$(document).ready(function() {

  // Initialize Game Settings
  var sequence = [];
  var score = 0;
  var gameTempo = 1100; // Lowest tempo available
  var gameMode = "Normal";
  var thisRound = [];
  var playFieldId = "";
  const soundFiles = [
    ["https://crossorigin.me/https://s3.amazonaws.com/freecodecamp/simonSound1.mp3"], // Green
    ["https://crossorigin.me/https://s3.amazonaws.com/freecodecamp/simonSound2.mp3"], // Red
    ["https://crossorigin.me/https://s3.amazonaws.com/freecodecamp/simonSound3.mp3"], // Yellow
    ["https://crossorigin.me/https://s3.amazonaws.com/freecodecamp/simonSound4.mp3"], // Blue
    ["https://crossorigin.me/http://freesound.org/data/previews/142/142608_1840739-lq.mp3"] // Wrong
  ];

  // Function building the sequence for current game.
  // Abbrv. : G - Green. R - Red. Y - Yellow. B - Blue.
  var getSequence = function(sequenceSize) {
    for (var i = 0; i < sequenceSize; i++) {
      var rand = Math.random();
      if (rand < 0.25) {
        sequence.push("G");
      } else if (rand >= 0.25 && rand < 0.50) {
        sequence.push("R");
      } else if (rand >= 0.50 && rand < 0.75) {
        sequence.push("Y");
      } else {
        sequence.push("B");
      }
    }
  };

  // Function defining the game speed. Values in millisecond.
  var getTempo = function(score) {
    if (score < 5) {
      gameTempo = 200;
    } else if (score >= 5 && score < 9) {
      gameTempo = 350;
    } else if (score >= 9 && score < 13) {
      gameTempo = 830;
    } else {
      gameTempo = 740;
    }
  };

  // Function playing the sound files. Using Howler library.
  // Also, responsible for highlighting tile colors.
  var animateField = function(index) {
    var whichSound;
    if (index === "G") {
      whichSound = soundFiles[0];
      $("#G").animate({
        opacity: 0.2
      }, 200).animate({
        opacity: 1
      }, 100);
    } else if (index === "R") {
      whichSound = soundFiles[1];
      $("#R").animate({
        opacity: 0.2
      }, 200).animate({
        opacity: 1
      }, 100);
    } else if (index === "Y") {
      whichSound = soundFiles[2];
      $("#Y").animate({
        opacity: 0.2
      }, 200).animate({
        opacity: 1
      }, 100);
    } else if (index === "B") {
      whichSound = soundFiles[3];
      $("#B").animate({
        opacity: 0.2
      }, 200).animate({
        opacity: 1
      }, 100);
    } else if (index === "Wrong") {
      // Sound file for wrong moves.
      whichSound = soundFiles[4];
    }
    var soundUsingHowler = new Howl({
      src: whichSound
    });
    soundUsingHowler.play();
  };

  // Game Mode Button functionality
  $(".onoffswitch-label").on("click", function() {
    if (gameMode == "Normal") {
      gameMode = "Strict";
    } else {
      gameMode = "Normal";
    }
  });

  // Function timing the animation sequence according to tempo.
  var timedAnimations = function(index) {
    getTempo();
    $(".scoreCounter").text(score);
    setTimeout(function() {
      animateField(sequence[index]);
    }, index * gameTempo);
  };

  // Function responsible for the animations.
  var playSequence = function() {
    for (var j = 0; j <= score; j++) {
      thisRound.push(sequence[j]);
      timedAnimations(j);
      playFieldId = "";
    }
  };

  var clickOn = false; // Credit to Ken Haduch @khaduch for solving a crucial bug at this function.
  // Function that takes player input
  var getPlayerSequence = function() {
    // Play sequence up to the score point.
    playSequence();
    if (clickOn === false) {
      $('.playField').click(function() {
        // Animate user-pressed playing fields.
        playFieldId = $(this).attr('id');
        // If the last one is correct, proceed to next round.
        // Intoduces 1.5 second delay between rounds.
        if (playFieldId == thisRound[0] && thisRound.length === 1) {
          score += 1;
          // At score 20, Winning game condition.
          if (score == 20) {
            $(".gameBoard").css("display", "none");
            $(".winnerScreen").css("display", "block");
            Howler.mute(true);
          }
          animateField(playFieldId);
          setTimeout(function() {
            thisRound.shift();
            playFieldId = " ";
            playSequence();
          }, gameTempo);
          // Keep pushing till the last one.
        } else if (playFieldId == thisRound[0] && thisRound.length > 1) {
          animateField(playFieldId);
          thisRound.shift();
          playFieldId = " ";
        } else {
          // Wrong input.
          animateField("Wrong");
          if (gameMode == "Strict") {
            // Failing at strict mode ends the game.
            $(".gameBoard").css("display", "none");
            $(".resultScreen").css("display", "block");
            $(".scoreResults").text(score);
          } else {
            // Failing at Normal mode plays the sequence again.
            setTimeout(function() {
              thisRound = [];
              playSequence();
            }, 500);
          }
        }

      });
    }
    clickOn = true;
  };

  // Button functionality
  $(".btn").on("click", function() {
    var whichButton = $(this).text();
    if (whichButton === "Play Now!") {
      $(".startScreen").css("display", "none");
      $(".gameBoard").css("display", "block");
      // Reset Game Settings.
      score = 0;
      thisRound = [];
      sequence = [];
      Howler.mute(false);
      // Initiate new game.
      getSequence(20);
      getPlayerSequence();
    } else if (whichButton === "Play Again!" || whichButton === "I dare you!") {
      $(".resultScreen").css("display", "none");
      $(".winnerScreen").css("display", "none");
      $(".startScreen").css("display", "block");
    } else if (whichButton === "Stop") {
      Howler.mute(true);
      $(".gameBoard").css("display", "none");
      $(".resultScreen").css("display", "block");
      $(".scoreResults").text(score);
    }
  });

});