Improve behavior of "Fork" button (#17288)

* Improbe behaviour of fork button

* Apply suggestions from code review

* Remove old lines

* Apply suggestions

* Fix test

* Remove unnecessary or

* Update templates/repo/header.tmpl

Co-authored-by: silverwind <me@silverwind.io>

* Add comment

* Fix situation if you can't fork but don't have forks

* Fix lint

* Apply changes from #17783

* fmt

* fmt

* Apply tweaks

Co-authored by: silverwind <me@silverwind.io>

* Rm dupl css

* Fix build

Co-authored-by: 6543 <6543@obermui.de>
Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

5 files changed, 97 insertions, 5 deletions

diff --git a/models/repo.go b/models/repo.go
index 397b4380d6..897ceeede9 100644
--- a/models/repo.go
+++ b/models/repo.go
@@ -294,6 +294,36 @@ func CanUserForkRepo(user *user_model.User, repo *repo_model.Repository) (bool,
 	return false, nil
 }
 
+// GetForksByUserAndOrgs return forked repos of the user and owned orgs
+func GetForksByUserAndOrgs(user *user_model.User, repo *repo_model.Repository) ([]*repo_model.Repository, error) {
+	var repoList []*repo_model.Repository
+	if user == nil {
+		return repoList, nil
+	}
+	var forkedRepo *repo_model.Repository
+	forkedRepo, err := repo_model.GetUserFork(repo.ID, user.ID)
+	if err != nil {
+		return repoList, err
+	}
+	if forkedRepo != nil {
+		repoList = append(repoList, forkedRepo)
+	}
+	canCreateRepos, err := GetOrgsCanCreateRepoByUserID(user.ID)
+	if err != nil {
+		return repoList, err
+	}
+	for _, org := range canCreateRepos {
+		forkedRepo, err := repo_model.GetUserFork(repo.ID, org.ID)
+		if err != nil {
+			return repoList, err
+		}
+		if forkedRepo != nil {
+			repoList = append(repoList, forkedRepo)
+		}
+	}
+	return repoList, nil
+}
+
 // CanUserDelete returns true if user could delete the repository
 func CanUserDelete(repo *repo_model.Repository, user *user_model.User) (bool, error) {
 	if user.IsAdmin || user.ID == repo.OwnerID {
diff --git a/modules/context/repo.go b/modules/context/repo.go
index b54401f348..010d3b7f81 100644
--- a/modules/context/repo.go
+++ b/modules/context/repo.go
@@ -499,10 +499,24 @@ func RepoAssignment(ctx *Context) (cancel context.CancelFunc) {
 	ctx.Data["CanWriteIssues"] = ctx.Repo.CanWrite(unit_model.TypeIssues)
 	ctx.Data["CanWritePulls"] = ctx.Repo.CanWrite(unit_model.TypePullRequests)
 
-	if ctx.Data["CanSignedUserFork"], err = models.CanUserForkRepo(ctx.User, ctx.Repo.Repository); err != nil {
-		ctx.ServerError("CanSignedUserFork", err)
+	canSignedUserFork, err := models.CanUserForkRepo(ctx.User, ctx.Repo.Repository)
+	if err != nil {
+		ctx.ServerError("CanUserForkRepo", err)
+		return
+	}
+	ctx.Data["CanSignedUserFork"] = canSignedUserFork
+
+	userAndOrgForks, err := models.GetForksByUserAndOrgs(ctx.User, ctx.Repo.Repository)
+	if err != nil {
+		ctx.ServerError("GetForksByUserAndOrgs", err)
 		return
 	}
+	ctx.Data["UserAndOrgForks"] = userAndOrgForks
+
+	// canSignedUserFork is true if the current user doesn't have a fork of this repo yet or
+	// if he owns an org that doesn't have a fork of this repo yet
+	// If multiple forks are available or if the user can fork to another account, but there is already a fork: open selection dialog
+	ctx.Data["ShowForkModal"] = len(userAndOrgForks) > 1 || (canSignedUserFork && len(userAndOrgForks) > 0)
 
