Refactor rename user and rename organization (#24052)

This PR is a refactor at the beginning. And now it did 4 things.
- [x] Move renaming organizaiton and user logics into services layer and
merged as one function
- [x] Support rename a user capitalization only. For example, rename the
user from `Lunny` to `lunny`. We just need to change one table `user`
and others should not be touched.
- [x] Before this PR, some renaming were missed like `agit`
- [x] Fix bug the API reutrned from `http.StatusNoContent` to `http.StatusOK`

2 files changed, 31 insertions, 52 deletions

diff --git a/models/user/error.go b/models/user/error.go
index 306b9ee9d9..f512994169 100644
--- a/models/user/error.go
+++ b/models/user/error.go
@@ -9,13 +9,6 @@ import (
 	"code.gitea.io/gitea/modules/util"
 )
 
-//  ____ ___
-// |    |   \______ ___________
-// |    |   /  ___// __ \_  __ \
-// |    |  /\___ \\  ___/|  | \/
-// |______//____  >\___  >__|
-//              \/     \/
-
 // ErrUserAlreadyExist represents a "user already exists" error.
 type ErrUserAlreadyExist struct {
 	Name string
@@ -99,3 +92,34 @@ func (err ErrUserInactive) Error() string {
 func (err ErrUserInactive) Unwrap() error {
 	return util.ErrPermissionDenied
 }
+
+// ErrUserIsNotLocal represents a "ErrUserIsNotLocal" kind of error.
+type ErrUserIsNotLocal struct {
+	UID  int64
+	Name string
+}
+
+func (err ErrUserIsNotLocal) Error() string {
+	return fmt.Sprintf("user is not local type [uid: %d, name: %s]", err.UID, err.Name)
+}
+
+// IsErrUserIsNotLocal
+func IsErrUserIsNotLocal(err error) bool {
+	_, ok := err.(ErrUserIsNotLocal)
+	return ok
+}
+
+type ErrUsernameNotChanged struct {
+	UID  int64
+	Name string
+}
+
+func (err ErrUsernameNotChanged) Error() string {
+	return fmt.Sprintf("username hasn't been changed[uid: %d, name: %s]", err.UID, err.Name)
+}
+
+// IsErrUsernameNotChanged
+func IsErrUsernameNotChanged(err error) bool {
+	_, ok := err.(ErrUsernameNotChanged)
+	return ok
+}
diff --git a/models/user/user.go b/models/user/user.go
index 46c4440e5f..7428e51065 100644
--- a/models/user/user.go
+++ b/models/user/user.go
@@ -9,7 +9,6 @@ import (
 	"encoding/hex"
 	"fmt"
 	"net/url"
-	"os"
 	"path/filepath"
 	"strings"
 	"time"
@@ -756,50 +755,6 @@ func VerifyUserActiveCode(code string) (user *User) {
 	return nil
 }
 
-// ChangeUserName changes all corresponding setting from old user name to new one.
-func ChangeUserName(ctx context.Context, u *User, newUserName string) (err error) {
-	oldUserName := u.Name
-	if err = IsUsableUsername(newUserName); err != nil {
-		return err
-	}
-
-	ctx, committer, err := db.TxContext(ctx)
-	if err != nil {
-		return err
-	}
-	defer committer.Close()
-
-	isExist, err := IsUserExist(ctx, 0, newUserName)
-	if err != nil {
-		return err
-	} else if isExist {
-		return ErrUserAlreadyExist{newUserName}
-	}
-
-	if _, err = db.GetEngine(ctx).Exec("UPDATE `repository` SET owner_name=? WHERE owner_name=?", newUserName, oldUserName); err != nil {
-		return fmt.Errorf("Change repo owner name: %w", err)
-	}
-
-	// Do not fail if directory does not exist
-	if err = util.Rename(UserPath(oldUserName), UserPath(newUserName)); err != nil && !os.IsNotExist(err) {
-		return fmt.Errorf("Rename user directory: %w", err)
-	}
-
-	if err = NewUserRedirect(ctx, u.ID, oldUserName, newUserName); err != nil {
-		return err
-	}
-
-	if err = committer.Commit(); err != nil {
-		if err2 := util.Rename(UserPath(newUserName), UserPath(oldUserName)); err2 != nil && !os.IsNotExist(err2) {
-			log.Critical("Unable to rollback directory change during failed username change from: %s to: %s. DB Error: %v. Filesystem Error: %v", oldUserName, newUserName, err, err2)
-			return fmt.Errorf("failed to rollback directory change during failed username change from: %s to: %s. DB Error: %w. Filesystem Error: %v", oldUserName, newUserName, err, err2)
-		}
-		return err
-	}
-
-	return nil
-}
-
 // checkDupEmail checks whether there are the same email with the user
 func checkDupEmail(ctx context.Context, u *User) error {
 	u.Email = strings.ToLower(u.Email)