/* GNU AGPLv3 (or later at your option)
   see bottom for more license info */

/* spin thing that erin likes */
$fn = 75;

layer_height = 0.35;

weight = "penny";
// weight = "608zz";

bearing = "608zz";
// bearing = "625rs";

weight_lip_overhang = 0.3;
bearing_lip_overhang = weight_lip_overhang;
wall = 3;
penny_thickness = 1.52;
penny_radius = 19.05 / 2;

_608zz_radius = 22 / 2;
_608zz_inner_radius = 8.1 / 2;
_608zz_cover_radius = _608zz_radius;
_608zz_cap_footprint_radius = 12 / 2;
_608zz_thickness = 7;

_625rs_radius = 16 / 2;
_625rs_inner_radius = 5 / 2;
_625rs_thickness = 5;
_625rs_cover_radius = _625rs_radius;
_625rs_cap_footprint_radius = _625rs_inner_radius + 1;

weight_radius = (weight == "penny") ? penny_radius : _608zz_radius;
weight_thickness = (weight == "penny") ?
     penny_thickness * 5 : _608zz_thickness;

bearing_radius =
  (bearing == "608zz") ? _608zz_radius
  : (bearing == "625rs") ? _625rs_radius
  : 1/0;
bearing_window_radius = bearing_radius - bearing_lip_overhang - 1;
bearing_inner_radius =
  (bearing == "608zz") ? _608zz_inner_radius
  : (bearing == "625rs") ? _608zz_inner_radius
  : 1/0;
bearing_cover_radius =
  (bearing == "608zz") ? _608zz_cover_radius
  : (bearing == "625rs") ? _625rs_cover_radius
  : 1/0;
bearing_cap_footprint_radius =
  (bearing == "608zz") ? _608zz_cap_footprint_radius
  : (bearing == "625rs" ) ? _625rs_cap_footprint_radius
  : 1/0;
bearing_thickness =
  (bearing == "608zz") ? _608zz_thickness
  : (bearing == "625rs") ? _625rs_thickness
  : 1/0;

spinner_height = penny_thickness * 5 + 2;
arms = 3;

module cap(bearing_inner_radius,
           bearing_cap_footprint_radius,
           bearing_cover_radius,
           bearing_thickness,
           bearing_window_radius) {
  footprint_height = 4.5;
  footprint_radius_safety = 0.2;
  cap_height = 3;
  bearing_thickness_safety = 0.6;
  finger_spot_height = cap_height / 10;

  difference() {
    union() {
      cylinder(r1 = bearing_cover_radius - tan(30) * cap_height,
               r2 = bearing_cover_radius,
               h = cap_height);
      linear_extrude(height = cap_height
                              + footprint_height
                              - 1.05) {
        circle(bearing_window_radius - 1); }
      linear_extrude(height = cap_height + footprint_height) {
        circle(bearing_cap_footprint_radius - footprint_radius_safety); }
      linear_extrude(height = cap_height
                              + footprint_height
                              + bearing_thickness / 2
                              - bearing_thickness_safety) {
        circle(bearing_inner_radius); }
    }
    translate([0, 0, -0.01]) {
      cylinder(r1 = bearing_inner_radius,
               r2 = bearing_inner_radius - tan(30) * finger_spot_height,
               h = finger_spot_height); } } }

module donut(height, footprint_radius) {
  bread_radius = height / 2;
  rotate_extrude() {
    translate([footprint_radius, 0]) {
      circle(bread_radius); } } }

module donut_hole(height, footprint_radius) {
  difference() {
    cylinder(r = footprint_radius, h = height, center = true);
    donut(height, footprint_radius); } }

module jelly_filled(height, footprint_radius) {
  cylinder(r = footprint_radius, h = height, center = true);
  donut(height, footprint_radius); }

module fillet(r) {
  offset(r = -r) { offset(delta = r) { children(); } } }

module mirrored(axis) {
  children();
  mirror(axis) children(); }

module spin_slice(weight_radius,
                  bearing_radius,
                  round_extra,
                  wall,
                  arms) {
  joiner_radius = (bearing_radius + weight_radius) / 2;

  bearing_xy = [0, 0];
  // a = side along x axis
  a = bearing_radius + weight_radius + wall;
  // b = side from center to joiner
  b = bearing_radius + joiner_radius + round_extra;
  // c = side between joiner and arm center
  c = joiner_radius + weight_radius + round_extra;

  weight_xy = [a, 0];

