bitcoinex

defmodule Bitcoinex.Secp256k1.PointTest do
  use ExUnit.Case
  doctest Bitcoinex.Secp256k1.Point

  alias Bitcoinex.Secp256k1
  alias Bitcoinex.Secp256k1.Point

  @x_only_pubkeys [
    "F9308A019258C31049344F85F89D5229B531C845836F99B08601F113BCE036F9",
    "DFF1D77F2A671C5F36183726DB2341BE58FEAE1DA2DECED843240F7B502BA659",
    "DD308AFEC5777E13121FA72B9CC1B7CC0139715309B086C960E18FD969774EB8",
    "25D1DFF95105F5253C4022F628A996AD3A0D95FBF21D468A1B33F8C160D8F517",
    "D69C3509BB99E412E68B0FE8544E72837DFA30746D8BE2AA65975F29D22DC7B9"
  ]

  describe "serialize_public_key/1" do
    test "successfully pad public key" do
      assert "020003b94aecea4d0a57a6c87cf43c50c8b3736f33ab7fd34f02441b6e94477689" ==
               Point.serialize_public_key(%Point{
                 x:
                   6_579_384_254_631_425_969_190_483_614_785_133_746_155_874_651_439_631_590_927_590_192_220_436_105,
                 y:
                   71_870_263_570_581_286_056_939_190_487_148_011_225_641_308_782_404_760_504_903_461_107_415_970_265_024
               })
    end
  end

  describe "parse_public_key/1" do
    test "successfully parse public key from sec" do
      sec =
        Base.decode16!("033b15e1b8c51bb947a134d17addc3eb6abbda551ad02137699636f907ad7e0f1a",
          case: :lower
        )

      assert Point.parse_public_key(sec) ==
               {:ok,
                %Point{
                  x:
                    26_725_119_729_089_203_965_150_132_282_997_341_343_516_273_140_835_737_223_575_952_640_907_021_258_522,
                  y:
                    35_176_335_436_138_229_778_595_179_837_068_778_482_032_382_451_813_967_420_917_290_469_529_927_283_651
                }}
    end

    test "successfully parse uncompressed key from sec" do
      sec =
        Base.decode16!(
          "048fdc3d8944cc8d8fe6c666c41a8ed42e60aa399861a756707e127a80b383d178edfbf94dda0487f7910d130f2a37a0647be9335eab5b8d3aa5242445e1604024",
          case: :lower
        )

      assert Point.parse_public_key(sec) ==
               {:ok,
                %Point{
                  x: 0x8FDC3D8944CC8D8FE6C666C41A8ED42E60AA399861A756707E127A80B383D178,
                  y: 0xEDFBF94DDA0487F7910D130F2A37A0647BE9335EAB5B8D3AA5242445E1604024
                }}
    end

    test "successfully parse compressed key from sec hex" do
      sec = "0299d7ff3d96c731e54e75637798cab801fe80827191e280f53427bc8915323e8b"

      pk = %Point{
        x:
          69_585_499_557_921_076_123_288_400_932_281_161_043_766_220_600_235_811_505_715_105_664_976_077_078_155,
        y:
          102_549_807_389_226_195_103_316_638_704_859_105_787_106_440_500_810_433_784_118_696_258_589_643_376_818,
        z: 0
      }

      assert Point.parse_public_key(sec) == {:ok, pk}
      assert Point.serialize_public_key(pk) == sec
    end
  end

  describe "sec/1" do
    test "successfully calculate SEC encoding and hash160 of public key" do
      correct_hash160 = "d1914384b57de2944ce1b6a90adf2f7b72cfe61e"

      hash160 =
        %Point{
          x:
            26_725_119_729_089_203_965_150_132_282_997_341_343_516_273_140_835_737_223_575_952_640_907_021_258_522,
          y:
            35_176_335_436_138_229_778_595_179_837_068_778_482_032_382_451_813_967_420_917_290_469_529_927_283_651
        }
        |> Point.sec()
        |> Bitcoinex.Utils.hash160()
        |> Base.encode16(case: :lower)

      assert correct_hash160 == hash160
    end
  end

  describe "lift_x/1" do
    test "lift_x on 32-byte x-only pubkeys" do
      for t <- @x_only_pubkeys do
        {:ok, pubkey} = Point.lift_x(t)
        assert Point.has_even_y(pubkey)
        assert Secp256k1.verify_point(pubkey)
      end
    end

    test "return error when x is equal or greater than Secp256k1 p" do
      for i <- 0..2 do
        assert {:error, error} = Point.lift_x(Bitcoinex.Secp256k1.Params.curve().p + i)
        assert String.match?(error, ~r/(too large)/)
      end
    end
  end
end