PLT-3114 Moved preview collapse out of pre-release features (#3206)

* Added user setting to auto collapse image previews

* Added slash commands for collapsing/expanding image previews

* Added translation strings for collapse setting

* Add default props for preview collapse setting

api/command_expand_collapse.go

@@ -0,0 +1,77 @@
+// Copyright (c) 2016 Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+package api
+
+import (
+	"github.com/mattermost/platform/model"
+)
+
+type ExpandProvider struct {
+}
+
+type CollapseProvider struct {
+}
+
+const (
+	CMD_EXPAND   = "expand"
+	CMD_COLLAPSE = "collapse"
+)
+
+func init() {
+	RegisterCommandProvider(&ExpandProvider{})
+	RegisterCommandProvider(&CollapseProvider{})
+}
+
+func (me *ExpandProvider) GetTrigger() string {
+	return CMD_EXPAND
+}
+
+func (me *CollapseProvider) GetTrigger() string {
+	return CMD_COLLAPSE
+}
+
+func (me *ExpandProvider) GetCommand(c *Context) *model.Command {
+	return &model.Command{
+		Trigger:          CMD_EXPAND,
+		AutoComplete:     true,
+		AutoCompleteDesc: c.T("api.command_expand.desc"),
+		DisplayName:      c.T("api.command_expand.name"),
+	}
+}
+
+func (me *CollapseProvider) GetCommand(c *Context) *model.Command {
+	return &model.Command{
+		Trigger:          CMD_COLLAPSE,
+		AutoComplete:     true,
+		AutoCompleteDesc: c.T("api.command_collapse.desc"),
+		DisplayName:      c.T("api.command_collapse.name"),
+	}
+}
+
+func (me *ExpandProvider) DoCommand(c *Context, channelId string, message string) *model.CommandResponse {
+	return setCollapsePreference(c, "false")
+}
+
+func (me *CollapseProvider) DoCommand(c *Context, channelId string, message string) *model.CommandResponse {
+	return setCollapsePreference(c, "true")
+}
+
+func setCollapsePreference(c *Context, value string) *model.CommandResponse {
+	pref := model.Preference{
+		UserId:   c.Session.UserId,
+		Category: model.PREFERENCE_CATEGORY_DISPLAY_SETTINGS,
+		Name:     model.PREFERENCE_NAME_COLLAPSE_SETTING,
+		Value:    value,
+	}
+
+	if result := <-Srv.Store.Preference().Save(&model.Preferences{pref}); result.Err != nil {
+		return &model.CommandResponse{Text: c.T("api.command_expand_collapse.fail.app_error"), ResponseType: model.COMMAND_RESPONSE_TYPE_EPHEMERAL}
+	}
+
+	socketMessage := model.NewMessage("", "", c.Session.UserId, model.ACTION_PREFERENCE_CHANGED)
+	socketMessage.Add("preference", pref.ToJson())
+	go Publish(socketMessage)
+
+	return &model.CommandResponse{}
+}