From 00e00f5538b726b2a81b22606faabb77edafb689 Mon Sep 17 00:00:00 2001
From: Chris Done <git@chrisdone.com>
Date: Mon, 24 May 2021 11:55:51 +0100
Subject: [PATCH] Add piped mode

---
 app/Main.hs | 79 +++++++++++++++++++++++++++++++++--------------------
 1 file changed, 50 insertions(+), 29 deletions(-)

diff --git a/app/Main.hs b/app/Main.hs
index 8888ec5..f95935a 100644
--- a/app/Main.hs
+++ b/app/Main.hs
@@ -20,7 +20,10 @@ main = do
   case args of
     [connStr] -> do
       conn <- ODBC.connect (T.pack connStr)
-      repl conn
+      term<- hIsTerminalDevice stdin
+      if term
+         then repl conn
+         else piped conn
     _ -> error "usage: <connection string>"
 
 -- | Accepts a query/command and prints any results.
@@ -40,32 +43,50 @@ repl c = do
               e -> throwIO e))
         (\(e :: ODBC.ODBCException) -> putStrLn (displayException e))
       repl c
+
+-- | Accepts a single input and prints any results.
+piped :: ODBC.Connection -> IO ()
+piped c = do
+  input <- T.hGetContents stdin
+  hSetBuffering stdout LineBuffering
+  catch
+    (catch
+       (do (_, count) <- ODBC.stream c input output (False, 0 :: Int)
+           putStrLn ("Rows: " ++ show count))
+       (\case
+          UserInterrupt -> pure ()
+          e -> throwIO e))
+    (\(e :: ODBC.ODBCException) -> putStrLn (displayException e))
+  repl c
+
+prompt :: IO (Maybe T.Text)
+prompt = do
+  hSetBuffering stdout NoBuffering
+  putStr "> "
+  catch (fmap Just T.getLine) (\(_ :: IOException) -> pure Nothing)
+
+output :: (Show b, Num b) => (a, b) -> [(ODBC.Column, ODBC.Value)] -> IO (ODBC.Step (Bool, b))
+output (_printedHeaders, count) rowWithHeaders = do
+  T.putStrLn
+    ("[row " <> T.pack (show count) <> "]\n" <>
+     T.unlines
+       (map
+          (\(name, value) ->
+             ODBC.columnName name <> ": " <> T.pack (showColumn value))
+          rowWithHeaders))
+  pure (ODBC.Continue (True, count + 1))
   where
-    prompt = do
-      hSetBuffering stdout NoBuffering
-      putStr "> "
-      catch (fmap Just T.getLine) (\(_ :: IOException) -> pure Nothing)
-    output (_printedHeaders, count) rowWithHeaders = do
-      T.putStrLn
-        ("[row " <> T.pack (show count) <> "]\n" <>
-         T.unlines
-           (map
-              (\(name, value) ->
-                 ODBC.columnName name <> ": " <> T.pack (showColumn value))
-              rowWithHeaders))
-      pure (ODBC.Continue (True, count + 1))
-      where
-        showColumn =
-          \case
-            ODBC.NullValue -> "NULL"
-            ODBC.TextValue t -> show t
-            ODBC.ByteStringValue bs -> show bs
-            ODBC.BinaryValue bs -> show bs
-            ODBC.BoolValue b -> show b
-            ODBC.DoubleValue d -> printf "%f" d
-            ODBC.FloatValue d -> printf "%f" d
-            ODBC.IntValue i -> show i
-            ODBC.DayValue d -> show d
-            ODBC.ByteValue b -> show b
-            ODBC.TimeOfDayValue v -> show v
-            ODBC.LocalTimeValue v -> show v
+    showColumn =
+      \case
+        ODBC.NullValue -> "NULL"
+        ODBC.TextValue t -> show t
+        ODBC.ByteStringValue bs -> show bs
+        ODBC.BinaryValue bs -> show bs
+        ODBC.BoolValue b -> show b
+        ODBC.DoubleValue d -> printf "%f" d
+        ODBC.FloatValue d -> printf "%f" d
+        ODBC.IntValue i -> show i
+        ODBC.DayValue d -> show d
+        ODBC.ByteValue b -> show b
+        ODBC.TimeOfDayValue v -> show v
+        ODBC.LocalTimeValue v -> show v