package main

import (
	"errors"
	"fmt"
	"log"
	"os"
	"regexp"
	"time"

	"github.com/urfave/cli"
)

const (
	zoneFilePath = "/var/bind/pri/localhost.zone"
)

var re = regexp.MustCompile(`^([0-9]{1,3})\.([0-9]{1,3})\.([0-9]{1,3})\.([0-9]{1,3})$`)

func main() {
	app := cli.NewApp()
	app.Name = "spamip"
	app.Version = "0.1"
	app.Compiled = time.Now()
	app.Authors = []cli.Author{
		{
			Name:  "Darko Luketic",
			Email: "info@icod.de",
		},
	}
	app.Usage = "spamip is a tool that adds an IP to a bind zone file in DNSBL format"

	app.Flags = []cli.Flag{
		cli.StringFlag{
			Name:      "file, f",
			Usage:     "path/filename of the zone file",
			EnvVar:    "SPAMIP_FILE",
			Required:  false,
			Hidden:    false,
			TakesFile: false,
			Value:     zoneFilePath,
		},
	}

	app.Commands = []cli.Command{
		{
			Name:    "add",
			Aliases: []string{"a"},
			Usage:   "add an IP address to the zone file",
			Action: func(c *cli.Context) error {
				if len(c.Args()) != 1 {
					return errors.New("add takes exactly 1 argument, an IPv4 address")
				}
				if !re.MatchString(c.Args().First()) {
					return errors.New(c.Args().First() + "is not an IPv4 address")
				}
				s := re.FindStringSubmatch(c.Args().First())
				text := fmt.Sprintf("%s.%s.%s.%s\tIN\tA\t127.0.0.3\n", s[4], s[3], s[2], s[1])
				return appendText(text, c.GlobalString("file"))
			},
		},
	}
	err := app.Run(os.Args)
	if err != nil {
		log.Fatal(err)
	}
}

func appendText(text, file string) error {
	f, e := os.OpenFile(file, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
	if e != nil {
		return e
	}
	if n, e := f.WriteString(text); e != nil {
		return e
	} else if n != len(text) {
		return errors.New("did not write all the text")
	}
	return f.Close()
}