uci/README.md

# UCI

UCI is an acronym for **U**niversal **C**hess **I**nterface. It is a standard for communication that competes with
XBoard/Winboard. [http://wbec-ridderkerk.nl/html/UCIProtocol.html](UCI) makes communication a little easier, but
it seems there's a nearly religious debate on which is better.

Here are some benefits to using UCI:

* It works with Chessbase 14
* Simple to use
* Fewer bugs in code
* Built from scratch rather than ad-hoc
* Flexible time controls
* Additional search information can be displayed

and to be fair, some downsides:

* Stateless
* Delegates some important decisions to the GUI
* Difficult to add new features on top of it
* Sends the whole move list each turn

Overall, UCI seems to be fairly popular and is worth considering for your next engine.

## Why

People shouldn't waste their time implementing protocols that really should be libraries. With this, you can
include it in your project, build your engine on top of it, and be able to focus on what matters - beating Stockfish.

## Will You Implement Winboard?

Yeah, probably.

## Why GPL 3.0?

I have noticed that there are no good _free_ solutions so that anyone can build a chess engine. Since UCI is
a common format, and something all engines (should) implement, making this chunk of it free makes _total_ sense.

## Usage

UCI is designed to complement your chess engine rather than be a one-stop shop for engine development.

As such, you will be responsible for maintaining the game loop. What UCI provides is a series of functions
that will help you send data to, and receive data from the GUI.

### First Steps

Your engine will first need to wait on STDIN for a command `uci` from the GUI. This indicates that your engine should
switch to UCI mode. You can use `commands::UCI` to make sure the command text you are waiting for is correct.


Next, you'll need to create a copy of `Engine` by calling `Engine::new`. Once this is setup, you can call
`Engine::identify` to send identification information to the GUI.

Once identification is done, you need to send your configuration options. This is dependent on your engine. Refer to
the UCI standard for the available options:

```EXAMPLE OF CONFIGURATION OF OPTIONS```

As nice as it would be to have fully typechecked options you will need to be careful a little here. The available
options your engine uses must be passed to `Engine::new` as an array of `Options::EngineOption<T>`
from `options.rs`. Every `Options::EngineOption<T>` has a `name`, which you can use any of the
`Options::*` constants to represent, a `type`, which can be an `Options::EngineOptionType`, and a hashmap
of `Options::EngineOptionDataType` to `Options::EngineOptionDataValue<T>`. Refer to the standard for more
information on option configurations. The `T` type parameters represents the type of that particular
`Options::EngineOption<T>` and allows us to at least fix the type in the HashMap to a single type. You can still
hurt yourself, but doing this makes it much harder. Keep this list of options close, the GUI may send back
information after call `Engine::send_available_options` to reconfigure default settings.

You must configure this before calling `Engine::new` so the rest of this  guide assumes you've done that already.

To send your configuration options simply call `Engine::send_available_options`. Once this finishes `uciok` will
also be sent, indicating to the GUI your engine is ready to roll. At this point you need to set up two threads, one
to calculate with your engine, and one to read STDIN.

```
EXAMPLE HERE WITH LOOPS IN THREADS AND BLOCKING AND WHATEVER
```

Notice how in our STDIN thread we are calling `Engine::parse` and the handling the output using a match statement
depending on what kind of token it was. You are responsible for obeying the commands from this thread, the UCI library
just makes it convenient to work with.

At this point the engine will send a series of `setoption` commands to you in your STDIN thread. We can use the
`Engine::parse` function to get these:

```
EXAMPLE HERE
```

Once the options are extracted you will be responsible for configuring your engine with the values. The GUI will send
an `isready` command which you will be responsible for replying to by using `Engine::ready`.

**TODO: MORE STUFF WITH EXAMPLES**
**THINGS LIKE SENDINB BEST MOVE AFTER CALCULATING, ETC**
**RECEIVING SETOPTION COMMANDS AND PROCESSING THEM**


### Other Options

**TODO: Talk about the additional helpers available in the UCI library and what-not**.

* Copy protection checking
* Registration checking

** TODO: Put an example engine under `/examples` that does nothing but talks to the GUI and receives commands.
** Document it here and mention it can be used for guidance.