 	ctx.Data["DisableSSH"] = setting.SSH.Disabled
 	ctx.Data["ExposeAnonSSH"] = setting.SSH.ExposeAnonymous
diff --git a/options/locale/locale_en-US.ini b/options/locale/locale_en-US.ini
index b1f8b7994b..c70002278c 100644
--- a/options/locale/locale_en-US.ini
+++ b/options/locale/locale_en-US.ini
@@ -785,6 +785,8 @@ visibility_fork_helper = (Changing this will affect all forks.)
 clone_helper = Need help cloning? Visit <a target="_blank" rel="noopener noreferrer" href="%s">Help</a>.
 fork_repo = Fork Repository
 fork_from = Fork From
+already_forked = You've already forked %s
+fork_to_different_account = Fork to a different account
 fork_visibility_helper = The visibility of a forked repository cannot be changed.
 use_template = Use this template
 clone_in_vsc = Clone in VS Code
diff --git a/templates/repo/header.tmpl b/templates/repo/header.tmpl
index 4fb5e1941b..014623dc9a 100644
--- a/templates/repo/header.tmpl
+++ b/templates/repo/header.tmpl
@@ -85,10 +85,55 @@
 						</form>
 					{{end}}
 					{{if and (not .IsEmpty) ($.Permission.CanRead $.UnitTypeCode)}}
-						<div class="ui labeled button{{if not $.CanSignedUserFork}} tooltip disabled{{end}}"{{if and (not $.CanSignedUserFork) $.IsSigned}} data-content="{{$.i18n.Tr "repo.fork_from_self"}}" {{else if not $.IsSigned}} data-content="{{$.i18n.Tr "repo.fork_guest_user"}}"{{end}} data-position="top center" tabindex="0">
-							<a class="ui compact small basic button"{{if $.CanSignedUserFork}} href="{{AppSubUrl}}/repo/fork/{{.ID}}"{{end}}>
+						<div class="ui labeled button
+							{{if or (not $.IsSigned) (and (not $.CanSignedUserFork) (eq (len $.UserAndOrgForks) 0))}}
+								tooltip disabled
+							{{end}}"
+							{{if not $.IsSigned}}
+								data-content="{{$.i18n.Tr "repo.fork_guest_user"}}"
+							{{else if and (not $.CanSignedUserFork) (eq (len $.UserAndOrgForks) 0)}}
+								data-content="{{$.i18n.Tr "repo.fork_from_self"}}"
+							{{end}}
+						data-position="top center" data-variation="tiny" tabindex="0">
+							<a class="ui compact{{if $.ShowForkModal}} show-modal{{end}} small basic button"
+								{{if not $.CanSignedUserFork}}
+									{{if gt (len $.UserAndOrgForks) 1}}
+										data-modal="#fork-repo-modal"
+									{{else if eq (len $.UserAndOrgForks) 1}}
+										href="{{AppSubUrl}}/{{(index $.UserAndOrgForks 0).FullName}}"
+									{{/*else is not required here, because the button shouldn't link to any site if you can't create a fork*/}}
+									{{end}}
+								{{else if eq (len $.UserAndOrgForks) 0}}
+									href="{{AppSubUrl}}/repo/fork/{{.ID}}"
+								{{else}}
+									data-modal="#fork-repo-modal"
+								{{end}}
+							>
 								{{svg "octicon-repo-forked"}}{{$.i18n.Tr "repo.fork"}}
 							</a>
+							<div class="ui small modal" id="fork-repo-modal">
+								{{svg "octicon-x" 16 "close inside"}}
+								<div class="header">
+									{{$.i18n.Tr "repo.already_forked" .Name}}
+								</div>
+								<div class="content tl">
+									<div class="ui list">
+										{{range $.UserAndOrgForks}}
+											<div class="ui item py-3">
+												<a href="{{.Link}}">
+													{{svg "octicon-repo-forked" 16 "mr-3"}}{{.FullName}}
+												</a>
+											</div>
+										{{end}}
+									</div>
+									{{if $.CanSignedUserFork}}
+									<div class="ui divider"></div>
+									<a href="{{AppSubUrl}}/repo/fork/{{.ID}}">
+										{{$.i18n.Tr "repo.fork_to_different_account"}}
+									</a>
+									{{end}}
+								</div>
+							</div>
 							<a class="ui basic label" href="{{.Link}}/forks">
 								{{CountFmt .NumForks}}
 							</a>
diff --git a/web_src/less/_repository.less b/web_src/less/_repository.less
index dab9b6ad00..94ab67ef47 100644
--- a/web_src/less/_repository.less
+++ b/web_src/less/_repository.less
@@ -2746,7 +2746,8 @@
 #delete-repo-modal,
 #delete-wiki-modal,
 #convert-fork-repo-modal,
-#convert-mirror-repo-modal {
+#convert-mirror-repo-modal,
+#fork-repo-modal {
   .ui.message {
     width: 100% !important;
   }