xchess/lib/file.js

Chess Engine

export {File, files}

import {INVALID_FILE} from './errors.js'
import {ConstNumberObject} from './ansi-style.js'
import {inspect} from './inspect.js'

const size = 8;
const files = [];
const map = new Map();

function nameAt(x){
	return String.fromCharCode(x + 97);
}

function iccfAt(x){
	return (x + 1) * 10;
}

function file(value){
	const file = map.get(value);
	if(file)
		return file;
	throw INVALID_FILE(value);
}

class File {

	static from(value){
		return file(value);
	}

	static is(value){
		return map.has(value);
	}

	static all(){
		return files;
	}

	static reverse(){
		return ReverseFiles;
	}

	#x;
	#name;
	#iccf;
	#squares = [];

	constructor(x){
		this.#x = x;
		this.#iccf = iccfAt(x);
		this.#name = nameAt(x);
	}

	get x(){
		return this.#x;
	}

	get name(){
		return this.#name;
	}

	get iccf(){
		return this.#iccf;
	}

	get squares(){
		return this.#squares;
	}

	toString(){
		return this.name;
	}

	valueOf(){
		return this.x;
	}

	[inspect.custom](depth, opts){
		return ConstNumberObject(`[File ${this.name.toUpperCase()}]`);
	}
}

// generate all

while(files.length < size){
	const x = files.length;
	const file = new File(x);
	files.push(file);
	map.set(file, file);
	map.set(file.x, file);
	map.set(file.name, file);
	map.set(file.name.toUpperCase(), file);
}

const ReverseFiles = [... files];
ReverseFiles.reverse();

Object.freeze(files);
Object.freeze(ReverseFiles);