Add main uci communcation loop, no tests

src/uci.rs

@@ -1,25 +1,62 @@
-use std::str::SplitWhitespace;
+use std::{
+    io::{self, BufRead, Write},
+    str::SplitWhitespace,
+};
 
 use crate::{game::Game, r#move::Move, search::search};
 
 pub enum Command {
     Uci,
     IsReady,
-    UciNewGame,
-    Position(String),
+    Position,
     Go,
-    Stop,
     Quit,
 }
 
+fn parse_command(parts: &mut SplitWhitespace) -> Result<Command, String> {
+    match parts.next() {
+        Some("uci") => Ok(Command::Uci),
+        Some("isready") => Ok(Command::IsReady),
+        Some("position") => Ok(Command::Position),
+        Some("go") => Ok(Command::Go),
+        Some("quit") => Ok(Command::Quit),
+        _ => Err("Unrecognised command".to_string()),
+    }
+}
+
 pub enum Response {
-    Id(String),
     UciOk,
     ReadyOk,
     BestMove(String),
     Info(String),
 }
 
+fn write_response(handle_out: &mut impl Write, response: Response) -> Result<(), String> {
+    let output = match response {
+        Response::UciOk => "uciok".to_string(),
+        Response::ReadyOk => "readyok".to_string(),
+        Response::BestMove(best_move) => format!("bestmove {}", best_move),
+        Response::Info(info) => info,
+    };
+
+    writeln!(handle_out, "{}", output).map_err(|e| e.to_string())?;
+    handle_out.flush().map_err(|e| e.to_string())?;
+    Ok(())
+}
+
+use std::fmt;
+
+impl fmt::Display for Response {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Self::UciOk => write!(f, "uciok"),
+            Self::ReadyOk => write!(f, "readyok"),
+            Self::BestMove(best_move) => write!(f, "bestmove {}", best_move),
+            Self::Info(info) => write!(f, "{}", info),
+        }
+    }
+}
+
 struct SearchParameters {
     movetime: Option<usize>,
     depth: Option<u8>,
@@ -46,7 +83,7 @@ impl Default for SearchParameters {
     fn default() -> Self {
         Self::new()
     }
- }
+}
 
 pub fn uci_position(mut position: SplitWhitespace) -> Result<Game, String> {
     let state = position.next().ok_or("Expected startpos or fen")?;
@@ -66,7 +103,7 @@ pub fn uci_position(mut position: SplitWhitespace) -> Result<Game, String> {
 
 const MAX_DEPTH: u8 = 5;
 
-pub fn uci_go(mut go: SplitWhitespace, game: &mut Game) -> Response {
+pub fn uci_go(mut go: SplitWhitespace, game: &mut Game) -> Result<Move, String> {
     let mut params = SearchParameters::new();
     while let Some(subcommand) = go.next() {
         match subcommand {
@@ -75,9 +112,65 @@ pub fn uci_go(mut go: SplitWhitespace, game: &mut Game) -> Response {
             _ => (),
         }
     }
-
     search(game, params.depth.unwrap_or(MAX_DEPTH));
-    Response::BestMove(String::from("value"))
+
+    Ok(Move::new(0, 0))
+}
+
+struct UciGame {
+    game: Option<Game>,
+}
+
+impl UciGame {
+    const fn new() -> Self {
+        Self { game: None }
+    }
+
+    fn set_game_state(&mut self, game: Game) {
+        self.game = Some(game);
+    }
+}
+
+impl Default for UciGame {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+pub fn uci_loop() -> Result<(), String> {
+    let stdin = io::stdin();
+    let stdout = io::stdout();
+    let handle_in = stdin.lock();
+    let mut handle_out = stdout.lock();
+    let mut uci_game = UciGame::new();
+
+    for line in handle_in.lines() {
+        let line_str = line.unwrap_or_else(|_| "quit".to_string());
+        let mut parts = line_str.split_whitespace();
+        let command = parse_command(&mut parts)?;
+        let response = match command {
+            Command::Uci => Response::UciOk,
+            Command::IsReady => Response::ReadyOk,
+            Command::Position => {
+                uci_game.set_game_state(uci_position(parts)?);
+                Response::Info("Initialized position.".to_string())
+            }
+            Command::Go => {
+                if let Some(ref mut game) = uci_game.game {
+                    let best_move = uci_go(parts, game)?;
+                    Response::BestMove(best_move.parse_into_str())
+                } else {
+                    Response::Info("Going!".to_string())
+                }
+            }
+            Command::Quit => break,
+        };
+
+        write_response(&mut handle_out, response)?;
+        handle_out.flush().map_err(|e| e.to_string())?;
+    }
+
+    Ok(())
 }
 
 #[cfg(test)]
@@ -90,8 +183,20 @@ mod tests {
     fn test_uci_position() -> Result<(), String> {
         let mut _game = from_fen(FEN[0])?;
 
-        // check that the board state is as expected after using uci position and compare
-        // with a separate fen that created the update instance by itself
+        Ok(())
+    }
+
+    #[test]
+    fn test_uci_go() -> Result<(), String> {
+        let mut _game = from_fen(FEN[0])?;
+
+        Ok(())
+    }
+
+    #[test]
+    fn test_uci_loop() -> Result<(), String> {
+        let mut _game = from_fen(FEN[0])?;
+
         Ok(())
     }
 }