():
	case <-device_v6.Wait():
	}
	logger4.Verbosef("Shutting down")
	return
}

func Event_server_pong_hendler(graph path.IG, events path.SUPER_Events) {
	for {
		pongmsg := <-events.Event_server_pong
		changed := graph.UpdateLentancy(pongmsg.Src_nodeID, pongmsg.Dst_nodeID, pongmsg.Timediff, true)
		if changed {
			NhTable := graph.GetNHTable(false)
			NhTablestr, _ := json.Marshal(NhTable)
			md5_hash_raw := md5.Sum(http_NhTableStr)
			new_hash := hex.EncodeToString(md5_hash_raw[:])
			if http_NhTable_Hash != new_hash {
				http_NhTable_Hash = new_hash
				http_NhTableStr = NhTablestr
				NhTable_Hash_fixbyte := [32]byte{}
				copy(NhTable_Hash_fixbyte[:], []byte(http_NhTable_Hash))
				body, err := path.GetByte(path.UpdateNhTableMsg{
					State_hash: NhTable_Hash_fixbyte,
				})
				if err != nil {
					fmt.Println("Error get byte")
					continue
				}
				buf := make([]byte, path.EgHeaderLen+len(body))
				header, _ := path.NewEgHeader(buf[:path.EgHeaderLen])
				header.SetDst(path.SuperNodeMessage)
				header.SetPacketLength(uint16(len(body)))
				header.SetSrc(path.SuperNodeMessage)
				header.SetTTL(0)
				header.SetUsage(path.UpdateNhTable)
				copy(buf[path.EgHeaderLen:], body)
				for pkstr, peerstate := range http_PeerState {
					if peerstate.NhTableState != http_NhTable_Hash {
						if peer := http_device4.LookupPeerByStr(pkstr); peer != nil {
							http_device4.SendPacket(peer, buf, device.MessageTransportOffsetContent)
						}
						if peer := http_device6.LookupPeerByStr(pkstr); peer != nil {
							http_device6.SendPacket(peer, buf, device.MessageTransportOffsetContent)
						}
					}

				}
			}
		}
	}
}

func Event_server_register_hendler(raph path.IG, events path.SUPER_Events) {
	for {
		reg_msg := <-events.Event_server_register
		PubKey := http_PeerID2Map[reg_msg.Node_id]
		if peer := http_device4.LookupPeerByStr(PubKey); peer != nil {
			if connstr := peer.GetEndpointDstStr(); connstr != "" {
				http_PeerInfos.Peers[PubKey].Connurl[connstr] = true
			}
		}
		if peer := http_device6.LookupPeerByStr(PubKey); peer != nil {
			if connstr := peer.GetEndpointDstStr(); connstr != "" {
				http_PeerInfos.Peers[PubKey].Connurl[connstr] = true
			}
		}
		http_PeerInfoStr, _ = json.Marshal(&http_PeerInfos)
		PeerInfo_hash_raw := md5.Sum(http_PeerInfoStr)
		PeerInfo_hash := hex.EncodeToString(PeerInfo_hash_raw[:])
		http_PeerInfo_hash_fixbyte := [32]byte{}
		copy(http_PeerInfo_hash_fixbyte[:], []byte(PeerInfo_hash))
		if http_PeerInfo_hash != PeerInfo_hash {
			http_PeerInfo_hash = PeerInfo_hash
			body, err := path.GetByte(path.UpdatePeerMsg{
				State_hash: http_PeerInfo_hash_fixbyte,
			})
			if err != nil {
				fmt.Println("Error get byte")
				continue
			}
			buf := make([]byte, path.EgHeaderLen+len(body))
			header, _ := path.NewEgHeader(buf[:path.EgHeaderLen])
			header.SetDst(path.SuperNodeMessage)
			header.SetPacketLength(uint16(len(body)))
			header.SetSrc(path.SuperNodeMessage)
			header.SetTTL(0)
			header.SetUsage(path.UpdatePeer)
			copy(buf[path.EgHeaderLen:], body)
			for pkstr, peerstate := range http_PeerState {
				if peerstate.PeerInfoState != PeerInfo_hash {
					if peer := http_device4.LookupPeerByStr(pkstr); peer != nil {
						http_device4.SendPacket(peer, buf, device.MessageTransportOffsetContent)
					}
					if peer := http_device6.LookupPeerByStr(pkstr); peer != nil {
						http_device6.SendPacket(peer, buf, device.MessageTransportOffsetContent)
					}
				}
			}
		}
	}
}

func startUAPI(interfaceName string, logger *device.Logger, the_device *device.Device, errs chan error) (net.Listener, error) {
	fileUAPI, err := func() (*os.File, error) {
		uapiFdStr := os.Getenv(ENV_WP_UAPI_FD)
		if uapiFdStr == "" {
			return ipc.UAPIOpen(interfaceName)
		}
		// use supplied fd
		fd, err := strconv.ParseUint(uapiFdStr, 10, 32)
		if err != nil {
			return nil, err
		}
		return os.NewFile(uintptr(fd), ""), nil
	}()
	uapi, err := ipc.UAPIListen(interfaceName, fileUAPI)
	if err != nil {
		logger.Errorf("Failed to listen on uapi socket: %v", err)
		os.Exit(ExitSetupFailed)
	}

	go func() {
		for {
			conn, err := uapi.Accept()
			if err != nil {
				errs <- err
				return
			}
			go the_device.IpcHandle(conn)
		}
	}()
	logger.Verbosef("UAPI listener started")
	return uapi, err
}