<main class="container">

  <div class="calculator-case">
    <input id="display" class="display" readonly type="text" dir="rtl" maxlength="8" placeholder="" />

    <div class="button-grid">
      <div class="top-rows">
        <div class="button-body button-blue">
          <button class="button-cap blue-cap-blue">C</button>
        </div>

        <div class="button-body button-blue">
          <button class="button-cap blue-cap-blue">CE</button>
        </div>

        <div class="button-body button-blue">
          <button class="button-cap blue-cap-blue">%</button>
        </div>

        <div class="button-body button-blue">
          <button class="button-cap blue-cap-blue">÷</button>
        </div>

        <div class="button-body">
          <button class="button-cap">7</button>
        </div>

        <div class="button-body">
          <button class="button-cap">8</button>
        </div>

        <div class="button-body">
          <button class="button-cap">9</button>
        </div>

        <div class="button-body button-blue">
          <button class="button-cap blue-cap-blue">x</button>
        </div>

        <div class="button-body">
          <button class="button-cap">4</button>
        </div>

        <div class="button-body">
          <button class="button-cap">5</button>
        </div>

        <div class="button-body">
          <button class="button-cap">6</button>
        </div>

        <div class="button-body button-blue">
          <button class="button-cap blue-cap-blue">-</button>
        </div>

        <div class="button-body">
          <button class="button-cap">1</button>
        </div>

        <div class="button-body">
          <button class="button-cap">2</button>
        </div>

        <div class="button-body">
          <button class="button-cap">3</button>
        </div>

        <div class="button-body button-blue">
          <button class="button-cap blue-cap-blue">+</button>
        </div>

      </div>
      <div class="bottom-row">
        <div class="button-body wider-button">
          <button class="button-cap wider-cap">0</button>
        </div>
        <div class="button-body">
          <button class="button-cap">.</button>
        </div>
        <div class="button-body wider-button">
          <button class="button-cap wider-cap">=</button>
        </div>
      </div>
    </div>

</main>

@import url(https://fonts.googleapis.com/css?family=Audiowide);

* {
  box-sizing: border-box;
}

body {
  padding: 0;
  margin: 0;
}

// I'm using this to center the button to the screen
.container {
  /* layout */
  display: flex;
  width: 100vw;
  height: 100vh;
  justify-content: center;
  align-items: center;

  /* style */
  background: #2b3d25;
}

.button-grid {
  display: grid;
}

.top-rows {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 3px;
}

.button-body {
  /* layout */
  display: flex;
  justify-content: center;
  width: 75px;
  height: 75px;

  padding-top: 2px;

  /* style */
  background: linear-gradient(145deg, rgb(120, 118, 99), #fff9d6);
  border-radius: 3px;
  box-shadow: 0 0 0 1px rgba(16, 22, 26, 0.1), 0 0px 2px rgba(16, 22, 26, 0.2),
    0 0px 1px rgba(16, 22, 26, 0.2);

  /* effects */
  &:active {
    transform: scale(0.95); /* Add this line */
    background: linear-gradient(145deg, rgb(120, 118, 99), #fff9d6);
    box-shadow: 0 0 0 1px rgba(16, 22, 26, 0.1), 0 0px 2px rgba(16, 22, 26, 0.2),
      0 0px 1px rgba(16, 22, 26, 0.2);
  }
}

.button-cap {
  /* layout */
  width: 65px;
  height: 65px;
  border-radius: 5px;

  /* style */
  border: none;
  background: linear-gradient(145deg, #d6d2b4, #fff9d6);
  box-shadow: 0 0 0 1px rgba(16, 22, 26, 0.1), 0 0px 2px rgba(16, 22, 26, 0.2),
    0 0px 1px rgba(16, 22, 26, 0.2);

  /* typography */
  font-family: "Audiowide", cursive;
  color: black;
  font-size: larger;

  /* effects */
  &:active {
    transform: scale(0.95); /* Add this line */
    background: linear-gradient(145deg, #d6d2b4, #fff9d6);
    box-shadow: 0 0 0 1px rgba(16, 22, 26, 0.1), 0 0px 2px rgba(16, 22, 26, 0.2),
      0 0px 1px rgba(16, 22, 26, 0.2);
  }

  &:hover {
    cursor: pointer;
  }
}

.button-blue {
  background: linear-gradient(145deg, rgb(110, 131, 129), #d6fff9);

