PLT-2555/PLT-5009/PLT-5225 Changed system messages to be rendered by the client (#5209)

* Moved rendering of (message deleted) into PostMessageView

* Added additional post types to constants on client

* Changed system messages to be rendered in the client's language

* Updated new system messages to have relevant usernames highlighted and have markdown rendered in header change messages

3 files changed, 274 insertions, 29 deletions

diff --git a/webapp/components/post_view/components/post_body.jsx b/webapp/components/post_view/components/post_body.jsx
index e690b3702..8b650423f 100644
--- a/webapp/components/post_view/components/post_body.jsx
+++ b/webapp/components/post_view/components/post_body.jsx
@@ -156,22 +156,6 @@ export default class PostBody extends React.Component {
             );
         }
 
-        let message;
-        if (this.props.post.state === Constants.POST_DELETED) {
-            message = (
-                <p>
-                    <FormattedMessage
-                        id='post_body.deleted'
-                        defaultMessage='(message deleted)'
-                    />
-                </p>
-            );
-        } else {
-            message = (
-                <PostMessageContainer post={this.props.post}/>
-            );
-        }
-
         const messageWrapper = (
             <div
                 key={`${post.id}_message`}
@@ -179,7 +163,7 @@ export default class PostBody extends React.Component {
                 className={postClass}
             >
                 {loading}
-                {message}
+                <PostMessageContainer post={this.props.post}/>
             </div>
         );
 
diff --git a/webapp/components/post_view/components/post_message_view.jsx b/webapp/components/post_view/components/post_message_view.jsx
index eff791aec..371dd64eb 100644
--- a/webapp/components/post_view/components/post_message_view.jsx
+++ b/webapp/components/post_view/components/post_message_view.jsx
@@ -4,9 +4,12 @@
 import React from 'react';
 import {FormattedMessage} from 'react-intl';
 
+import Constants from 'utils/constants.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 * as PostUtils from 'utils/post_utils.jsx';
+
+import {renderSystemMessage} from './system_message_helpers.jsx';
 
 export default class PostMessageView extends React.Component {
     static propTypes = {
@@ -29,6 +32,14 @@ export default class PostMessageView extends React.Component {
             return true;
         }
 
+        if (nextProps.post.state !== this.props.post.state) {
+            return true;
+        }
+
+        if (nextProps.post.type !== this.props.post.type) {
+            return true;
+        }
+
         // emojis are immutable
         if (nextProps.emojis !== this.props.emojis) {
             return true;
@@ -49,26 +60,43 @@ export default class PostMessageView extends React.Component {
         return false;
     }
 
-    editedIndicator() {
+    renderDeletedPost() {
         return (
-            PostUtils.isEdited(this.props.post) ?
-                <span className='edited'>
-                    <FormattedMessage
-                        id='post_message_view.edited'
-                        defaultMessage='(edited)'
-                    />
-                </span> :
-                ''
+            <p>
+                <FormattedMessage
+                    id='post_body.deleted'
+                    defaultMessage='(message deleted)'
+                />
+            </p>
+        );
+    }
+
+    renderEditedIndicator() {
+        if (!PostUtils.isEdited(this.props.post)) {
+            return null;
+        }
+
+        return (
+            <span className='edited'>
+                <FormattedMessage
+                    id='post_message_view.edited'
+                    defaultMessage='(edited)'
+                />
+            </span>
         );
     }
 
     render() {
+        if (this.props.post.state === Constants.POST_DELETED) {
+            return this.renderDeletedPost();
+        }
+
         if (!this.props.enableFormatting) {
             return (
                 <span>
                     {this.props.post.message}
                     &nbsp;
-                    {this.editedIndicator()}
+                    {this.renderEditedIndicator()}
                 </span>
             );
         }
@@ -82,13 +110,18 @@ export default class PostMessageView extends React.Component {
             team: this.props.team
         });
 
