Use comonads

imageduplicates.cabal

@@ -35,5 +35,7 @@ executable imageduplicates
                      , recursion-schemes
                      , text
                      , transformers
+                     , directory
+                     , filepath
   hs-source-dirs:      src
   default-language:    Haskell2010

src/Data/BKTree.hs

@@ -4,14 +4,17 @@
 {-# LANGUAGE DeriveTraversable   #-}
 {-# LANGUAGE KindSignatures      #-}
 {-# LANGUAGE LambdaCase          #-}
+{-# LANGUAGE ScopedTypeVariables #-}
 {-# LANGUAGE TemplateHaskell     #-}
 {-# LANGUAGE TypeFamilies        #-}
-{-# LANGUAGE ScopedTypeVariables      #-}
 module Data.BKTree where
 
-import           Data.Functor.Foldable.TH
 import           Data.Functor.Foldable
+import           Data.Functor.Foldable.TH
 import           GHC.Generics             (Generic)
+import Data.List (foldl')
+import Data.Foldable (foldMap)
+import Data.Monoid (Endo(..))
 
 -- Point for testing purposes
 data Point = Point Int Int deriving Show
@@ -22,11 +25,25 @@ instance Metric Point where
 class Metric a where
   distance :: a -> a -> Int
 
+data Tuple a = Tuple !Int a deriving (Show, Functor, Foldable, Traversable)
+
 data BKTree a = Empty
-              | Node a [(Int, BKTree a)] deriving (Show, Generic)
+              | Node !a [Tuple (BKTree a)] deriving (Show, Generic, Functor, Traversable, Foldable)
 
 makeBaseFunctor ''BKTree
 
+empty :: BKTree a
+empty = Empty
+
+singleton :: Metric a => a -> BKTree a
+singleton a = insert a empty
+
+fromList :: Metric a => [a] -> BKTree a
+fromList = foldl' (\acc x -> insert x acc) empty
+
+toList :: BKTree a -> [a]
+toList tree = appEndo (foldMap (\x -> Endo ([x] ++)) tree) []
+
 insert :: Metric a => a -> BKTree a -> BKTree a
 insert a = \case
   Empty -> Node a []
@@ -35,9 +52,9 @@ insert a = \case
     in Node b (addChild newDistance children)
   where
     addChild d = \case
-      [] -> (d, insert a Empty) : []
-      (d',child):children | d == d' -> (d', insert a child) : children
-                          | otherwise -> (d',child) : addChild d children
+      [] -> (Tuple d  (insert a Empty)) : []
+      (Tuple d' child):children | d == d' -> (Tuple d' (insert a child)) : children
+                          | otherwise -> (Tuple d' child) : addChild d children
 
 
 search :: forall a. Metric a => Int -> a -> BKTree a -> [a]
@@ -50,5 +67,5 @@ search n a tree = cata alg tree
         let thisDistance = distance a x
             upper = thisDistance + n
             lower = thisDistance - n
-            filteredChildren = concat [xs | (d, xs) <- children, d <= upper, d >= lower]
+            filteredChildren = concat [xs | Tuple d xs <- children, d <= upper, d >= lower]
         in if thisDistance <= n then x : filteredChildren else filteredChildren

src/Main.hs

@@ -1,45 +1,97 @@
 {-# LANGUAGE DeriveAnyClass      #-}
+{-# LANGUAGE DeriveFunctor       #-}
 {-# LANGUAGE DeriveGeneric       #-}
 {-# LANGUAGE OverloadedStrings   #-}
 {-# LANGUAGE RecordWildCards     #-}
 {-# LANGUAGE ScopedTypeVariables #-}
 {-# LANGUAGE TupleSections       #-}
+{-# LANGUAGE TypeApplications    #-}
 module Main where
 
 import           Codec.Picture
 import           Codec.Picture.Extra   (scaleBilinear)
-import           Data.Bifunctor      (second)
+import           Control.Comonad       (extend, extract)
+import           Control.Comonad.Store (Store, experiment, seek, store)
+import           Control.Exception     (SomeException, try)
+import           Control.Monad         (forM_, void, when)
 import           Data.Bits
+import qualified Data.BKTree           as BK
 import           Data.List             (foldl')
+import           Data.Maybe            (fromMaybe)
 import           Data.Word             (Word64)
 import           Options.Generic
 import           Pipes
 import           Pipes.Files
 import qualified Pipes.Prelude         as P
 import           Pipes.Safe            (runSafeT)
+import           System.Directory      (createDirectoryIfMissing,
+                                        createFileLink)
+import           System.FilePath       (takeFileName, (</>))
 
