package cli

import (
	"flag"
	"fmt"
	"io"
	"os"
)

type AutoloopParams struct {
	Iface           string
	Table           string
	MTU             int
	StateDir        string
	DefaultLocation string
}

type AutoloopDeps struct {
	StateDirDefault string
	ResolveIface    func(flagIface string) string
	Run             func(params AutoloopParams)
	Stderr          io.Writer
}

func RunAutoloop(args []string, deps AutoloopDeps) int {
	if deps.ResolveIface == nil || deps.Run == nil {
		return 1
	}
	stderr := deps.Stderr
	if stderr == nil {
		stderr = os.Stderr
	}

	fs := flag.NewFlagSet("autoloop", flag.ContinueOnError)
	fs.SetOutput(stderr)
	iface := fs.String("iface", "", "VPN interface (empty/auto = detect active)")
	table := fs.String("table", "agvpn", "routing table name")
	mtu := fs.Int("mtu", 1380, "MTU for default route")
	stateDir := fs.String("state-dir", deps.StateDirDefault, "state directory")
	defaultLoc := fs.String("default-location", "Austria", "default location")
	if err := fs.Parse(args); err != nil {
		return 2
	}

	resolvedIface := deps.ResolveIface(*iface)
	if resolvedIface == "" {
		fmt.Fprintln(stderr, "autoloop: cannot resolve VPN interface (set --iface or preferred iface)")
		return 1
	}

	deps.Run(AutoloopParams{
		Iface:           resolvedIface,
		Table:           *table,
		MTU:             *mtu,
		StateDir:        *stateDir,
		DefaultLocation: *defaultLoc,
	})
	return 0
}