defmodule Aprsme.ConvertTest do
  use ExUnit.Case, async: true
  use ExUnitProperties

  alias Aprsme.Convert

  describe "wind/3" do
    test "converts ultimeter mph" do
      assert Convert.wind(55, :ultimeter, :mph) == 3.417541556
    end

    test "zero stays zero" do
      assert Convert.wind(0, :ultimeter, :mph) == 0.0
    end
  end

  describe "temp/3" do
    test "converts ultimeter f" do
      assert Convert.temp(55, :ultimeter, :f) == 5.5
    end

    test "zero stays zero" do
      assert Convert.temp(0, :ultimeter, :f) == 0.0
    end
  end

  describe "speed/3" do
    test "converts knots to mph" do
      assert Convert.speed(55, :knots, :mph) == 63.29
    end

    test "zero knots is zero mph" do
      assert Convert.speed(0, :knots, :mph) == 0.0
    end

    test "rounds to two decimal places" do
      # 10 knots * 1.15077945 = 11.5077945, rounded = 11.51
      assert Convert.speed(10, :knots, :mph) == 11.51
    end
  end

  describe "f_to_c/1 and c_to_f/1" do
    test "converts freezing point" do
      assert Convert.f_to_c(32) == 0.0
      assert Convert.c_to_f(0) == 32.0
    end

    test "converts boiling point" do
      assert_in_delta Convert.f_to_c(212), 100.0, 0.0001
      assert_in_delta Convert.c_to_f(100), 212.0, 0.0001
    end

    test "-40 is the same in both scales" do
      assert_in_delta Convert.f_to_c(-40), -40.0, 0.0001
      assert_in_delta Convert.c_to_f(-40), -40.0, 0.0001
    end

    property "f_to_c and c_to_f are inverses" do
      check all(f <- float(min: -200.0, max: 300.0)) do
        assert_in_delta Convert.c_to_f(Convert.f_to_c(f)), f, 0.0001
      end
    end
  end

  describe "mph_to_kph/1 and kph_to_mph/1" do
    test "converts known value" do
      assert_in_delta Convert.mph_to_kph(1), 1.60934, 0.0001
      assert_in_delta Convert.kph_to_mph(1), 0.6214, 0.001
    end

    test "zero stays zero" do
      assert Convert.mph_to_kph(0) == 0.0
      assert Convert.kph_to_mph(0) == 0.0
    end

    property "mph_to_kph and kph_to_mph are inverses" do
      check all(v <- float(min: 0.0, max: 1000.0)) do
        assert_in_delta Convert.kph_to_mph(Convert.mph_to_kph(v)), v, 0.0001
      end
    end
  end

  describe "inches_to_mm/1 and mm_to_inches/1" do
    test "one inch is 25.4 mm" do
      assert Convert.inches_to_mm(1) == 25.4
      assert_in_delta Convert.mm_to_inches(25.4), 1.0, 0.0001
    end

    test "zero stays zero" do
      assert Convert.inches_to_mm(0) == 0.0
      assert Convert.mm_to_inches(0) == 0.0
    end

    property "inches_to_mm and mm_to_inches are inverses" do
      check all(v <- float(min: 0.0, max: 1000.0)) do
        assert_in_delta Convert.mm_to_inches(Convert.inches_to_mm(v)), v, 0.0001
      end
    end
  end
end
