make auto update optional

src/Tldr/App.hs

@@ -17,14 +17,22 @@ import Control.Monad (void)
 
 programOptions :: Parser TldrOpts
 programOptions =
-  TldrOpts <$> (updateIndexCommand <|> viewPageCommand <|> aboutFlag)
+  TldrOpts <$> (updateIndexCommand <|> viewPageCommand <|> aboutFlag) <*> autoUpdateIntervalOpt
 
 updateIndexCommand :: Parser TldrCommand
 updateIndexCommand =
   flag'
     UpdateIndex
     (long "update" <> short 'u' <> help "Update offline cache of tldr pages")
 
+autoUpdateIntervalOpt :: Parser (Maybe Int)
+autoUpdateIntervalOpt =
+  optional
+    (option auto
+       (long "auto-update-interval" <> metavar "DAYS" <>
+        help
+          "Perform an automatic update if the cache is older than DAYS"))
+
 aboutFlag :: Parser TldrCommand
 aboutFlag = flag' About (long "about" <> short 'a' <> help "About this program")
 

src/Tldr/App/Handler.hs

@@ -73,8 +73,8 @@ handleTldrOpts opts@TldrOpts {..} =
     UpdateIndex -> updateTldrPages
     About -> handleAboutFlag
     ViewPage voptions pages -> do
-      performUpdate <- updateNecessary
-      when performUpdate updateTldrPages 
+      shouldPerformUpdate <- updateNecessary opts
+      when shouldPerformUpdate updateTldrPages 
       let npage = intercalate "-" pages
       locale <-
         case languageOption voptions of
@@ -94,20 +94,19 @@ handleTldrOpts opts@TldrOpts {..} =
                           ViewPage (englishViewOptions voptions) pages
                       })
 
--- We update if the data directory does not exist.
--- We also update if the cached pages version is older than 7 days.
--- TODO: Make the auto-update interval configurable.
--- TODO: Add command line option to skip auto update.
-updateNecessary :: IO Bool
-updateNecessary = do
+updateNecessary :: TldrOpts -> IO Bool
+updateNecessary TldrOpts{..} = do
   dataDir <- getXdgDirectory XdgData tldrDirName
   dataDirExists <- doesDirectoryExist dataDir
   if not dataDirExists 
     then return True
     else do
       lastCachedTime <- getModificationTime dataDir
       currentTime <- getCurrentTime
-      return $ currentTime `diffUTCTime` lastCachedTime > 7 * nominalDay
+      let diffExceedsLimit limit 
+            = currentTime `diffUTCTime` lastCachedTime 
+              > fromIntegral limit * nominalDay
+      return $ maybe False diffExceedsLimit autoUpdateInterval
 
 updateTldrPages :: IO ()
 updateTldrPages = do

src/Tldr/Types.hs

@@ -15,8 +15,9 @@ data ConsoleSetting =
     , consoleIntensity :: ConsoleIntensity
     }
 
-newtype TldrOpts = TldrOpts
+data TldrOpts = TldrOpts
   { tldrAction :: TldrCommand
+  , autoUpdateInterval :: Maybe Int
   } deriving (Show)
 
 data TldrCommand