*, *::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";
  margin: 0;
  background-color: #020617;
  background-image: radial-gradient(circle, #1e293b 1px, transparent 1px);
  background-size: 30px 30px;
  min-height: 100vh;
  overflow: hidden;
}

.workspace {
  position: relative;
  width: 100vw;
  height: 100vh;
}

.svg-layer {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 1;
}

.flow-line {
  fill: none;
  stroke: #0ea5e9;
  stroke-width: 3;
  stroke-dasharray: 8 8;
  animation: dashAnim 1s linear infinite;
  filter: drop-shadow(0 0 6px rgba(14, 165, 233, 0.6));
}

@keyframes dashAnim {
  to { stroke-dashoffset: -16; }
}

.flow-node {
  position: absolute;
  width: 240px;
  background: rgba(15, 23, 42, 0.9);
  backdrop-filter: blur(12px);
  border: 1px solid rgba(14, 165, 233, 0.4);
  border-top: 4px solid #0ea5e9;
  border-radius: 12px;
  box-shadow: 0 15px 30px rgba(0, 0, 0, 0.5);
  z-index: 10;
  cursor: grab;
  user-select: none;
  display: flex;
  flex-direction: column;
  transition: box-shadow 0.2s, border-color 0.2s;
}

.flow-node:hover {
  border-color: #38bdf8;
}

.flow-node:active {
  cursor: grabbing;
  box-shadow: 0 25px 50px rgba(0, 0, 0, 0.8);
}

.node-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 12px 16px;
  background: rgba(255, 255, 255, 0.05);
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.editable {
  color: #f8fafc;
  font-weight: 600;
  outline: none;
  padding: 4px;
  border-radius: 4px;
  border: 1px solid transparent;
  transition: border-color 0.2s, background 0.2s;
  cursor: text;
  flex-grow: 1;
}

.editable:focus {
  border-color: rgba(14, 165, 233, 0.5);
  background: rgba(0, 0, 0, 0.3);
}

.delete-btn {
  background: transparent;
  color: #94a3b8;
  border: none;
  font-size: 1.25rem;
  cursor: pointer;
  border-radius: 50%;
  width: 24px;
  height: 24px;
  display: flex;
  justify-content: center;
  align-items: center;
  transition: background 0.2s, color 0.2s;
  margin-left: 8px;
}

.delete-btn:hover {
  background: #ef4444;
  color: #ffffff;
}

.node-body {
  padding: 16px;
  color: #cbd5e1;
  font-size: 0.95rem;
  font-weight: 400;
  line-height: 1.5;
  margin-bottom: 8px; /* Room for the add button */
}

.add-node-btn {
  position: absolute;
  bottom: -16px;
  left: 50%;
  transform: translateX(-50%);
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: #10b981;
  color: #ffffff;
  border: 3px solid #0f172a;
  display: flex;
  justify-content: center;
  align-items: center;
  font-size: 1.25rem;
  font-weight: bold;
  cursor: pointer;
  box-shadow: 0 4px 10px rgba(0,0,0,0.4);
  transition: background 0.2s, transform 0.2s;
  z-index: 20;
}

.add-node-btn:hover {
  background: #059669;
  transform: translateX(-50%) scale(1.1);
}

const workspace = document.getElementById("workspace");
const svgLayer = document.getElementById("svg-layer");

let activeNode = null;
let offsetX = 0;
let offsetY = 0;
let nodeCounter = 1;

function drawLines() {
  while (svgLayer.firstChild) {
    svgLayer.removeChild(svgLayer.firstChild);
  }
  
  const nodes = document.querySelectorAll(".flow-node");
  for (let i = 0; i < nodes.length; i++) {
    const child = nodes.item(i);
    const parentId = child.getAttribute("data-parent");
    
    if (parentId) {
      const parent = document.getElementById(parentId);
      if (parent) {
        const r1 = parent.getBoundingClientRect();
        const r2 = child.getBoundingClientRect();
        
        // Bottom center of parent
        const c1x = r1.left + (r1.width / 2);
        const c1y = r1.top + r1.height;
        
        // Top center of child
        const c2x = r2.left + (r2.width / 2);
        const c2y = r2.top;
        
