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`

4 files changed, 156 insertions, 98 deletions

diff --git a/services/org/org.go b/services/org/org.go
index e45fb305de..a62e5b6fc8 100644
--- a/services/org/org.go
+++ b/services/org/org.go
@@ -4,20 +4,22 @@
 package org
 
 import (
+	"context"
 	"fmt"
 
 	"code.gitea.io/gitea/models"
 	"code.gitea.io/gitea/models/db"
-	"code.gitea.io/gitea/models/organization"
+	org_model "code.gitea.io/gitea/models/organization"
 	packages_model "code.gitea.io/gitea/models/packages"
 	repo_model "code.gitea.io/gitea/models/repo"
 	user_model "code.gitea.io/gitea/models/user"
 	"code.gitea.io/gitea/modules/storage"
 	"code.gitea.io/gitea/modules/util"
+	user_service "code.gitea.io/gitea/services/user"
 )
 
 // DeleteOrganization completely and permanently deletes everything of organization.
-func DeleteOrganization(org *organization.Organization) error {
+func DeleteOrganization(org *org_model.Organization) error {
 	ctx, commiter, err := db.TxContext(db.DefaultContext)
 	if err != nil {
 		return err
@@ -39,7 +41,7 @@ func DeleteOrganization(org *organization.Organization) error {
 		return models.ErrUserOwnPackages{UID: org.ID}
 	}
 
-	if err := organization.DeleteOrganization(ctx, org); err != nil {
+	if err := org_model.DeleteOrganization(ctx, org); err != nil {
 		return fmt.Errorf("DeleteOrganization: %w", err)
 	}
 
@@ -53,15 +55,20 @@ func DeleteOrganization(org *organization.Organization) error {
 	path := user_model.UserPath(org.Name)
 
 	if err := util.RemoveAll(path); err != nil {
-		return fmt.Errorf("Failed to RemoveAll %s: %w", path, err)
+		return fmt.Errorf("failed to RemoveAll %s: %w", path, err)
 	}
 
 	if len(org.Avatar) > 0 {
 		avatarPath := org.CustomAvatarRelativePath()
 		if err := storage.Avatars.Delete(avatarPath); err != nil {
-			return fmt.Errorf("Failed to remove %s: %w", avatarPath, err)
+			return fmt.Errorf("failed to remove %s: %w", avatarPath, err)
 		}
 	}
 
