chess-tools/epd/entry.js

A collection of tools / libraries for programming chess applications.

"use strict";
const Chess = require('chess.js').Chess

/*
See https://chessprogramming.wikispaces.com/Extended+Position+Description
*/
function getIntValue(value) {
    return parseInt(value.trim());
}
function getMoves(value) {
    let moves = [];
    let vs = value.split(" ");
    for (let v of vs) {
        if (v) {
            if (v === 'O-O-O' || v === 'O-O' || v.match(/[abcdefghrbknqpx1-8]+[\+\?!]*/i)) {
              if (v.match(/[^RBKNQPabcdefghrbknqpx1-8\+\?!]/)) {
                //this is not a move skip it.
              } else {
                moves.push(v);
              }
            } else {
                console.log("Unknown value for move", v);
            }
        }
    }
    return moves;
}

function getText(value) {
    let output = value.trim();
    output = output.replace(/"/g, "");
    return output;
}
function getTrue() {
    return true;
}

const OPCODES = {
    'acn' : getIntValue,
    'acs' : getIntValue,
    'am' : getMoves,//avoid moves
    'bm' : getMoves, //best moves,
    'ce' : getIntValue,
    'dm' : getIntValue,
    'draw_accept' : getTrue,
    'draw_offer' : getTrue,
    'draw_reject' : getTrue,
    'eco' : getText,
    'fmvn' : getIntValue,
    'hmvc' : getIntValue,
    'nic' : getText,
    'noop' : getText,
    'pm' : getMoves,
    'pv' : getText,
    'rc' : getIntValue,
    'resign' : getTrue,
    'sm' : getMoves,
    'tcgs' : getIntValue,
    'tcri' : getText,
    'v0' : getText,
    'v1' : getText,
    'v2' : getText,
    'v3' : getText,
    'v4' : getText,
    'v5' : getText,
    'v6' : getText,
    'v7' : getText,
    'v8' : getText,
    'v9' : getText,

}

class EPDEntry {
    static fromLine(line) {
        let position = new EPDEntry();
        let elements = line.split(";");
        let fen_elements = elements[0].split(" ");
        let fen = fen_elements.slice(0,4).join(" ");
        position.fen = fen + " 0 1";
        elements[0] = fen_elements.slice(4).join(" ");
        for (let element of elements) {
            let em = element.trim().match(/(\w+)\s+(.+)/);
            let command = em[1];
            let value = em[2];
            if (command === 'id') {
                position.id = getText(value);
            } else if (command.match(/c\d/)) {
                let num = parseInt(command.substring(1,command.length));
                position.comments[num] = getText(value); 
            } else if (OPCODES[command]) {
                position.operations[command] = OPCODES[command](value);
            } else {
                console.log("Invalid command", command);
                console.log("Value is", value);
            }

        }
        return position;
    }
    constructor() {
        this.fen = "";
        this.id = "";
        this.operations = {};
        this.comments = [];
    }
    toChess() {
        let chess = new Chess();
        if (!chess.load(this.fen)) {
            console.log("unable to load fen", this.fen);
            process.exit();
        }   
        console.log(chess.fen())
        return chess;
    }
    get best_move() {
        return this.operations.bm;
    }
}
module.exports=EPDEntry;