class Vector3

# Vector3 provides the geometry/Vector3 standard library API.
class Vector3
  # Vector3.x stores instance state.
  # @type Int
  x: 0

  # Vector3.y stores instance state.
  # @type Int
  y: 0

  # Vector3.z stores instance state.
  # @type Int
  z: 0

  # Vector3.initialize provides the geometry/Vector3 standard library operation.
  # @param x Int x value.
  # @param y Int y value.
  # @param z Int z value.
  # @return Self the initialized object.
  initialize: x = 0, y = 0, z = 0 ->
    self.x = self.number(x, "x")
    self.y = self.number(y, "y")
    self.z = self.number(z, "z")

  # Vector3.abs provides the geometry/Vector3 standard library operation.
  # @param value String value value.
  # @return Any the resulting value.
  abs: value ->
    if value < 0
      return 0 - value
    value

  # Vector3.add provides the geometry/Vector3 standard library operation.
  # @param a Int a value.
  # @param b Int b value.
  # @return Any the resulting value.
  add: a, b = nil ->
    if b == nil
      b = a
      a = self
    self.expect(a, "a")
    self.expect(b, "b")
    Vector3(a.x + b.x, a.y + b.y, a.z + b.z)

  # Vector3.cross provides the geometry/Vector3 standard library operation.
  # @param a Int a value.
  # @param b Int b value.
  # @return Any the resulting value.
  cross: a, b = nil ->
    if b == nil
      b = a
      a = self
    self.expect(a, "a")
    self.expect(b, "b")
    Vector3(a.y * b.z - a.z * b.y, a.z * b.x - a.x * b.z, a.x * b.y - a.y * b.x)

  # Vector3.distance provides the geometry/Vector3 standard library operation.
  # @param a Int a value.
  # @param b Int b value.
  # @return Any the resulting value.
  distance: a, b = nil ->
    if b == nil
      b = a
      a = self
    math_sqrt(self.distance_squared(a, b))

  # Vector3.distance_squared provides the geometry/Vector3 standard library operation.
  # @param a Int a value.
  # @param b Int b value.
  # @return Any the resulting value.
  distance_squared: a, b = nil ->
    if b == nil
      b = a
      a = self
    self.length_squared(self.sub(a, b))

  # Vector3.div provides the geometry/Vector3 standard library operation.
  # @param v Any v value.
  # @param k Any k value.
  # @return Any the resulting value.
  div: v, k = nil ->
    if k == nil
      k = v
      v = self
    self.expect(v, "v")
    self.number(k, "k")
    if k == 0
      raise error("geometry.Vector3.div: divide by zero")
    Vector3(v.x / k, v.y / k, v.z / k)

  # Vector3.dot provides the geometry/Vector3 standard library operation.
  # @param a Int a value.
  # @param b Int b value.
  # @return Any the resulting value.
  dot: a, b = nil ->
    if b == nil
      b = a
      a = self
    self.expect(a, "a")
    self.expect(b, "b")
    a.x * b.x + a.y * b.y + a.z * b.z

  # Vector3.equal? provides the geometry/Vector3 standard library operation.
  # @param a Int a value.
  # @param b Int b value.
  # @return Boolean whether the condition is true.
  equal?: a, b = nil ->
    if b == nil
      b = a
      a = self
    a.class == Vector3 and b.class == Vector3 and a.x == b.x and a.y == b.y and a.z == b.z

  # Vector3.expect provides the geometry/Vector3 standard library operation.
  # @param value String value value.
  # @param name String name value.
  # @return Any the resulting value.
  expect: value, name ->
    if value.class != Vector3
      raise error("geometry.Vector3: " + name + " must be a Vector3")

  # Vector3.from_array provides the geometry/Vector3 standard library operation.
  # @param values Array values value.
  # @return Array the resulting value.
  from_array: values ->
    if values.class != Array or values.len() != 3
      raise error("geometry.Vector3.from_array: expected three-number array")
    Vector3(values[0], values[1], values[2])

  # Vector3.length provides the geometry/Vector3 standard library operation.
  # @param v Any v value.
  # @return Any the resulting value.
  length: v = nil ->
    if v == nil
      v = self
    math_sqrt(self.length_squared(v))

  # Vector3.length_squared provides the geometry/Vector3 standard library operation.
  # @param v Any v value.
  # @return Any the resulting value.
  length_squared: v = nil ->
    if v == nil
      v = self
    self.expect(v, "v")
    self.dot(v, v)

  # Vector3.lerp provides the geometry/Vector3 standard library operation.
  # @param a Int a value.
  # @param b Int b value.
  # @param t Any t value.
  # @return Any the resulting value.
  lerp: a, b, t ->
    self.expect(a, "a")
    self.expect(b, "b")
    self.number(t, "t")
    Vector3(a.x + (b.x - a.x) * t, a.y + (b.y - a.y) * t, a.z + (b.z - a.z) * t)

  # Vector3.nearly_equal? provides the geometry/Vector3 standard library operation.
  # @param a Int a value.
  # @param b Int b value.
  # @param epsilon Any epsilon value.
  # @return Boolean whether the condition is true.
  nearly_equal?: a, b, epsilon = nil ->
    if epsilon == nil
      epsilon = b
      b = a
      a = self
    self.expect(a, "a")
    self.expect(b, "b")
    if epsilon < 0
      raise error("geometry.Vector3.nearly_equal?: epsilon must be non-negative")
    self.abs(a.x - b.x) <= epsilon and self.abs(a.y - b.y) <= epsilon and self.abs(a.z - b.z) <= epsilon

  # Vector3.new provides the geometry/Vector3 standard library operation.
  # @param x Int x value.
  # @param y Int y value.
  # @param z Int z value.
  # @return Self the resulting value.
  new: x, y, z ->
    Vector3(x, y, z)

  # Vector3.normalize provides the geometry/Vector3 standard library operation.
  # @param v Any v value.
  # @return String the resulting value.
  normalize: v = nil ->
    if v == nil
      v = self
    geometry_len = self.length(v)
    if geometry_len == 0
      return self.zero()
    self.div(v, geometry_len)

  # Vector3.number provides the geometry/Vector3 standard library operation.
  # @param value String value value.
  # @param name String name value.
  # @return Any the resulting value.
  number: value, name ->
    if value.class != Number
      raise error("geometry.Vector3: " + name + " must be a number")
    value

  # Vector3.one provides the geometry/Vector3 standard library operation.
  # @return Any the resulting value.
  one: ->
    Vector3(1, 1, 1)

  # Vector3.scale provides the geometry/Vector3 standard library operation.
  # @param v Any v value.
  # @param k Any k value.
  # @return Any the resulting value.
  scale: v, k = nil ->
    if k == nil
      k = v
      v = self
    self.expect(v, "v")
    self.number(k, "k")
    Vector3(v.x * k, v.y * k, v.z * k)

  # Vector3.sub provides the geometry/Vector3 standard library operation.
  # @param a Int a value.
  # @param b Int b value.
  # @return Any the resulting value.
  sub: a, b = nil ->
    if b == nil
      b = a
      a = self
    self.expect(a, "a")
    self.expect(b, "b")
    Vector3(a.x - b.x, a.y - b.y, a.z - b.z)

  # Vector3.to_array provides the geometry/Vector3 standard library operation.
  # @param v Any v value.
  # @return Array the resulting value.
  to_array: v = nil ->
    if v == nil
      v = self
    self.expect(v, "v")
    [v.x, v.y, v.z]

  # Vector3.zero provides the geometry/Vector3 standard library operation.
  # @return Any the resulting value.
  zero: ->
    Vector3(0, 0, 0)