Implement initial login functionality

internal/dis/component/auth/user.go

@@ -0,0 +1,176 @@
+package auth
+
+import (
+	"context"
+	"errors"
+	"fmt"
+
+	"github.com/FAU-CDI/wisski-distillery/internal/models"
+	"golang.org/x/crypto/bcrypt"
+)
+
+// ErrUserNotFound is returned when a user is not found
+var ErrUserNotFound = errors.New("user not found")
+
+// Users returns all users in the database
+func (auth *Auth) Users(ctx context.Context) (users []*AuthUser, err error) {
+	// query the user table
+	table, err := auth.Dependencies.SQL.QueryTable(ctx, false, models.UserTable)
+	if err != nil {
+		return
+	}
+
+	// find all the users
+	var dUsers []models.User
+	err = table.Find(&dUsers).Error
+	if err != nil {
+		return nil, err
+	}
+
+	// and map them to high-level user objects
+	users = make([]*AuthUser, len(dUsers))
+	for i, user := range dUsers {
+		users[i] = &AuthUser{
+			User: user,
+			auth: auth,
+		}
+	}
+
+	return users, nil
+}
+
+// User returns a single user.
+// If the user does not exist, returns ErrUserNotFound.
+func (auth *Auth) User(ctx context.Context, name string) (user *AuthUser, err error) {
+	// quick and dirty check for the empty username (which is not allowed)
+	if name == "" {
+		return nil, ErrUserNotFound
+	}
+
+	// return the user
+	table, err := auth.Dependencies.SQL.QueryTable(ctx, false, models.UserTable)
+	if err != nil {
+		return
+	}
+
+	user = &AuthUser{}
+
+	// find the user
+	res := table.Where(&models.User{User: name}).Find(&user.User)
+	err = res.Error
+	if err != nil {
+		return
+	}
+
+	// check if the user was not found
+	if res.RowsAffected == 0 {
+		return nil, ErrUserNotFound
+	}
+
+	user.auth = auth
+
+	return
+}
+
+// CreateUser creates a new user and returns it.
+// The user is not associated to any WissKIs, and has no password set.
+func (auth *Auth) CreateUser(ctx context.Context, name string) (user *AuthUser, err error) {
+	// return the user
+	table, err := auth.Dependencies.SQL.QueryTable(ctx, false, models.UserTable)
+	if err != nil {
+		return
+	}
+
+	user = &AuthUser{
+		User: models.User{
+			User:    name,
+			Enabled: false,
+		},
+	}
+
+	// do the create statement
+	err = table.Create(&user.User).Error
+	if err != nil {
+		return nil, err
+	}
+
+	user.auth = auth
+	return user, nil
+}
+
+// AuthUser represents an authorized user
+type AuthUser struct {
+	auth *Auth
+	models.User
+}
+
+func (au AuthUser) String() string {
+	hasPassword := len(au.PasswordHash) > 0
+	return fmt.Sprintf("User{Name:%q,Enabled:%t,HasPassword:%t,Admin:%t}", au.User.User, au.User.Enabled, hasPassword, au.User.Admin)
+}
+
+// SetPassword sets the password for this user and turns the user on
+func (au *AuthUser) SetPassword(ctx context.Context, password []byte) (err error) {
+	au.User.PasswordHash, err = bcrypt.GenerateFromPassword(password, bcrypt.DefaultCost)
+	if err != nil {
+		return err
+	}
+	au.User.Enabled = true
+	return au.Save(ctx)
+}
+
+// UnsetPassword removes the password from this user, and disables them
+func (au *AuthUser) UnsetPassword(ctx context.Context) error {
+	au.User.PasswordHash = nil
+	au.User.Enabled = false
+	return au.Save(ctx)
+}
+
+var ErrUserDisabled = errors.New("user is disabled")
+var ErrUserBlank = errors.New("user has no password set")
+
+// CheckPassword checks if this user can login with the provided password.
+// Returns nil on success, an error otherwise.
+func (au *AuthUser) CheckPassword(ctx context.Context, password []byte) error {
+	if !au.User.Enabled {
+		return ErrUserDisabled
+	}
+
+	if len(au.User.PasswordHash) == 0 {
+		return ErrUserDisabled
+	}
+
+	return bcrypt.CompareHashAndPassword(au.User.PasswordHash, password)
+}
+
+// MakeAdmin makes this user an admin, and saves the update in the database.
+// If the user is already an admin, does not return an error.
+func (au *AuthUser) MakeAdmin(ctx context.Context) error {
+	au.User.Admin = true
+	return au.Save(ctx)
+}
+
+// MakeRegular removes admin rights from this user.
+// If this user is not an dmin, does not return an error.
+func (au *AuthUser) MakeRegular(ctx context.Context) error {
+	au.User.Admin = true
+	return au.Save(ctx)
+}
+
+// Save saves the given user in the database
+func (au *AuthUser) Save(ctx context.Context) error {
+	table, err := au.auth.Dependencies.SQL.QueryTable(ctx, false, models.UserTable)
+	if err != nil {
+		return err
+	}
+	return table.Save(&au.User).Error
+}
+
+// Delete deletes the user from the database
+func (au *AuthUser) Delete(ctx context.Context) error {
+	table, err := au.auth.Dependencies.SQL.QueryTable(ctx, false, models.UserTable)
+	if err != nil {
+		return err
+	}
+	return table.Delete(&au.User).Error
+}