Display progress bar when running ag

app/Main.hs

@@ -1,6 +1,9 @@
 module Main where
 
+import Control.Monad.State
+import System.IO (hSetBuffering, BufferMode(NoBuffering), stdout)
 import System.Console.ANSI
+import System.ProgressBar
 import Unused.TermSearch (search)
 import Unused.Parser (parseLines, ParseError)
 import Unused.Types
@@ -21,9 +24,56 @@ main = do
 
 executeSearch :: [String] -> IO [String]
 executeSearch terms = do
-    results <- mapM search terms
+    resetScreen
+    printAnalysisHeader terms
+    (results, _) <- runStateT (performSearch $ length terms) terms
+    resetScreen
+
     return $ concat results
 
+performSearch :: Int -> StateT [String] IO [[String]]
+performSearch total = do
+    currentTerm <- getSearchTerm
+    searchResults <- liftIO $ search currentTerm
+
+    remainingTerms <- get
+    let remaining = length remainingTerms
+
+    liftIO $ printProgressBar (total - remaining) total
+
+    if remaining > 0
+        then do
+            res <- performSearch total
+            return $ searchResults:res
+        else return [searchResults]
+
+getSearchTerm :: StateT [String] IO String
+getSearchTerm = do
+    (x:xs) <- get
+    put xs
+    return x
+
+printProgressBar :: Int -> Int -> IO ()
+printProgressBar complete total = do
+    let message = "Working"
+    let progressBarWidth = 60
+
+    hSetBuffering stdout NoBuffering
+    progressBar (msg message) percentage progressBarWidth (toInteger complete) (toInteger total)
+
+printAnalysisHeader :: [String] -> IO ()
+printAnalysisHeader terms = do
+    setSGR [SetConsoleIntensity BoldIntensity]
+    putStr "Unused: "
+    setSGR [Reset]
+
+    putStr "analyzing "
+
+    setSGR [SetColor Foreground Dull Green]
+    putStr $ show $ length terms
+    setSGR [Reset]
+    putStr " terms\n\n"
+
 printMatchPair :: (String, [TermMatch]) -> IO ()
 printMatchPair (term', matches) = do
     setSGR   [SetColor Foreground Vivid Red]
@@ -62,3 +112,8 @@ printParseError e = do
     putStr "\n"
 
     setSGR [Reset]
+
+resetScreen :: IO ()
+resetScreen = do
+    clearScreen
+    setCursorPosition 0 0

unused.cabal

@@ -33,6 +33,8 @@ executable unused
                      , unused
                      , ansi-terminal
                      , containers
+                     , terminal-progress-bar
+                     , mtl
   default-language:    Haskell2010
 
 test-suite unused-test