btroops/index.js

var rect = document.querySelector('rect#map');
var toFixed = n => Number.parseFloat(n).toFixed(2);

var svgns = "http://www.w3.org/2000/svg",
    svg = document.querySelector('svg');

rect.addEventListener('mousemove', e => {
  var rect = e.target.getBoundingClientRect();
  var x = e.clientX - rect.left; // x position within the element
  var y = e.clientY - rect.top;  // y position within the element

  console.log(
    'x: ' + toFixed(x / rect.width * e.target.width.baseVal.valueInSpecifiedUnits) + '"',
    'y: ' + toFixed(y / rect.height * e.target.height.baseVal.valueInSpecifiedUnits) + '"'
  );

  let aim = document.querySelector('.firing-arc.active');

  if (aim) {
    aim.setAttributeNS(null, 'x2', `${x / rect.width * e.target.width.baseVal.valueInSpecifiedUnits}in`);
    aim.setAttributeNS(null, 'y2', `${y / rect.height * e.target.height.baseVal.valueInSpecifiedUnits}in`);
  }
});

document.querySelectorAll('.soldier-record').forEach(el =>
  el.addEventListener('click', e => {
    if (e.target.classList.contains('selected')) {
      e.target.classList.remove('selected');
    } else {
      document.querySelectorAll('.soldier-record.selected').forEach(el =>
        el.classList.remove('selected')
      );
      e.target.classList.add('selected');
    }
  })
);

document.querySelector('#set-firing-arc').addEventListener('click', e => {
  let selectedSoldier = document.querySelector('.soldier-record.selected');

  if (selectedSoldier) {
    let {troopNumber, troopAllegiance} = selectedSoldier.dataset;

    let firingArc = document.querySelector(
      `.firing-arc[data-troop-number="${troopNumber}"][data-troop-allegiance="${troopAllegiance}"]`
    );

    if (firingArc) { firingArc.remove() }

    let counter = document.querySelector(
      `circle.counter[data-troop-number="${troopNumber}"][data-troop-allegiance="${troopAllegiance}"]`
    );

    let aim = document.createElementNS(svgns, 'line');

    aim.classList.add('firing-arc', 'active');
    aim.dataset.troopNumber = troopNumber;
    aim.dataset.troopAllegiance = troopAllegiance;
    aim.setAttributeNS(null, 'x1', counter.cx.baseVal.valueAsString);
    aim.setAttributeNS(null, 'y1', counter.cy.baseVal.valueAsString);
    aim.setAttributeNS(null, 'x2', counter.cx.baseVal.valueAsString);
    aim.setAttributeNS(null, 'y2', counter.cy.baseVal.valueAsString);

    svg.appendChild(aim);

    aim.addEventListener('click', e => {
      e.target.classList.remove('active');
      document.querySelector('circle#point').style.display = '';
    });

    document.querySelector('circle#point').style.display = 'none';
  }
});

var columnCount = 33,
    rowCount = 25,
    pointDistanceInInches = 1.005;

var isEven = n => n % 2 === 0;

var columns = [...Array(columnCount).keys()],
    rows = [...Array(rowCount).keys()],
    points = rows.map(y => columns.map(x => [x, y]));

var xOffset = 0.25,
    yOffset = 0.45;
    calcY = Math.sqrt(3) * pointDistanceInInches / 2,
    alternatingOffset = pointDistanceInInches / 2;

points.forEach((row, index) => row.forEach(([x, y]) => {
  var cx = x * pointDistanceInInches + xOffset + (isEven(index) ? alternatingOffset : 0),
      cy = y * pointDistanceInInches * calcY + yOffset,
      point = document.createElementNS(svgns, 'use');

  point.setAttributeNS(null, 'href', `#point`);
  point.setAttributeNS(null, 'x', `${cx}in`);
  point.setAttributeNS(null, 'y', `${cy}in`);
  point.dataset.x = x;
  point.dataset.y = y;

  point.addEventListener('click', e => {
    let selectedSoldier = document.querySelector('.soldier-record.selected');

    if (selectedSoldier) {
      let counter = document.createElementNS(svgns, 'circle');
      let text = document.createElementNS(svgns, 'text');

      counter.setAttributeNS(null, 'cx', `${cx}in`);
      counter.setAttributeNS(null, 'cy', `${cy}in`);
      counter.setAttributeNS(null, 'r', '0.25in');
      counter.dataset.troopNumber = selectedSoldier.dataset.troopNumber;
      counter.dataset.troopAllegiance = selectedSoldier.dataset.troopAllegiance;
      counter.classList.add('counter');

      text.setAttributeNS(null, 'text-anchor', 'middle');
      text.setAttributeNS(null, 'x', `${cx}in`);
      text.setAttributeNS(null, 'y', `${cy + 0.25}in`);
      text.dataset.troopNumber = selectedSoldier.dataset.troopNumber;
      text.dataset.troopAllegiance = selectedSoldier.dataset.troopAllegiance;
      text.textContent = `${selectedSoldier.dataset.troopNumber}`;
      text.classList.add('counter');

      document.querySelectorAll(
        `.counter[data-troop-number="${selectedSoldier.dataset.troopNumber}"][data-troop-allegiance="${selectedSoldier.dataset.troopAllegiance}"]`
      ).forEach(el => el.remove());

      svg.appendChild(counter);
      svg.appendChild(text);
    }
  });

  svg.appendChild(point);
}));

let getPointCoords = (x, y) => {
  let point = document.querySelector(`[data-x="${x}"][data-y="${y}"]`);

  return [point.x.baseVal.value, point.y.baseVal.value]
};


let smallArc = document.createElementNS(svgns, 'polygon');
let smallArcPoints = `${getPointCoords(1, 24)} ${getPointCoords(1, 21)} ${getPointCoords(2, 21)}`;
smallArc.setAttributeNS(null, 'points', smallArcPoints);

svg.appendChild(smallArc);

let medArc = document.createElementNS(svgns, 'polygon');
let medArcPoints = `${getPointCoords(4, 24)} ${getPointCoords(3, 21)} ${getPointCoords(6, 21)}`;
medArc.setAttributeNS(null, 'points', medArcPoints);

svg.appendChild(medArc);

let lrgArc = document.createElementNS(svgns, 'polygon');
let lrgArcPoints = `${getPointCoords(19, 24)} ${getPointCoords(9, 21)} ${getPointCoords(30, 21)}`;
lrgArc.setAttributeNS(null, 'points', lrgArcPoints);

svg.appendChild(lrgArc);