From 54ddd70f1dcf0db02f4767f9d54e70b8a66a51ba Mon Sep 17 00:00:00 2001
From: Martin Potier <martin.potier@marvid.fr>
Date: Wed, 9 Dec 2020 14:04:43 +0200
Subject: [PATCH] Day 8 in progress

---
 day8/main.hs | 70 +++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 69 insertions(+), 1 deletion(-)

diff --git a/day8/main.hs b/day8/main.hs
index d81a1ab..fabae32 100755
--- a/day8/main.hs
+++ b/day8/main.hs
@@ -1,10 +1,78 @@
 #! /usr/bin/env -S"ANSWER=42" nix-shell
 #! nix-shell -p ghcid
-#! nix-shell -p "haskellPackages.ghcWithPackages (p: with p; [shower])"
+#! nix-shell -p "haskellPackages.ghcWithPackages (p: with p; [pretty-simple vector containers])"
 #! nix-shell -i "ghcid -c 'ghci -Wall' -T main"
 
 {-# LANGUAGE OverloadedStrings #-}
 
+import Text.Pretty.Simple
+-- import Data.List.NonEmpty (NonEmpty(..))
+-- import qualified Data.List.NonEmpty as NE
+import Data.Vector (Vector)
+import Debug.Trace (trace)
+import Data.List (unfoldr)
+import qualified Data.Vector as V
+
+data Op = OpNop
+        | OpJmp !Int
+        | OpAcc !Int
+  deriving (Show, Ord, Eq)
+
+data VMState = VMRun
+  deriving (Show, Ord, Eq)
+
+data VirtualMachine = VM
+  { pgmCounter      :: !Int
+  , pgmAccumulator  :: !Int
+  , pgmInstructions :: Vector Op
+  , vmState         :: VMState
+  }
+  deriving (Show, Ord, Eq)
+
+initialVM :: Vector Op -> VirtualMachine
+initialVM ins = VM 1 0 ins VMRun
+
+stepVM :: VirtualMachine -> Maybe (VirtualMachine, VirtualMachine)
+stepVM vm@(VM c a ins VMRun) = Just (vm, go (ins V.! (c-1)))
+  where
+    go OpNop     = VM (c+1) a     ins VMRun
+    go (OpJmp n) = VM (c+n) a     ins VMRun
+    go (OpAcc n) = VM (c+1) (a+n) ins VMRun
+
+exampleData :: [String]
+exampleData =
+  [ "nop +0"
+  , "acc +1"
+  , "jmp +4"
+  , "acc +3"
+  , "jmp -3"
+  , "acc -99"
+  , "acc +1"
+  , "jmp -4"
+  , "acc +6"
+  ]
+
+vmFromInput :: [String] -> VirtualMachine
+vmFromInput input = initialVM (ins input)
+  where
+    ins = V.fromList . (map (parseOp . (\(x,y)-> (x,tail y)) . break (== ' ')))
+    parseOp :: (String,String) -> Op
+    parseOp ("nop",_)     = OpNop
+    parseOp ("acc",'+':s) = OpAcc (read s :: Int)
+    parseOp ("jmp",'+':s) = OpJmp (read s :: Int)
+    parseOp ("acc",s) = OpAcc (read s :: Int)
+    parseOp ("jmp",s) = OpJmp (read s :: Int)
+    parseOp s@_ = trace (show s) $ undefined
+
+-- Find smallest looping prefix in list of Int, returns associated pgmAccumulator
+solvePart1 :: VirtualMachine -> Int
+solvePart1 vm = undefined vm
+
 main :: IO ()
 main = do
   putStrLn "Day 8 - Part 1"
+  putStrLn ":: Tests"
+  pPrint exampleData
+  print $ take 10 $ (\vm -> (pgmCounter vm, pgmAccumulator vm)) <$> unfoldr stepVM (vmFromInput exampleData)
+  putStrLn ":: Solving part 1"
+  print $ solvePart1 (vmFromInput exampleData)