Allow to archive labels (#26478)

## Archived labels 

This adds the structure to allow for archived labels.
Archived labels are, just like closed milestones or projects, a medium to hide information without deleting it.
It is especially useful if there are outdated labels that should no longer be used without deleting the label entirely.

## Changes

1. UI and API have been equipped with the support to mark a label as archived
2. The time when a label has been archived will be stored in the DB

## Outsourced for the future

There's no special handling for archived labels at the moment.
This will be done in the future.

## Screenshots

![image](https://github.com/go-gitea/gitea/assets/80308335/208f95cd-42e4-4ed7-9a1f-cd2050a645d4)

![image](https://github.com/go-gitea/gitea/assets/80308335/746428e0-40bb-45b3-b992-85602feb371d)

Part of https://github.com/go-gitea/gitea/issues/25237

---------

Co-authored-by: delvh <dev.lh@web.de>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

5 files changed, 52 insertions, 6 deletions

diff --git a/models/fixtures/label.yml b/models/fixtures/label.yml
index ab4d5ef944..2242b90dcd 100644
--- a/models/fixtures/label.yml
+++ b/models/fixtures/label.yml
@@ -7,6 +7,7 @@
   exclusive: false
   num_issues: 2
   num_closed_issues: 0
+  archived_unix: 0
 
 -
   id: 2
@@ -17,6 +18,7 @@
   exclusive: false
   num_issues: 1
   num_closed_issues: 1
+  archived_unix: 0
 
 -
   id: 3
@@ -27,6 +29,7 @@
   exclusive: false
   num_issues: 0
   num_closed_issues: 0
+  archived_unix: 0
 
 -
   id: 4
@@ -37,6 +40,7 @@
   exclusive: false
   num_issues: 1
   num_closed_issues: 0
+  archived_unix: 0
 
 -
   id: 5
@@ -47,6 +51,7 @@
   exclusive: false
   num_issues: 0
   num_closed_issues: 0
+  archived_unix: 0
 
 -
   id: 6
@@ -57,6 +62,7 @@
   exclusive: false
   num_issues: 0
   num_closed_issues: 0
+  archived_unix: 0
 
 -
   id: 7
@@ -67,6 +73,7 @@
   exclusive: true
   num_issues: 0
   num_closed_issues: 0
+  archived_unix: 0
 
 -
   id: 8
@@ -77,6 +84,7 @@
   exclusive: true
   num_issues: 0
   num_closed_issues: 0
+  archived_unix: 0
 
 -
   id: 9
@@ -87,3 +95,4 @@
   exclusive: true
   num_issues: 0
   num_closed_issues: 0
+  archived_unix: 0
diff --git a/models/issues/label.go b/models/issues/label.go
index 57a2e67f8c..70906efb47 100644
--- a/models/issues/label.go
+++ b/models/issues/label.go
@@ -97,6 +97,8 @@ type Label struct {
 	QueryString       string `xorm:"-"`
 	IsSelected        bool   `xorm:"-"`
 	IsExcluded        bool   `xorm:"-"`
+
+	ArchivedUnix timeutil.TimeStamp `xorm:"DEFAULT NULL"`
 }
 
 func init() {
@@ -109,6 +111,15 @@ func (l *Label) CalOpenIssues() {
 	l.NumOpenIssues = l.NumIssues - l.NumClosedIssues
 }
 
+// SetArchived set the label as archived
+func (l *Label) SetArchived(isArchived bool) {
+	if isArchived && l.ArchivedUnix.IsZero() {
+		l.ArchivedUnix = timeutil.TimeStampNow()
+	} else {
+		l.ArchivedUnix = timeutil.TimeStamp(0)
+	}
+}
+
 // CalOpenOrgIssues calculates the open issues of a label for a specific repo
 func (l *Label) CalOpenOrgIssues(ctx context.Context, repoID, labelID int64) {
 	counts, _ := CountIssuesByRepo(ctx, &IssuesOptions{
@@ -153,6 +164,11 @@ func (l *Label) BelongsToOrg() bool {
 	return l.OrgID > 0
 }
 
