const lines = [];
const lineHeight = 35;
const framesPerChange = 9;
const framesPerOff = 20;

function setup() {
  createCanvas(1000, 1000);
  background('#0a0a1b');

  const lineCount = 40;

  for (let i = 0; i < lineCount; i++) {
    const line = {
      text: randomText(),
      y: height + i * lineHeight,
      speed: 21,
      framesUntilChange: framesPerChange,
      framesUntilOff: framesPerOff,
    };
    lines.push(line);
  }
}

function draw() {
  background('#0a0a1b');

  for (const line of lines) {
    moveLine(line);
    displayLine(line);

    line.framesUntilChange--;
    line.framesUntilOff--;

    if (line.framesUntilChange <= 0) {
      changeRandomCharacter(line);
      line.framesUntilChange = framesPerChange;
    }

    if (line.framesUntilOff <= 0) {
      turnOffRandomCharacter(line);
      line.framesUntilOff = framesPerOff;
    }

    if (line.y < -lineHeight) {
      line.y = height;
    }
  }
}

function randomText() {
  const word = `01110111 01100101 01101100 01100011 01101111 01101101 01100101 00100000 01110100 01101111 00100000 01110011 01110100 01110010 01100001 01101110 01100111 01100101 01110010 00100000 01101101 01100001 01101110 01110011 01101001 01101111 01101110`;
  return word;
}

function moveLine(line) {
  line.y -= line.speed;
}

function displayLine(line) {
  textSize(16);
  fill('#ff3600');
  noStroke();
  text(line.text, 20, line.y);
}

function changeRandomCharacter(line) {
  const index = floor(random(line.text.length));
  const newCharacter = '₿';
  line.text = line.text.substr(0, index) + newCharacter + line.text.substr(index + 1);
}

function turnOffRandomCharacter(line) {
  const index = floor(random(line.text.length));
  const offCharacter = ' ';
  line.text = line.text.substr(0, index) + offCharacter + line.text.substr(index + 1);
}