From 02b62f919bea776126a2229c542931291aa3ed97 Mon Sep 17 00:00:00 2001
From: qvalentin <valentin.theodor@web.de>
Date: Fri, 16 Dec 2022 20:59:53 +0100
Subject: [PATCH] finish parsing of day seven

---
 seven.hs | 50 ++++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 40 insertions(+), 10 deletions(-)

diff --git a/seven.hs b/seven.hs
index 9a2c80f..b54c035 100644
--- a/seven.hs
+++ b/seven.hs
@@ -1,21 +1,17 @@
+-- everything stolen from http://learnyouahaskell.com/zippers#a-very-simple-file-system
+
+
 data FS = FS [Inode]
-
 data Inode = Dir Name [Inode] | File Name Size deriving(Show)
-
 type Name = String
 type Size = Int
-
-
 data Command = Ls | Cd Name | CdUp | CdRoot deriving(Show)
-
-
 data Line = LineC Command | LineI Inode deriving(Show)
 
 parseCommand :: String -> Command
-parseCommand ('c':'d':' ':name) =(Cd name)
 parseCommand "ls"               =Ls
 parseCommand "cd .."            =CdUp
-parseCommand "cd /"             =CdRoot
+parseCommand ('c':'d':' ':name) =(Cd name)
 
 parseInode :: String -> Inode
 parseInode ('d':'i':'r':' ': name) = Dir name []
@@ -26,9 +22,43 @@ parseEither :: String -> Line
 parseEither ('$':' ':command) =LineC $  parseCommand command
 parseEither input=            LineI $            parseInode input
 
+foldFunction :: FSZipper -> Line -> FSZipper
+foldFunction zipper (LineC Ls)        = zipper
+foldFunction zipper (LineC (Cd name)) = fsTo name zipper
+foldFunction zipper (LineC CdUp)      = fsUp zipper
+foldFunction zipper (LineI inode)     = fsNewInode inode zipper
+
+data FSCrumb = FSCrumb Name [Inode] [Inode] deriving (Show)
+
+type FSZipper = (Inode,[FSCrumb])
+
+fsUp :: FSZipper -> FSZipper
+fsUp (item, FSCrumb name ls rs:bs) = (Dir name (ls ++ [item] ++ rs), bs)
+
+
+fsUpToRoot :: FSZipper -> FSZipper
+fsUpToRoot ((Dir "/" content),bc) = ((Dir "/" content),bc)
+fsUpToRoot zipper                 = fsUp zipper
+
+fsTo :: Name -> FSZipper -> FSZipper
+fsTo name (Dir folderName items, bs) =
+    let (ls, item:rs) = break (nameIs name) items
+    in  (item, FSCrumb folderName ls rs:bs)
+
+nameIs :: Name -> Inode -> Bool
+nameIs name (Dir folderName _) = name == folderName
+nameIs name (File fileName _)  = name == fileName
+
+
+fsNewInode :: Inode -> FSZipper -> FSZipper
+fsNewInode newInode ((Dir name content),bc) = (Dir name (newInode:content),bc)
+
+initZipper :: FSZipper
+initZipper = (Dir "/" [],[])
 
 
 main = do
   content <- readFile "seven-input.txt"
-  let statements = map parseEither $ lines content
-  print statements
+  let statements = map parseEither $ drop 1 $ lines content
+  let a = foldl foldFunction initZipper statements
+  print $ fsUpToRoot a