4 files changed, 115 insertions, 10 deletions
diff --git a/services/issue/issue.go b/services/issue/issue.go
index a28916a7f9..a5f725ab70 100644
--- a/services/issue/issue.go
+++ b/services/issue/issue.go
@@ -9,12 +9,13 @@ import (
 
 	"code.gitea.io/gitea/models"
 	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/notification"
 	api "code.gitea.io/gitea/modules/structs"
 )
 
 // NewIssue creates new issue with labels for repository.
-func NewIssue(repo *models.Repository, issue *models.Issue, labelIDs []int64, assigneeIDs []int64, uuids []string) error {
-	if err := models.NewIssue(repo, issue, labelIDs, assigneeIDs, uuids); err != nil {
+func NewIssue(repo *models.Repository, issue *models.Issue, labelIDs []int64, uuids []string) error {
+	if err := models.NewIssue(repo, issue, labelIDs, uuids); err != nil {
 		return err
 	}
 
@@ -96,3 +97,104 @@ func ChangeTitle(issue *models.Issue, doer *models.User, title string) (err erro
 
 	return nil
 }
+
+// UpdateAssignees is a helper function to add or delete one or multiple issue assignee(s)
+// Deleting is done the GitHub way (quote from their api documentation):
+// https://developer.github.com/v3/issues/#edit-an-issue
+// "assignees" (array): Logins for Users to assign to this issue.
+// Pass one or more user logins to replace the set of assignees on this Issue.
+// Send an empty array ([]) to clear all assignees from the Issue.
+func UpdateAssignees(issue *models.Issue, oneAssignee string, multipleAssignees []string, doer *models.User) (err error) {
+	var allNewAssignees []*models.User
+
+	// Keep the old assignee thingy for compatibility reasons
+	if oneAssignee != "" {
+		// Prevent double adding assignees
+		var isDouble bool
+		for _, assignee := range multipleAssignees {
+			if assignee == oneAssignee {
+				isDouble = true
+				break
+			}
+		}
+
+		if !isDouble {
+			multipleAssignees = append(multipleAssignees, oneAssignee)
+		}
+	}
+
+	// Loop through all assignees to add them
+	for _, assigneeName := range multipleAssignees {
+		assignee, err := models.GetUserByName(assigneeName)
+		if err != nil {
+			return err
+		}
+
+		allNewAssignees = append(allNewAssignees, assignee)
+	}
+
+	// Delete all old assignees not passed
+	if err = models.DeleteNotPassedAssignee(issue, doer, allNewAssignees); err != nil {
+		return err
+	}
+
+	// Add all new assignees
+	// Update the assignee. The function will check if the user exists, is already
+	// assigned (which he shouldn't as we deleted all assignees before) and
+	// has access to the repo.
+	for _, assignee := range allNewAssignees {
+		// Extra method to prevent double adding (which would result in removing)
+		err = AddAssigneeIfNotAssigned(issue, doer, assignee.ID)
+		if err != nil {
+			return err
+		}
+	}
+
+	return
+}
+
+// AddAssigneeIfNotAssigned adds an assignee only if he isn't already assigned to the issue.
+// Also checks for access of assigned user
+func AddAssigneeIfNotAssigned(issue *models.Issue, doer *models.User, assigneeID int64) (err error) {
+	assignee, err := models.GetUserByID(assigneeID)
+	if err != nil {
+		return err
+	}
+
+	// Check if the user is already assigned
+	isAssigned, err := models.IsUserAssignedToIssue(issue, assignee)
+	if err != nil {
+		return err
+	}
+	if isAssigned {
+		// nothing to to
+		return nil
+	}
+
+	valid, err := models.CanBeAssigned(assignee, issue.Repo, issue.IsPull)
+	if err != nil {
+		return err
+	}
+	if !valid {
+		return models.ErrUserDoesNotHaveAccessToRepo{UserID: assigneeID, RepoName: issue.Repo.Name}
+	}
+
+	removed, comment, err := issue.ToggleAssignee(doer, assigneeID)
+	if err != nil {
+		return err
+	}
+
+	notification.NotifyIssueChangeAssignee(doer, issue, assignee, removed, comment)
+
+	return nil
+}
+
+// AddAssignees adds a list of assignes (from IDs) to an issue
+func AddAssignees(issue *models.Issue, doer *models.User, assigneeIDs []int64) (err error) {
+	for _, assigneeID := range assigneeIDs {
+		if err = AddAssigneeIfNotAssigned(issue, doer, assigneeID); err != nil {
+			return err
+		}
+	}
+	return nil
+}
diff --git a/services/mailer/mail.go b/services/mailer/mail.go
index 3f0a789dc4..bc2aff7314 100644
--- a/services/mailer/mail.go
+++ b/services/mailer/mail.go
@@ -28,8 +28,9 @@ const (
 	mailAuthResetPassword  base.TplName = "auth/reset_passwd"
 	mailAuthRegisterNotify base.TplName = "auth/register_notify"
 
