{-# LANGUAGE MagicHash #-}
module Word12BuilderSpec where
import Test.Hspec
import Test.Hspec.QuickCheck
import Test.QuickCheck
import Data.Bits
import Data.Word12.Internal
import Data.ByteString.Lazy.Builder
import qualified Data.ByteString.Lazy as BL

instance Arbitrary Word12 where
  arbitrary = arbitrarySizedBoundedIntegral
  shrink    = shrinkIntegral

spec :: Spec
spec = do
  describe "split4'8" $ do
    it "0xabc" $ do
      split4'8 0xabc `shouldBe` (0x0a, 0xbc)
    it "0xfff" $ do
      split4'8 0xfff `shouldBe` (0x0f, 0xff)

    describe "(x, y) = split4'8 z" $ do
      prop "x <= 0x0f" $
        \z -> let (x, _) =  split4'8 z in x <= 0x0f
      prop "x << 8 | y == z" $ do
        \z -> let (x, y) = split4'8 z in
          fromIntegral x `shiftL` 8 .|. fromIntegral y == z

  describe "split8'4" $ do
    it "0xabc" $ do
      split8'4 0xabc `shouldBe` (0xab, 0xc0)
    it "0xfff" $ do
      split8'4 0xfff `shouldBe` (0xff, 0xf0)

    describe "(x, y) = split8'4 z" $ do
      prop "y == 0 || y >= 0x10" $
        \z -> let (_, y) =  split8'4 z in
          y == 0 || y >= 0x10
      prop "x << 4 | y >> 4 == z" $ do
        \z -> let (x, y) = split8'4 z in
          fromIntegral x `shiftL` 4 .|. fromIntegral y `shiftR` 4 == z

  describe "fromWord12sle" $ do
    it "[0xff8, 0xfff, 0x123, 0x456]" $ do
      let w12s = [0xff8, 0xfff, 0x123, 0x456]
      toLazyByteString (fromWord12sle w12s)
        `shouldBe` BL.pack [0xf8, 0xff, 0xff, 0x23, 0x61, 0x45]
    it "[0x123, 0x456, 0x789, 0xabc, 0xdef]" $ do
      let w12s = [0x123, 0x456, 0x789, 0xabc, 0xdef]
      toLazyByteString (fromWord12sle w12s)
        `shouldBe` BL.pack [0x23, 0x61, 0x45, 0x89, 0xc7, 0xab, 0xef, 0x0d]
    it "[0x123, 0x456, 0x789]" $ do
      let w12s = [0x123, 0x456, 0x789]
      toLazyByteString (fromWord12sle w12s)
        `shouldBe` BL.pack [0x23, 0x61, 0x45, 0x89, 0x07]
    it "[]" $ do
      let w12s = []
      toLazyByteString (fromWord12sle w12s)
        `shouldBe` BL.pack []
    it "[0x109]" $ do
      let w12s = [0x109]
      toLazyByteString (fromWord12sle w12s)
        `shouldBe` BL.pack [0x09, 0x01]
    it "[0x019]" $ do
      let w12s = [0x019]
      toLazyByteString (fromWord12sle w12s)
        `shouldBe` BL.pack [0x19, 0x00]
    it "[0x000]" $ do
      let w12s = [0x000]
      toLazyByteString (fromWord12sle w12s)
        `shouldBe` BL.pack [0x00, 0x00]
    it "[0xff8]" $ do
      let w12s = [0xff8]
      toLazyByteString (fromWord12sle w12s)
        `shouldBe` BL.pack [0xf8, 0x0f]
    it "[0x123,0xff8]" $ do
      let w12s = [0x123, 0xff8]
      toLazyByteString (fromWord12sle w12s)
        `shouldBe` BL.pack [0x23, 0x81, 0xff]
    prop "odd (length w12s) && last w12s < 0x100 ==> BL.last (toLazyByteString (fromWord12sle w12s)) == 0" $
      forAll (choose (0,0x0ff :: Int)) $ \i -> \w12s' -> let w12s = [w12s'] ++ [w12s'] ++ [fromIntegral i] in
        BL.last (toLazyByteString (fromWord12sle w12s)) == 0

  describe "fromWord12sbe" $ do
    it "[0xff8, 0xfff, 0x123, 0x456]" $ do
      let w12s = [0xff8, 0xfff, 0x123, 0x456]
      toLazyByteString (fromWord12sbe w12s)
        `shouldBe` BL.pack [0xff, 0x8f, 0xff, 0x12, 0x34, 0x56]
    it "[0x123, 0x456, 0x789, 0xabc, 0xdef]" $ do
      let w12s = [0x123, 0x456, 0x789, 0xabc, 0xdef]
      toLazyByteString (fromWord12sbe w12s)
        `shouldBe` BL.pack [0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0]
    it "[]" $ do
      let w12s = []
      toLazyByteString (fromWord12sbe w12s)
        `shouldBe` BL.pack []
    it "[0x109]" $ do
      let w12s = [0x109]
      toLazyByteString (fromWord12sbe w12s)
        `shouldBe` BL.pack [0x10, 0x90]
    it "[0x190]" $ do
      let w12s = [0x190]
      toLazyByteString (fromWord12sbe w12s)
        `shouldBe` BL.pack [0x19, 0x00]
    it "[0x000]" $ do
      let w12s = [0x000]
      toLazyByteString (fromWord12sle w12s)
        `shouldBe` BL.pack [0x00, 0x00]