function createMatrix(w, h, defaultValue){
  const matrix = [];
  while (h--) {
    matrix.push(new Array(w).fill(defaultValue));
  }
  return matrix;
}

function copyMatrix(original, copy){
  if ((original.length !== copy.length) || (original[0].length != copy[0].length)){
    throw new Error('Matrix copy error: matrices dimensions mismatch.');
  }

  for (let i = 0; i < original.length; i++){
    for (let j = 0; j < original[i].length; j++){
      copy[i][j] = original[i][j];
    }
  }
}

function clamp(value, min, max){
  return Math.max(min, Math.min(value, max));
}

function now(){
  return new Date().getTime();
}

function deltaTime(startTime){
  return (now() - startTime);
}

function sleep(milliseconds){
  var currentTime = now();
  while (currentTime + milliseconds >= now()){}
}

function randomIntFromInterval(min, max){
  return Math.floor(Math.random()*(max-min+1)+min);
}

function getAllDropCombinations(onlyNumbers){
  const combinations = [];

  for (let col = 1; col <= 7; col++){
    for (let number = 1; number <= 7; number++){
      combinations.push({
        col: col,
        piece: new NumberedPiece(number)
      });
    }

    if (!onlyNumbers){
      combinations.push({
        col: col,
        piece: SolidPiece.getRandomSolidPiece()
      });
    }
  }

  return combinations;
}

function getMaxDrops(){
  if (mode === 'classic' || mode === 'sequence'){
    return classicSequenceDrops;
  } else if (mode === 'blitz'){
    return blitzDrops;
  } else {
    throw new Error('Invalid game mode ' + mode);
  }
}

function getFormattedScore(unformattedScore){
  let formattedScore = '';
  let scoreStr = '' + unformattedScore;
  let sinceLastComma = 0;

  for (let i = scoreStr.length-1; i >= 0; i--){
    if (sinceLastComma === 3){
      formattedScore = ',' + formattedScore;
      sinceLastComma = 0;
    }
    formattedScore = scoreStr.charAt(i) + formattedScore;
    sinceLastComma++;
  }

  return formattedScore;
}

function getAvgScores(){
  let prevAvgScore = 0;
  let prevScoresSum = 0;
  for (let i = 0; i < scores[mode].length - 1; i++){
    prevScoresSum += scores[mode][i];
  }
  if (scores[mode].length - 1 > 0){
    prevAvgScore = Math.floor(prevScoresSum / (scores[mode].length - 1));
  }

  const newAvgScore = Math.floor((prevScoresSum+score) / scores[mode].length);

  return[prevAvgScore, newAvgScore];
}

function isNewHighscore(){
  let isHighscore = true;
  for (let i = 0; i < scores[mode].length - 1; i++){
    if (scores[mode][i] >= score){
      isHighscore = false;
      break;
    }
  }

  return isHighscore;
}

function np(number){
  return new NumberedPiece(number);
}

function sp(number){
  return new SolidPiece(new NumberedPiece(number));
}

function inAnimation(){
  let inAnimation = false;

  inAnimation |= fallingPieces > 0;
  inAnimation |= explodingPieces > 0;
  inAnimation |= animatingNextLevel;
  inAnimation |= animatingBoardClear;

  return inAnimation;
}

function playAudio(audioName){
  let audio = audios[audioName.src];
  if (audioName.clone){
    audio = audio.cloneNode(true);
  }
  audio.play();
}

function pauseAudio(audioName){
  audios[audioName.src].pause();
}

function replayAudio(audioName){
  const audio = audios[audioName.src];
  audio.currentTime = 0;
  playAudio(audioName);
}