local Vector3 = {
  x = 0,
  y = 0,
  z = 0,

  _CLASS_ = "Vector3"
}

setmetatable(Vector3, Vector3)

local function is_weak_vector3(t)
  if type(t) ~= "table" then return false end

  local haskeys = t.x ~= nil and t.y ~= nil and t.z ~= nil
  if not haskeys then
    return type(t[1]) == "number" and type(t[2]) == "number" and type(t[3]) == "number"
  else
    return type(t.x) == "number" and type(t.y) == "number" and type(t.z) == "number"
  end
end

function Vector3:__mul(b)
  if type(b) == "number" then
    return Vector3{
      x = self.x * b,
      y = self.y * b,
      z = self.z * b,
    }
  elseif type(b) == "table" and is_weak_vector3(b) then
    local other = Vector3(b)
    return Vector3{
      self.x * other.x,
      self.y * other.y,
      self.z * other.z,
    }
  end

  error("Vector3: other must be either a number or a Vector3-like table.")
  return Vector3()
end

function Vector3:__div(b)
  if type(b) == "number" then
    return Vector3{
      x = self.x / b,
      y = self.y / b,
      z = self.z / b,
    }
  elseif type(b) == "table" and is_weak_vector3(b) then
    local other = Vector3(b)
    return Vector3{
      self.x / other.x,
      self.y / other.y,
      self.z / other.z,
    }
  end

  error("Vector3: other must be either a number or a Vector3-like table.")
  return Vector3()
end

function Vector3:__add(b)
  if not is_weak_vector3(b) then
    error("Vector3: other must be a Vector3-like table.")
    return self
  end
  local other = Vector3(b)
  return Vector3{
    self.x + other.x,
    self.y + other.y,
    self.z + other.z,
  }
end

function Vector3:__sub(b)
  if not is_weak_vector3(b) then
    error("Vector3: other must be a Vector3-like table.")
    return self
  end
  local other = Vector3(b)
  return Vector3{
    self.x - other.x,
    self.y - other.y,
    self.z - other.z,
  }
end

function Vector3:__unm()
  return Vector3{
    -self.x,
    -self.y,
    -self.z,
  }
end

function Vector3:__call(...)
  local args = ...
  local nv = {x = 0, y = 0, z = 0}
  setmetatable(nv, Vector3)
  if type(args) == "number" then
      nv.x, nv.y, nv.z = args, args, args
  elseif type(args) == "table" then
    if args.x ~= nil then
      nv.x, nv.y, nv.z = args.x, args.y, args.z
    else
      nv.x, nv.y, nv.z = args[1], args[2], args[3]
    end
  end
  return nv
end

function Vector3:__tostring()
  return "Vector3(" .. tostring(self.x) .. ", " .. tostring(self.y) .. ", " .. tostring(self.z) .. ")"
end

return Vector3