[NEW] Reply preview

[ubarsaiyan]

@RocketChat/core

Closes #9912
This adds a Whatsapp like preview feature to replies, ie. the user can see the mssg he/she is replying to. I tried to do this in the minimal amount of code, hence I reused the messageAttachment Template which is used for displaying replies or attachments to a message. When replying to a reply, the preview only shows the outermost mssg (only one level of reply) as it would take a lot of space to display all the levels. The preview can also show formatted mssgs. Deleting the whole message removes the reply preview. Sending the mssg also removes the reply preview. Many many optimisations and new features can be incorporated further such as:

• adding a 'x' button to hide the preview Done
• removing the url of the message being replied to from the input box Done
• beautifying the reply preview Done

[MartinSchoeler]

Please remove the package-lock json files from this pull request, files such as this should be ignored when committing changes.

[ubarsaiyan]

@MartinSchoeler I'm sorry to have included the unnecessary files. I have removed them now and also combined the commits into one.

[rodrigok]

That is really amazing @ubarsaiyan thank you.

I have a suggestion, what if you remove the Markdown that includes the mention (that link to the message) from the input field and add before send the message? That way we hide that ugly part.

Other good addition would be a X button to close/remove the mention, if you implement my suggestion above that would be the only way users could do that.

[ubarsaiyan]

@rodrigok Yes, I will implement that too :) and improve the ui too.

[ubarsaiyan]

@rodrigok @MartinSchoeler I have made the necessary changes: Implemented the ui of @ mention popup, adding a cancel reply button, removing the URL of the mssg being replied to from the input box. I have taken care that the code is bug-free and does the work minimal amount of code. The message in the input box is retained upon closing the reply and replying after writing the mssg.