[PLT-6707] /header [text] slash command: Edit the channel header (#6566)

* add /header slash command

* update websocket

* updater per review

8 files changed, 141 insertions, 8 deletions

diff --git a/app/command_channel_header.go b/app/command_channel_header.go
new file mode 100644
index 000000000..b5a70ef89
--- /dev/null
+++ b/app/command_channel_header.go
@@ -0,0 +1,73 @@
+// Copyright (c) 2017-present Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+package app
+
+import (
+	l4g "github.com/alecthomas/log4go"
+	"github.com/mattermost/platform/model"
+
+	goi18n "github.com/nicksnyder/go-i18n/i18n"
+)
+
+type HeaderProvider struct {
+}
+
+const (
+	CMD_HEADER = "header"
+)
+
+func init() {
+	RegisterCommandProvider(&HeaderProvider{})
+}
+
+func (me *HeaderProvider) GetTrigger() string {
+	return CMD_HEADER
+}
+
+func (me *HeaderProvider) GetCommand(T goi18n.TranslateFunc) *model.Command {
+	return &model.Command{
+		Trigger:          CMD_HEADER,
+		AutoComplete:     true,
+		AutoCompleteDesc: T("api.command_channel_header.desc"),
+		AutoCompleteHint: T("api.command_channel_header.hint"),
+		DisplayName:      T("api.command_channel_header.name"),
+	}
+}
+
+func (me *HeaderProvider) DoCommand(args *model.CommandArgs, message string) *model.CommandResponse {
+	channel, err := GetChannel(args.ChannelId)
+	if err != nil {
+		return &model.CommandResponse{Text: args.T("api.command_channel_header.channel.app_error"), ResponseType: model.COMMAND_RESPONSE_TYPE_EPHEMERAL}
+	}
+
+	if channel.Type == model.CHANNEL_OPEN && !SessionHasPermissionToChannel(args.Session, args.ChannelId, model.PERMISSION_MANAGE_PUBLIC_CHANNEL_PROPERTIES) {
+		return &model.CommandResponse{Text: args.T("api.command_channel_header.permission.app_error"), ResponseType: model.COMMAND_RESPONSE_TYPE_EPHEMERAL}
+	}
+
+	if channel.Type == model.CHANNEL_PRIVATE && !SessionHasPermissionToChannel(args.Session, args.ChannelId, model.PERMISSION_MANAGE_PRIVATE_CHANNEL_PROPERTIES) {
+		return &model.CommandResponse{Text: args.T("api.command_channel_header.permission.app_error"), ResponseType: model.COMMAND_RESPONSE_TYPE_EPHEMERAL}
+	}
+
+	if len(message) == 0 {
+		return &model.CommandResponse{Text: args.T("api.command_channel_header.message.app_error"), ResponseType: model.COMMAND_RESPONSE_TYPE_EPHEMERAL}
+	}
+
+	oldChannelHeader := channel.Header
+	channel.Header = message
+
+	updateChannel, err := UpdateChannel(channel)
+	if err != nil {
+		return &model.CommandResponse{Text: args.T("api.command_channel_header.update_channel.app_error"), ResponseType: model.COMMAND_RESPONSE_TYPE_EPHEMERAL}
+	}
+
+	messageWs := model.NewWebSocketEvent(model.WEBSOCKET_EVENT_CHANNEL_UPDATED, "", channel.Id, "", nil)
+	messageWs.Add("channel", channel.ToJson())
+	Publish(messageWs)
+
+	if err := PostUpdateChannelHeaderMessage(args.Session.UserId, channel.Id, args.TeamId, oldChannelHeader, updateChannel.Header); err != nil {
+		l4g.Error(err.Error())
+	}
+
+	return &model.CommandResponse{}
+}
diff --git a/i18n/en.json b/i18n/en.json
index 38273bfe4..a2d1637a3 100644
--- a/i18n/en.json
+++ b/i18n/en.json
@@ -536,6 +536,38 @@
     "translation": "echo"
   },
   {
+    "id": "api.command_channel_header.desc",
+    "translation": "Edit the channel header"
+  },
+  {
+    "id": "api.command_channel_header.hint",
+    "translation": "[text]"
+  },
+  {
+    "id": "api.command_channel_header.name",
+    "translation": "header"
+  },
+  {
+    "id": "api.command_channel_header.message.app_error",
+    "translation": "Text must be provided with the /header command."
+  },
+  {
+    "id": "api.command_channel_header.channel.app_error",
+    "translation": "Error to retrieve the current channel."
+  },
+  {
+    "id": "api.command_channel_header.permission.app_error",
+    "translation": "You do not have the appropriate permissions to edit the channel header."
+  },
+  {
+    "id": "api.command_channel_header.update_channel.app_error",
+    "translation": "Error to update the current channel."
+  },
+  {
+    "id": "api.command_channel_header.update_channel.success",
+    "translation": "Channel header successfully updated."
+  },
+  {
     "id": "api.command_expand.desc",
     "translation": "Turn off auto-collapsing of image previews"
   },
diff --git a/webapp/actions/global_actions.jsx b/webapp/actions/global_actions.jsx
index ea08d6671..a154d556d 100644
--- a/webapp/actions/global_actions.jsx
+++ b/webapp/actions/global_actions.jsx
@@ -212,6 +212,14 @@ export function showDeletePostModal(post, commentCount = 0) {
     });
 }
 
