package user

import (
	"context"
	"errors"
	"time"

	"github.com/SamuelTariku/FortuneBet-Backend/internal/domain"
	"golang.org/x/crypto/bcrypt"
)

const (
	OtpExpiry = 5 * time.Minute
)

var (
	ErrOtpAlreadyUsed = errors.New("otp already used")
	ErrInvalidOtp     = errors.New("invalid otp")
	ErrOtpExpired     = errors.New("otp expired")
)

type Service struct {
	userStore    UserStore
	otpStore     OtpStore
	smsGateway   SmsGateway
	emailGateway EmailGateway
}

func NewService(
	userStore UserStore, RefreshExpiry int,
	otpStore OtpStore, smsGateway SmsGateway,
	emailGateway EmailGateway,
) *Service {
	return &Service{
		userStore: userStore,
		otpStore:  otpStore,
	}
}

func (s *Service) CheckPhoneEmailExist(ctx context.Context, phoneNum, email string) (bool, bool, error) { // email,phone,error
	return s.userStore.CheckPhoneEmailExist(ctx, phoneNum, email)
}
func (s *Service) SendRegisterCode(ctx context.Context, medium domain.OtpMedium, sentTo string) error {
	var err error
	// check if user exists
	switch medium {
	case domain.OtpMediumEmail:
		_, err = s.userStore.GetUserByEmail(ctx, sentTo)
	case domain.OtpMediumSms:
		_, err = s.userStore.GetUserByPhone(ctx, sentTo)
	}

	if err != nil {
		return err
	}

	// send otp based on the medium
	return s.SendOtp(ctx, sentTo, domain.OtpReset, medium)
}
func (s *Service) RegisterUser(ctx context.Context, registerReq domain.RegisterUserReq) (domain.User, error) { // normal
	// get otp
	var sentTo string
	if registerReq.OtpMedium == domain.OtpMediumEmail {
		sentTo = registerReq.Email
	} else {
		sentTo = registerReq.PhoneNumber
	}
	//
	otp, err := s.otpStore.GetOtp(
		ctx, sentTo,
		domain.OtpRegister, registerReq.OtpMedium)
	if err != nil {
		return domain.User{}, err
	}
	// verify otp
	if otp.Used {
		return domain.User{}, ErrOtpAlreadyUsed
	}
	if time.Now().After(otp.ExpiresAt) {
		return domain.User{}, ErrOtpExpired
	}
	if otp.Otp != registerReq.Otp {
		return domain.User{}, ErrInvalidOtp
	}

	hashedPassword, err := hashPassword(registerReq.Password)
	if err != nil {
		return domain.User{}, err
	}
	userR := domain.User{
		FirstName:     registerReq.FirstName,
		LastName:      registerReq.LastName,
		Email:         registerReq.Email,
		PhoneNumber:   registerReq.PhoneNumber,
		Password:      hashedPassword,
		Role:          "user",
		EmailVerified: registerReq.OtpMedium == domain.OtpMediumEmail,
		PhoneVerified: registerReq.OtpMedium == domain.OtpMediumSms,
	}
	// create the user and mark otp as used
	user, err := s.userStore.CreateUser(ctx, userR, otp.ID)
	if err != nil {
		return domain.User{}, err
	}
	return user, nil
}

func (s *Service) SendResetCode(ctx context.Context, medium domain.OtpMedium, sentTo string) error {

	var err error
	// check if user exists
	switch medium {
	case domain.OtpMediumEmail:
		_, err = s.userStore.GetUserByEmail(ctx, sentTo)
	case domain.OtpMediumSms:
		_, err = s.userStore.GetUserByPhone(ctx, sentTo)
	}

	if err != nil {
		return err
	}

	return s.SendOtp(ctx, sentTo, domain.OtpReset, medium)

}

func (s *Service) ResetPassword(ctx context.Context, resetReq domain.ResetPasswordReq) error {
	var sentTo string
	if resetReq.OtpMedium == domain.OtpMediumEmail {
		sentTo = resetReq.Email
	} else {
		sentTo = resetReq.PhoneNumber
	}
	otp, err := s.otpStore.GetOtp(
		ctx, sentTo,
		domain.OtpRegister, resetReq.OtpMedium)
	if err != nil {
		return err
	}
	//
	if otp.Used {
		return ErrOtpAlreadyUsed
	}
	if time.Now().After(otp.ExpiresAt) {
		return ErrOtpExpired
	}
	if otp.Otp != resetReq.Otp {
		return ErrInvalidOtp
	}
	// hash password
	hashedPassword, err := hashPassword(resetReq.Password)
	if err != nil {
		return err
	}
	// reset pass and mark otp as used
	err = s.userStore.UpdatePassword(ctx, sentTo, hashedPassword, otp.ID)
	if err != nil {
		return err
	}
	return nil
}
func (s *Service) SendOtp(ctx context.Context, sentTo string, otpFor domain.OtpFor, medium domain.OtpMedium) error {
	otpCode := "123456" // Generate OTP code

	otp := domain.Otp{
		SentTo:    sentTo,
		Medium:    medium,
		For:       otpFor,
		Otp:       otpCode,
		Used:      false,
		CreatedAt: time.Now(),
		ExpiresAt: time.Now().Add(OtpExpiry),
	}

	err := s.otpStore.CreateOtp(ctx, otp)
	if err != nil {
		return err
	}

	switch medium {
	case domain.OtpMediumSms:
		return s.smsGateway.SendSMSOTP(ctx, sentTo, otpCode)
	case domain.OtpMediumEmail:
		return s.emailGateway.SendEmailOTP(ctx, sentTo, otpCode)
	}
	return nil
}

func (s *Service) UpdateUser(ctx context.Context, user domain.UpdateUserReq) error {
	// update user
	return s.userStore.UpdateUser(ctx, user)

}
func (s *Service) GetUserByID(ctx context.Context, id int64) (domain.User, error) {
	return s.userStore.GetUserByID(ctx, id)
}

func hashPassword(plaintextPassword string) ([]byte, error) {
	hash, err := bcrypt.GenerateFromPassword([]byte(plaintextPassword), 12)
	if err != nil {
		return []byte{}, err
	}

	return hash, nil
}