const outerRadius = 8.9 / 2;
const ringHeight = 1.2;
const innerRadius = 7.26 / 2;
const stopperHeight = 0.3;

function innerRing(offset = 0) {
  return cylinder({ r1: innerRadius + offset, r2: innerRadius + offset, h: ringHeight * 2, fn: 128 }).translate([
    0,
    0,
    -ringHeight
  ]);
}

function innerTab() {
  const w = 2;
  const tabDepth = 0.075;
  const tabHeight = 0.8;
  return intersection(
    cube({ size: [innerRadius + tabDepth, w, tabHeight] }).translate([0, -w / 2, -stopperHeight]),
    innerRing(tabDepth)
  );
}

function innerTabStop() {
  const w = 1;
  return cube({ size: [1, w, 0.45] })
    .translate([innerRadius - 0.5, -w / 2, -stopperHeight - 0.05])
    .rotateX(1.5);
}

function ring() {
  const stopperRadius = 9.6 / 2;
  const innerTabStopAngle = 68.15;
  return union(
    difference(
      union(
        cylinder({ r1: outerRadius, r2: outerRadius, h: ringHeight, fn: 128 }),
        cylinder({ r1: stopperRadius, r2: stopperRadius, h: stopperHeight, fn: 128 }).translate([0, 0, -stopperHeight])
      ),
      innerRing(),
      innerTab().rotateZ(60),
      innerTab().rotateZ(60 + 120),
      innerTab().rotateZ(60 + 240)
    ),
    difference(
      union(
        innerTabStop().rotateZ(innerTabStopAngle),
        innerTabStop().rotateZ(innerTabStopAngle + 120),
        innerTabStop().rotateZ(innerTabStopAngle + 240)
      ),
      innerRing(),
      cylinder({ r1: stopperRadius, r2: stopperRadius, h: stopperHeight, fn: 128 }).translate([
        0,
        0,
        -stopperHeight * 2
      ])
    )
  );
}

function tab() {
  const w = 1.5;
  const tabDepth = 0.2;
  const tabHeight = 0.4;
  return intersection(
    difference(
      cube({ size: [outerRadius + tabDepth, w, tabHeight] })
        .translate([0, -w / 2, ringHeight / 2 - tabHeight / 2])
        .rotateX(2.5)
        .setColor(1, 0, 0),
      innerRing()
    ),
    cylinder({ r1: outerRadius + tabDepth, r2: outerRadius + tabDepth, h: ringHeight, fn: 128 })
  );
}

function main() {
  return union(ring(), tab().rotateZ(120), tab().rotateZ(240), tab());
}