+export function showChannelHeaderUpdateModal(channel) {
+    AppDispatcher.handleViewAction({
+        type: ActionTypes.TOGGLE_CHANNEL_HEADER_UPDATE_MODAL,
+        value: true,
+        channel
+    });
+}
+
 export function showGetPostLinkModal(post) {
     AppDispatcher.handleViewAction({
         type: ActionTypes.TOGGLE_GET_POST_LINK_MODAL,
diff --git a/webapp/actions/websocket_actions.jsx b/webapp/actions/websocket_actions.jsx
index 52bd61006..2af9a5d96 100644
--- a/webapp/actions/websocket_actions.jsx
+++ b/webapp/actions/websocket_actions.jsx
@@ -229,6 +229,11 @@ function handleEvent(msg) {
     }
 }
 
+function handleChannelUpdatedEvent(msg) {
+    const channel = JSON.parse(msg.data.channel);
+    dispatch({type: ChannelTypes.RECEIVED_CHANNEL, data: channel});
+}
+
 function handleNewPostEvent(msg) {
     const post = JSON.parse(msg.data.post);
     handleNewPost(post, msg);
@@ -341,11 +346,6 @@ function handleUserRemovedEvent(msg) {
     }
 }
 
-function handleChannelUpdatedEvent(msg) {
-    const channel = JSON.parse(msg.data.channel);
-    dispatch({type: ChannelTypes.RECEIVED_CHANNEL, data: channel});
-}
-
 function handleUserUpdatedEvent(msg) {
     const user = msg.data.user;
     if (UserStore.getCurrentId() !== user.id) {
diff --git a/webapp/components/create_post.jsx b/webapp/components/create_post.jsx
index d0f2a0afd..8ec671e45 100644
--- a/webapp/components/create_post.jsx
+++ b/webapp/components/create_post.jsx
@@ -76,14 +76,15 @@ export default class CreatePost extends React.Component {
 
         PostStore.clearDraftUploads();
 
-        const channelId = ChannelStore.getCurrentId();
-        const draft = PostStore.getDraft(channelId);
-
+        const channel = ChannelStore.getCurrent();
+        const channelId = channel.id;
+        const draft = PostStore.getPostDraft(channelId);
         const stats = ChannelStore.getCurrentStats();
         const members = stats.member_count - 1;
 
         this.state = {
             channelId,
+            channel,
             message: draft.message,
             uploadsInProgress: draft.uploadsInProgress,
             fileInfos: draft.fileInfos,
@@ -213,12 +214,20 @@ export default class CreatePost extends React.Component {
     handleSubmit(e) {
         const stats = ChannelStore.getCurrentStats();
         const members = stats.member_count - 1;
+        const updateChannel = ChannelStore.getCurrent();
 
