/* base */
base_w = 10;
roundness = 0.5; /* should match offset constraint in sovlespace */
wall_thickness = 1.0;

side_dxf = "knob_side.dxf";

/* stem */
stem_wall_thickness = 1.5;
stem_w = 2.4;
stem_h = 6.8;
cut_corners_w = 1.6;
cut_corners_h = 2.0;

/* don't touch */
lots = 1000;
eps = 0.01;

module offset_shell(offx) {
    intersection() {
        translate([-lots/2, 0, 0])
        square([lots, lots]);
        
        offset(r=-offx)
        union() {
            children();
            mirror([0, 1, 0]) children();
        }
    }
}

module dxf_shell(file, w, d, r) {
    intersection() {
        translate([0, 0, lots/2])
        cube([lots, lots, lots], center=true);
        
        difference() {
            minkowski(){
                sphere(r=r, $fn=32);
                
                rotate([90, 0, 0])
                linear_extrude(height=w - 2*r, center=true)
                offset_shell(r)
                import(file, $fn=128);
            }
            
            translate([0, 0, -eps])
            rotate([90, 0, 0])
            linear_extrude(height=w-2*d, center=true)
            offset_shell(d)
            import(file, $fn=128);
        }
    }
}

module stem() {
    difference() {
        cube([stem_h + 2*stem_wall_thickness, stem_w + 2*stem_wall_thickness, lots], center=true);
        cube([stem_h, stem_w, lots], center=true);
        
        translate([0, 0, -lots/2])
        cube([lots, lots, lots], center=true);
        
        translate([-(stem_h+stem_wall_thickness)/2-eps, -(stem_w+stem_wall_thickness)/2-eps, 0])
        cube([cut_corners_h, cut_corners_w, lots], center=true);
        translate([(stem_h+stem_wall_thickness)/2+eps, -(stem_w+stem_wall_thickness)/2-eps, 0])
        cube([cut_corners_h, cut_corners_w, lots], center=true);
        translate([-(stem_h+stem_wall_thickness)/2-eps, (stem_w+stem_wall_thickness)/2+eps, 0])
        cube([cut_corners_h, cut_corners_w, lots], center=true);
        translate([(stem_h+stem_wall_thickness)/2+eps, (stem_w+stem_wall_thickness)/2+eps, 0])
        cube([cut_corners_h, cut_corners_w, lots], center=true);
    }
}

ridge_w = 0.8;
ridge_f = 0.3;
ridge_h = 3.7;

difference() {
    union () {
        dxf_shell(side_dxf, base_w, wall_thickness, roundness);

        intersection() {
            stem();
            
            rotate([90, 0, 0])
            linear_extrude(height=base_w, center=true)
            import(side_dxf, $fn=128);
        }
    }
    
    translate([0, -base_w/2 - ridge_w*ridge_f, -eps])
    cylinder(d=ridge_w, h=lots, $fn=32);
    
    translate([0, base_w/2 + ridge_w*ridge_f, -eps])
    cylinder(d=ridge_w, h=lots, $fn=32);
    
    translate([0, 0, ridge_h])
    rotate([90, 0, 0])
    cylinder(d=ridge_w, h=lots, center=true, $fn=32);    
}