{-# LANGUAGE QuasiQuotes #-}
module Day5Spec (spec) where

import Test.Hspec
import Text.Heredoc
import qualified Data.Sequence as S

import Day5.Part1
import Day5.Part2
import Day5.Shared

inputPart1 :: String
inputPart1 = [str|    [D]
                 |[N] [C]
                 |[Z] [M] [P]
                 | 1   2   3
                 |
                 |move 1 from 2 to 1
                 |move 3 from 1 to 3
                 |move 2 from 2 to 1
                 |move 1 from 1 to 2
                 |]

inputStacks :: String
inputStacks = [str|    [D]
                  |[N] [C]
                  |[Z] [M] [P]
                  | 1   2   3
                  |]

inputOperations :: String
inputOperations = [str|move 1 from 2 to 1
                      |move 3 from 1 to 3
                      |move 2 from 2 to 1
                      |move 1 from 1 to 2
                      |]
spec :: Spec
spec =
  describe "Day5" $ do
    describe "Part1" $ do
      it "parses Operations" $ do
        let operation = head . lines $ inputOperations
        parseOperation operation `shouldBe` Operation { count = 1, from = StackIndex 2, to = StackIndex 1 }
      it "parses stacks" $ do
        parseStacks (lines inputStacks) `shouldBe` S.fromList [Stack "NZ", Stack "DCM", Stack "P"]
      it "parses a single line of stacks" $ do
        let row = head . lines $ inputStacks
        parseRow row  `shouldBe` S.fromList [Stack "", Stack "D"]
      it "combines stacks" $ do
        (Stack "AB" <> Stack "CD") `shouldBe` Stack "ABCD"
      it "combines rows" $ do
        S.fromList [Stack "", Stack "A"] `combineRows` S.fromList [Stack "B", Stack "B"] `shouldBe` S.fromList [Stack "B", Stack "AB"]
        S.empty `combineRows` S.fromList [Stack "B", Stack "B"] `shouldBe` S.fromList [Stack "B", Stack "B"]
        S.fromList [Stack "A", Stack "B"] `combineRows` S.empty `shouldBe` S.fromList [Stack "A", Stack "B"]
        S.singleton (Stack "") `combineRows` S.fromList[Stack "B", Stack "B"] `shouldBe` S.fromList [Stack "B", Stack "B"]
        S.fromList [Stack "A", Stack "B"] `combineRows` S.singleton (Stack "") `shouldBe` S.fromList [Stack "A", Stack "B"]
      it "splits input into stacks and operations" $ do
        parseInput inputPart1 `shouldBe`
         (S.fromList [Stack "NZ", Stack "DCM", Stack "P"],
          [ Operation { count = 1, from = StackIndex 2, to = StackIndex 1},
            Operation { count = 3, from = StackIndex 1, to = StackIndex 3},
            Operation { count = 2, from = StackIndex 2, to = StackIndex 1},
            Operation { count = 1, from = StackIndex 1, to = StackIndex 2}])
      it "exeutes a count=1 operation on a row" $ do
        let op = Operation { count = 1, from = StackIndex 2, to = StackIndex 3}
        let row = S.fromList [Stack "NZ", Stack "DCM", Stack "P"]
        executeOperation row op `shouldBe` S.fromList [Stack "NZ", Stack "CM", Stack "DP"]
      it "exeutes a count > 1 operation on a row" $ do
        let op = Operation { count = 2, from = StackIndex 2, to = StackIndex 3}
        let row = S.fromList [Stack "NZ", Stack "DCM", Stack "P"]
        executeOperation row op `shouldBe` S.fromList [Stack "NZ", Stack "M", Stack "CDP"]
      it "finds the top items on stacks" $ do
         let row = S.fromList [Stack "NZ", Stack "DCM", Stack "P"]
         findTopOfStacks row `shouldBe` S.fromList "NDP"
      it "solves the demo" $ do
         day5_1 inputPart1 `shouldBe` "CMZ"
    describe "Part1" $ do
      it "executes 9001 operations on a row" $ do
        let op = Operation { count = 2, from = StackIndex 2, to = StackIndex 3}
        let row = S.fromList [Stack "NZ", Stack "DCM", Stack "P"]
        execute9001Operation row op `shouldBe` S.fromList [Stack "NZ", Stack "M", Stack "DCP"]
      it "solves the demo" $ do
         day5_2 inputPart1 `shouldBe` "MCD"