import { MARKINGS, RINK } from './rink.js';

/**
 * The net, and what counts as a goal.
 *
 * Pure numbers and pure predicates, so the shootout logic and the tests can
 * agree about scoring without a physics world in the room.
 */

/** Regulation: 6ft wide, 4ft tall, 44in deep. */
export const NET = Object.freeze({
  width: 1.83,
  height: 1.22,
  depth: 1.12,
  postRadius: 0.048,
  /** Crease: 6ft radius arc off the goal line. */
  creaseRadius: 1.83,
});

/**
 * Goal line X for an end. `end` is +1 for the +X end, −1 for −X.
 * The net's mouth sits *on* this line, opening back toward centre ice.
 */
export const goalLineX = (end) => end * MARKINGS.goalLine;

/**
 * Has the puck fully crossed the line, between the posts and under the bar?
 *
 * "Fully" is the rule and it matters: a puck resting on the line is not a goal.
 * The whole puck has to be past, so the test is against the puck's leading edge
 * — its centre plus its radius.
 */
export function isGoal(puck, end, puckRadius = 0.0381) {
  const line = goalLineX(end);
  // Leading edge past the line, travelling into the net.
  const past = end > 0 ? puck.x - puckRadius > line : puck.x + puckRadius < line;
  if (!past) return false;
  // ...but not out the back of it.
  if (Math.abs(puck.x - line) > NET.depth) return false;
  if (Math.abs(puck.z) > NET.width / 2 - puckRadius) return false;
  return (puck.y ?? 0) < NET.height;
}

/** True once the puck is behind the goal line but wide or high — a miss. */
export function isWide(puck, end, puckRadius = 0.0381) {
  const line = goalLineX(end);
  const past = end > 0 ? puck.x - puckRadius > line : puck.x + puckRadius < line;
  return past && !isGoal(puck, end, puckRadius);
}

/**
 * Where a goalie should stand, given where the puck is.
 *
 * Angle play, which is the whole of goaltending positioning: stand on the line
 * between the puck and the middle of the net, `depth` metres out from the goal
 * line. Cover the angle and the shooter has nothing to shoot at; the rest is
 * reflexes.
 *
 * Returns a point, clamped so the goalie never wanders past the posts by more
 * than a pad's width — a goalie who chases the puck to the corner has left an
 * open net, which reads as broken rather than as aggressive.
 */
export function goalieSpot(puck, end, depth = 0.55, out = { x: 0, z: 0 }) {
  const line = goalLineX(end);
  // Aim from the middle of the goal mouth toward the puck.
  const dx = puck.x - line;
  const dz = puck.z - 0;
  const len = Math.hypot(dx, dz);
  if (len < 1e-4) {
    out.x = line - end * 0.1;
    out.z = 0;
    return out;
  }
  out.x = line + (dx / len) * depth;
  out.z = (dz / len) * depth;

  // Two clamps, and *both* were originally the wrong way round — between them
  // they teleported the goalie onto the puck and then pinned them to the goal
  // line, which threw away every bit of angle the depth was there to buy.
  //
  // "Out" means toward centre ice, which is decreasing x at the +X end. So
  // coming out past the puck is `out.x < puck.x` there, and going behind the
  // line is `out.x > line`.
  if (end > 0 ? out.x < puck.x : out.x > puck.x) out.x = puck.x;
  if (end > 0 ? out.x > line : out.x < line) out.x = line;
  // Stay within the posts, plus a little for a pad sticking out.
  const limit = NET.width / 2 + 0.22;
  out.z = Math.max(-limit, Math.min(limit, out.z));
  return out;
}

/** Centre ice, facing the end being shot at — where a shootout attempt starts. */
export function shootoutStart(end) {
  return { x: 0, z: 0, yaw: end > 0 ? Math.PI / 2 : -Math.PI / 2 };
}

/** Is the puck still in a sensible place for a live attempt? */
export function attemptLive(puck, end) {
  if (Math.abs(puck.z) > RINK.halfZ) return false;
  // Past the goal line at that end, one way or another, ends it.
  return end > 0 ? puck.x < goalLineX(end) + NET.depth : puck.x > goalLineX(end) - NET.depth;
}