package main

import (
	"bytes"
	"flag"
	"fmt"
	"io"
	"log"
	"os"
	"runtime/debug"
	"runtime/pprof"
	"strings"
	"time"

	"github.com/pkg/profile"
	"go.uber.org/zap"
	"go.uber.org/zap/zapcore"

	"github.com/e1732a364fed/v2ray_simple/machine"
	"github.com/e1732a364fed/v2ray_simple/netLayer"
	"github.com/e1732a364fed/v2ray_simple/proxy"
	"github.com/e1732a364fed/v2ray_simple/utils"
)

type confFileArrayFlags []string

func (i *confFileArrayFlags) String() string {
	return "my string representation"
}

func (i *confFileArrayFlags) Set(value string) error {
	*i = append(*i, value)
	return nil
}

var (
	configFiles confFileArrayFlags

	useNativeUrlFormat bool
	disableSplice      bool
	startPProf         bool
	startMProf         bool
	gui_mode           bool
	interactive_mode   bool

	listenURL string //用于命令行模式
	dialURL   string //用于命令行模式

	dialTimeoutSecond int

	runCli func()
	runGui func()

	mainM *machine.M
)

const (
	defaultLogFile = "vs_log"
	defaultConfFn  = "client.toml"
	defaultGeoipFn = "GeoLite2-Country.mmdb"

	willExitStr = "Neither valid proxy settings available, nor cli/apiServer/gui running. Exit now.\n"
)

func init() {
	mainM = machine.New()

	flag.Var(&configFiles, "c", "config files; mutiple files are possible, but must all be toml files, like -c c1.toml -c c2.toml")

	flag.IntVar(&utils.LogLevel, "ll", utils.DefaultLL, "log level,0=debug, 1=info, 2=warning, 3=error, 4=dpanic, 5=panic, 6=fatal")

	flag.IntVar(&utils.LogLevelForFile, "llf", -1, "log level for log file,if negative, it will be the same as ll.")

	//有时发现在某些情况下，dns查询或者tcp链接的建立很慢，甚至超过8秒, 所以开放自定义超时时间，便于在不同环境下测试
	flag.IntVar(&dialTimeoutSecond, "dt", int(netLayer.DefaultDialTimeout/time.Second), "dial timeout, in second")

	flag.BoolVar(&startPProf, "pp", false, "pprof")
	flag.BoolVar(&startMProf, "mp", false, "memory pprof")

	flag.BoolVar(&useNativeUrlFormat, "nu", false, "use the proxy-defined url format, instead of the standard verysimple one.")

	flag.BoolVar(&netLayer.UseReadv, "readv", netLayer.DefaultReadvOption, "toggle the use of 'readv' syscall")

	flag.BoolVar(&disableSplice, "ds", false, "if given, then the app won't use splice.")

	flag.StringVar(&listenURL, "L", "", "listen URL, only used when no config file is provided.")
	flag.StringVar(&dialURL, "D", "", "dial URL, only used when no config file is provided.")

	flag.StringVar(&utils.LogOutFileName, "lf", defaultLogFile, "output file for log; If empty, no log file will be used.")

	flag.StringVar(&netLayer.GeoipFileName, "geoip", defaultGeoipFn, "geoip maxmind file name (relative or absolute path)")
	flag.StringVar(&netLayer.GeositeFolder, "geosite", netLayer.DefaultGeositeFolder, "geosite folder name (set it to the relative or absolute path of your geosite/data folder)")
	flag.StringVar(&utils.ExtraSearchPath, "path", "", "search path for mmdb, geosite and other required files")

}

func main() {
	os.Exit(mainFunc())
}

func mainFunc() (result int) {

	initExitCmds()
	mainM.CmdApiServerConf.SetupFlags(nil)

	defer func() {
		//注意，这个recover代码并不是万能的，有时捕捉不到panic。
		if r := recover(); r != nil {
			if ce := utils.CanLogErr("Captured panic!"); ce != nil {

				stack := debug.Stack()

				stackStr := string(stack)

				ce.Write(
					zap.Any("err:", r),
					zap.String("stacktrace", stackStr),
				)

				log.Println(stackStr) //因为 zap 使用json存储值，所以stack这种多行字符串里的换行符和tab 都被转译了，导致可读性比较差，所以还是要 log单独打印出来，可增强命令行的可读性

			} else {
				log.Println("panic captured!", r, "\n", string(debug.Stack()))
			}

			result = -3

			stopMachineAndExit(mainM)
		}
	}()

	utils.ParseFlags()

	if runExitCommands() {
		return
	} else {

		printVersion(os.Stdout)

	}

	// config params step
	setupSystemParemeters()

	runPreCommands()

	var tomlBuf *bytes.Buffer

	var configFileName string

	switch len(configFiles) {
	case 0:
		configFileName = defaultConfFn

	case 1:
		configFileName = configFiles[0]

	default:
		tomlBuf = utils.GetBuf()

		for _, fn := range configFiles {
			curfile, err := os.Open(utils.GetFilePath(fn))
			if err != nil {
				log.Fatalln("failed to open config file:", err)
			}
			defer curfile.Close()

