# -*- encoding: utf-8 -*-
# -*- frozen_string_literal: true -*-
# -*- warn_indent: true -*-

UnitMeasurements::SolidAngle = UnitMeasurements.build do
  primitive "sr"

  system :metric do
    si_unit "sr", aliases: ["steradian", "steradians"]

    unit "deg²", value: [((Math::PI / 180) ** 2), "sr"], aliases: ["(°)²", "sq °", "square degree", "square degrees"] # (π / 180)² sr
  end

  unit "sp", value: [(4 * Math::PI), "sr"], aliases: ["spat", "spats"] # (4 * π) sr

  unit "arcmin²", value: [(Rational(1, 60) ** 2), "deg²"], aliases: ["(′)²", "sq ′", "square arcminute", "square arcminutes"] # ((π / 180) * (1 / 60))² sr
  unit "arcsec²", value: [(Rational(1, 60) ** 2), "arcmin²"], aliases: ["(″)²", "sq ″", "square arcsecond", "square arcseconds"] # ((π / 180) * (1 / 3600))² sr
end