Implement basic frontend-engine interaction

Use a Flask-based Python server as an adapter to the engine's
stdin-stdout inferface.

adapter/adapter.py

@@ -0,0 +1,46 @@
+import os
+import subprocess
+
+import flask
+from flask_cors import CORS
+
+
+PIECE_TYPE = [("P", "pawn")]
+COLOR = [
+    ("W", "white"),
+    ("B", "black"),
+]
+
+HERE = os.path.abspath(os.path.dirname(__file__))
+app = flask.Flask(__name__)
+CORS(app)
+engine = subprocess.Popen(
+    [os.path.join(HERE, "../rs/target/debug/schach")],
+    stdin=subprocess.PIPE,
+    stdout=subprocess.PIPE,
+)
+
+
+def make_piece(piece_str):
+    piece_type, color, file, rank = piece_str
+    return {
+        "who": dict(PIECE_TYPE)[piece_type],
+        "color": dict(COLOR)[color],
+        "position": f"{file}{rank}",
+    }
+
+
+@app.route("/get_state/")
+def get_state():
+    engine.stdin.write(b"get_state\n")
+    engine.stdin.flush()
+    position_str = engine.stdout.readline().decode("ascii").strip()
+    position = [
+        make_piece(position_str[i : i + 4])
+        for i in range(0, len(position_str), 4)
+    ]
+    return flask.jsonify(position)
+
+
+if __name__ == "__main__":
+    app.run(debug=True, host="127.0.0.1", port=3000)

frontend/main.js

@@ -1,42 +1,24 @@
 import * as visuals from "./visuals.js";
 
-function setupBoard() {
-  let pawns = [];
-  for (let x of "abcdefgh") {
-    pawns.push(
-      new Piece("pawn", "black", `${x}7`),
-      new Piece("pawn", "white", `${x}2`)
-    );
-  }
-  return new Configuration([
-    new Piece("rook", "black", "a8"),
-    new Piece("rook", "black", "h8"),
-    new Piece("knight", "black", "b8"),
-    new Piece("knight", "black", "g8"),
-    new Piece("bishop", "black", "c8"),
-    new Piece("bishop", "black", "f8"),
-    new Piece("queen", "black", "d8"),
-    new Piece("king", "black", "e8"),
-
-    ...pawns,
-
-    new Piece("rook", "white", "a1"),
-    new Piece("rook", "white", "h1"),
-    new Piece("knight", "white", "b1"),
-    new Piece("knight", "white", "g1"),
-    new Piece("bishop", "white", "c1"),
-    new Piece("bishop", "white", "f1"),
-    new Piece("queen", "white", "d1"),
-    new Piece("king", "white", "e1"),
-  ]);
+function get_json(url) {
+  var request = new XMLHttpRequest();
+  request.open("get", url, false);
+  request.send(null);
+  return JSON.parse(request.responseText);
 }
 
 class Backend {
   constructor() {
-    this.config = setupBoard();
+    this.config = this.getConfig();
   }
   getConfig() {
-    return this.config.clone();
+    return new Configuration(
+      get_json("http://localhost:3000/get_state/").map((p) => {
+        let piece = new Piece();
+        Object.assign(piece, p);
+        return piece;
+      })
+    );
   }
   makeMove(move) {
     this.config = this.config.makeMove(move);

rs/src/board.rs

@@ -224,15 +224,17 @@ impl Board {
         };
     }
     pub fn new() -> Board {
-        let mut board = Board {
+        Board {
             state: Default::default(),
-        };
+        }
+    }
+    pub fn reset(&mut self) {
+        self.state.clear();
         for piece_type in &[PieceType::Pawn] {
             for (piece, position) in piece_type.initial_setup() {
-                board.set_at(position, Some(piece));
+                self.set_at(position, Some(piece));
             }
         }
-        board
     }
     pub fn iter(&self) -> impl Iterator<Item = (&Position, &Piece)> {
         self.state.iter()

rs/src/main.rs

@@ -1,7 +1,19 @@
+use std::io::BufRead;
 mod board;
 mod ui;
 
-fn main() {
-    let board = board::Board::new();
-    println!("{}", board.to_string());
+fn main() -> Result<(), ()> {
+    let mut board = board::Board::new();
+    board.reset();
+    let stdin = std::io::stdin();
+    let mut input_lines = stdin.lock().lines();
+    loop {
+        match input_lines.next() {
+            None => break Ok(()),
+            Some(line) => match &line.unwrap()[..] {
+                "get_state" => println!("{}", board.to_string()),
+                _ => break Err(()),
+            },
+        }
+    }
 }