$fn=256;
dimLeg = [32, 32, 50];
dimCaster = [31, 31, 50];
casterPinDia = 7.5;
casterRestDia = 14;
casterRestHeight = 3;
pipeThickness = 2.2;
wallThickness = 4;
legCutHeight = 96;
ep = 0.01;

dimOuter = dimLeg + [wallThickness, wallThickness, 0];

module casterReceiver1() {
  translate([0, 0, dimCaster[2]/2])
  difference() {
    cube(dimCaster, center=true);
    cylinder(h=dimCaster[2]+2*ep, d=casterPinDia, center=true);
    translate([0, 0, -dimCaster[2]/2-ep]) cylinder(h=casterRestHeight+ep, d=casterRestDia);
  }
}

module casterReceiver2() {
}

module legReceiver() {
  translate([0, 0, dimLeg[2]/2]);
  difference() {
    cube(dimLeg + [2*wallThickness, 2*wallThickness, 0], center=true);
    cube(dimLeg + [0, 0, 2*ep], center=true);
  }
}

module singlePiece() {

  difference() {
    union() {
      // Caster receiver blank
      linear_extrude(
        height=dimCaster[2],
        scale = [
          dimOuter[0] / (casterRestDia + wallThickness),
          dimOuter[1] / (casterRestDia + wallThickness)])
        square(
          [ casterRestDia + wallThickness,
            casterRestDia + wallThickness],
          center=true);

      // Leg extension
      translate([-dimOuter[0]/2, -dimOuter[1]/2, dimCaster[2] - ep])
        cube([dimOuter[0], dimOuter[1], legCutHeight - dimCaster[2] + dimLeg[2] + ep]);
    }

    // Caster receiver cuts
    cylinder(h=dimCaster[2], d=casterPinDia);
    translate([0, 0, -ep]) cylinder(h=casterRestHeight + ep, d=casterRestDia);

    // Leg receiver cut
    translate([0, 0, (legCutHeight + dimLeg[2]/2)])
      cube(dimLeg + [0, 0, ep], center=true);
  }
}

module supportRib() {
  sideLen = legCutHeight + dimLeg[2] * 3;
  supportHeight = legCutHeight + dimLeg[2];
  difference() {
    translate([0, 0, supportHeight/2])
      cube([sideLen, sideLen, supportHeight-ep], center=true);

    singlePiece();

    translate([-sideLen/2-ep, 1, -ep])
      cube([sideLen+2*ep, sideLen+2*ep, supportHeight+2*ep]);

    translate([-sideLen/2-ep, -sideLen-1, -ep])
      cube([sideLen+2*ep, sideLen+2*ep, supportHeight+2*ep]);

    translate([0, -sideLen/2-ep, -ep])
      cube([sideLen+2*ep, sideLen+2*ep, supportHeight+2*ep]);

    cylinder(h=legCutHeight, d=casterRestDia+2*ep);

    translate([0, 0, legCutHeight + dimLeg[2]/2 - ep])
      cube(dimLeg + [2*ep, 2*ep, 2*ep], center=true);
  }
}

difference() {
  union() {
    rotate([0, -45, 0])
    translate([(casterRestDia + wallThickness)/2, 0, 0])
    union() {
      singlePiece();

      for (i = [-1, 1]) {
        translate([-0.1, i*8, 0])
        supportRib();
      }
    }

    translate([-100, -30, 0]) cube([1, 60, 20]);
  }

  translate([-200, -200, -200]) cube([400, 400, 200]);
  translate([-210, -10, -ep]) cube([100, 20, 200]);
}