PLT-1378 Initial version of emoji reactions (#4520)

* Refactored emoji.json to support multiple aliases and emoji categories

* Added custom category to emoji.jsx and stabilized all fields

* Removed conflicting aliases for :mattermost: and :ca:

* fixup after store changes

* Added emoji reactions

* Removed reactions for an emoji when that emoji is deleted

* Fixed incorrect test case

* Renamed ReactionList to ReactionListView

* Fixed :+1: and :-1: not showing up as possible reactions

* Removed text emoticons from emoji reaction autocomplete

* Changed emoji reactions to be sorted by the order that they were first created

* Set a maximum number of listeners for the ReactionStore

* Removed unused code from Textbox component

* Fixed reaction permissions

* Changed error code when trying to modify reactions for another user

* Fixed merge conflicts

* Properly applied theme colours to reactions

* Fixed ESLint and gofmt errors

* Fixed ReactionListContainer to properly update when its post prop changes

* Removed unnecessary escape characters from reaction regexes

* Shared reaction message pattern between CreatePost and CreateComment

* Removed an unnecessary select query when saving a reaction

* Changed reactions route to be under /reactions

* Fixed copyright dates on newly added files

* Removed debug code that prevented all unit tests from being ran

* Cleaned up unnecessary code for reactions

* Renamed ReactionStore.List to ReactionStore.GetForPost

5 files changed, 182 insertions, 0 deletions

diff --git a/model/client.go b/model/client.go
index 631de9c56..f782940d8 100644
--- a/model/client.go
+++ b/model/client.go
@@ -2102,6 +2102,7 @@ func (c *Client) DeleteEmoji(id string) (bool, *AppError) {
 	if r, err := c.DoApiPost(c.GetEmojiRoute()+"/delete", MapToJson(data)); err != nil {
 		return false, err
 	} else {
+		defer closeBody(r)
 		c.fillInExtraProperties(r)
 		return c.CheckStatusOK(r), nil
 	}
@@ -2132,6 +2133,7 @@ func (c *Client) UploadCertificateFile(data []byte, contentType string) *AppErro
 		return AppErrorFromJson(rp.Body)
 	} else {
 		defer closeBody(rp)
+		c.fillInExtraProperties(rp)
 		return nil
 	}
 }
@@ -2143,6 +2145,7 @@ func (c *Client) RemoveCertificateFile(filename string) *AppError {
 		return err
 	} else {
 		defer closeBody(r)
+		c.fillInExtraProperties(r)
 		return nil
 	}
 }
@@ -2154,6 +2157,7 @@ func (c *Client) SamlCertificateStatus(filename string) (map[string]interface{},
 		return nil, err
 	} else {
 		defer closeBody(r)
+		c.fillInExtraProperties(r)
 		return StringInterfaceFromJson(r.Body), nil
 	}
 }
@@ -2182,3 +2186,36 @@ func (c *Client) GetFileInfosForPost(channelId string, postId string, etag strin
 		return FileInfosFromJson(r.Body), nil
 	}
 }
+
+// Saves an emoji reaction for a post in the given channel. Returns the saved reaction if successful, otherwise returns an AppError.
+func (c *Client) SaveReaction(channelId string, reaction *Reaction) (*Reaction, *AppError) {
+	if r, err := c.DoApiPost(c.GetChannelRoute(channelId)+fmt.Sprintf("/posts/%v/reactions/save", reaction.PostId), reaction.ToJson()); err != nil {
+		return nil, err
+	} else {
+		defer closeBody(r)
+		c.fillInExtraProperties(r)
+		return ReactionFromJson(r.Body), nil
+	}
+}
+
+// Removes an emoji reaction for a post in the given channel. Returns nil if successful, otherwise returns an AppError.
+func (c *Client) DeleteReaction(channelId string, reaction *Reaction) *AppError {
+	if r, err := c.DoApiPost(c.GetChannelRoute(channelId)+fmt.Sprintf("/posts/%v/reactions/delete", reaction.PostId), reaction.ToJson()); err != nil {
+		return err
+	} else {
+		defer closeBody(r)
+		c.fillInExtraProperties(r)
+		return nil
+	}
+}
+
+// Lists all emoji reactions made for the given post in the given channel. Returns a list of Reactions if successful, otherwise returns an AppError.
+func (c *Client) ListReactions(channelId string, postId string) ([]*Reaction, *AppError) {
+	if r, err := c.DoApiGet(c.GetChannelRoute(channelId)+fmt.Sprintf("/posts/%v/reactions", postId), "", ""); err != nil {
+		return nil, err
+	} else {
+		defer closeBody(r)
+		c.fillInExtraProperties(r)
+		return ReactionsFromJson(r.Body), nil
+	}
+}
diff --git a/model/post.go b/model/post.go
index da14b650f..b5dcc4539 100644
--- a/model/post.go
+++ b/model/post.go
@@ -38,6 +38,7 @@ type Post struct {
 	Filenames     StringArray     `json:"filenames,omitempty"` // Deprecated, do not use this field any more
 	FileIds       StringArray     `json:"file_ids,omitempty"`
 	PendingPostId string          `json:"pending_post_id" db:"-"`
+	HasReactions  bool            `json:"has_reactions,omitempty"`
 }
 
