package services

import (
	"fmt"
	"time"

	"github.com/pquerna/otp"
	"github.com/pquerna/otp/totp"
	"golang.org/x/crypto/bcrypt"
)

type AuthService struct {
	issuer string
}

func NewAuthService(issuer string) *AuthService {
	return &AuthService{issuer: issuer}
}

func (a *AuthService) HashPassword(password string) (string, error) {
	hashed, err := bcrypt.GenerateFromPassword([]byte(password), bcrypt.DefaultCost)
	if err != nil {
		return "", err
	}

	return string(hashed), nil
}

func (a *AuthService) ComparePassword(hash, password string) error {
	return bcrypt.CompareHashAndPassword([]byte(hash), []byte(password))
}

func (a *AuthService) NewOTP(email string) (*otp.Key, error) {
	return totp.Generate(totp.GenerateOpts{
		Issuer:      a.issuer,
		AccountName: email,
	})
}

func (a *AuthService) VerifyOTP(secret, code string) bool {
	return totp.Validate(code, secret)
}

func (a *AuthService) BuildOTPURI(email, secret string) string {
	return fmt.Sprintf("otpauth://totp/%s:%s?secret=%s&issuer=%s", a.issuer, email, secret, a.issuer)
}

func (a *AuthService) OTPCode(secret string, at time.Time) (string, error) {
	return totp.GenerateCode(secret, at)
}