 
+data Alg = Average | DHash deriving (Read, Show, Generic)
+
+instance ParseField Alg
+
 data Cmd = Cmd { source    :: FilePath
                , target    :: FilePath
-               , recursive :: Bool
+               , range     :: Maybe Int
+               , algorithm :: Maybe Alg
                } deriving (Show, Generic, ParseRecord)
 
-fingerprint :: DynamicImage -> Word64
-fingerprint = hash . grey . scale . convertRGB8
+data Fingerprint =
+  Fingerprint { imagePath :: FilePath
+              , hash      :: !Word64
+              } deriving Show
+
+instance BK.Metric Fingerprint where
+  -- hamming distance
+  distance (Fingerprint _ a) (Fingerprint _ b) =
+    let xored = a `xor` b
+    in foldr (\shiftA acc -> acc + if 1 `shift` shiftA .&. xored > 0 then 1 else 0) 0 [0..63]
+
+fingerprint :: Alg -> DynamicImage -> Word64
+fingerprint alg = hash . grey . scale . convertRGB8
   where
     scale :: Image PixelRGB8 -> Image PixelRGB8
     scale = scaleBilinear 8 8
     grey :: Image PixelRGB8 -> Image Pixel8
     grey = pixelMap (\(PixelRGB8 r g b) -> ceiling ((fromIntegral r * (0.3 :: Double)) + (fromIntegral g * 0.59) + (fromIntegral b * 0.11)))
+    indexes = [(x,y) | x <- [0..7], y <- [0..7]]
+    hashWith :: Image Pixel8 -> (Store (Int, Int) Pixel8 -> Bool) -> Word64
+    hashWith img f =
+      let s = store (uncurry (pixelAt img)) (0,0)
+          img' = extend f s
+          at pos = extract $ seek pos img'
+      in foldr (\(shiftA, b) acc -> if b then 1 `shift` shiftA .|. acc else acc) 0 $ zip [0..] $ map at indexes
     hash :: Image Pixel8 -> Word64
-    hash img = -- the average fingerprint method
-      let avg = fromIntegral (foldl' (\acc (x,y) -> acc + fromIntegral (pixelAt img x y)) (0 :: Int) [(x,y) | x <- [0..7], y <- [0..7]] `div` 64)
-      in foldr (\(shiftA, b) acc -> if b then 1 `shift` shiftA .|. acc else acc) 0 $ zip [0..] [pixelAt img x y > avg | x <- [0..7], y <- [0..7]]
+    hash img = case alg of
+                Average ->
+                  let avg = fromIntegral (foldl' (\acc (x,y) -> acc + fromIntegral (pixelAt img x y)) (0 :: Int) [(x,y) | (x,y) <- indexes] `div` 64)
+                  in img `hashWith` (avgAlg avg)
+                DHash -> img `hashWith` dAlg
+    dAlg :: Store (Int, Int) Pixel8 -> Bool
+    dAlg img = case experiment (\(x,y) -> [(x,y), (succ x `mod` 8, y)]) img of
+                    [l,r] -> l > r
+                    _     -> False
+    avgAlg :: Pixel8 -> Store (Int, Int) Pixel8 -> Bool
+    avgAlg avg img = extract img > avg
 
 main :: IO ()
 main = do
   Cmd{..} <- getRecord "Image duplicate finder"
-  runSafeT $
-    runEffect $
-      for (find source (glob "*.jpg" <> regular) >-> P.mapM (\path -> fmap (path,) <$> liftIO (readImage path)) >-> P.map (fmap (second fingerprint))) (liftIO . print)
-  putStrLn "Hello, Haskell!"
+  index <- runSafeT (P.fold foldTree BK.empty id (find source (glob "*.jpg" <> regular)
+    >-> P.mapM readImg
+    >-> P.map (fmap (toFingerprint (fromMaybe Average algorithm)))))
+  forM_ index $ \fp -> do
+    let similar = BK.search (fromMaybe 1 range) fp index
+    when (length similar > 1) $ do
+      print similar
+      let targetDir = target </> show (hash fp)
+      createDirectoryIfMissing True targetDir
+      forM_ similar $ \fp' ->
+        void $ try @SomeException (createFileLink (imagePath fp') (targetDir </> takeFileName (imagePath fp')))
+  where
+    readImg path = liftIO (putStrLn path >> fmap (path,) <$> readImage path)
+    foldTree acc = either (const acc) (\x -> x `seq` BK.insert x acc)
+    toFingerprint alg (path,img) = Fingerprint path (fingerprint alg img)