 func (o *Post) ToJson() string {
diff --git a/model/reaction.go b/model/reaction.go
new file mode 100644
index 000000000..afbdd1e88
--- /dev/null
+++ b/model/reaction.go
@@ -0,0 +1,78 @@
+// Copyright (c) 2016 Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+package model
+
+import (
+	"encoding/json"
+	"io"
+)
+
+type Reaction struct {
+	UserId    string `json:"user_id"`
+	PostId    string `json:"post_id"`
+	EmojiName string `json:"emoji_name"`
+	CreateAt  int64  `json:"create_at"`
+}
+
+func (o *Reaction) ToJson() string {
+	if b, err := json.Marshal(o); err != nil {
+		return ""
+	} else {
+		return string(b)
+	}
+}
+
+func ReactionFromJson(data io.Reader) *Reaction {
+	var o Reaction
+
+	if err := json.NewDecoder(data).Decode(&o); err != nil {
+		return nil
+	} else {
+		return &o
+	}
+}
+
+func ReactionsToJson(o []*Reaction) string {
+	if b, err := json.Marshal(o); err != nil {
+		return ""
+	} else {
+		return string(b)
+	}
+}
+
+func ReactionsFromJson(data io.Reader) []*Reaction {
+	var o []*Reaction
+
+	if err := json.NewDecoder(data).Decode(&o); err != nil {
+		return nil
+	} else {
+		return o
+	}
+}
+
+func (o *Reaction) IsValid() *AppError {
+	if len(o.UserId) != 26 {
+		return NewLocAppError("Reaction.IsValid", "model.reaction.is_valid.user_id.app_error", nil, "user_id="+o.UserId)
+	}
+
+	if len(o.PostId) != 26 {
+		return NewLocAppError("Reaction.IsValid", "model.reaction.is_valid.post_id.app_error", nil, "post_id="+o.PostId)
+	}
+
+	if len(o.EmojiName) == 0 || len(o.EmojiName) > 64 {
+		return NewLocAppError("Reaction.IsValid", "model.reaction.is_valid.emoji_name.app_error", nil, "emoji_name="+o.EmojiName)
+	}
+
+	if o.CreateAt == 0 {
+		return NewLocAppError("Reaction.IsValid", "model.reaction.is_valid.create_at.app_error", nil, "")
+	}
+
+	return nil
+}
+
+func (o *Reaction) PreSave() {
+	if o.CreateAt == 0 {
+		o.CreateAt = GetMillis()
+	}
+}
diff --git a/model/reaction_test.go b/model/reaction_test.go
new file mode 100644
index 000000000..da73f477a
--- /dev/null
+++ b/model/reaction_test.go
@@ -0,0 +1,64 @@
+// Copyright (c) 2016 Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+package model
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestReactionIsValid(t *testing.T) {
+	reaction := Reaction{
+		UserId:    NewId(),
+		PostId:    NewId(),
+		EmojiName: "emoji",
+		CreateAt:  GetMillis(),
+	}
+
+	if err := reaction.IsValid(); err != nil {
+		t.Fatal(err)
+	}
+
+	reaction.UserId = ""
+	if err := reaction.IsValid(); err == nil {
+		t.Fatal("user id should be invalid")
+	}
+
+	reaction.UserId = "1234garbage"
+	if err := reaction.IsValid(); err == nil {
+		t.Fatal("user id should be invalid")
+	}
+
+	reaction.UserId = NewId()
+	reaction.PostId = ""
+	if err := reaction.IsValid(); err == nil {
+		t.Fatal("post id should be invalid")
+	}
+
+	reaction.PostId = "1234garbage"
+	if err := reaction.IsValid(); err == nil {
+		t.Fatal("post id should be invalid")
+	}
+
+	reaction.PostId = NewId()
+	reaction.EmojiName = ""
+	if err := reaction.IsValid(); err == nil {
+		t.Fatal("emoji name should be invalid")
+	}
+
+	reaction.EmojiName = strings.Repeat("a", 65)
+	if err := reaction.IsValid(); err == nil {
+		t.Fatal("emoji name should be invalid")
+	}
+
+	reaction.EmojiName = strings.Repeat("a", 64)
+	if err := reaction.IsValid(); err != nil {
+		t.Fatal(err)
+	}
+
+	reaction.CreateAt = 0
+	if err := reaction.IsValid(); err == nil {
+		t.Fatal("create at should be invalid")
+	}
+}
diff --git a/model/websocket_message.go b/model/websocket_message.go
index 3fa58aeb3..c3530c038 100644
--- a/model/websocket_message.go
+++ b/model/websocket_message.go
@@ -27,6 +27,8 @@ const (
 	WEBSOCKET_EVENT_HELLO              = "hello"
 	WEBSOCKET_EVENT_WEBRTC             = "webrtc"
 	WEBSOCKET_AUTHENTICATION_CHALLENGE = "authentication_challenge"
+	WEBSOCKET_EVENT_REACTION_ADDED     = "reaction_added"
+	WEBSOCKET_EVENT_REACTION_REMOVED   = "reaction_removed"
 )
 
 type WebSocketMessage interface {