// Package main implements an example CLI client
package main

import (
	"context"
	"flag"
	"fmt"
	"os"
	"reflect"
	"strings"

	"codeberg.org/eduVPN/eduvpn-common/client"
	"codeberg.org/eduVPN/eduvpn-common/i18n"
	"codeberg.org/eduVPN/eduvpn-common/internal/commonver"
	"codeberg.org/eduVPN/eduvpn-common/types/cookie"
	srvtypes "codeberg.org/eduVPN/eduvpn-common/types/server"

	"github.com/pkg/browser"
)

// Open a browser with xdg-open.
func openBrowser(data any) {
	str, ok := data.(string)
	if !ok {
		return
	}
	go func() {
		err := browser.OpenURL(str)
		if err != nil {
			fmt.Fprintln(os.Stderr, "failed to open browser with error:", err)
			fmt.Println("Please open your browser manually")
		}
	}()
}

func getProfileInteractive(profiles *srvtypes.Profiles, data any) (string, error) {
	fmt.Printf("Multiple VPN profiles found. Please select a profile by entering e.g. 1")
	var ps strings.Builder
	var options []string
	i := 0
	for k, v := range profiles.Map {
		ps.WriteString(fmt.Sprintf("\n%d - %s", i+1, i18n.GetLanguageMatched(v.DisplayName, "en")))
		options = append(options, k)
		i++
	}

	// Show the profiles
	fmt.Println(ps.String())

	var idx int
	if _, err := fmt.Scanf("%d", &idx); err != nil || idx <= 0 ||
		idx > len(profiles.Map) {
		fmt.Fprintln(os.Stderr, "invalid profile chosen, please retry")
		return getProfileInteractive(profiles, data)
	}

	p := options[idx-1]
	fmt.Println("Sending profile ID", p)
	return p, nil
}

func sendProfile(profile string, data any) {
	d, ok := data.(*srvtypes.RequiredAskTransition)
	if !ok {
		fmt.Fprintf(os.Stderr, "\ninvalid data type: %v\n", reflect.TypeOf(data))
		os.Exit(1)
	}
	sps, ok := d.Data.(*srvtypes.Profiles)
	if !ok {
		fmt.Fprintf(os.Stderr, "\ninvalid data type for profiles: %v\n", reflect.TypeOf(d.Data))
		os.Exit(1)
	}

	if profile == "" {
		gprof, err := getProfileInteractive(sps, data)
		if err != nil {
			fmt.Fprintf(os.Stderr, "failed getting profile interactively: %v\n", err)
			os.Exit(1)
		}
		profile = gprof
	}
	if err := d.C.Send(profile); err != nil {
		fmt.Fprintf(os.Stderr, "failed setting profile with error: %v\n", err)
		os.Exit(1)
	}
}

// The callback function
// If OAuth is started we open the browser with the Auth URL
// If we ask for a profile, we send the profile using command line input
// Note that this has an additional argument, the vpn state which was wrapped into this callback function below.
func stateCallback(_ client.FSMStateID, newState client.FSMStateID, data any, prof string, dir string) {
	if newState == client.StateOAuthStarted {
		openBrowser(data)
	}

	if newState == client.StateAskProfile {
		sendProfile(prof, data)
	}

	if newState == client.StateAskLocation {
		// removing is best effort
		_ = os.RemoveAll(dir)
		fmt.Fprint(os.Stderr, "An invalid secure location is stored. This CLI doesn't support interactively choosing a location yet. Give a correct location with the -country-code flag")
		os.Exit(1)
	}
}

// Get a config for Institute Access or Secure Internet Server.
func getConfig(state *client.Client, url string, srvType srvtypes.Type, cc string, prof string) (*srvtypes.Configuration, error) {
	if !strings.HasPrefix(url, "http") {
		url = "https://" + url
	}
	ck := cookie.NewWithContext(context.Background())
	defer ck.Cancel() //nolint:errcheck
	err := state.AddServer(ck, url, srvType, nil)
	if err != nil {
		// TODO: This is quite hacky :^)
		if !strings.Contains(err.Error(), "a secure internet server already exists.") {
			return nil, err
		}
	}
	if cc != "" {
		err = state.SetSecureLocation(url, cc)
		if err != nil {
			return nil, err
		}
	}

	if prof != "" {
		// this is best effort, e.g. if no server was chosen before this fails
		_ = state.SetProfileID(prof) //nolint:errcheck
	}

	return state.GetConfig(ck, url, srvType, false, false)
}

// Get a config for a single server, Institute Access or Secure Internet.
func printConfig(url string, cc string, srvType srvtypes.Type, prof string) error {
	var c *client.Client
	var err error
	var dir string
	dir, err = os.MkdirTemp("", "eduvpn-common")
	if err != nil {
		return err
	}
	// removing is best effort
	defer os.RemoveAll(dir) //nolint:errcheck
	c, err = client.New(
		"org.eduvpn.app.linux",
		fmt.Sprintf("%s-cli", commonver.Version),
		dir,
		func(oldState client.FSMStateID, newState client.FSMStateID, data any) bool {
			stateCallback(oldState, newState, data, prof, dir)
			return true
		},
		nil,
	)
	if err != nil {
		return err
	}
	_ = c.Register()

	ck := cookie.NewWithContext(context.Background())
	_, err = c.DiscoOrganizations(ck, false, "")
	if err != nil {
		return err
	}
	_, err = c.DiscoServers(ck, false, "")
	if err != nil {
		return err
	}

	defer c.Deregister()

	cfg, err := getConfig(c, url, srvType, cc, prof)
	if err != nil {
		return err
	}
	fmt.Println(cfg.VPNConfig)
	return nil
}

// The main function
// It parses the arguments and executes the correct functions.
func main() {
	cu := flag.String("get-custom", "", "The url of a custom server to connect to")
	u := flag.String("get-institute", "", "The url of an institute to connect to")
	sec := flag.String("get-secure", "", "Gets secure internet servers")
	cc := flag.String("country-code", "", "The country code to use in case of a secure internet server")
	prof := flag.String("profile", "", "The profile ID to choose")
	flag.Parse()

	// Connect to a VPN by getting an Institute Access config
	var err error
	switch {
	case *cu != "":
		err = printConfig(*cu, "", srvtypes.TypeCustom, *prof)
	case *u != "":
		err = printConfig(*u, "", srvtypes.TypeInstituteAccess, *prof)
	case *sec != "":
		err = printConfig(*sec, *cc, srvtypes.TypeSecureInternet, *prof)
	default:
		flag.PrintDefaults()
	}

	if err != nil {
		fmt.Fprintf(os.Stderr, "failed to get a VPN config: %v\n", err)
	}
}