-	mailIssueComment base.TplName = "issue/comment"
-	mailIssueMention base.TplName = "issue/mention"
+	mailIssueComment  base.TplName = "issue/comment"
+	mailIssueMention  base.TplName = "issue/mention"
+	mailIssueAssigned base.TplName = "issue/assigned"
 
 	mailNotifyCollaborator base.TplName = "notify/collaborator"
 )
@@ -183,6 +184,7 @@ func composeIssueCommentMessage(issue *models.Issue, doer *models.User, content
 		data = composeTplData(subject, body, issue.HTMLURL())
 	}
 	data["Doer"] = doer
+	data["Issue"] = issue
 
 	var mailBody bytes.Buffer
 
@@ -220,3 +222,8 @@ func SendIssueMentionMail(issue *models.Issue, doer *models.User, content string
 	}
 	SendAsync(composeIssueCommentMessage(issue, doer, content, comment, mailIssueMention, tos, "issue mention"))
 }
+
+// SendIssueAssignedMail composes and sends issue assigned email
+func SendIssueAssignedMail(issue *models.Issue, doer *models.User, content string, comment *models.Comment, tos []string) {
+	SendAsync(composeIssueCommentMessage(issue, doer, content, comment, mailIssueAssigned, tos, "issue assigned"))
+}
diff --git a/services/mailer/mail_issue.go b/services/mailer/mail_issue.go
index b16323909c..a5f3251807 100644
--- a/services/mailer/mail_issue.go
+++ b/services/mailer/mail_issue.go
@@ -10,7 +10,6 @@ import (
 	"code.gitea.io/gitea/models"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/references"
-	"code.gitea.io/gitea/modules/setting"
 
 	"github.com/unknwon/com"
 )
@@ -24,9 +23,6 @@ func mailSubject(issue *models.Issue) string {
 // 1. Repository watchers and users who are participated in comments.
 // 2. Users who are not in 1. but get mentioned in current issue/comment.
 func mailIssueCommentToParticipants(issue *models.Issue, doer *models.User, content string, comment *models.Comment, mentions []string) error {
-	if !setting.Service.EnableNotifyMail {
-		return nil
-	}
 
 	watchers, err := models.GetWatchers(issue.RepoID)
 	if err != nil {
diff --git a/services/pull/pull.go b/services/pull/pull.go
index 3c584fce74..959da67405 100644
--- a/services/pull/pull.go
+++ b/services/pull/pull.go
@@ -14,8 +14,8 @@ import (
 )
 
 // NewPullRequest creates new pull request with labels for repository.
-func NewPullRequest(repo *models.Repository, pull *models.Issue, labelIDs []int64, uuids []string, pr *models.PullRequest, patch []byte, assigneeIDs []int64) error {
-	if err := models.NewPullRequest(repo, pull, labelIDs, uuids, pr, patch, assigneeIDs); err != nil {
+func NewPullRequest(repo *models.Repository, pull *models.Issue, labelIDs []int64, uuids []string, pr *models.PullRequest, patch []byte) error {
+	if err := models.NewPullRequest(repo, pull, labelIDs, uuids, pr, patch); err != nil {
 		return err
 	}