package main

import (
	"errors"
	"fmt"
	"net/mail"
	"os"
	"regexp"
	"strings"

	"git.tilde.town/tildetown/town/invites"
	"git.tilde.town/tildetown/town/sshkey"
	"git.tilde.town/tildetown/town/stats"
	"github.com/AlecAivazis/survey/v2"
	"github.com/charmbracelet/lipgloss"

	_ "embed"
)

//go:embed welcome.txt
var welcomeArt string

// TODO move magic key machine to static page

type newUserData struct {
	Username    string
	DisplayName string
	Email       string
	PubKey      string
}

func surveyIconSet(icons *survey.IconSet) {
	icons.Question.Text = "~"
	icons.Question.Format = "magenta:b"
}

func promptCode() (code string, err error) {
	err = survey.AskOne(&survey.Input{
		Message: "invite code?",
	}, &code,
		survey.WithValidator(survey.Required),
		survey.WithIcons(surveyIconSet))
	code = strings.TrimSpace(code)
	return
}

func promptUsername(townData stats.TildeData) (un string, err error) {
	// copied from /etc/adduser.conf
	usernameRE := regexp.MustCompile(`^[a-z][-a-z0-9_]*$`)
	err = survey.AskOne(
		&survey.Input{
			Message: "desired username?",
		}, &un,
		survey.WithValidator(survey.Required),
		survey.WithIcons(surveyIconSet),
		survey.WithValidator(func(val interface{}) error {
			un := val.(string)
			if len(un) > 32 {
				return fmt.Errorf("username '%s' is too long", un)
			}

			return nil
		}),
		survey.WithValidator(func(val interface{}) error {
			un := val.(string)
			if !usernameRE.MatchString(un) {
				return errors.New("usernames must start with a letter and only contain letters, nubers, - or _")
			}

			return nil
		}),
		survey.WithValidator(func(val interface{}) error {
			un := val.(string)
			for _, v := range townData.Users {
				if v.Username == un {
					return fmt.Errorf("username '%s' is already in use", un)
				}
			}
			return nil
		}))

	return "", nil
}

func promptEmail(defaultEmail string) (email string, err error) {
	err = survey.AskOne(
		&survey.Input{
			Message: "e-mail (for account recovery only)?",
			Default: defaultEmail,
		}, &email,
		survey.WithValidator(survey.Required),
		survey.WithIcons(surveyIconSet),
		survey.WithValidator(func(val interface{}) error {
			email := val.(string)
			_, err := mail.ParseAddress(email)
			if err != nil {
				return fmt.Errorf("'%s' doesn't look like an email: %w", email, err)
			}

			if !strings.Contains(email, ".") {
				return fmt.Errorf("'%s' doesn't look like an email: domain not fully qualified", email)
			}

			return nil
		}))

	return "", nil
}

func promptKey() (key string, err error) {
	err = survey.AskOne(
		&survey.Input{
			Message: "SSH public key?",
		}, &key,
		survey.WithValidator(survey.Required),
		survey.WithIcons(surveyIconSet),
		survey.WithValidator(func(v interface{}) error {
			key := v.(string)
			valid, err := sshkey.ValidKey(key)
			if err != nil {
				return fmt.Errorf("failed to validate key: %w", err)
			}

			if !valid {
				return errors.New("that doesn't seem like a valid SSH key. try another public key?")
			}

			return nil
		}))

	return
}

func _main() error {
	townData, err := stats.Stats()
	if err != nil {
		return err
	}

	inviteDB, err := invites.ConnectDB()
	if err != nil {
		return err
	}

	data := &newUserData{}

	s := lipgloss.NewStyle().
		Foreground(lipgloss.AdaptiveColor{
			Light: "#7D19BD",
			Dark:  "#E0B0FF",
		})

	s = s.SetString(welcomeArt)
	fmt.Println(s)

	code, err := promptCode()
	if err != nil {
		return err
	}

	invite, err := invites.Get(inviteDB, code)
	if err != nil {
		return fmt.Errorf("could not look up invite code: %w", err)
	}

	if invite.Used {
		return errors.New("that invite code has already been used.")
	}

	s = s.SetString("thanks!! just gotta collect some information now and then your account will be ready.")

	fmt.Println(s)

	data.Username, err = promptUsername(townData)
	if err != nil {
		return err
	}

	data.Email, err = promptEmail(invite.Email)
	if err != nil {
		return err
	}

	data.PubKey, err = promptKey()
	if err != nil {
		return err
	}

	// TODO should I allow a review+edit step?

	// TODO have enough to make account; can now do that
	// TODO assuming account creation succeeded, mark invite as used

	return nil
}

func main() {
	// TODO friendlier error handling
	err := _main()
	if err != nil {
		fmt.Fprintln(os.Stderr, err)
		os.Exit(1)
	}
}