         if ((this.state.message.includes('@all') || this.state.message.includes('@channel')) && members >= Constants.NOTIFY_ALL_MEMBERS) {
             this.setState({totalMembers: members});
             this.showNotifyAllModal();
             return;
         }
+
+        if (this.state.message.endsWith('/header ')) {
+            GlobalActions.showChannelHeaderUpdateModal(updateChannel);
+            this.setState({message: ''});
+            return;
+        }
+
         this.doSubmit(e);
     }
 
diff --git a/webapp/components/navbar.jsx b/webapp/components/navbar.jsx
index 0f8de01a3..b27e22709 100644
--- a/webapp/components/navbar.jsx
+++ b/webapp/components/navbar.jsx
@@ -55,6 +55,7 @@ export default class Navbar extends React.Component {
         this.showSearch = this.showSearch.bind(this);
 
         this.showEditChannelHeaderModal = this.showEditChannelHeaderModal.bind(this);
+        this.hideEditChannelHeaderModal = this.hideEditChannelHeaderModal.bind(this);
         this.showRenameChannelModal = this.showRenameChannelModal.bind(this);
         this.hideRenameChannelModal = this.hideRenameChannelModal.bind(this);
         this.isStateValid = this.isStateValid.bind(this);
@@ -110,6 +111,7 @@ export default class Navbar extends React.Component {
         UserStore.addChangeListener(this.onChange);
         PreferenceStore.addChangeListener(this.onChange);
         ModalStore.addModalListener(ActionTypes.TOGGLE_QUICK_SWITCH_MODAL, this.toggleQuickSwitchModal);
+        ModalStore.addModalListener(ActionTypes.TOGGLE_CHANNEL_HEADER_UPDATE_MODAL, this.showEditChannelHeaderModal);
         $('.inner-wrap').click(this.hideSidebars);
         document.addEventListener('keydown', this.handleQuickSwitchKeyPress);
     }
@@ -121,6 +123,7 @@ export default class Navbar extends React.Component {
         UserStore.removeChangeListener(this.onChange);
         PreferenceStore.removeChangeListener(this.onChange);
         ModalStore.removeModalListener(ActionTypes.TOGGLE_QUICK_SWITCH_MODAL, this.toggleQuickSwitchModal);
+        ModalStore.addModalListener(ActionTypes.TOGGLE_CHANNEL_HEADER_UPDATE_MODAL, this.hideEditChannelHeaderModal);
         document.removeEventListener('keydown', this.handleQuickSwitchKeyPress);
     }
 
@@ -193,6 +196,12 @@ export default class Navbar extends React.Component {
         });
     }
 
+    hideEditChannelHeaderModal() {
+        this.setState({
+            showEditChannelHeaderModal: false
+        });
+    }
+
     showRenameChannelModal(e) {
         e.preventDefault();
 
diff --git a/webapp/stores/modal_store.jsx b/webapp/stores/modal_store.jsx
index 07842ca59..434efcf90 100644
--- a/webapp/stores/modal_store.jsx
+++ b/webapp/stores/modal_store.jsx
@@ -41,6 +41,7 @@ class ModalStoreClass extends EventEmitter {
         case ActionTypes.TOGGLE_GET_PUBLIC_LINK_MODAL:
         case ActionTypes.TOGGLE_DM_MODAL:
         case ActionTypes.TOGGLE_QUICK_SWITCH_MODAL:
+        case ActionTypes.TOGGLE_CHANNEL_HEADER_UPDATE_MODAL:
             this.emit(type, value, args);
             break;
         }
diff --git a/webapp/utils/constants.jsx b/webapp/utils/constants.jsx
index f5e67bcaf..477495423 100644
--- a/webapp/utils/constants.jsx
+++ b/webapp/utils/constants.jsx
@@ -176,6 +176,7 @@ export const ActionTypes = keyMirror({
     TOGGLE_GET_PUBLIC_LINK_MODAL: null,
     TOGGLE_DM_MODAL: null,
     TOGGLE_QUICK_SWITCH_MODAL: null,
+    TOGGLE_CHANNEL_HEADER_UPDATE_MODAL: null,
 
     SUGGESTION_PRETEXT_CHANGED: null,
     SUGGESTION_RECEIVED_SUGGESTIONS: null,