ymir-js/src/packages/checkers/international/board.ts

This toolkit is created to make it easier for you to develop games like chess, checkers, go, match 3 puzzle and more. It is still under development.

import * as _ from 'lodash';

import getAvailableColumns from '../../../utils/getAvailableColumns';
import Board from '../../core/board';
import { MovementType } from '../../core/item';
import Item, { CheckersColorType, CheckersItemType } from './item';

export type BoardConfig = {
  x: number;
  y: number;
};

export type CheckersBoardType = { [key: string]: { item: CheckersItemType } };

export type AttactCoord = { coord: string; destroyItemCoord: string };

export type DefendCoord = { coord: string; inDangerItemCoord: string };

class InternationalCheckersBoard extends Board {
  board: CheckersBoardType;

  constructor(config: BoardConfig = { x: 10, y: 10 }) {
    super(config);

    return this;
  }

  init() {
    const whiteItemCoords =
      '0|1 0|3 0|5 0|7 0|9 1|0 1|2 1|4 1|6 1|8 2|1 2|3 2|5 2|7 2|9 3|0 3|2 3|4 3|6 3|8';
    const blackItemCoords =
      '6|1 6|3 6|5 6|7 6|9 7|0 7|2 7|4 7|6 7|8 8|1 8|3 8|5 8|7 8|9 9|0 9|2 9|4 9|6 9|8';

    whiteItemCoords.split(' ').forEach((coord) => {
      this.setItem(coord, new Item({ color: 'white' }));
    });

    blackItemCoords.split(' ').forEach((coord) => {
      this.setItem(coord, new Item({ color: 'black' }));
    });

    return this;
  }

  reset(): void {
    Object.keys(this.board).forEach(this.removeItem);

    this.init();
  }

  getItemsBetweenTwoCoords(fromCoord: string, toCoord: string): string[] {
    const direction = this.getDirection(fromCoord, toCoord);
    const distance = this.getDistanceBetweenTwoCoords(fromCoord, toCoord);
    const convertDirection = {
      top: 'y',
      bottom: 'y',
      left: 'x',
      right: 'x',
    };
    const stepCount = Math.abs(distance[convertDirection[direction]]) || 1;
    const movement = { stepCount };

    movement[direction] = true;

    const betweenCoords = [];

    return betweenCoords
      .concat(...Object.values(getAvailableColumns(fromCoord, movement)))
      .filter((coord) => !this.isEmpty(coord));
  }

  getAvailableCoordsByColor = (
    color: CheckersColorType
  ): Record<string, string[]> => {
    const currentItems = [];
    const availableCoords = {};

    Object.entries(this.board).forEach(([coord, col]) => {
      if (col.item && col.item.color === color) {
        currentItems.push(coord);
      }
    });

    currentItems.forEach((coord) => {
      const item = this.getItem(coord);
      const currentAvailableCoords = this.getAvailableColumns(
        coord,
        item.movement
      );

      if (currentAvailableCoords.length) {
        availableCoords[coord] = currentAvailableCoords;
      }
    });

    return availableCoords;
  };

  getAttackCoordsByColor = (
    color: CheckersColorType
  ): { [coord: string]: AttactCoord[] } => {
    const availableCoords = this.getAvailableCoordsByColor(color);
    const attackCoords = {};

    Object.entries(availableCoords).forEach(
      ([coord, currentAvailableCoords]) => {
        currentAvailableCoords.forEach((currentAvailableCoord) => {
          const [destroyItemCoord] = this.getItemsBetweenTwoCoords(
            coord,
            currentAvailableCoord
          );

          if (destroyItemCoord) {
            if (attackCoords[coord]) {
              attackCoords[coord].push({
                coord: currentAvailableCoord,
                destroyItemCoord,
              });
            } else {
              attackCoords[coord] = [
                { coord: currentAvailableCoord, destroyItemCoord },
              ];
            }
          }
        });
      }
    );

    return attackCoords;
  };

  getDefendCoordsByColor = (
    color: CheckersColorType
  ): { [coord: string]: DefendCoord[] } => {
    const defendCoords = {};

    const enemyColor = color === 'white' ? 'black' : 'white';
    const availableCoords = this.getAvailableCoordsByColor(color);
    const enemyAttackCoords = this.getAttackCoordsByColor(enemyColor);

    Object.entries(enemyAttackCoords).forEach(([, enemyAttack]) => {
      Object.values(enemyAttack).forEach((enemyAttackCoord) => {
        Object.keys(availableCoords).forEach((availableItemOrigin) => {
          const availableColumnCoords = availableCoords[availableItemOrigin];

          if (
            availableColumnCoords.includes(enemyAttackCoord.coord) &&
            availableItemOrigin !== enemyAttackCoord.destroyItemCoord
          ) {
            const defendCoordItem = {
              coord: enemyAttackCoord.coord,
              inDangerCoord: enemyAttackCoord.destroyItemCoord,
            };

            if (defendCoords[availableItemOrigin]) {
              defendCoords[availableItemOrigin].push(defendCoordItem);
            } else {
              defendCoords[availableItemOrigin] = [defendCoordItem];
            }
          }
        });
      });
    });

    return defendCoords;
  };

  getItemsByColor = (color: CheckersColorType): CheckersItemType[] => {
    return Object.values(this.board)
      .filter(({ item }) => item?.color === color)
      .map(({ item }) => item);
  };

  getAvailableColumns = (coord: string, movement: MovementType): string[] => {
    if (this.isEmpty(coord)) return [];

    const columns = getAvailableColumns(coord, movement);
    const availableColumns: Record<string, string[]> = {};
    const captureAvailableColumns = {};
    const item = this.getItem(coord);

    Object.keys(columns).forEach((key) => {
      availableColumns[key] = [];
      let isFoundCapture = false;

      for (let i = 0; i < columns[key].length; i += 1) {
        const currentCoord = columns[key][i];

        if (!this.isExistCoord(currentCoord)) continue;
        if (this.isEmpty(currentCoord)) {
          availableColumns[key].push(currentCoord);
          continue;
        } else if (isFoundCapture) {
          break;
        }

        const nextCoordItem = this.getItem(currentCoord);

        if (nextCoordItem?.color === item.color) {
          break;
        } else if (
          !isFoundCapture &&
          nextCoordItem &&
          nextCoordItem.color !== item.color
        ) {
          const direction = this.getDirection(coord, currentCoord);
          const movementRule = {
            stepCount: 1,
            [direction]: true,
          };

          const [afterCoord] = Object.values(
            getAvailableColumns(currentCoord, movementRule)
          )
            .filter((arr) => arr.length)
            .flat();

          const afterItem = this.getItem(afterCoord);

          if (afterItem) break;

          if (this.isEmpty(afterCoord)) {
            availableColumns[key] = [afterCoord];
            captureAvailableColumns[key] = true;
            isFoundCapture = true;
          } else {
            break;
          }
        }
      }
    });

    const resultCoords: Record<string, string[]> = {};

    const isFoundAnySuccessDirection = Object.values(
      captureAvailableColumns
    ).some((direction) => direction);

    Object.keys(availableColumns).forEach((key) => {
      if (!isFoundAnySuccessDirection) {
        resultCoords[key] = _.uniq(availableColumns[key]);
      } else if (captureAvailableColumns[key]) {
        resultCoords[key] = _.uniq(availableColumns[key]);
      }
    });

    return Object.values(resultCoords).flat();
  };
}

export default InternationalCheckersBoard;