# LiChess

Summarizing my attempts to understand LiChess.

### Arch

<https://pbs.twimg.com/media/CYGyi12UwAArCU9?format=png&name=medium>

* The main diagram is not very clear, or helpful.
* Where's Redis? Or does the diagram predate it?

### API

<https://lichess.org/api>

* They stream board events with ndjson <https://lichess.org/api#operation/apiStreamEvent>. It's long polling I suppose?
* Can't find API to actually make moves. I suppose it's done via websockets?
* Can't find API to actually do puzzles. Only see API to get daily puzzle. Perhaps it's also done with web sockets.
* There's an API to send a message, but I see no API to view messages.

### Code

{% embed url="<https://lichess.org/source>" %}

### Lila

<https://github.com/ornicar/lila>

* Doesn't seem to have many tests.
* Board literals in tests whoa <https://github.com/ornicar/scalachess/blob/master/src/test/scala/BishopTest.scala#L32-L40>

### WS

* WS deploy command whoa <https://github.com/ornicar/lila-ws/blob/master/deploy.sh> Just like that.
* **Very** magic numbers are all over the place <https://github.com/ornicar/lila-ws/blob/3bf35711609034235dcf77e2fccfc5b1c4a53a5b/src/main/scala/LilaWsServer.scala#L65-L74>
* Few comments, very hard to follow which class is doing what.
* No tests apparently.
* WFH is anaMove?
* Actually receive move from Lila <https://github.com/ornicar/lila-ws/blob/c18ac9df67893e22c2196f5745c53eae83b8251b/src/main/scala/LilaHandler.scala#L128-L132>
* Send the move to watching clients <https://github.com/ornicar/lila-ws/blob/c18ac9df67893e22c2196f5745c53eae83b8251b/src/main/scala/Fens.scala#L56-L77>

## UI

* Arguments: t, d, o. <https://github.com/ornicar/lila/blob/6bdf93d27ac08cb9321e439fcf3b10f235c373ac/ui/site/src/component/socket.ts#L147> How is anyone supposed to understand what it means?

Tracking how a move is sent to the server:

* <https://github.com/ornicar/lila/blob/97a46cfa5d7334904d0ee0698e7822ee9314d052/ui/round/src/ctrl.ts#L303>
* <https://github.com/ornicar/lila/blob/97a46cfa5d7334904d0ee0698e7822ee9314d052/ui/round/src/ctrl.ts#L277>

### Puzzler

{% embed url="<https://github.com/ornicar/lichess-puzzler>" %}

Overall, seems very basic stuff. It feels like it's possible to do a lot better.

* Main script (?) <https://github.com/ornicar/lichess-puzzler/blob/master/bin/import-more.sh>
* Generator <https://github.com/ornicar/lichess-puzzler/tree/master/generator>
* Extracting puzzle from a game <https://github.com/ornicar/lichess-puzzler/blob/master/generator/generator.py>

### Cheat detection

<https://github.com/clarkerubber/irwin>

<https://github.com/ornicar/lila/tree/master/modules/irwin/src/main>