        // Control points for smooth bezier curve
        const cp1x = c1x;
        const cp1y = c1y + 50;
        const cp2x = c2x;
        const cp2y = c2y - 50;
        
        const path = document.createElementNS("http://www.w3.org/2000/svg", "path");
        path.setAttribute("class", "flow-line");
        path.setAttribute("d", "M " + c1x + " " + c1y + " C " + cp1x + " " + cp1y + ", " + cp2x + " " + cp2y + ", " + c2x + " " + c2y);
        svgLayer.appendChild(path);
      }
    }
  }
}

function deleteNodeAndChildren(nodeId) {
  const node = document.getElementById(nodeId);
  if (node) {
    node.remove();
  }
  
  // Recursively find and delete any children attached to this node
  const nodes = document.querySelectorAll(".flow-node");
  for (let i = 0; i < nodes.length; i++) {
    const child = nodes.item(i);
    if (child.getAttribute("data-parent") === nodeId) {
      deleteNodeAndChildren(child.id);
    }
  }
}

function startDrag(e, node) {
  // Prevent dragging when clicking interactive elements
  if (e.target.classList.contains("editable") || e.target.classList.contains("delete-btn") || e.target.classList.contains("add-node-btn")) {
    return;
  }
  activeNode = node;
  const rect = node.getBoundingClientRect();
  offsetX = e.clientX - rect.left;
  offsetY = e.clientY - rect.top;
  node.style.zIndex = 100;
}

function attachListeners(node) {
  node.addEventListener("pointerdown", function(e) {
    startDrag(e, node);
  });
  
  const delBtn = node.querySelector(".delete-btn");
  if (delBtn) {
    delBtn.addEventListener("click", function() {
      deleteNodeAndChildren(node.id);
      drawLines();
    });
  }
  
  const addBtn = node.querySelector(".add-node-btn");
  if (addBtn) {
    addBtn.addEventListener("click", function() {
      createNewNode(node.id);
    });
  }
  
  const editables = node.querySelectorAll(".editable");
  for (let i = 0; i < editables.length; i++) {
    editables.item(i).addEventListener("pointerdown", function(e) {
      e.stopPropagation();
    });
    editables.item(i).addEventListener("input", function() {
      drawLines();
    });
  }
}

function createNewNode(parentId) {
  nodeCounter++;
  const parent = document.getElementById(parentId);
  const pr = parent.getBoundingClientRect();
  
  const newNode = document.createElement("div");
  const newId = "node-" + nodeCounter;
  newNode.id = newId;
  newNode.className = "flow-node";
  newNode.setAttribute("data-parent", parentId);
  
  // Offset new node slightly below and randomly to the side of the parent
  const newX = pr.left + (Math.random() * 100 - 50);
  const newY = pr.top + 150;
  
  newNode.style.left = newX + "px";
  newNode.style.top = newY + "px";
  
  const header = document.createElement("div");
  header.className = "node-header";
  
  const title = document.createElement("div");
  title.className = "editable";
  title.setAttribute("contenteditable", "true");
  title.innerText = "Step " + nodeCounter;
  
  const delBtn = document.createElement("button");
  delBtn.className = "delete-btn";
  delBtn.innerText = "×";
  
  header.appendChild(title);
  header.appendChild(delBtn);
  
  const bodyDiv = document.createElement("div");
  bodyDiv.className = "node-body editable";
  bodyDiv.setAttribute("contenteditable", "true");
  bodyDiv.innerText = "Enter details here...";
  
  const addBtn = document.createElement("button");
  addBtn.className = "add-node-btn";
  addBtn.innerText = "+";
  
  newNode.appendChild(header);
  newNode.appendChild(bodyDiv);
  newNode.appendChild(addBtn);
  
  workspace.appendChild(newNode);
  attachListeners(newNode);
  drawLines();
}

// Attach listeners to the initial root node
const rootNode = document.getElementById("node-root");
attachListeners(rootNode);

window.addEventListener("pointermove", function(e) {
  if (!activeNode) return;
  
  const x = e.clientX - offsetX;
  const y = e.clientY - offsetY;
  
  activeNode.style.left = x + "px";
  activeNode.style.top = y + "px";
  
  drawLines();
});

window.addEventListener("pointerup", function() {
  if (activeNode) {
    activeNode.style.zIndex = 10;
    activeNode = null;
  }
});

window.addEventListener("resize", drawLines);
setTimeout(drawLines, 100);