  cos_C = (pow(a, 2) + pow(b, 2) - pow(c, 2)) / (2 * a * b);
  sin_C = sqrt(1 - pow(cos_C, 2));

  joiner_xy = [cos_C, sin_C] * b;

  for(arm = [0 : arms - 1]) {
    rotate(arm * (360 / arms)) {
      difference() {
        union() {
          translate(bearing_xy) {
            circle(bearing_radius + round_extra); }
          translate(weight_xy) {
            circle(weight_radius + round_extra); }
          mirrored([0, 1]) {
            polygon([bearing_xy, weight_xy, joiner_xy]); } }
        mirrored([0, 1]) {
          translate(joiner_xy) {
            circle(joiner_radius); } } } } } }

module spin_slices(weight_radius,
                   weight_thickness,
                   bearing_radius,
                   bearing_thickness,
                   weight_lip_overhang = 0.3,
                   bearing_lip_overhang = 0.3,
                   wall = 3,
                   arms = 3,
                   layer_height = 0.15) {
  thicker_thickness = (bearing_thickness > weight_thickness) ?
    bearing_thickness : weight_thickness;
  calculated_height = thicker_thickness + 2 * wall;
  layers = 2 * ceil(ceil(calculated_height / layer_height) / 2);
  actual_height = layers * layer_height;
  round_radius = actual_height / 2;

  /* rounding the outside edge of the spinner with a semi-circle leads
     to a shape that an overhang on the second layer several times the
     thickness of a printed extrusion width.

     rather than using a full semi-circle, this code aims to use just the
     portion in the middle, where the overhang is less severe */
  old_start = 0;
  old_end = (layers / 2) - 1;

  /* add one to have some thickness all around weight holes
     for first layer */
  new_start = old_end / 16 + 1;
  new_end = old_end;

  old_range = old_end - old_start;
  new_range = new_end - new_start;

  factor = new_range / old_range;

  /* initial adjacent is adjusted to (new start - 1) to allow some
     thickness all around weight holes on first layer */
  initial_adjacent = round_radius - ((new_start - 1) * layer_height);
  initial_angle = acos(initial_adjacent / round_radius);
  initial_round_extra = initial_adjacent * tan(initial_angle);

  difference() {
    mirrored([0, 0, 1]) {
      for(layer = [0 : (layers / 2) - 1]) {
        translate([0, 0, layer * layer_height - actual_height / 2]) {
          linear_extrude(height = layer_height) {
            new_layer = (layer - old_start) * factor + new_start;
            adjacent = round_radius - (new_layer * layer_height);
            angle = acos(adjacent / round_radius);
            round_extra = adjacent * tan(angle) - initial_round_extra;
            spin_slice(weight_radius,
                       bearing_radius,
                       round_extra,
                       wall,
                       arms); } } } }
    cylinder(h = actual_height + 0.1,
             r = bearing_radius - bearing_lip_overhang,
             center = true);
    cylinder(h = bearing_thickness + 0.05,
             r = bearing_radius + 0.15,
             center = true);
    for(arm = [0 : arms - 1]) {
      rotate(arm * (360 / arms)) {
        translate([bearing_radius + wall + weight_radius, 0]) {
          cylinder(h = actual_height + 0.1,
                   r = weight_radius - weight_lip_overhang,
                   center = true);
          cylinder(h = weight_thickness + 0.05,
                   r = weight_radius + 0.15,
                   center = true); } } } } }

module spin_donut(weight_radius,
                  weight_thickness,
                  bearing_radius,
                  bearing_thickness,
                  weight_lip_overhang,
                  bearing_lip_overhang,
                  wall,
                  arms) {
  thicker_thickness = (bearing_thickness > weight_thickness)
    ? bearing_thickness : weight_thickness;
  height = thicker_thickness + wall * 2;

  center_to_arm_center = bearing_radius + wall + weight_radius;

  jelly_filled(height, bearing_radius);
  for(arm = [0 : arms]) {
    rotate(arm * (360 / arms)) {
      translate([center_to_arm_center, 0, 0]) {
        jelly_filled(height, weight_radius); } } } }

/*
  This file is part of 3d-printables.

  3d-printables is free software: you can redistribute it and/or modify
  it under the terms of the GNU Affero General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  3d-printables is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU Affero General Public License for more details.

  You should have received a copy of the GNU Affero General Public License
  along with challenge-bot.  If not, see <http://www.gnu.org/licenses/>.
*/