/**
 * This collar is the most difficult part about this pattern
 * That's because slash&spread is easy with paper and scissors
 * but gets complicated when doing it in code.
 */

export default function(part) {
  let { paperless, sa, snippets, Snippet, utils, store, complete, points, measurements, options, macro, Point, paths, Path } = part.shorthand();

  // We're going to slash and spread this collar. Slashing first:
  // Divide top in 5 parts
  points.cutTop1 = points.topLeft.shiftFractionTowards(points.topRight, 0.2);
  points.cutTop2 = points.topLeft.shiftFractionTowards(points.topRight, 0.4);
  points.cutTop3 = points.topLeft.shiftFractionTowards(points.topRight, 0.6);
  points.cutTop4 = points.topLeft.shiftFractionTowards(points.topRight, 0.8);

  // Divide bottom in 4 parts
  let bottom = new Path()
    .move(points.standTop)
    .curve_(points.standTopCp, points.standTip)
  points.cutBottom1 = bottom.shiftFractionAlong(0.25);
  points.cutBottom2 = bottom.shiftFractionAlong(0.5);
  points.cutBottom3 = bottom.shiftFractionAlong(0.75);
  // Split curve, extract control points from ops
  let halves = bottom.split(points.cutBottom2);
  let quarters = [];
  quarters.push(...halves[0].split(points.cutBottom1));
  quarters.push(...halves[1].split(points.cutBottom3));
  points.q1Cp1 = quarters[0].ops[1].cp1;
  points.q1Cp2 = quarters[0].ops[1].cp2;
  points.q2Cp1 = quarters[1].ops[1].cp1;
  points.q2Cp2 = quarters[1].ops[1].cp2;
  points.q3Cp1 = quarters[2].ops[1].cp1;
  points.q3Cp2 = quarters[2].ops[1].cp2;
  points.q4Cp1 = quarters[3].ops[1].cp1;
  points.q4Cp2 = quarters[3].ops[1].cp2;

  // Collar slashed, not let's spread by rotating
  let rotate = {
    1: {
      pivot: "cutBottom1",
      points: ["cutBottom2", "cutTop1", "cutTop2", "q2Cp1", "q2Cp2"]
    },
    2: {
      pivot: "cutBottom2",
      points: ["cutBottom3", "cutTop2", "cutTop3", "q3Cp1", "q3Cp2"]
    },
    3: {
      pivot: "cutBottom3",
      points: ["standTip", "bottomRight", "cutTop4", "cutTop3", "q4Cp1"]
    },
    4: {
      pivot: "standTip",
      points: ["topRight", "bottomRight", "cutTop4"]
    },
  };

  let angle = -1 * options.collarSpread;
  let alsoRotate = [];
  for (let nr of [4,3,2,1]) {
    let step = rotate[nr];
    let pivot = step.pivot;
    let first = false;
    for (let pnt of step.points) {
      if(first === false) first = pnt;
      let id = `rot${nr}${pnt}`;
      points[id] = points[pnt].rotate(angle, points[pivot]);
      alsoRotate.push(id);
    }
    if(nr <4) for (let pnt of alsoRotate) points[pnt] = points[pnt].rotate(angle, points[pivot]);
  }

  // Shift panel 2 in place
  angle = points.cutBottom2.angle(points.rot1cutBottom2) + 180;
  let distance = -1 * points.cutBottom2.dist(points.rot1cutBottom2);
  for (let i of [
    'cutBottom2',
    'rot2cutTop2',
    'rot2cutTop3',
    'rot2cutBottom3',
    'rot2q3Cp1',
    'rot2q3Cp2'
  ]) points[i] = points[i].shift(angle, distance);

  // Shift panel 3 in place
  angle = points.cutBottom3.angle(points.rot2cutBottom3) + 180;
  distance = -1 * points.cutBottom3.dist(points.rot2cutBottom3);
  for (let i of [
    'cutBottom3',
    'rot3cutTop3',
    'rot3cutTop4',
    'rot3standTip',
    'rot3q4Cp1',
  ]) points[i] = points[i].shift(angle, distance);

  // Shift panel 4 in place
  angle = points.standTip.angle(points.rot3standTip) + 180;
  distance = -1 * points.standTip.dist(points.rot3standTip);
  for (let i of [
    'standTip',
    'rot4cutTop4',
    'rot4topRight',
    'rot4bottomRight'
  ]) points[i] = points[i].shift(angle, distance);

  // Top control point
  points.topLeftCp = points.topLeft.shift(0, points.rot4topRight.x * 0.6);

  // Paths
  /* Uncomment these paths to gain insight into what's happening here
  paths.collarStand = paths.seam.clone(); // Needed because it gets overwritten later
  paths.panels = new Path()
    .move(points.cutTop1).line(points.cutBottom1)
    .move(points.cutTop2).line(points.cutBottom2)
    .move(points.cutTop3).line(points.cutBottom3)
    .move(points.cutTop4).line(points.standTip)

  paths.outline = new Path()
    .move(points.bottomLeft)
    .curve(points.bottomLeftCp, points.standTipCp, points.standTip)
    ._curve(points.standTopCp, points.standTop)
    .curve_(points.standTopCpLeft, points.standTipLeft)
    .curve(points.standTipCpLeft, points.bottomLeftCpLeft, points.bottomLeft)
    .close()
    .move(points.topLeft)
    .line(points.topRight)
    .line(points.bottomRight);

  paths.panel2 = new Path()
    .move(points.cutBottom1)
    .line(points.rot1cutBottom2)
    .line(points.rot1cutTop2)
    .line(points.rot1cutTop1)
    .close()
    .attr("class", "dashed");

  paths.panel3 = new Path()
    .move(points.cutBottom2)
    .line(points.rot2cutBottom3)
    .line(points.rot2cutTop3)
    .line(points.rot2cutTop2)
    .close()
    .attr("class", "dashed");

  paths.panel4 = new Path()
    .move(points.cutBottom3)
    .line(points.rot3standTip)
    .line(points.rot3cutTop4)
    .line(points.rot3cutTop3)
    .close()
    .attr("class", "dashed");

  paths.panel5 = new Path()
    .move(points.standTip)
    .line(points.rot4bottomRight)
    .line(points.rot4topRight)
    .line(points.rot4cutTop4)
    .close()
    .attr("class", "dashed");
   */


  paths.seam = new Path()
    .move(points.standTop)
    /** This is the non-slashed path. We use this instead of the slashed
     *  parts of the path, so that we get a smooth line
     */
    .curve_(points.standTopCp, points.rot3standTip)
    /** These are the slashed parts. We're not using these, but you can change that if you want
     *  Just uncomment this, and comment out the non-slashed curve operation above
     */
    //.curve(points.q1Cp1, points.q1Cp2, points.cutBottom1)
    //.curve(points.rot1q2Cp1, points.rot1q2Cp2, points.rot1cutBottom2)
    //.curve(points.rot2q3Cp1, points.rot2q3Cp2, points.rot2cutBottom3)
    //.curve_(points.rot3q4Cp1, points.rot3standTip)
    .line(points.rot4bottomRight)
    .line(points.rot4topRight)
    ._curve(points.topLeftCp, points.topLeft)
    .line(points.standTop)
    .close()
    .attr("class", "fabric");

  return part;
}