 	return nil
 }
+
+// RenameOrganization renames an organization.
+func RenameOrganization(ctx context.Context, org *org_model.Organization, newName string) error {
+	return user_service.RenameUser(ctx, org.AsUser(), newName)
+}
diff --git a/services/user/avatar.go b/services/user/avatar.go
new file mode 100644
index 0000000000..26c100abdb
--- /dev/null
+++ b/services/user/avatar.go
@@ -0,0 +1,62 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package user
+
+import (
+	"fmt"
+	"io"
+
+	"code.gitea.io/gitea/models/db"
+	user_model "code.gitea.io/gitea/models/user"
+	"code.gitea.io/gitea/modules/avatar"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/storage"
+)
+
+// UploadAvatar saves custom avatar for user.
+func UploadAvatar(u *user_model.User, data []byte) error {
+	avatarData, err := avatar.ProcessAvatarImage(data)
+	if err != nil {
+		return err
+	}
+
+	ctx, committer, err := db.TxContext(db.DefaultContext)
+	if err != nil {
+		return err
+	}
+	defer committer.Close()
+
+	u.UseCustomAvatar = true
+	u.Avatar = avatar.HashAvatar(u.ID, data)
+	if err = user_model.UpdateUserCols(ctx, u, "use_custom_avatar", "avatar"); err != nil {
+		return fmt.Errorf("updateUser: %w", err)
+	}
+
+	if err := storage.SaveFrom(storage.Avatars, u.CustomAvatarRelativePath(), func(w io.Writer) error {
+		_, err := w.Write(avatarData)
+		return err
+	}); err != nil {
+		return fmt.Errorf("Failed to create dir %s: %w", u.CustomAvatarRelativePath(), err)
+	}
+
+	return committer.Commit()
+}
+
+// DeleteAvatar deletes the user's custom avatar.
+func DeleteAvatar(u *user_model.User) error {
+	aPath := u.CustomAvatarRelativePath()
+	log.Trace("DeleteAvatar[%d]: %s", u.ID, aPath)
+	if len(u.Avatar) > 0 {
+		if err := storage.Avatars.Delete(aPath); err != nil {
+			return fmt.Errorf("Failed to remove %s: %w", aPath, err)
+		}
+	}
+
+	u.UseCustomAvatar = false
+	u.Avatar = ""
+	if _, err := db.GetEngine(db.DefaultContext).ID(u.ID).Cols("avatar, use_custom_avatar").Update(u); err != nil {
+		return fmt.Errorf("UpdateUser: %w", err)
+	}
+	return nil
+}
diff --git a/services/user/rename.go b/services/user/rename.go
deleted file mode 100644
index af195d7d76..0000000000
--- a/services/user/rename.go
+++ /dev/null
@@ -1,41 +0,0 @@
-// Copyright 2023 The Gitea Authors. All rights reserved.
-// SPDX-License-Identifier: MIT
-
-package user
-
-import (
-	"context"
-	"fmt"
-	"strings"
-
-	user_model "code.gitea.io/gitea/models/user"
-	"code.gitea.io/gitea/modules/log"
-	"code.gitea.io/gitea/services/agit"
-	container_service "code.gitea.io/gitea/services/packages/container"
-)
-
-func renameUser(ctx context.Context, u *user_model.User, newUserName string) error {
-	if u.IsOrganization() {
-		return fmt.Errorf("cannot rename organization")
-	}
-
-	if err := user_model.ChangeUserName(ctx, u, newUserName); err != nil {
-		return err
-	}
-
-	if err := agit.UserNameChanged(ctx, u, newUserName); err != nil {
-		return err
-	}
-	if err := container_service.UpdateRepositoryNames(ctx, u, newUserName); err != nil {
-		return err
-	}
-
-	u.Name = newUserName
-	u.LowerName = strings.ToLower(newUserName)
-	if err := user_model.UpdateUser(ctx, u, false); err != nil {
-		return err
-	}
-
-	log.Trace("User name changed: %s -> %s", u.Name, newUserName)
-	return nil
-}
diff --git a/services/user/user.go b/services/user/user.go
index 5148f2168d..e0815bd860 100644
--- a/services/user/user.go
+++ b/services/user/user.go
@@ -6,7 +6,8 @@ package user
 import (
 	"context"
 	"fmt"
-	"io"
+	"os"
+	"strings"
 	"time"
 
 	"code.gitea.io/gitea/models"
@@ -17,29 +18,105 @@ import (
 	repo_model "code.gitea.io/gitea/models/repo"
 	system_model "code.gitea.io/gitea/models/system"
 	user_model "code.gitea.io/gitea/models/user"
-	"code.gitea.io/gitea/modules/avatar"
 	"code.gitea.io/gitea/modules/eventsource"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
 	"code.gitea.io/gitea/modules/storage"
 	"code.gitea.io/gitea/modules/util"
+	"code.gitea.io/gitea/services/agit"
 	"code.gitea.io/gitea/services/packages"
+	container_service "code.gitea.io/gitea/services/packages/container"
 )
 
