package services

import (
	"database/sql"
	"errors"
	"strings"

	"git.jamestombleson.com/jtom38/go-cook/internal/domain"
	"git.jamestombleson.com/jtom38/go-cook/internal/repositories"

	"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"
)

type Users interface {
	DoesUserExist(username string) error
	DoesPasswordMatchHash(username, password string) error
	GetUser(username string) (domain.UserEntity, error)
	AddScopes(username string, scopes []string) error
	RemoveScopes(username string, scopes []string) error
	Create(name, password, scope string) (domain.UserEntity, error)
	CheckPasswordForRequirements(password string) error
}

// 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) AddScopes(username string, scopes []string) error {
	usr, err := us.repo.GetByName(username)
	if err != nil {
		return err
	}

	if usr.Name != username {
		return errors.New(repositories.ErrUserNotFound)
	}

	currentScopes := strings.Split(usr.Scopes, ",")

	// check the current scopes
	for _, item := range scopes {
		if !strings.Contains(usr.Scopes, item) {
			currentScopes = append(currentScopes, item)
		}
	}
	return us.repo.UpdateScopes(username, strings.Join(currentScopes, ","))
}

func (us UserService) RemoveScopes(username string, scopes []string) error {
	usr, err := us.repo.GetByName(username)
	if err != nil {
		return err
	}

	if usr.Name != username {
		return errors.New(repositories.ErrUserNotFound)
	}

	var newScopes []string

	// check all the scopes that are currently assigned
	for _, item := range strings.Split(usr.Scopes, ",") {

		// check the scopes given, if one matches skip it
		if us.doesScopeExist(scopes, item) {
			continue
		}

		// did not match, add it
		newScopes = append(newScopes, item)
	}

	return us.repo.UpdateScopes(username, strings.Join(newScopes, ","))
}

func (us UserService) doesScopeExist(scopes []string, target string) bool {
	for _, item := range scopes {
		if item == target {
			return true
		}
	}
	return false
}

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

	us.repo.Create(name, password, domain.ScopeRecipeRead)
	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)
}