package service

import (
	"context"
	"encoding/hex"
	"errors"
	"net/mail"

	normalizer "github.com/dimuska139/go-email-normalizer"
	"github.com/google/uuid"
	"github.com/labstack/echo-contrib/session"
	"github.com/labstack/echo/v4"
	"golang.org/x/crypto/bcrypt"
	"gorm.io/gorm"

	"gitrepo.ru/neonxp/nquest/pkg/models"
)

var (
	ErrInvalidUsername      = errors.New("invalid username")
	ErrInvalidPassword      = errors.New("invalid password")
	ErrInvalidEmail         = errors.New("invalid email")
	ErrDiffferentPassword   = errors.New("different password")
	ErrDuplicateUser        = errors.New("duplicate user")
	ErrIvalidUserOrPassword = errors.New("invalid user or password")
)

type User struct {
	DB *gorm.DB
}

// NewUser returns new User.
func NewUser(db *gorm.DB) *User {
	return &User{
		DB: db,
	}
}

func (s *User) Register(ctx context.Context, username, email, password, password2 string) (*models.User, error) {
	if len(username) < 3 || len(username) > 36 {
		return nil, ErrInvalidUsername
	}

	if len(password) < 8 {
		return nil, ErrInvalidPassword
	}

	if password != password2 {
		return nil, ErrDiffferentPassword
	}

	if !isValidEmail(email) {
		return nil, ErrInvalidEmail
	}

	hashed, err := bcrypt.GenerateFromPassword([]byte(password), bcrypt.DefaultCost)
	if err != nil {
		return nil, err
	}

	u := &models.User{
		ID:       uuid.New(),
		Username: username,
		Email:    normalizer.NewNormalizer().Normalize(email),
		Password: hex.EncodeToString(hashed),
	}

	err = s.DB.WithContext(ctx).Create(u).Error
	switch {
	case errors.Is(err, models.ErrEmptyPassword):
		return nil, ErrInvalidPassword
	case errors.Is(err, gorm.ErrDuplicatedKey):
		return nil, ErrDuplicateUser
	case err != nil:
		return nil, err
	}

	return u, nil
}

func (s *User) Login(ctx context.Context, email, password string) (*models.User, error) {
	u := new(models.User)
	nemail := normalizer.NewNormalizer().Normalize(email)
	err := s.DB.
		WithContext(ctx).
		Preload("Games", `Finish = true`).
		Preload("Games.Game").
		Where("email = ?", nemail).
		First(u).
		Error
	if err != nil {
		return nil, ErrIvalidUserOrPassword
	}

	b, err := hex.DecodeString(u.Password)
	if err != nil {
		return nil, ErrIvalidUserOrPassword
	}
	if err := bcrypt.CompareHashAndPassword(b, []byte(password)); err != nil {
		return nil, ErrIvalidUserOrPassword
	}

	return u, nil
}

func (s *User) GetUserByID(ctx context.Context, userID uuid.UUID) (*models.User, error) {
	u := new(models.User)

	return u, s.DB.WithContext(ctx).
		Preload("Games", `Finish = true`).
		Preload("Games.Game").
		First(u, userID).Error
}

func (s *User) GetUser(c echo.Context) *models.User {
	sess, err := session.Get("session", c)
	if err != nil {
		return nil
	}

	userID, ok := sess.Values["userID"].(string)
	if !ok {
		return nil
	}
	uid, err := uuid.Parse(userID)
	if err != nil {
		return nil
	}

	user, err := s.GetUserByID(c.Request().Context(), uid)
	if err != nil {
		return nil
	}

	return user
}

func (s *User) List(ctx context.Context) ([]models.User, error) {
	res := make([]models.User, 0)

	return res, s.DB.WithContext(ctx).
		Preload("Games").
		Order("experience DESC").
		Limit(100).
		Find(&res).
		Error
}

func (s *User) Update(ctx context.Context, user *models.User) error {
	return s.DB.WithContext(ctx).Session(&gorm.Session{FullSaveAssociations: true}).Save(user).Error
}

func isValidEmail(email string) bool {
	_, err := mail.ParseAddress(email)
	return err == nil
}