package flags

import (
	"errors"
	"fmt"
	goflags "github.com/jessevdk/go-flags"
	"os"
)

var PrintedHelpErr = goflags.ErrHelp
var NotEnoughArgs = errors.New("not enough arguments")

type Options struct {
	Foreground bool   `short:"f" long:"foreground" description:"Run in the foreground"`
	ConfigFile string `short:"c" long:"config" description:"Configuration file location" value-name:"FILE"`
	PidFile    string `short:"p" long:"pid" description:"PID file location"`

	Positional struct {
		InterfaceName string `required:"yes" positional-arg-name:"INTERFACE-NAME" description:"Interface name"`
	} `positional-args:"yes"`
}

func ParseFlags() (*Options, error) {
	o := new(Options)
	parser := goflags.NewParser(o, goflags.Default)

	_, err := parser.Parse()
	if err != nil {
		parser.WriteHelp(os.Stdout)
		return nil, err
	}

	if o.ConfigFile == "" {
		o.ConfigFile = fmt.Sprintf(DefaultConfigFile, o.Positional.InterfaceName)
	}
	if o.PidFile == "" {
		o.PidFile = fmt.Sprintf(DefaultPidFile, o.Positional.InterfaceName)
	}

	return o, nil
}