*, *::before, *::after {
  box-sizing: border-box;
}

body {
  font-family: system-ui, "Segoe UI", Roboto, Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";
  background: #f1f5f9;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  margin: 0;
  overflow: hidden;
}

.swipe-app {
  display: flex;
  flex-direction: column;
  align-items: center;
  width: 100%;
}

.stack-container {
  position: relative;
  width: 320px;
  height: 450px;
  /* Prevents native mobile page scrolling when dragging the cards */
  touch-action: none;
}

.swipe-card {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: #ffffff;
  border-radius: 24px;
  box-shadow: 0 15px 25px -5px rgba(0, 0, 0, 0.15);
  overflow: hidden;
  will-change: transform;
  transform-origin: 50% 100%;
  cursor: grab;
  user-select: none;
}

.swipe-card.dragging {
  cursor: grabbing;
}

/* Dynamic stacking trick: targets elements from bottom to top */
.swipe-card:nth-last-child(1) {
  transform: translateY(0px) scale(1);
  z-index: 3;
}

.swipe-card:nth-last-child(2) {
  transform: translateY(16px) scale(0.95);
  z-index: 2;
  opacity: 0.9;
}

.swipe-card:nth-last-child(3) {
  transform: translateY(32px) scale(0.9);
  z-index: 1;
  opacity: 0.8;
}

.swipe-card img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  /* Prevents native drag ghosting on desktop */
  pointer-events: none;
}

.card-info {
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  padding: 40px 24px 24px 24px;
  background: linear-gradient(to top, rgba(0,0,0,0.85) 0%, rgba(0,0,0,0) 100%);
  color: #ffffff;
  pointer-events: none;
}

.card-info h3 {
  margin: 0 0 4px 0;
  font-size: 1.75rem;
  letter-spacing: -0.5px;
}

.card-info p {
  margin: 0;
  font-size: 1rem;
  color: #cbd5e1;
}

.action-buttons {
  display: flex;
  justify-content: center;
  gap: 24px;
  margin-top: 50px;
  z-index: 10;
}

.btn-action {
  width: 72px;
  height: 72px;
  border-radius: 50%;
  border: none;
  background: #ffffff;
  display: flex;
  justify-content: center;
  align-items: center;
  box-shadow: 0 10px 20px -5px rgba(0, 0, 0, 0.1);
  cursor: pointer;
  transition: transform 0.2s cubic-bezier(0.34, 1.56, 0.64, 1), box-shadow 0.2s;
}

.btn-action:active {
  transform: scale(0.85);
  box-shadow: 0 4px 10px -2px rgba(0, 0, 0, 0.1);
}

.btn-nope {
  color: #ef4444;
}

.btn-yep {
  color: #10b981;
}

const stack = document.getElementById("card-stack");
const btnNope = document.getElementById("btn-nope");
const btnYep = document.getElementById("btn-yep");

let isDragging = false;
let startX = 0;
let currentX = 0;
let activeCard = null;

// Pointer events handle both mouse and touch flawlessly
stack.addEventListener("pointerdown", function(e) {
  // Always grab the top-most card in the DOM
  activeCard = stack.lastElementChild;
  if (!activeCard) return;
  
  isDragging = true;
  startX = e.clientX;
  
  activeCard.classList.add("dragging");
  activeCard.style.transition = "none";
  activeCard.setPointerCapture(e.pointerId);
});

stack.addEventListener("pointermove", function(e) {
  if (!isDragging || !activeCard) return;
  
  currentX = e.clientX - startX;
  // Calculate rotation based on drag distance
  const rotate = currentX * 0.05;
  
  activeCard.style.transform = "translate(" + currentX + "px, 0px) rotate(" + rotate + "deg)";
});

function endDrag(e) {
  if (!isDragging || !activeCard) return;
  isDragging = false;
  
  activeCard.classList.remove("dragging");
  activeCard.style.transition = "transform 0.4s cubic-bezier(0.2, 0.8, 0.2, 1)";
  
  // If dragged far enough, swipe it away
  if (Math.abs(currentX) > 100) {
    const direction = currentX > 0 ? 1 : -1;
    swipeOut(activeCard, direction);
  } else {
    // Snap back to center
    activeCard.style.transform = "translate(0px, 0px) rotate(0deg)";
  }
  
  activeCard = null;
  currentX = 0;
}

stack.addEventListener("pointerup", endDrag);
stack.addEventListener("pointercancel", endDrag);

// Helper function to animate card out and remove it
function swipeOut(card, direction) {
  const throwX = window.innerWidth * direction;
  const throwRotate = direction * 30;
  
  card.style.transition = "transform 0.5s ease-out";
  card.style.transform = "translate(" + throwX + "px, 0px) rotate(" + throwRotate + "deg)";
  
  setTimeout(function() {
    if (card.parentElement) {
      card.parentElement.removeChild(card);
    }
  }, 500);
}

// Button controls
btnNope.addEventListener("click", function() {
  const topCard = stack.lastElementChild;
  if (topCard) swipeOut(topCard, -1);
});

btnYep.addEventListener("click", function() {
  const topCard = stack.lastElementChild;
  if (topCard) swipeOut(topCard, 1);
});