package services

import (
	"database/sql"
	"errors"
	"go-cook/api/domain"
	"go-cook/api/repositories"
	"strings"

	"golang.org/x/crypto/bcrypt"
)

const (
	ErrPasswordNotLongEnough           = "password needs to be 8 character or longer"
	ErrPasswordMissingSpecialCharacter = "password needs to contain one of the following: !, @, #"
	ErrInvalidPassword                 = "invalid password"
)

// This will handle operations that are user related, but one layer higher then the repository
type UserService struct {
	repo repositories.IUserTable
}

func NewUserService(conn *sql.DB) UserService {
	return UserService{
		repo: repositories.NewUserRepository(conn),
	}
}

func (us UserService) DoesUserExist(username string) error {
	_, err := us.repo.GetByName(username)
	if err != nil {
		return err
	}
	return nil
}

func (us UserService) DoesPasswordMatchHash(username, password string) error {
	model, err := us.GetUser(username)
	if err != nil {
		return err
	}

	err = bcrypt.CompareHashAndPassword([]byte(model.Hash), []byte(password))
	if err != nil {
		return errors.New(ErrInvalidPassword)
	}

	return nil
}

func (us UserService) GetUser(username string) (domain.UserEntity, error) {
	return us.repo.GetByName(username)
}

func (us UserService) CreateNewUser(name, password string) (domain.UserEntity, error) {
	err := us.CheckPasswordForRequirements(password)
	if err != nil {
		return domain.UserEntity{}, err
	}

	us.repo.Create(name, password)
	return domain.UserEntity{}, nil
}

func (us UserService) CheckPasswordForRequirements(password string) error {
	err := us.checkPasswordLength(password)
	if err != nil {
		return err
	}

	err = us.checkPasswordForSpecialCharacters(password)
	if err != nil {
		return err
	}

	return nil
}

func (us UserService) checkPasswordLength(password string) error {
	if len(password) < 8 {
		return errors.New(ErrPasswordNotLongEnough)
	}
	return nil
}

func (us UserService) checkPasswordForSpecialCharacters(password string) error {
	var chars []string
	chars = append(chars, "!")
	chars = append(chars, "@")
	chars = append(chars, "#")

	for _, char := range chars {
		if strings.Contains(password, char) {
			return nil
		}
	}

	return errors.New(ErrPasswordMissingSpecialCharacter)
}