Add team member invite by email (#20307)

Allows to add (not registered) team members by email.

related #5353

Invite by mail:

![grafik](https://user-images.githubusercontent.com/1666336/178154779-adcc547f-c0b7-4a2a-a131-4e41a3d9d3ad.png)

Pending invitations:

![grafik](https://user-images.githubusercontent.com/1666336/178154882-9d739bb8-2b04-46c1-a025-c1f4be26af98.png)

Email:

![grafik](https://user-images.githubusercontent.com/1666336/178164716-f2f90893-7ba6-4a5e-a3db-42538a660258.png)

Join form:

![grafik](https://user-images.githubusercontent.com/1666336/178154840-aaab983a-d922-4414-b01a-9b1a19c5cef7.png)

Co-authored-by: Jack Hay <jjphay@gmail.com>

4 files changed, 214 insertions, 1 deletions

diff --git a/models/organization/org.go b/models/organization/org.go
index fbbf6d04fa..58b58e6732 100644
--- a/models/organization/org.go
+++ b/models/organization/org.go
@@ -370,8 +370,9 @@ func DeleteOrganization(ctx context.Context, org *Organization) error {
 		&OrgUser{OrgID: org.ID},
 		&TeamUser{OrgID: org.ID},
 		&TeamUnit{OrgID: org.ID},
+		&TeamInvite{OrgID: org.ID},
 	); err != nil {
-		return fmt.Errorf("deleteBeans: %v", err)
+		return fmt.Errorf("DeleteBeans: %v", err)
 	}
 
 	if _, err := db.GetEngine(ctx).ID(org.ID).Delete(new(user_model.User)); err != nil {
diff --git a/models/organization/team.go b/models/organization/team.go
index 83e5bd6fe1..aa9b24b57f 100644
--- a/models/organization/team.go
+++ b/models/organization/team.go
@@ -94,6 +94,7 @@ func init() {
 	db.RegisterModel(new(TeamUser))
 	db.RegisterModel(new(TeamRepo))
 	db.RegisterModel(new(TeamUnit))
+	db.RegisterModel(new(TeamInvite))
 }
 
