const statusEl = document.querySelector('#status');
const svg = d3.select('#topology');
const width = 1000;
const height = 600;

const linkGroup = svg.append('g').attr('class', 'links');
const nodeGroup = svg.append('g').attr('class', 'nodes');

const simulation = d3.forceSimulation()
  .force('link', d3.forceLink().id(d => d.ip).distance(140))
  .force('charge', d3.forceManyBody().strength(-200))
  .force('center', d3.forceCenter(width / 2, height / 2));

function colorForNode(node) {
  if (node.comment && node.comment.includes('gateway')) return '#ffb347';
  if (node.comment && node.comment.includes('scanner')) return '#4db8ff';
  return node.via_ssh ? '#7fbea6' : '#d4d4d4';
}

function render(data) {
  const edges = data.edges.map(edge => ({
    ...edge,
    source: edge.source,
    target: edge.target,
  }));

  const link = linkGroup.selectAll('line').data(edges, d => `${d.source}|${d.target}|${d.relation}`);
  link.join(
    enter => enter.append('line').attr('stroke-width', 2),
    update => update,
    exit => exit.remove()
  ).attr('stroke', '#999');

  const node = nodeGroup.selectAll('g').data(data.nodes, d => d.ip);
  const nodeEnter = node.enter().append('g').call(d3.drag()
    .on('start', dragstarted)
    .on('drag', dragged)
    .on('end', dragended));

  nodeEnter.append('circle').attr('r', 26);
  nodeEnter.append('text')
    .attr('text-anchor', 'middle')
    .attr('dy', '0.35em')
    .text(d => d.ip);

  nodeEnter.append('title');

  const nodeMerged = nodeEnter.merge(node);
  nodeMerged.select('circle').attr('fill', colorForNode);
  nodeMerged.select('title').text(d => `${d.ip}\n${d.dns_name || 'no reverse host'}\nvia SSH: ${d.via_ssh}`);

  node.exit().remove();

  simulation.nodes(data.nodes).on('tick', ticked);
  simulation.force('link').links(edges);
  simulation.alpha(1).restart();
}

function ticked() {
  linkGroup.selectAll('line')
    .attr('x1', d => d.source.x)
    .attr('y1', d => d.source.y)
    .attr('x2', d => d.target.x)
    .attr('y2', d => d.target.y);

  nodeGroup.selectAll('g')
    .attr('transform', d => `translate(${d.x},${d.y})`);
}

function dragstarted(event, d) {
  if (!event.active) simulation.alphaTarget(0.3).restart();
  d.fx = d.x;
  d.fy = d.y;
}

function dragged(event, d) {
  d.fx = event.x;
  d.fy = event.y;
}

function dragended(event, d) {
  if (!event.active) simulation.alphaTarget(0);
  d.fx = null;
  d.fy = null;
}

async function refresh() {
  try {
    statusEl.textContent = 'Scanning local LAN…';
    const response = await fetch('/api/scan');
    if (!response.ok) {
      throw new Error(`scan failed: ${response.status}`);
    }
    const payload = await response.json();
    render(payload);
    statusEl.textContent = `Last scanned ${new Date().toLocaleTimeString()}`;
  } catch (error) {
    statusEl.textContent = `Error: ${error.message}`;
  }
}

document.querySelector('#refresh').addEventListener('click', refresh);
refresh();