+        const renderedSystemMessage = renderSystemMessage(this.props.post, options);
+        if (renderedSystemMessage) {
+            return <div>{renderedSystemMessage}</div>;
+        }
+
         return (
             <div>
                 <span
                     onClick={Utils.handleFormattedTextClick}
                     dangerouslySetInnerHTML={{__html: TextFormatting.formatText(this.props.post.message, options)}}
                 />
-                {this.editedIndicator()}
+                {this.renderEditedIndicator()}
             </div>
         );
     }
diff --git a/webapp/components/post_view/components/system_message_helpers.jsx b/webapp/components/post_view/components/system_message_helpers.jsx
new file mode 100644
index 000000000..6f6454599
--- /dev/null
+++ b/webapp/components/post_view/components/system_message_helpers.jsx
@@ -0,0 +1,228 @@
+// Copyright (c) 2017 Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+import React from 'react';
+import {FormattedMessage} from 'react-intl';
+
+import {PostTypes} from 'utils/constants.jsx';
+import {formatText} from 'utils/text_formatting.jsx';
+
+function renderFormattedText(value, options) {
+    return <span dangerouslySetInnerHTML={{__html: formatText(value, options)}}/>;
+}
+
+function renderJoinChannelMessage(post, options) {
+    const username = renderFormattedText(post.props.username, options);
+
+    return (
+        <FormattedMessage
+            id='api.channel.join_channel.post_and_forget'
+            defaultMessage='{username} has joined the channel.'
+            values={{username}}
+        />
+    );
+}
+
+function renderLeaveChannelMessage(post, options) {
+    const username = renderFormattedText(post.props.username, options);
+
+    return (
+        <FormattedMessage
+            id='api.channel.leave.left'
+            defaultMessage='{username} has left the channel.'
+            values={{username}}
+        />
+    );
+}
+
+function renderAddToChannelMessage(post, options) {
+    const username = renderFormattedText(post.props.username, options);
+    const addedUsername = renderFormattedText(post.props.addedUsername, options);
+
+    return (
+        <FormattedMessage
+            id='api.channel.add_member.added'
+            defaultMessage='{addedUsername} added to the channel by {username}'
+            values={{
+                username,
+                addedUsername
+            }}
+        />
+    );
+}
+
+function renderRemoveFromChannelMessage(post, options) {
+    const removedUsername = renderFormattedText(post.props.removedUsername, options);
+
+    return (
+        <FormattedMessage
+            id='api.channel.remove_member.removed'
+            defaultMessage='{removedUsername} was removed from the channel'
+            values={{
+                removedUsername
+            }}
+        />
+    );
+}
+
+function renderHeaderChangeMessage(post, options) {
+    if (!post.props.username) {
+        return null;
+    }
+
+    const headerOptions = {
+        ...options,
+        singleline: true
+    };
+
+    const username = renderFormattedText(post.props.username, options);
+    const oldHeader = post.props.old_header ? renderFormattedText(post.props.old_header, headerOptions) : null;
+    const newHeader = post.props.new_header ? renderFormattedText(post.props.new_header, headerOptions) : null;
+
+    if (post.props.new_header) {
+        if (post.props.old_header) {
+            return (
+                <FormattedMessage
+                    id='api.channel.post_update_channel_header_message_and_forget.updated_from'
+                    defaultMessage='{username} updated the channel header from: {old} to: {new}'
+                    values={{
+                        username,
+                        old: oldHeader,
+                        new: newHeader
+                    }}
+                />
+            );
+        }
+
+        return (
+            <FormattedMessage
+                id='api.channel.post_update_channel_header_message_and_forget.updated_to'
+                defaultMessage='{username} updated the channel header to: {new}'
+                values={{
+                    username,
+                    new: newHeader
+                }}
+            />
+        );
+    } else if (post.props.old_header) {
+        return (
+            <FormattedMessage
+                id='api.channel.post_update_channel_header_message_and_forget.removed'
+                defaultMessage='{username} removed the channel header (was: {old})'
+                values={{
+                    username,
+                    old: oldHeader
+                }}
+            />
+        );
+    }
+
+    return null;
+}
+
+function renderDisplayNameChangeMessage(post, options) {
+    if (!(post.props.username && post.props.old_displayname && post.props.new_displayname)) {
+        return null;
+    }
+
+    const username = renderFormattedText(post.props.username, options);
+    const oldDisplayName = post.props.old_displayname;
+    const newDisplayName = post.props.new_displayname;
+
+    return (
+        <FormattedMessage
+            id='api.channel.post_update_channel_displayname_message_and_forget.updated_from'
+            defaultMessage='{username} updated the channel display name from: {old} to: {new}'
+            values={{
+                username,
+                old: oldDisplayName,
+                new: newDisplayName
+            }}
+        />
+    );
+}
+
+function renderPurposeChangeMessage(post, options) {
+    if (!post.props.username) {
+        return null;
+    }
+
+    const username = renderFormattedText(post.props.username, options);
+    const oldPurpose = post.props.old_purpose;
+    const newPurpose = post.props.new_purpose;
+
+    if (post.props.new_purpose) {
+        if (post.props.old_purpose) {
+            return (
+                <FormattedMessage
+                    id='app.channel.post_update_channel_purpose_message.updated_from'
+                    defaultMessage='{username} updated the channel purpose from: {old} to: {new}'
+                    values={{
+                        username,
+                        old: oldPurpose,
+                        new: newPurpose
+                    }}
+                />
+            );
+        }
+
+        return (
+            <FormattedMessage
+                id='app.channel.post_update_channel_purpose_message.updated_to'
+                defaultMessage='{username} updated the channel purpose to: {new}'
+                values={{
+                    username,
+                    new: newPurpose
+                }}
+            />
+        );
+    } else if (post.props.old_purpose) {
+        return (
+            <FormattedMessage
+                id='app.channel.post_update_channel_purpose_message.removed'
+                defaultMessage='{username} removed the channel purpose (was: {old})'
+                values={{
+                    username,
+                    old: oldPurpose
+                }}
+            />
+        );
+    }
+
+    return null;
+}
+
+function renderChannelDeletedMessage(post, options) {
+    if (!post.props.username) {
+        return null;
+    }
+
+    const username = renderFormattedText(post.props.username, options);
+
+    return (
+        <FormattedMessage
+            id='api.channel.delete_channel.archived'
+            defaultMessage='{username} has archived the channel.'
+            values={{username}}
+        />
+    );
+}
+
+const systemMessageRenderers = {
+    [PostTypes.JOIN_CHANNEL]: renderJoinChannelMessage,
+    [PostTypes.LEAVE_CHANNEL]: renderLeaveChannelMessage,
+    [PostTypes.ADD_TO_CHANNEL]: renderAddToChannelMessage,
+    [PostTypes.REMOVE_FROM_CHANNEL]: renderRemoveFromChannelMessage,
+    [PostTypes.HEADER_CHANGE]: renderHeaderChangeMessage,
+    [PostTypes.DISPLAYNAME_CHANGE]: renderDisplayNameChangeMessage,
+    [PostTypes.PURPOSE_CHANGE]: renderPurposeChangeMessage,
+    [PostTypes.CHANNEL_DELETED]: renderChannelDeletedMessage
+};
+
+export function renderSystemMessage(post, options) {
+    if (!systemMessageRenderers[post.type]) {
+        return null;
+    }
+
+    return systemMessageRenderers[post.type](post, options);
+}