feat: move entity and usecase to root folder

entity/user.go

@@ -0,0 +1,97 @@
+package entity
+
+import (
+	"time"
+
+	"golang.org/x/crypto/bcrypt"
+)
+
+//User data
+type User struct {
+	ID        ID
+	Email     string
+	Password  string
+	FirstName string
+	LastName  string
+	CreatedAt time.Time
+	UpdatedAt time.Time
+	Books     []ID
+}
+
+//NewUser create a new user
+func NewUser(email, password, firstName, lastName string) (*User, error) {
+	u := &User{
+		ID:        NewID(),
+		Email:     email,
+		FirstName: firstName,
+		LastName:  lastName,
+		CreatedAt: time.Now(),
+	}
+	pwd, err := generatePassword(password)
+	if err != nil {
+		return nil, err
+	}
+	u.Password = pwd
+	err = u.Validate()
+	if err != nil {
+		return nil, ErrInvalidEntity
+	}
+	return u, nil
+}
+
+//AddBook add a book
+func (u *User) AddBook(id ID) error {
+	_, err := u.GetBook(id)
+	if err == nil {
+		return ErrBookAlreadyBorrowed
+	}
+	u.Books = append(u.Books, id)
+	return nil
+}
+
+//RemoveBook remove a book
+func (u *User) RemoveBook(id ID) error {
+	for i, j := range u.Books {
+		if j == id {
+			u.Books = append(u.Books[:i], u.Books[i+1:]...)
+			return nil
+		}
+	}
+	return ErrNotFound
+}
+
+//GetBook get a book
+func (u *User) GetBook(id ID) (ID, error) {
+	for _, v := range u.Books {
+		if v == id {
+			return id, nil
+		}
+	}
+	return id, ErrNotFound
+}
+
+//Validate validate data
+func (u *User) Validate() error {
+	if u.Email == "" || u.FirstName == "" || u.LastName == "" || u.Password == "" {
+		return ErrInvalidEntity
+	}
+
+	return nil
+}
+
+//ValidatePassword
+func (u *User) ValidatePassword(p string) error {
+	err := bcrypt.CompareHashAndPassword([]byte(u.Password), []byte(p))
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func generatePassword(raw string) (string, error) {
+	hash, err := bcrypt.GenerateFromPassword([]byte(raw), 10)
+	if err != nil {
+		return "", err
+	}
+	return string(hash), nil
+}