Revamp the discord interaction format

[m-haisham]

Discussed in #1318

^{Originally posted by mensch272 March 30, 2022}

Proposal

I'm essentially proposing forgoing the current start and the other choices that follow by introducing a small domain-specific language.

Grammar

The following describes the grammar in a readable manner.

Download => [download] <url> [from <from:int>] [to <to:int>] [into <...target:str>]
Select   => [select] <option:int>
Close    => close [session]
Search   => search [with] <key:any>
Status   => [show] status

Where [optional] <input>

Example

Usecase 1: Download with just URL

The user sends the following message in the private channel:

https://www.webnovel.com/book/my-vampire-system_16709365405930105

This falls under the download rule, hence the bot will fill in the other options with defaults (ex: from=0 to=end, target=['epub']) and create a new download session.

Usecase 2: Download with other information

The user sends the message:

https://www.webnovel.com/book/my-vampire-system_16709365405930105 from 25 to 100 into epub, text, html

The bot will then start a download session using the provided information.