package constant

import (
	"archive/tar"
	"compress/gzip"
	"io"
	"net/http"
	"os"
	"os/user"
	"path"
	"strings"

	log "github.com/sirupsen/logrus"
)

const (
	Name             = "clash"
	DefalutHTTPPort  = 7890
	DefalutSOCKSPort = 7891
)

var (
	HomeDir    string
	ConfigPath string
	MMDBPath   string
)

type General struct {
	Mode      *string `json:"mode,omitempty"`
	AllowLan  *bool   `json:"allow-lan,omitempty"`
	Port      *int    `json:"port,omitempty"`
	SocksPort *int    `json:"socks-port,omitempty"`
}

func init() {
	currentUser, err := user.Current()
	if err != nil {
		dir := os.Getenv("HOME")
		if dir == "" {
			log.Fatalf("Can't get current user: %s", err.Error())
		}
		HomeDir = dir
	} else {
		HomeDir = currentUser.HomeDir
	}

	dirPath := path.Join(HomeDir, ".config", Name)
	if _, err := os.Stat(dirPath); os.IsNotExist(err) {
		if err := os.MkdirAll(dirPath, 0777); err != nil {
			log.Fatalf("Can't create config directory %s: %s", dirPath, err.Error())
		}
	}

	ConfigPath = path.Join(dirPath, "config.ini")
	if _, err := os.Stat(ConfigPath); os.IsNotExist(err) {
		log.Info("Can't find config, create a empty file")
		os.OpenFile(ConfigPath, os.O_CREATE|os.O_WRONLY, 0644)
	}

	MMDBPath = path.Join(dirPath, "Country.mmdb")
	if _, err := os.Stat(MMDBPath); os.IsNotExist(err) {
		log.Info("Can't find MMDB, start download")
		err := downloadMMDB(MMDBPath)
		if err != nil {
			log.Fatalf("Can't download MMDB: %s", err.Error())
		}
	}
}

func downloadMMDB(path string) (err error) {
	resp, err := http.Get("http://geolite.maxmind.com/download/geoip/database/GeoLite2-Country.tar.gz")
	if err != nil {
		return
	}
	defer resp.Body.Close()

	gr, err := gzip.NewReader(resp.Body)
	if err != nil {
		return
	}
	defer gr.Close()

	tr := tar.NewReader(gr)
	for {
		h, err := tr.Next()
		if err == io.EOF {
			break
		} else if err != nil {
			return err
		}

		if !strings.HasSuffix(h.Name, "GeoLite2-Country.mmdb") {
			continue
		}

		f, err := os.OpenFile(path, os.O_CREATE|os.O_WRONLY, 0644)
		if err != nil {
			return err
		}
		defer f.Close()
		_, err = io.Copy(f, tr)
		if err != nil {
			return err
		}
	}

	return nil
}