script.js

const resultEl = document.getElementById('result')
const lengthEl = document.getElementById('length')
const uppercaseEl = document.getElementById('uppercase')
const lowercaseEl = document.getElementById('lowercase')
const numbersEl = document.getElementById('numbers')
const symbolsEl = document.getElementById('symbols')
const generateEl = document.getElementById('generate')
const clipboardEl = document.getElementById('clipboard')

const randomFunc = {
    lower: getRandomLower,
    upper: getRandomUpper,
    number: getRandomNumber,
    symbol: getRandomSymbol
}

clipboardEl.addEventListener('click', () => {
  const textarea = document.createElement('textarea');
  const password = resultEl.innerText;

  if (!password) {
    return;
  }

  textarea.style.position = 'fixed';
  textarea.style.top = '-9999px';  // Position off-screen
  textarea.value = password;
  document.body.appendChild(textarea);
  textarea.select();

  try {
    if (document.execCommand('copy')) {
      textarea.remove();
      alert('The password we have generated has been copied to your clipboard.');
    } else {
      throw new Error('Copying to clipboard failed.');
    }
  } catch (error) {
    console.error('Failed to copy password to clipboard:', error);
    document.body.removeChild(textarea);
    fallbackCopyToClipboard(password);
    alert('The password we have generated has been copied to your clipboard (fallback method).');
  }
});

function fallbackCopyToClipboard(password) {
  const fallbackTextArea = document.createElement('textarea');
  fallbackTextArea.value = password;
  document.body.appendChild(fallbackTextArea);
  fallbackTextArea.select();
  document.execCommand('copy');
  document.body.removeChild(fallbackTextArea);
}


generateEl.addEventListener('click', () => {
    const length = +lengthEl.value
    const hasLower = lowercaseEl.checked
    const hasUpper = uppercaseEl.checked
    const hasNumber = numbersEl.checked
    const hasSymbol = symbolsEl.checked

    resultEl.innerText = generatePassword(hasLower, hasUpper, hasNumber, hasSymbol, length)
})

function generatePassword(lower, upper, number, symbol, length) {
    let generatedPassword = ''
    const typesCount = lower + upper + number + symbol
    const typesArr = [{lower}, {upper}, {number}, {symbol}].filter(item => Object.values(item)[0])
    
    if(typesCount === 0) {
        return ''
    }

    for(let i = 0; i < length; i += typesCount) {
        typesArr.forEach(type => {
            const funcName = Object.keys(type)[0]
            generatedPassword += randomFunc[funcName]()
        })
    }

    const finalPassword = generatedPassword.slice(0, length)

    return finalPassword
}

function getRandomLower() {
    return String.fromCharCode(Math.floor(Math.random() * 26) + 97)
}

function getRandomUpper() {
    return String.fromCharCode(Math.floor(Math.random() * 26) + 65)
}

function getRandomNumber() {
    return String.fromCharCode(Math.floor(Math.random() * 10) + 48)
}

function getRandomSymbol() {
    const symbols = '!@#$%^&*(){}[]=<>/,.'
    return symbols[Math.floor(Math.random() * symbols.length)]
}