 // SearchTeamOptions holds the search options
diff --git a/models/organization/team_invite.go b/models/organization/team_invite.go
new file mode 100644
index 0000000000..4504a2e9fe
--- /dev/null
+++ b/models/organization/team_invite.go
@@ -0,0 +1,162 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package organization
+
+import (
+	"context"
+	"fmt"
+
+	"code.gitea.io/gitea/models/db"
+	user_model "code.gitea.io/gitea/models/user"
+	"code.gitea.io/gitea/modules/timeutil"
+	"code.gitea.io/gitea/modules/util"
+
+	"xorm.io/builder"
+)
+
+type ErrTeamInviteAlreadyExist struct {
+	TeamID int64
+	Email  string
+}
+
+func IsErrTeamInviteAlreadyExist(err error) bool {
+	_, ok := err.(ErrTeamInviteAlreadyExist)
+	return ok
+}
+
+func (err ErrTeamInviteAlreadyExist) Error() string {
+	return fmt.Sprintf("team invite already exists [team_id: %d, email: %s]", err.TeamID, err.Email)
+}
+
+func (err ErrTeamInviteAlreadyExist) Unwrap() error {
+	return util.ErrAlreadyExist
+}
+
+type ErrTeamInviteNotFound struct {
+	Token string
+}
+
+func IsErrTeamInviteNotFound(err error) bool {
+	_, ok := err.(ErrTeamInviteNotFound)
+	return ok
+}
+
+func (err ErrTeamInviteNotFound) Error() string {
+	return fmt.Sprintf("team invite was not found [token: %s]", err.Token)
+}
+
+func (err ErrTeamInviteNotFound) Unwrap() error {
+	return util.ErrNotExist
+}
+
+// ErrUserEmailAlreadyAdded represents a "user by email already added to team" error.
+type ErrUserEmailAlreadyAdded struct {
+	Email string
+}
+
+// IsErrUserEmailAlreadyAdded checks if an error is a ErrUserEmailAlreadyAdded.
+func IsErrUserEmailAlreadyAdded(err error) bool {
+	_, ok := err.(ErrUserEmailAlreadyAdded)
+	return ok
+}
+
+func (err ErrUserEmailAlreadyAdded) Error() string {
+	return fmt.Sprintf("user with email already added [email: %s]", err.Email)
+}
+
+func (err ErrUserEmailAlreadyAdded) Unwrap() error {
+	return util.ErrAlreadyExist
+}
+
+// TeamInvite represents an invite to a team
+type TeamInvite struct {
+	ID          int64              `xorm:"pk autoincr"`
+	Token       string             `xorm:"UNIQUE(token) INDEX NOT NULL DEFAULT ''"`
+	InviterID   int64              `xorm:"NOT NULL DEFAULT 0"`
+	OrgID       int64              `xorm:"INDEX NOT NULL DEFAULT 0"`
+	TeamID      int64              `xorm:"UNIQUE(team_mail) INDEX NOT NULL DEFAULT 0"`
+	Email       string             `xorm:"UNIQUE(team_mail) NOT NULL DEFAULT ''"`
+	CreatedUnix timeutil.TimeStamp `xorm:"INDEX created"`
+	UpdatedUnix timeutil.TimeStamp `xorm:"INDEX updated"`
+}
+
+func CreateTeamInvite(ctx context.Context, doer *user_model.User, team *Team, email string) (*TeamInvite, error) {
+	has, err := db.GetEngine(ctx).Exist(&TeamInvite{
+		TeamID: team.ID,
+		Email:  email,
+	})
+	if err != nil {
+		return nil, err
+	}
+	if has {
+		return nil, ErrTeamInviteAlreadyExist{
+			TeamID: team.ID,
+			Email:  email,
+		}
+	}
+
+	// check if the user is already a team member by email
+	exist, err := db.GetEngine(ctx).
+		Where(builder.Eq{
+			"team_user.org_id":  team.OrgID,
+			"team_user.team_id": team.ID,
+			"`user`.email":      email,
+		}).
+		Join("INNER", "`user`", "`user`.id = team_user.uid").
+		Table("team_user").
+		Exist()
+	if err != nil {
+		return nil, err
+	}
+
+	if exist {
+		return nil, ErrUserEmailAlreadyAdded{
+			Email: email,
+		}
+	}
+
+	token, err := util.CryptoRandomString(25)
+	if err != nil {
+		return nil, err
+	}
+
+	invite := &TeamInvite{
+		Token:     token,
+		InviterID: doer.ID,
+		OrgID:     team.OrgID,
+		TeamID:    team.ID,
+		Email:     email,
+	}
+
+	return invite, db.Insert(ctx, invite)
+}
+
+func RemoveInviteByID(ctx context.Context, inviteID, teamID int64) error {
+	_, err := db.DeleteByBean(ctx, &TeamInvite{
+		ID:     inviteID,
+		TeamID: teamID,
+	})
+	return err
+}
+
+func GetInvitesByTeamID(ctx context.Context, teamID int64) ([]*TeamInvite, error) {
+	invites := make([]*TeamInvite, 0, 10)
+	return invites, db.GetEngine(ctx).
+		Where("team_id=?", teamID).
+		Find(&invites)
+}
+
+func GetInviteByToken(ctx context.Context, token string) (*TeamInvite, error) {
+	invite := &TeamInvite{}
+
+	has, err := db.GetEngine(ctx).Where("token=?", token).Get(invite)
+	if err != nil {
+		return nil, err
+	}
+	if !has {
+		return nil, ErrTeamInviteNotFound{Token: token}
+	}
+	return invite, nil
+}
diff --git a/models/organization/team_invite_test.go b/models/organization/team_invite_test.go
new file mode 100644
index 0000000000..e0596ec28d
--- /dev/null
+++ b/models/organization/team_invite_test.go
@@ -0,0 +1,49 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package organization_test
+
+import (
+	"testing"
+
+	"code.gitea.io/gitea/models/db"
+	"code.gitea.io/gitea/models/organization"
+	"code.gitea.io/gitea/models/unittest"
+	user_model "code.gitea.io/gitea/models/user"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestTeamInvite(t *testing.T) {
+	assert.NoError(t, unittest.PrepareTestDatabase())
+
+	team := unittest.AssertExistsAndLoadBean(t, &organization.Team{ID: 2})
+
+	t.Run("MailExistsInTeam", func(t *testing.T) {
+		user2 := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 2})
+
+		// user 2 already added to team 2, should result in error
+		_, err := organization.CreateTeamInvite(db.DefaultContext, user2, team, user2.Email)
+		assert.Error(t, err)
+	})
+
+	t.Run("CreateAndRemove", func(t *testing.T) {
+		user1 := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 1})
+
+		invite, err := organization.CreateTeamInvite(db.DefaultContext, user1, team, "user3@example.com")
+		assert.NotNil(t, invite)
+		assert.NoError(t, err)
+
+		// Shouldn't allow duplicate invite
+		_, err = organization.CreateTeamInvite(db.DefaultContext, user1, team, "user3@example.com")
+		assert.Error(t, err)
+
+		// should remove invite
+		assert.NoError(t, organization.RemoveInviteByID(db.DefaultContext, invite.ID, invite.TeamID))
+
+		// invite should not exist
+		_, err = organization.GetInviteByToken(db.DefaultContext, invite.Token)
+		assert.Error(t, err)
+	})
+}