From 08c77d4d0fa6a27e936ecb4c5f46a669694ffbbe Mon Sep 17 00:00:00 2001
From: Jonathan Lamothe <jonathan@jlamothe.net>
Date: Tue, 19 Apr 2022 16:03:14 -0400
Subject: [PATCH] wrote basic structure of decodeRows

---
 csv-slurp.cabal            |  6 ++++++
 package.yaml               |  3 +++
 src/Data/CSV/Slurp.hs      | 25 ++++++++++++++++++++++++-
 test/Data/CSV/SlurpSpec.hs | 38 ++++++++++++++++++++++++++++++++++++--
 test/Spec.hs               |  2 +-
 5 files changed, 70 insertions(+), 4 deletions(-)

diff --git a/csv-slurp.cabal b/csv-slurp.cabal
index 9e0d86c..4a556f3 100644
--- a/csv-slurp.cabal
+++ b/csv-slurp.cabal
@@ -29,6 +29,9 @@ library
   ghc-options: -Wall
   build-depends:
       base >=4.7 && <5
+    , bytestring
+    , conduit >=1.3.4.2 && <1.4
+    , text
   default-language: Haskell2010
   autogen-modules: Paths_csv_slurp
 
@@ -43,7 +46,10 @@ test-suite csv-slurp-test
   ghc-options: -Wall -threaded -rtsopts -with-rtsopts=-N
   build-depends:
       base >=4.7 && <5
+    , bytestring
+    , conduit >=1.3.4.2 && <1.4
     , csv-slurp
     , hspec >=2.8.5 && <2.9
+    , text
   default-language: Haskell2010
   autogen-modules: Paths_csv_slurp
diff --git a/package.yaml b/package.yaml
index 1dc1f2c..3f71495 100644
--- a/package.yaml
+++ b/package.yaml
@@ -23,6 +23,9 @@ ghc-options:
 
 dependencies:
 - base >= 4.7 && < 5
+- bytestring
+- conduit >= 1.3.4.2 && < 1.4
+- text
 
 library:
   source-dirs: src
diff --git a/src/Data/CSV/Slurp.hs b/src/Data/CSV/Slurp.hs
index 15a618b..8803a34 100644
--- a/src/Data/CSV/Slurp.hs
+++ b/src/Data/CSV/Slurp.hs
@@ -23,6 +23,29 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 -}
 
-module Data.CSV.Slurp where
+{-# LANGUAGE OverloadedStrings #-}
+
+module Data.CSV.Slurp (
+  decodeRows,
+  decodeRawRows,
+  decodeUTF8,
+) where
+
+import Conduit (ConduitT, mapC, (.|))
+import qualified Data.ByteString as BS
+import Data.Maybe (fromMaybe)
+import qualified Data.Text as T
+
+-- | decode the rows from a stream of ByteStrings
+decodeRows :: Monad m => ConduitT BS.ByteString [T.Text] m ()
+decodeRows = decodeRawRows .| mapC (map $ fromMaybe "" . decodeUTF8)
+
+-- | decode the rows returning raw ByteStrings instead of text
+decodeRawRows :: Monad m => ConduitT BS.ByteString [BS.ByteString] m ()
+decodeRawRows = return ()
+
+-- | decode a raw ByteString into Text (if possible)
+decodeUTF8 :: BS.ByteString -> Maybe T.Text
+decodeUTF8 = const Nothing
 
 --jl
diff --git a/test/Data/CSV/SlurpSpec.hs b/test/Data/CSV/SlurpSpec.hs
index e7aef42..1fdc4fd 100644
--- a/test/Data/CSV/SlurpSpec.hs
+++ b/test/Data/CSV/SlurpSpec.hs
@@ -18,11 +18,45 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 -}
 
+{-# LANGUAGE OverloadedStrings #-}
+
 module Data.CSV.SlurpSpec (spec) where
 
-import Test.Hspec (Spec, describe)
+import Conduit (runConduit, (.|))
+import Data.Conduit.List (consume, sourceList)
+import Test.Hspec (Spec, context, describe, shouldBe, xit)
+
+import Data.CSV.Slurp
 
 spec :: Spec
-spec = describe "Data.CSV.Slurp" $ return ()
+spec = describe "Data.CSV.Slurp"
+  decodeRowsSpec
+
+decodeRowsSpec :: Spec
+decodeRowsSpec = describe "decodeRows" $ mapM_
+  ( \(label, input, expected) -> context label $ do
+    result <- runConduit $ sourceList input .| decodeRows .| consume
+    let
+      expLen = length expected
+      resLen = length result
+    xit ("should have " ++ show expLen ++ " rows") $
+      resLen `shouldBe` expLen
+    mapM_
+      ( \(n, expected', result') -> context ("row " ++ show n) $
+        xit ("should be " ++ show expected') $
+          result' `shouldBe` expected'
+      ) $ zip3 [(0::Int)..] expected result
+  )
+
+  --  label,     input,     expected
+  [ ( "valid",   validIn,   validRes )
+  , ( "invalid", invalidIn, []       )
+  , ( "empty",   [],        []       )
+  ]
+
+  where
+    validIn   = ["foo,bar\r\n", "baz,quuux\r\n"]
+    invalidIn = ["\"a"]
+    validRes  = [["foo", "bar"], ["baz", "quux"]]
 
 --jl
diff --git a/test/Spec.hs b/test/Spec.hs
index e9dacd8..f38586a 100644
--- a/test/Spec.hs
+++ b/test/Spec.hs
@@ -25,6 +25,6 @@ import Test.Hspec (hspec)
 import qualified Data.CSV.SlurpSpec as Slurp
 
 main :: IO ()
-main = hspec $ Slurp.spec
+main = hspec Slurp.spec
 
 --jl