package models

import (
	"image"
	"net/url"
	"strconv"
	"time"

	"github.com/pquerna/otp"
)

// TOTPConfiguration represents a users TOTP configuration row in the database.
type TOTPConfiguration struct {
	ID         int        `db:"id" json:"-"`
	CreatedAt  time.Time  `db:"created_at" json:"-"`
	LastUsedAt *time.Time `db:"last_used_at" json:"-"`
	Username   string     `db:"username" json:"-"`
	Issuer     string     `db:"issuer" json:"-"`
	Algorithm  string     `db:"algorithm" json:"-"`
	Digits     uint       `db:"digits" json:"digits"`
	Period     uint       `db:"period" json:"period"`
	Secret     []byte     `db:"secret" json:"-"`
}

// URI shows the configuration in the URI representation.
func (c TOTPConfiguration) URI() (uri string) {
	v := url.Values{}
	v.Set("secret", string(c.Secret))
	v.Set("issuer", c.Issuer)
	v.Set("period", strconv.FormatUint(uint64(c.Period), 10))
	v.Set("algorithm", c.Algorithm)
	v.Set("digits", strconv.Itoa(int(c.Digits)))

	u := url.URL{
		Scheme:   "otpauth",
		Host:     "totp",
		Path:     "/" + c.Issuer + ":" + c.Username,
		RawQuery: v.Encode(),
	}

	return u.String()
}

// UpdateSignInInfo adjusts the values of the TOTPConfiguration after a sign in.
func (c *TOTPConfiguration) UpdateSignInInfo(now time.Time) {
	c.LastUsedAt = &now
}

// Key returns the *otp.Key using TOTPConfiguration.URI with otp.NewKeyFromURL.
func (c TOTPConfiguration) Key() (key *otp.Key, err error) {
	return otp.NewKeyFromURL(c.URI())
}

// Image returns the image.Image of the TOTPConfiguration using the Image func from the return of TOTPConfiguration.Key.
func (c TOTPConfiguration) Image(width, height int) (img image.Image, err error) {
	var key *otp.Key

	if key, err = c.Key(); err != nil {
		return nil, err
	}

	return key.Image(width, height)
}