  /* effects */
  &:active {
    transform: scale(0.95); /* Add this line */
    background: linear-gradient(145deg, rgb(110, 131, 129), #d6fff9);
    box-shadow: 0 0 0 1px rgba(16, 22, 26, 0.1), 0 0px 2px rgba(16, 22, 26, 0.2),
      0 0px 1px rgba(16, 22, 26, 0.2);
  }
}

.blue-cap-blue {
  background: linear-gradient(145deg, #b4d6d2, #d6fff9);

  &:active {
    transform: scale(0.95); /* Add this line */
    background: linear-gradient(145deg, #b4d6d2, #d6fff9);

    box-shadow: 0 0 0 1px rgba(16, 22, 26, 0.1), 0 0px 2px rgba(16, 22, 26, 0.2),
      0 0px 1px rgba(16, 22, 26, 0.2);
  }
}

.bottom-row {
  display: flex;
  justify-content: space-between;
  gap: 5px;
  padding-top: 3px;
}

.wider-button {
  width: 35%;
}

.wider-cap {
  width: 90%;
}

.display {
  /* layout */
  overflow: hidden;

  padding: 5px;
  height: 75px;
  width: 320px;

  /* style */
  background: rgba(56, 62, 37, 1);
  box-shadow: inset 1px 1px 6px 0px #050505, 0px 0px 4px 2px #000,
    0px 0px 4px 2px #777;

  /* typography */
  color: black;
  font-size: 3rem;
  font-family: "Audiowide", cursive;

  /* effects */
  &:hover {
    cursor: cell;
  }
}

.calculator-case {
  /* layout */
  display: flex;
  flex-direction: column;
  gap: 20px;
  padding: 25px;

  /* style */
  border-radius: 15px;
  background: #d6d2b4;
  box-shadow: inset 5px 5px 18px #c7c3a7, inset -5px -5px 18px #e5e1c1;
}

document.addEventListener('DOMContentLoaded', function () {
  const display = document.getElementById('display');
  const buttons = document.querySelectorAll('.button-cap');

  let currentInput = '';
  let previousInput = '';
  let operator = '';

  buttons.forEach(button => {
    button.addEventListener('click', function () {
      handleButtonClick(this.innerText);
      updateDisplay();
    });
  });

  function handleButtonClick(value) {
    if (isNumber(value) || value === '.') {
      handleNumberClick(value);
    } else if (isOperator(value)) {
      handleOperatorClick(value);
    } else if (value === 'C') {
      clearDisplay();
    } else if (value === 'CE') {
      clearEntry();
    } else if (value === '%') {
      calculatePercentage();
    } else if (value === '=') {
      calculateResult();
    }
  }

  function isNumber(value) {
    return !isNaN(parseFloat(value)) && isFinite(value);
  }

  function isOperator(value) {
    return ['+', '-', 'x', '÷'].includes(value);
  }

  function handleNumberClick(value) {
     if (currentInput.length < 8) {
      currentInput += value;
    }
  }

  function handleOperatorClick(value) {
    if (currentInput !== '') {
      if (previousInput !== '') {
        calculateResult();
      }
      operator = value;
      previousInput = currentInput;
      currentInput = '';
    }
  }

  function calculateResult() {
    if (currentInput !== '') {
      switch (operator) {
        case '+':
          currentInput = (parseFloat(previousInput) + parseFloat(currentInput)).toString();
          break;
        case '-':
          currentInput = (parseFloat(previousInput) - parseFloat(currentInput)).toString();
          break;
        case 'x':
          currentInput = (parseFloat(previousInput) * parseFloat(currentInput)).toString();
          break;
        case '÷':
          currentInput = (parseFloat(previousInput) / parseFloat(currentInput)).toString();
          break;
      }
      operator = '';
      previousInput = '';
    }
    currentInput = currentInput.length > 8 ? 'ERROR' : currentInput;
  }

  function calculatePercentage() {
    if (currentInput !== '') {
      currentInput = (parseFloat(currentInput) / 100).toString();
    }
  }

  function clearDisplay() {
    currentInput = '';
    previousInput = '';
    operator = '';
  }

  function clearEntry() {
    currentInput = '';
  }

  function updateDisplay() {
    display.value = currentInput === '' ? '0' : currentInput;
  }
});