PLT-4457 Added AtMention component to better render at mentions (#6563)

* Moved Utils.searchForTerm into an action

* Added easier importing of index.jsx files

* PLT-4457 Added AtMention component to better render at mentions

* Fixed client unit tests

* Fixed merge conflict

* Fixed merge conflicts

4 files changed, 162 insertions, 23 deletions

diff --git a/webapp/components/at_mention/at_mention.jsx b/webapp/components/at_mention/at_mention.jsx
new file mode 100644
index 000000000..760884b88
--- /dev/null
+++ b/webapp/components/at_mention/at_mention.jsx
@@ -0,0 +1,79 @@
+// Copyright (c) 2017-present Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+import React from 'react';
+import PropTypes from 'prop-types';
+
+export default class AtMention extends React.PureComponent {
+    static propTypes = {
+        mentionName: PropTypes.string.isRequired,
+        usersByUsername: PropTypes.object.isRequired,
+        actions: PropTypes.shape({
+            searchForTerm: PropTypes.func.isRequired
+        }).isRequired
+    };
+
+    constructor(props) {
+        super(props);
+
+        this.state = {
+            username: this.getUsernameFromMentionName(props)
+        };
+    }
+
+    componentWillReceiveProps(nextProps) {
+        if (nextProps.mentionName !== this.props.mentionName || nextProps.usersByUsername !== this.props.usersByUsername) {
+            this.setState({
+                username: this.getUsernameFromMentionName(nextProps)
+            });
+        }
+    }
+
+    getUsernameFromMentionName(props) {
+        let mentionName = props.mentionName;
+
+        while (mentionName.length > 0) {
+            if (props.usersByUsername[mentionName]) {
+                return props.usersByUsername[mentionName].username;
+            }
+
+            // Repeatedly trim off trailing punctuation in case this is at the end of a sentence
+            if ((/[._-]$/).test(mentionName)) {
+                mentionName = mentionName.substring(0, mentionName.length - 1);
+            } else {
+                break;
+            }
+        }
+
+        return '';
+    }
+
+    search = (e) => {
+        e.preventDefault();
+
+        this.props.actions.searchForTerm(this.state.username);
+    }
+
+    render() {
+        const username = this.state.username;
+
+        if (!username) {
+            return <span>{'@' + this.props.mentionName}</span>;
+        }
+
+        const suffix = this.props.mentionName.substring(username.length);
+
+        return (
+            <span>
+                <a
+                    className='mention-link'
+                    href='#'
+                    onClick={this.search}
+                >
+                    {'@' + username}
+                </a>
+                {suffix}
+            </span>
+        );
+    }
+}
diff --git a/webapp/components/at_mention/index.jsx b/webapp/components/at_mention/index.jsx
new file mode 100644
index 000000000..c733158c6
--- /dev/null
+++ b/webapp/components/at_mention/index.jsx
@@ -0,0 +1,27 @@
+// Copyright (c) 2017-present Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+import {connect} from 'react-redux';
+
+import {getUsersByUsername} from 'mattermost-redux/selectors/entities/users';
+
+import {searchForTerm} from 'actions/post_actions.jsx';
+
+import AtMention from './at_mention.jsx';
+
+function mapStateToProps(state, ownProps) {
+    return {
+        ...ownProps,
+        usersByUsername: getUsersByUsername(state)
+    };
+}
+
+function mapDispatchToProps() {
+    return {
+        actions: {
+            searchForTerm
+        }
+    };
+}
+
+export default connect(mapStateToProps, mapDispatchToProps)(AtMention);
diff --git a/webapp/components/post_view/post_body/post_body.jsx b/webapp/components/post_view/post_body/post_body.jsx
index a14141dcd..044b46c55 100644
--- a/webapp/components/post_view/post_body/post_body.jsx
+++ b/webapp/components/post_view/post_body/post_body.jsx
@@ -1,20 +1,23 @@
 // Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
 // See License.txt for license information.
 
-import * as Utils from 'utils/utils.jsx';
-import * as PostUtils from 'utils/post_utils.jsx';
-import {Posts} from 'mattermost-redux/constants';
+import PropTypes from 'prop-types';
+import React from 'react';
+import {FormattedMessage} from 'react-intl';
+
+import * as PostActions from 'actions/post_actions.jsx';
 
-import CommentedOnFilesMessage from 'components/post_view/commented_on_files_message';
 import FileAttachmentListContainer from 'components/file_attachment_list';
+import CommentedOnFilesMessage from 'components/post_view/commented_on_files_message';
 import PostBodyAdditionalContent from 'components/post_view/post_body_additional_content.jsx';
-import PostMessageContainer from 'components/post_view/post_message_view';
-import ReactionListContainer from 'components/post_view/reaction_list';
 import FailedPostOptions from 'components/post_view/failed_post_options';
+import PostMessageView from 'components/post_view/post_message_view';
+import ReactionListContainer from 'components/post_view/reaction_list';
 
