recommendation.js

/**
 * @author C2-20
 * @param {Object} user an object with all the users FSLM values, ranging from -11 to 11
 * @param {Array} material an array of objects that contain all information about all the materials. Id, pole values etc.
 * @returns The sorted array of all given material, based on the users FSLM scores
 */
function recommendationAlgo(user, materials) {
  //Checks if there is user or material object
  if (!user || !materials) {
    return Error;
  }

  //Checks for null in user object
  const dimensions = Object.values(user);
  for (const value of dimensions) if (!value) return Error;

  let scoresArray = [];
  materials.forEach((material) => {
    scoresArray.push(calculateScore(user, material));
  });
  scoresArray = scoresArray.sort(byPersonalScore);
  return scoresArray;
}

/**
 * @author C2-20
 * Helper function to sort an array, based on .personalScore and sets the highest scoring material first.
 */
function byPersonalScore(a, b) {
  if (a.personalScore < b.personalScore) return 1;
  if (b.personalScore < a.personalScore) return -1;
  return 0;
}

/**
 * @author C2-20
 * @param {object} user an object with a single users information
 * @param {object} material an object with a single material and its values
 * @returns the material with a new value called .personalScore which contains a percentage of how will the fit is between the user and the material
 */
function calculateScore(user, material) {
  let totalScore = 0,
    score = 0,
    i = 3;
  let materialArray = Object.values(material);

  for (const key in user) {
    if (user[key] < 0) {
      //if the user is on the left side of a dimmension
      totalScore += Math.abs(user[key]);
      score += Math.abs(user[key]) * materialArray[i];
      i++;
    } else {
      //If the user is on the right side of a dimmension
      i++;
      totalScore += Math.abs(user[key]);
      score += user[key] * materialArray[i];
    }
    i++;
  }

  material.personalScore = score / totalScore;
  return material;
}

module.exports = {
  calculateScore,
  byPersonalScore,
  recommendationAlgo,
};