02. Song-Encryption-Without-Regex

function solve(input) {

  for (const line of input) {
    if (line === 'end') {
      break;
    }

    let [ artist, song ] = line.split(':');

    if (!artistIsValid(artist) || !songIsValid(song)) {
      console.log('Invalid input!');
      continue;
    }

    let key = artist.length;
    let encryptedString = '';
    for (const char of line) {
      if (char === ':') {
        encryptedString += '@';
        continue;
      }

      let asciiCode = char.charCodeAt(0);
      if ((asciiCode >= 65 && asciiCode <= 90)) {
        asciiCode += key;
        if (asciiCode > 90) {
          asciiCode -= 26;
        }
      }

      if ((asciiCode >= 97 && asciiCode <= 122)) {
        asciiCode += key;
        if (asciiCode > 122) {
          asciiCode -= 26;
        }
      }

      encryptedString += String.fromCharCode(asciiCode);
    }

    console.log(`Successful encryption: ${encryptedString}`);
  }

  function artistIsValid(artist) {
    let firstCharCode = artist.charCodeAt(0);
    if (firstCharCode < 65 || firstCharCode > 90) {
      return false;
    }

    for (let index = 1; index < artist.length; index++) {
      let asciiCode = artist.charCodeAt(index);
      if ((asciiCode >= 97 && asciiCode <= 122)
      || artist[index] === ' '
      || artist[index] === '\'') {
        continue;
      } else {
        return false;
      }
    }

    return true;
  }

  function songIsValid(song) {
    for (let index = 0; index < song.length; index++) {
      let asciiCode = song.charCodeAt(index);
      if ((asciiCode >= 65 && asciiCode <= 90)
      || song[index] === ' ') {
        continue;
      } else {
        return false;
      }

    }

    return true;
  }
}