-import React from 'react';
-import PropTypes from 'prop-types';
-import {FormattedMessage} from 'react-intl';
+import * as Utils from 'utils/utils.jsx';
+import * as PostUtils from 'utils/post_utils.jsx';
+
+import {Posts} from 'mattermost-redux/constants';
 
 export default class PostBody extends React.PureComponent {
     static propTypes = {
@@ -89,7 +92,7 @@ export default class PostBody extends React.PureComponent {
                 name = (
                     <a
                         className='theme'
-                        onClick={Utils.searchForTerm.bind(null, username)}
+                        onClick={PostActions.searchForTerm.bind(null, username)}
                     >
                         {username}
                     </a>
@@ -156,7 +159,7 @@ export default class PostBody extends React.PureComponent {
                 className={postClass}
             >
                 {failedOptions}
-                <PostMessageContainer
+                <PostMessageView
                     lastPostCount={this.props.lastPostCount}
                     post={this.props.post}
                 />
diff --git a/webapp/components/post_view/post_message_view/post_message_view.jsx b/webapp/components/post_view/post_message_view/post_message_view.jsx
index 66a8d01f8..d066183ff 100644
--- a/webapp/components/post_view/post_message_view/post_message_view.jsx
+++ b/webapp/components/post_view/post_message_view/post_message_view.jsx
@@ -1,17 +1,21 @@
 // Copyright (c) 2016-present Mattermost, Inc. All Rights Reserved.
 // See License.txt for license information.
 
-import React from 'react';
+import {Parser, ProcessNodeDefinitions} from 'html-to-react';
 import PropTypes from 'prop-types';
+import React from 'react';
 import {FormattedMessage} from 'react-intl';
 
+import AtMention from 'components/at_mention';
+
+import store from 'stores/redux_store.jsx';
+
 import * as PostUtils from 'utils/post_utils.jsx';
 import * as TextFormatting from 'utils/text_formatting.jsx';
 import * as Utils from 'utils/utils.jsx';
 
 import {getChannelsNameMapInCurrentTeam} from 'mattermost-redux/selectors/entities/channels';
 import {Posts} from 'mattermost-redux/constants';
-import store from 'stores/redux_store.jsx';
 
 import {renderSystemMessage} from './system_message_helpers.jsx';
 
@@ -44,11 +48,6 @@ export default class PostMessageView extends React.PureComponent {
         mentionKeys: PropTypes.arrayOf(PropTypes.string),
 
         /*
-         * Object mapping usernames to users
-         */
-        usernameMap: PropTypes.object,
-
-        /*
          * The URL that the app is hosted on
          */
         siteUrl: PropTypes.string,
@@ -66,8 +65,7 @@ export default class PostMessageView extends React.PureComponent {
 
     static defaultProps = {
         options: {},
-        mentionKeys: [],
-        usernameMap: {}
+        mentionKeys: []
     };
 
     renderDeletedPost() {
@@ -96,6 +94,34 @@ export default class PostMessageView extends React.PureComponent {
         );
     }
 
+    postMessageHtmlToComponent(html) {
+        const parser = new Parser();
+        const attrib = 'data-mention';
+        const processNodeDefinitions = new ProcessNodeDefinitions(React);
+
+        function isValidNode() {
+            return true;
+        }
+
+        const processingInstructions = [
+            {
+                replaceChildren: true,
+                shouldProcessNode: (node) => node.attribs && node.attribs[attrib],
+                processNode: (node) => {
+                    const mentionName = node.attribs[attrib];
+
+                    return <AtMention mentionName={mentionName}/>;
+                }
+            },
+            {
+                shouldProcessNode: () => true,
+                processNode: processNodeDefinitions.processDefaultNode
+            }
+        ];
+
+        return parser.parseWithInstructions(html, isValidNode, processingInstructions);
+    }
+
     render() {
         if (this.props.post.state === Posts.POST_DELETED) {
             return this.renderDeletedPost();
@@ -109,7 +135,7 @@ export default class PostMessageView extends React.PureComponent {
             emojis: this.props.emojis,
             siteURL: this.props.siteUrl,
             mentionKeys: this.props.mentionKeys,
-            usernameMap: this.props.usernameMap,
+            atMentions: true,
             channelNamesMap: getChannelsNameMapInCurrentTeam(store.getState()),
             team: this.props.team
         });
@@ -124,14 +150,18 @@ export default class PostMessageView extends React.PureComponent {
             postId = Utils.createSafeId('lastPostMessageText' + this.props.lastPostCount);
         }
 
+        const htmlFormattedText = TextFormatting.formatText(this.props.post.message, options);
+        const postMessageComponent = this.postMessageHtmlToComponent(htmlFormattedText);
+
         return (
             <div>
                 <span
                     id={postId}
                     className='post-message__text'
                     onClick={Utils.handleFormattedTextClick}
-                    dangerouslySetInnerHTML={{__html: TextFormatting.formatText(this.props.post.message, options)}}
-                />
+                >
+                    {postMessageComponent}
+                </span>
                 {this.renderEditedIndicator()}
             </div>
         );