+// IsArchived returns true if label is an archived
+func (l *Label) IsArchived() bool {
+	return l.ArchivedUnix > 0
+}
+
 // BelongsToRepo returns true if label is a repository label
 func (l *Label) BelongsToRepo() bool {
 	return l.RepoID > 0
@@ -211,7 +227,7 @@ func UpdateLabel(l *Label) error {
 	}
 	l.Color = color
 
-	return updateLabelCols(db.DefaultContext, l, "name", "description", "color", "exclusive")
+	return updateLabelCols(db.DefaultContext, l, "name", "description", "color", "exclusive", "archived_unix")
 }
 
 // DeleteLabel delete a label
diff --git a/models/issues/label_test.go b/models/issues/label_test.go
index 1bc5a1a935..3f0e980b31 100644
--- a/models/issues/label_test.go
+++ b/models/issues/label_test.go
@@ -11,6 +11,7 @@ import (
 	repo_model "code.gitea.io/gitea/models/repo"
 	"code.gitea.io/gitea/models/unittest"
 	user_model "code.gitea.io/gitea/models/user"
+	"code.gitea.io/gitea/modules/timeutil"
 
 	"github.com/stretchr/testify/assert"
 )
@@ -259,11 +260,12 @@ func TestUpdateLabel(t *testing.T) {
 	label := unittest.AssertExistsAndLoadBean(t, &issues_model.Label{ID: 1})
 	// make sure update wont overwrite it
 	update := &issues_model.Label{
-		ID:          label.ID,
-		Color:       "#ffff00",
-		Name:        "newLabelName",
-		Description: label.Description,
-		Exclusive:   false,
+		ID:           label.ID,
+		Color:        "#ffff00",
+		Name:         "newLabelName",
+		Description:  label.Description,
+		Exclusive:    false,
+		ArchivedUnix: timeutil.TimeStamp(0),
 	}
 	label.Color = update.Color
 	label.Name = update.Name
@@ -273,6 +275,7 @@ func TestUpdateLabel(t *testing.T) {
 	assert.EqualValues(t, label.Color, newLabel.Color)
 	assert.EqualValues(t, label.Name, newLabel.Name)
 	assert.EqualValues(t, label.Description, newLabel.Description)
+	assert.EqualValues(t, newLabel.ArchivedUnix, 0)
 	unittest.CheckConsistencyFor(t, &issues_model.Label{}, &repo_model.Repository{})
 }
 
diff --git a/models/migrations/migrations.go b/models/migrations/migrations.go
index 55107439b0..7a126593d1 100644
--- a/models/migrations/migrations.go
+++ b/models/migrations/migrations.go
@@ -522,6 +522,8 @@ var migrations = []Migration{
 	NewMigration("Drop deleted branch table", v1_21.DropDeletedBranchTable),
 	// v270 -> v271
 	NewMigration("Fix PackageProperty typo", v1_21.FixPackagePropertyTypo),
+	// v271 -> v272
+	NewMigration("Allow archiving labels", v1_21.AddArchivedUnixColumInLabelTable),
 }
 
 // GetCurrentDBVersion returns the current db version
diff --git a/models/migrations/v1_21/v271.go b/models/migrations/v1_21/v271.go
new file mode 100644
index 0000000000..098f6499d5
--- /dev/null
+++ b/models/migrations/v1_21/v271.go
@@ -0,0 +1,16 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package v1_21 //nolint
+import (
+	"code.gitea.io/gitea/modules/timeutil"
+
+	"xorm.io/xorm"
+)
+
+func AddArchivedUnixColumInLabelTable(x *xorm.Engine) error {
+	type Label struct {
+		ArchivedUnix timeutil.TimeStamp `xorm:"DEFAULT NULL"`
+	}
+	return x.Sync(new(Label))
+}