import { Vec2 } from './interfaces';

export const vec2Length = ([x, y]: Vec2) => Math.abs(Math.sqrt(x * x + y * y));

export const vec2Add = ([x1, y1]: Vec2, [x2, y2]: Vec2): Vec2 => [
  x1 + x2,
  y1 + y2,
];

export const vec2Sub = ([x1, y1]: Vec2, [x2, y2]: Vec2): Vec2 => [
  x1 - x2,
  y1 - y2,
];

export const vec2MultiplyScalar = ([x, y]: Vec2, scalar: number): Vec2 => [
  x * scalar,
  y * scalar,
];

export const vec2DivideScalar = ([x, y]: Vec2, scalar: number): Vec2 => [
  x / scalar,
  y / scalar,
];

export const vec2Normalize = (vec: Vec2): Vec2 =>
  vec2DivideScalar(vec, vec2Length(vec));

export const vec2Distance = (vec1: Vec2, vec2: Vec2) =>
  vec2Length(vec2Sub(vec2, vec1));

export const vec2InCircle = (circle: Vec2, point: Vec2, radius: number) =>
  vec2Distance(circle, point) <= radius;

export const vec2Inverse = (vec: Vec2): Vec2 => vec2MultiplyScalar(vec, -1);

export const vec2Snap = ([x, y]: Vec2, snapScale: number): Vec2 =>
  vec2MultiplyScalar(
    [Math.round(x / snapScale), Math.round(y / snapScale)],
    snapScale
  );

export const vec2Equals = ([x1, y1]: Vec2, [x2, y2]: Vec2) =>
  x1 === x2 && y1 === y2;

export const vec2AngleFromOrigin = (
  [x, y]: Vec2,
  [ox, oy]: Vec2 = [0, 0]
): number => Math.atan2(y - oy, x - ox);

export const vec2PointFromAngle = (
  angle: number,
  [ox, oy]: Vec2 = [0, 0]
): Vec2 => [Math.cos(angle) + ox, Math.sin(angle) + oy];

export const deg2rad = (deg: number) => deg * (Math.PI / 180);
export const rad2deg = (rad: number) => rad * (180 / Math.PI);