step-sequence-generator/dist/modules/roulette/weight-calculator/WeightCalculator.js

A step sequence generator for figure skating programs

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.WeightCalculator = void 0;
const round2_1 = require("../../../utils/round2");
/**
 * @name WeightCalculator
 * @param S тип для selection
 * @param M тип для ChanceRatioMap
 *
 * */
class WeightCalculator {
    /**
     * count
     * @param args
     * @arg args.selection элементы
     * @arg args.chanceRatioMap шансы на выпадение элемента в selection в процентах
     * @arg args.itemKeyExtractor callback для опредления ключа для weightMap
     */
    count(args) {
        const { selection, itemKeyExtractor, chanceRatioMap } = args;
        const groupItemCounted = this.groupAndCountItems(selection, itemKeyExtractor);
        return this.calcWeights(groupItemCounted, chanceRatioMap);
    }
    calcWeights(groupItemCounted, chanceRatioMap) {
        const totalItems = Array.from(groupItemCounted.values()).reduce((acc, cur) => acc + cur, 0);
        const weightMap = new Map();
        for (let [key, currentItemAmount] of groupItemCounted.entries()) {
            const desirePercent = chanceRatioMap.get(key) || 0;
            const weight = this.calcItemWeight({ currentItemAmount, desirePercent, totalItems });
            weightMap.set(key, weight);
        }
        return weightMap;
    }
    calcItemWeight(args) {
        const { currentItemAmount, desirePercent, totalItems } = args;
        const desireItemAmount = this.calcDesireItemAmount(totalItems, desirePercent);
        return this.calcWeight(currentItemAmount, desireItemAmount);
    }
    calcDesireItemAmount(totalItems, desirePercent) {
        const HUNDRED_PERCENT = 100;
        return (0, round2_1.round2)((totalItems / HUNDRED_PERCENT) * desirePercent);
    }
    calcWeight(currentItemAmount, desireItemAmount) {
        return (0, round2_1.round2)(desireItemAmount / currentItemAmount);
    }
    groupAndCountItems(selection, keyExtractor) {
        const map = new Map();
        for (let item of selection) {
            const key = keyExtractor(item);
            const value = map.get(key) || 0;
            map.set(key, value + 1);
        }
        return map;
    }
}
exports.WeightCalculator = WeightCalculator;