			_, err = io.Copy(tomlBuf, curfile)
			if err != nil {
				log.Fatalln("failed to append config file to tmpfile:", err)
			}

			tomlBuf.WriteString("\n")
		}
	}

	var configMode int
	var loadConfigErr error

	if tomlBuf != nil {
		configMode = proxy.StandardMode
		loadConfigErr = mainM.LoadConfigByTomlBytes(tomlBuf.Bytes())
		utils.PutBuf(tomlBuf)
		tomlBuf = nil
	} else {
		fpath := utils.GetFilePath(configFileName)
		if !utils.FileExist(fpath) {

			if utils.GivenFlags["c"] == nil {
				log.Printf("No -c provided and default %q doesn't exist", defaultConfFn)
			} else {
				log.Printf("-c provided but %q doesn't exist", configFileName)
			}

			configFileName = ""

		}

		configMode, loadConfigErr = mainM.LoadConfig(configFileName, listenURL, dialURL)

		if utils.LogOutFileName == defaultLogFile {

			if strings.Contains(configFileName, "server") {
				utils.LogOutFileName += "_server"
			} else if strings.Contains(configFileName, "client") {
				utils.LogOutFileName += "_client"
			}
		}
	}

	utils.InitLog("Program started")
	defer utils.Info("Program exited")

	utils.Info(versionStr())

	{
		wdir, err := os.Getwd()
		if err != nil {
			panic(err)
		}
		if ce := utils.CanLogInfo("Working at"); ce != nil {
			ce.Write(zap.String("dir", wdir))
		}
	}
	if ce := utils.CanLogDebug("All Given Flags"); ce != nil {
		ce.Write(zap.Any("flags", utils.GivenFlagKVs()))
	}

	if loadConfigErr != nil && !IsFlexible(mainM) {

		if ce := utils.CanLogErr(willExitStr); ce != nil {
			ce.Write(zap.Error(loadConfigErr))
		} else {
			log.Print(willExitStr)
		}

		return -1
	}

	fmt.Printf("Log Level:%d %s\n", utils.LogLevel, utils.LogLevelStr(utils.LogLevel))

	if ce := utils.CanLogInfo("Options"); ce != nil {
		fields := []zapcore.Field{
			zap.String("Log Level", utils.LogLevelStr(utils.LogLevel)),
			zap.Bool("UseReadv", netLayer.UseReadv),
		}

		if utils.LogLevelForFile >= 0 {
			fields = append(fields, zap.String("Log Level For File", utils.LogLevelStr(utils.LogLevelForFile)))
		}
		ce.Write(
			fields...,
		)
	} else {
		fmt.Printf("UseReadv:%t\n", netLayer.UseReadv)
	}

	switch configMode {
	case proxy.StandardMode:
		mainM.SetupListenAndRoute()
		mainM.SetupDial()
	}

	runPreCommandsAfterLoadConf()

	stopGorouteCaptureSignalChan := make(chan struct{})

	go func() {
		osSignals := utils.GetSystemKillChan()
		select {
		case <-stopGorouteCaptureSignalChan:
			return
		case <-osSignals:
			exitBySignal()
		}

	}()

	mainM.Start()

	//没可用的listen/dial，而且还无法动态更改配置
	if NoFuture(mainM) {
		utils.Error(willExitStr)
		return -1
	}

	if interactive_mode {
		if runCli != nil {
			runCli()
		}

		interactive_mode = false
	}

	if gui_mode {
		if runGui != nil {
			runGui()
		}
		gui_mode = false

	}

	if NothingRunning(mainM) {
		utils.Warn(willExitStr)
		return
	}

	{
		close(stopGorouteCaptureSignalChan)

		osSignals := utils.GetSystemKillChan()
		<-osSignals

		exitBySignal()
	}
	return
}

func stopMachineAndExit(m *machine.M) {

	ch := make(chan struct{})
	go func() {
		m.Stop()
		close(ch)
	}()
	tCh := time.After(time.Second * 2)
	select {
	case <-tCh:
		log.Println("Close timeout")
		os.Exit(-1)
	case <-ch:
		break
	}
	os.Exit(0)

}

// print close info and call stopMachineAndExit
func exitBySignal() {
	utils.Info("Program got close signal.")

	stopMachineAndExit(mainM)
}

// splice, pprof, urlFormat, dialtimeout
func setupSystemParemeters() {
	if disableSplice {
		netLayer.SystemCanSplice = false
	}
	if startPProf {
		const pprofFN = "cpu.pprof"
		f, err := os.OpenFile(pprofFN, os.O_CREATE|os.O_RDWR, 0644)

		if err == nil {
			defer f.Close()
			err = pprof.StartCPUProfile(f)
			if err == nil {
				defer pprof.StopCPUProfile()
			} else {
				log.Println("pprof.StartCPUProfile failed", err)

			}
		} else {
			log.Println(pprofFN, "can't be created,", err)
		}

	}
	if startMProf {
		//若不使用 NoShutdownHook, 则 我们ctrl+c退出时不会产生 pprof文件
		p := profile.Start(profile.MemProfile, profile.MemProfileRate(1), profile.NoShutdownHook)

		defer p.Stop()
	}

	if useNativeUrlFormat {
		proxy.UrlFormat = proxy.UrlNativeFormat
	}

	netLayer.DialTimeout = time.Duration(dialTimeoutSecond) * time.Second
}

// 是否可以在运行时动态修改配置。如果没有开启 apiServer 开关 也没有 动态修改配置的功能，则当前模式不灵活，无法动态修改
func IsFlexible(m *machine.M) bool {
	return interactive_mode || gui_mode || m.EnableApiServer
}

func NoFuture(m *machine.M) bool {
	return !m.HasProxyRunning() && !IsFlexible(m)
}

func NothingRunning(m *machine.M) bool {
	return !m.HasProxyRunning() && !(interactive_mode || gui_mode || m.IsApiServerRunning())
}