react-scrabble/dist/helpers/generator.js

The scrabble board game written in React

'use strict';

var matrix = null;
var placeHolder = '-1';

function defineMatrix(n) {
  var matrix = [];
  for (var i = 0; i < n; i++) {
    matrix[i] = new Array();
    for (var j = 0; j < n; j++) {
      matrix[i][j] = placeHolder;
    }
  }
  return matrix;
}

function fillWordAcrossRow(rowNum, startingPoint, word) {
  var wordArray = word.split('');
  for (var i = startingPoint, j = 0; i < word.length + startingPoint; i++, j++) {
    matrix[rowNum][i] = wordArray[j];
  }
}

function fillWordAcrossColumn(columnNum, startingPoint, word) {
  var wordArray = word.split('');
  for (var i = startingPoint, j = 0; i < word.length + startingPoint; i++, j++) {
    matrix[i][columnNum] = wordArray[j];
  }
}

function findCellsForRow(word, rowNum) {
  var len = matrix.length;
  var maxStartingPoint = len - word.length;
  for (var x = 1; x <= 3; x++) {
    var startingPoint = randomTill(maxStartingPoint);
    var canBeAllotted = true;
    for (var i = startingPoint; i < word.length + startingPoint; i++) {
      if (matrix[rowNum][i] != placeHolder) {
        canBeAllotted = false;
        break;
      }
    }
    if (canBeAllotted) {
      fillWordAcrossRow(rowNum, startingPoint, word);
      return true;
    }
  }
  return false;
}
function findCellsForColumn(word, columnNum) {
  var len = matrix.length;
  var maxStartingPoint = len - word.length;
  for (var x = 1; x <= 10; x++) {
    var startingPoint = randomTill(maxStartingPoint);
    var canBeAllotted = true;
    for (var i = startingPoint; i < word.length + startingPoint; i++) {
      if (matrix[i][columnNum] != placeHolder) {
        canBeAllotted = false;
        break;
      }
    }
    if (canBeAllotted) {
      fillWordAcrossColumn(columnNum, startingPoint, word);
      return true;
    }
  }
  return false;
}

function findCells(word, pos, direction) {
  if (direction == 'across') {
    return findCellsForRow(word, pos);
  } else {
    return findCellsForColumn(word, pos);
  }
}

function randomTill(n) {
  return Math.floor(Math.random() * (n - 0 + 1)) + 0;
}

function fillRandomAlphabets(n) {
  var alphabets = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
  for (var i = 0; i < n; i++) {
    for (var j = 0; j < n; j++) {
      if (matrix[i][j] === placeHolder) {
        matrix[i][j] = alphabets[Math.floor(Math.random() * alphabets.length)];
      }
    }
  }
}

function randomDirection() {
  var direction = ['across', 'down'];
  return direction[Math.floor(Math.random() * direction.length)];
}

function otherDirection(curDirection) {
  return curDirection === 'across' ? 'down' : 'across';
}

module.exports = {

  generateGrid: function generateGrid(words) {
    var n = 14;
    matrix = defineMatrix(n);
    words.sort(function (w1, w2) {
      return w2.length - w1.length;
    });

    var hintDirection = { across: [], down: [] };

    for (var i = 0; i < words.length; i++) {
      var word = words[i];
      var direction = randomDirection();
      var isAllocated = findCells(word, i, direction);
      isAllocated && hintDirection[direction].push(word);
      if (!isAllocated) {
        var newDirection = otherDirection(direction);
        isAllocated = findCells(word, i, newDirection);
        isAllocated && hintDirection[newDirection].push(word);
      }
      if (!isAllocated) {
        console.error("Could not allot word: " + word);
      }
    }
    fillRandomAlphabets(n);
    return { matrix: matrix, hintDirection: hintDirection };
  }
};