package main

//go:generate errorgen

import (
	"bytes"
	"encoding/json"
	"flag"
	"fmt"
	"os"
	"os/signal"
	"path/filepath"
	"runtime"
	"strings"
	"syscall"

	"v2ray.com/core"
	"v2ray.com/core/common/platform"
	_ "v2ray.com/core/main/distro/all"
)

type CmdConfig []string

func (c *CmdConfig) String() string {
	return strings.Join([]string(*c), ",")
}

func (c *CmdConfig) Set(value string) error {
	*c = append(*c, value)
	return nil
}

var (
	configFiles CmdConfig // "Config file for V2Ray.", the option is customed type, parse in main
	version     = flag.Bool("version", false, "Show current version of V2Ray.")
	test        = flag.Bool("test", false, "Test config file only, without launching V2Ray server.")
	format      = flag.String("format", "json", "Format of input file.")
)

func fileExists(file string) bool {
	info, err := os.Stat(file)
	return err == nil && !info.IsDir()
}

func getConfigFilePath() CmdConfig {

	if len(configFiles) > 0 {
		return configFiles
	}

	if workingDir, err := os.Getwd(); err == nil {
		configFile := filepath.Join(workingDir, "config.json")
		if fileExists(configFile) {
			return []string{configFile}
		}
	}

	if configFile := platform.GetConfigurationPath(); fileExists(configFile) {
		return []string{configFile}
	}

	return []string{}
}

func GetConfigFormat() string {
	switch strings.ToLower(*format) {
	case "pb", "protobuf":
		return "protobuf"
	default:
		return "json"
	}
}

func startV2Ray() (core.Server, error) {
	configFiles := getConfigFilePath()
	fs, _ := json.Marshal(configFiles)
	config, err := core.LoadConfig(GetConfigFormat(), configFiles[0], bytes.NewBuffer(fs))
	if err != nil {
		return nil, newError("failed to read config files: [", configFiles.String(), "]").Base(err)
	}

	server, err := core.New(config)
	if err != nil {
		return nil, newError("failed to create server").Base(err)
	}

	return server, nil
}

func printVersion() {
	version := core.VersionStatement()
	for _, s := range version {
		fmt.Println(s)
	}
}

func main() {
	flag.Var(&configFiles, "config", "Config file for V2Ray. Multiple assign is accepted (only json). Latter ones overrides the former ones.")
	flag.Parse()

	printVersion()

	if *version {
		return
	}

	server, err := startV2Ray()
	if err != nil {
		fmt.Println(err.Error())
		// Configuration error. Exit with a special value to prevent systemd from restarting.
		os.Exit(23)
	}

	if *test {
		fmt.Println("Configuration OK.")
		os.Exit(0)
	}

	if err := server.Start(); err != nil {
		fmt.Println("Failed to start", err)
		os.Exit(-1)
	}
	defer server.Close()

	// Explicitly triggering GC to remove garbage from config loading.
	runtime.GC()

	{
		osSignals := make(chan os.Signal, 1)
		signal.Notify(osSignals, os.Interrupt, os.Kill, syscall.SIGTERM)
		<-osSignals
	}
}