new option to use input file name as basis for output file name

Author: idrisr

knotools.cabal

@@ -47,6 +47,7 @@ test-suite tests
         TestCommand
         TestData
         TestParser
+        TestOutputFileName
     build-depends:
         base ^>=4.17.2.1
         , attoparsec

src/Command.hs

@@ -13,6 +13,9 @@ import Parser
 import System.FilePath
 import System.IO.Streams.Attoparsec.ByteString qualified as SP
 
+class ToCommand a where
+    command :: a -> [String]
+
 wgetCmd :: Params -> FilePath -> [String]
 wgetCmd p f =
     [ "wget"
@@ -40,9 +43,18 @@ pdftkCmd p f =
     , p ^. input
     , "cat"
     , "output"
-    , replaceExtension (p ^. output) "pdf"
+    , replaceExtension (outFile p (p ^. output)) "pdf"
     ]
 
+-- todo: fixme. dont pass in params and an elem from params
+-- maybe use derived lens
+outFile :: Params -> OutputFile -> FilePath
+outFile _ (OutputFile f) = f
+outFile p AppendInput = newFileName (p^.input) "new"
+
+newFileName :: FilePath -> String -> FilePath
+newFileName f e = takeBaseName f <.> e <.> takeExtension f
+
 makeWH :: Num a => PageMedia a -> (a, a)
 makeWH p =
     ( p ^. cropRect . topRight . x - p ^. cropRect . bottomLeft . x

src/Params.hs

@@ -8,10 +8,13 @@ import Lens.Micro.Platform
 data Params = Params
     { _input :: FilePath
     , _url :: String
-    , _output:: FilePath
+    , _output:: OutputFile
     }
     deriving (Show)
 
+data OutputFile = OutputFile FilePath | AppendInput
+    deriving (Show)
+
 makeLenses ''Params
 
 cmdLineParser :: IO Params
@@ -22,6 +25,33 @@ cmdLineParser = execParser opts
 parseParams :: Parser Params
 parseParams =
     Params
-        <$> strArgument (metavar "<INPUT>" <> help "pdf file for processing")
-        <*> strOption (metavar "<URL>" <> short 'u' <> long "url" <> help "url for new cover")
-        <*> strOption (metavar "<OUTPUT>" <> short 'o' <> long "output" <> help "output file for new pdf")
+        <$> strArgument
+            ( metavar "<INPUT>"
+                <> help "pdf file for processing"
+            )
+        <*> strOption
+            ( metavar "<URL>"
+                <> short 'u'
+                <> long "url"
+                <> help "url for new cover"
+            )
+        <*> (fileOutput <|> defaultOutput)
+
+fileOutput :: Parser OutputFile
+fileOutput =
+    OutputFile
+        <$> strOption
+            ( metavar "<OUTPUT>"
+                <> short 'o'
+                <> long "output"
+                <> help "output file for new pdf"
+            )
+
+defaultOutput :: Parser OutputFile
+defaultOutput =
+    flag'
+        AppendInput
+        ( long "append"
+            <> short 'a'
+            <> help "use input file name as basis for output file name"
+        )

test/Main.hs

@@ -3,13 +3,15 @@ module Main (main) where
 import Test.Tasty
 import TestParser
 import TestCommand
+import TestOutputFileName
 
 tests :: TestTree
 tests =
     testGroup
         "main"
         [ testParse
         , testCommand
+        , testOutputFileName
         ]
 
 main :: IO ()

test/TestOutputFileName.hs

@@ -0,0 +1,30 @@
+module TestOutputFileName (testOutputFileName) where
+
+import Test.Tasty
+import Test.Tasty.HUnit
+import Command
+
+testOutputFileName :: TestTree
+testOutputFileName = testGroup "output file name" [tests]
+
+tests:: TestTree
+tests=
+    testGroup
+        "filename"
+        [
+            let sut = "asdf.jpg"
+                got = newFileName sut "new"
+                wot = "asdf.new.jpg"
+            in
+                testCase "" $ wot @?= got
+          , let sut = "asdf"
+                got = newFileName sut "new"
+                wot = "asdf.new"
+            in
+                testCase "" $ wot @?= got
+          , let sut = "asdf.new.jpg"
+                got = newFileName sut "new"
+                wot = "asdf.new.new.jpg"
+            in
+                testCase "" $ wot @?= got
+        ]