 // RenameUser renames a user
 func RenameUser(ctx context.Context, u *user_model.User, newUserName string) error {
+	// Non-local users are not allowed to change their username.
+	if !u.IsOrganization() && !u.IsLocal() {
+		return user_model.ErrUserIsNotLocal{
+			UID:  u.ID,
+			Name: u.Name,
+		}
+	}
+
+	if newUserName == u.Name {
+		return user_model.ErrUsernameNotChanged{
+			UID:  u.ID,
+			Name: u.Name,
+		}
+	}
+
+	if err := user_model.IsUsableUsername(newUserName); err != nil {
+		return err
+	}
+
+	onlyCapitalization := strings.EqualFold(newUserName, u.Name)
+	oldUserName := u.Name
+
+	if onlyCapitalization {
+		u.Name = newUserName
+		if err := user_model.UpdateUserCols(ctx, u, "name"); err != nil {
+			u.Name = oldUserName
+			return err
+		}
+		return nil
+	}
+
 	ctx, committer, err := db.TxContext(ctx)
 	if err != nil {
 		return err
 	}
 	defer committer.Close()
-	if err := renameUser(ctx, u, newUserName); err != nil {
+
+	isExist, err := user_model.IsUserExist(ctx, u.ID, newUserName)
+	if err != nil {
 		return err
 	}
-	if err := committer.Commit(); err != nil {
+	if isExist {
+		return user_model.ErrUserAlreadyExist{
+			Name: newUserName,
+		}
+	}
+
+	if err = repo_model.UpdateRepositoryOwnerName(ctx, oldUserName, newUserName); err != nil {
+		return err
+	}
+
+	if err = user_model.NewUserRedirect(ctx, u.ID, oldUserName, newUserName); err != nil {
+		return err
+	}
+
+	if err := agit.UserNameChanged(ctx, u, newUserName); err != nil {
+		return err
+	}
+	if err := container_service.UpdateRepositoryNames(ctx, u, newUserName); err != nil {
+		return err
+	}
+
+	u.Name = newUserName
+	u.LowerName = strings.ToLower(newUserName)
+	if err := user_model.UpdateUserCols(ctx, u, "name", "lower_name"); err != nil {
+		u.Name = oldUserName
+		u.LowerName = strings.ToLower(oldUserName)
 		return err
 	}
-	return err
+
+	// Do not fail if directory does not exist
+	if err = util.Rename(user_model.UserPath(oldUserName), user_model.UserPath(newUserName)); err != nil && !os.IsNotExist(err) {
+		u.Name = oldUserName
+		u.LowerName = strings.ToLower(oldUserName)
+		return fmt.Errorf("rename user directory: %w", err)
+	}
+
+	if err = committer.Commit(); err != nil {
+		u.Name = oldUserName
+		u.LowerName = strings.ToLower(oldUserName)
+		if err2 := util.Rename(user_model.UserPath(newUserName), user_model.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
 }
 
 // DeleteUser completely and permanently deletes everything of a user,
@@ -240,50 +317,3 @@ func DeleteInactiveUsers(ctx context.Context, olderThan time.Duration) error {
 
 	return user_model.DeleteInactiveEmailAddresses(ctx)
 }
-
-// UploadAvatar saves custom avatar for user.
-func UploadAvatar(u *user_model.User, data []byte) error {
-	avatarData, err := avatar.ProcessAvatarImage(data)
-	if err != nil {
-		return err
-	}
-
-	ctx, committer, err := db.TxContext(db.DefaultContext)
-	if err != nil {
-		return err
-	}
-	defer committer.Close()
-
-	u.UseCustomAvatar = true
-	u.Avatar = avatar.HashAvatar(u.ID, data)
-	if err = user_model.UpdateUserCols(ctx, u, "use_custom_avatar", "avatar"); err != nil {
-		return fmt.Errorf("updateUser: %w", err)
-	}
-
-	if err := storage.SaveFrom(storage.Avatars, u.CustomAvatarRelativePath(), func(w io.Writer) error {
-		_, err := w.Write(avatarData)
-		return err
-	}); err != nil {
-		return fmt.Errorf("Failed to create dir %s: %w", u.CustomAvatarRelativePath(), err)
-	}
-
-	return committer.Commit()
-}
-
-// DeleteAvatar deletes the user's custom avatar.
-func DeleteAvatar(u *user_model.User) error {
-	aPath := u.CustomAvatarRelativePath()
-	log.Trace("DeleteAvatar[%d]: %s", u.ID, aPath)
-	if len(u.Avatar) > 0 {
-		if err := storage.Avatars.Delete(aPath); err != nil {
-			return fmt.Errorf("Failed to remove %s: %w", aPath, err)
-		}
-	}
-
-	u.UseCustomAvatar = false
-	u.Avatar = ""
-	if _, err := db.GetEngine(db.DefaultContext).ID(u.ID).Cols("avatar, use_custom_avatar").Update(u); err != nil {
-		return fmt.Errorf("UpdateUser: %w", err)
-	}
-	return nil
-}