script.js

document.addEventListener("DOMContentLoaded", () => {
  const binaryInput = document.getElementById("binary");
  const decimalOutput = document.getElementById("decimal-number");
  const copyButton = document.getElementById("copy-button");

  binaryInput.value = ""; // resets input after reload

  binaryInput.addEventListener("input", updateDecimalOutput);
  copyButton.addEventListener("click", copyToClipboard);

  const containsInvalidChars = (arr) =>
    arr.some((bit) => bit !== "0" && bit !== "1");

  function handleInvalidInput() {
    alert("This character is not permitted!");
    binaryInput.value = "";
    decimalOutput.innerText = "-";
  }

  function updateDecimalOutput() {
    const binaryInputArray = binaryInput.value.split("");

    if (containsInvalidChars(binaryInputArray)) {
      handleInvalidInput();
      return;
    }

    decimalOutput.innerHTML = binaryInputArray.every((bit) => bit === "0")
      ? 0
      : parseInt(binaryInput.value, 2);
  }

  function copyToClipboard() {
    const textToCopy = decimalOutput.innerText;

    if (decimalOutput.innerHTML !== "-") {
      const tempTextarea = document.createElement("textarea");
      tempTextarea.value = textToCopy;
      document.body.appendChild(tempTextarea);

      tempTextarea.select();
      tempTextarea.setSelectionRange(0, 99999);

      document.execCommand("copy");

      document.body.removeChild(tempTextarea);
    } else {
      alert("Can't copy if there isn't anything to copy.");
    }
  }

  let toggleMode = document.querySelector("#toggle-mode");

  toggleMode.addEventListener("click", () => {
    document.documentElement.classList.toggle("dark-mode");
  });

  if (
    window.matchMedia &&
    window.matchMedia("(prefers-color-scheme: dark)").matches
  ) {
    document.documentElement.classList.toggle("dark-mode");
  }
});