//! UCI is a simple library to allow people to ignore the lower-level protocol needed to create chess engines.
//! The engine is fully generic. By specifying a valid reader and writing you can send the messages to STDIN
//! and STDOUT, per the standard - or to memory for testing.

mod commands;

use std::io::{BufRead, Write};


#[derive(Debug)]
pub struct Engine<'a, R, W> {
  pub name: &'a str,
  pub author: &'a str,
  pub reader: R,
  pub writer: W,
}

/// Notes to delete later:
///
///
///  A way to make this comfortable for users to use is this provides easy access to commands as well as a
///  loop and stuff they can use. This way they don't have to override anything - they just include this
///  in their code for their engine to make the communication portion easy.
///
///  Think of this in the manner of a game engine. They don't provide the loop and everything, but they do
///  provide convenience functions and stuff to make _building_ that loop easier.
///
///  In other words, the engine writer still needs to know how the standard works. They just don't need to
///  implement all the nasty details.
///  For example, a start up function calls the correct "boot up" code for the engine so they only have to
///  worry about calling "boot up" prior to their main engine loop.
///
///  Additionally this code should have a parser. You call it with the reader supplied and it waits for a command
///  and parses it into a tuple of some kind for the user.

impl<'a, R, W> Engine<'a, R, W>
where
  R: BufRead,
  W: Write,
{
  pub fn new(name: &'a str, author: &'a str, reader: R, writer: W) -> Engine<'a, R, W> {

    // TODO: This should also take an EngineOptions thing that indicates which options are supported
    //       so that when called it can send them easily.
    //       Engine options are all optional and appeared to be fixed by the UCI standard.

    Engine {
      name: name,
      author: author,
      reader: reader,
      writer: writer,
    }
  }

  /// Sends identification messages to the writer for the GUI to pick up
  pub fn identify(&mut self) {
    let name_id: String = format!("{} {} {}\n", commands::ID, commands::NAME, self.name);
    let author_id: String = format!("{} {} {}\n", commands::ID, commands::AUTHOR, self.author);

    // For these two writes we can panic - there's no possibility of recovery if the engine fails at this stage
    write!(&mut self.writer, "{}", name_id).expect("failed to send name identification to writer");
    write!(&mut self.writer, "{}", author_id).expect("failed to send author identification to writer");
  }

  /// Sends all available options in the options configuration and a final UCIOK meaning we are reading to go.
  pub fn send_available_options(&mut self) {
    // NOTE: Options can be represented as a hashmap with keys that are constant strings in the options.rs
    //       file and values are the associated options.
    //       This function will construct the proper string from the objects.
    //       How can you make this as easy as possible for the user...give it some thought. The value has to be
    //       some sort of object that can store various optiobns that change on the option.
    //       Since options are fixed it would be nice to type check the key values. Maybe use a trait or something
    //       that is actually a wrapped string, but typecheckable so not just any string can be put in.
    //       TODO: This needs to be tested majorly

    // Again this command must complete before we can say the engine is connected, so panicking at this stage is ok
    write!(&mut self.writer, "{}", commands::UCIOK).expect("failed to send `uciok` command");
  }
}