-- SPDX-FileCopyrightText: Copyright (c) 2025 Objectionary.com
-- SPDX-License-Identifier: MIT

module ReplacerSpec where

import Ast
import Control.Monad (forM_)
import Replacer
import Test.Hspec (Example (Arg), Expectation, Spec, SpecWith, describe, it, shouldBe)

test :: ReplaceProgramFunc -> [(String, Program, [Expression], [Expression], Maybe Program)] -> SpecWith (Arg Expectation)
test function useCases =
  forM_ useCases $ \(desc, prog, ptns, repls, res) ->
    it desc $ function ptns repls (ReplaceProgramContext prog 3) `shouldBe` res

spec :: Spec
spec = do
  describe "replace program: Program => ([Expression], [Expression]) => Program" $
    test
      replaceProgram
      [ ( "Q -> Q.y.x => ([Q.y], [$]) => Q -> $.x",
          Program (ExDispatch (ExDispatch ExGlobal (AtLabel "y")) (AtLabel "x")),
          [ExDispatch ExGlobal (AtLabel "y")],
          [ExThis],
          Just (Program (ExDispatch ExThis (AtLabel "x")))
        ),
        ( "Q -> [[x -> [[y -> $]], z -> [[w -> $]] ]] => ([[y -> $], [w -> $]], [Q.y, Q.w]) => Q -> [[x -> Q.y, z -> Q.w]]",
          Program
            ( ExFormation
                [ BiTau (AtLabel "x") (ExFormation [BiTau (AtLabel "y") ExThis]),
                  BiTau (AtLabel "z") (ExFormation [BiTau (AtLabel "w") ExThis])
                ]
            ),
          [ExFormation [BiTau (AtLabel "y") ExThis], ExFormation [BiTau (AtLabel "w") ExThis]],
          [ExDispatch ExGlobal (AtLabel "y"), ExDispatch ExGlobal (AtLabel "w")],
          Just
            ( Program
                ( ExFormation
                    [ BiTau (AtLabel "x") (ExDispatch ExGlobal (AtLabel "y")),
                      BiTau (AtLabel "z") (ExDispatch ExGlobal (AtLabel "w"))
                    ]
                )
            )
        ),
        ("Q -> [[]] => ([], [$]) => X", Program (ExFormation []), [], [ExThis], Nothing),
        ( "Q -> [[L> Func, D> 00-]] => ([ [[L> Func, D> 00-]] ], [Q]) => Q -> Q",
          Program (ExFormation [BiLambda "Func", BiDelta (BtOne "00")]),
          [ExFormation [BiLambda "Func", BiDelta (BtOne "00")]],
          [ExGlobal],
          Just (Program ExGlobal)
        ),
        ( "Q -> Q.org.eolang => ([Q.org.eolang, Q.org], [$, $]) => $",
          Program (ExDispatch (ExDispatch ExGlobal (AtLabel "org")) (AtLabel "eolang")),
          [ExDispatch (ExDispatch ExGlobal (AtLabel "org")) (AtLabel "eolang"), ExDispatch ExGlobal (AtLabel "org")],
          [ExThis, ExThis],
          Just (Program ExThis)
        ),
        ( "Q -> [[ x -> $.t, t -> ? ]].t(^ -> [[ x -> $.t, t -> ? ]]) => ([ [[ x -> $.t, t -> ? ]].t ], [T]) => T(^ -> [[ x -> $.t, t -> ? ]])",
          Program
            ( ExApplication
                ( ExDispatch
                    ( ExFormation
                        [ BiTau (AtLabel "x") (ExDispatch ExThis (AtLabel "t")),
                          BiVoid (AtLabel "t")
                        ]
                    )
                    (AtLabel "t")
                )
                ( BiTau
                    AtRho
                    ( ExFormation
                        [ BiTau (AtLabel "x") (ExDispatch ExThis (AtLabel "t")),
                          BiVoid (AtLabel "t")
                        ]
                    )
                )
            ),
          [ ExDispatch
              ( ExFormation
                  [ BiTau (AtLabel "x") (ExDispatch ExThis (AtLabel "t")),
                    BiVoid (AtLabel "t")
                  ]
              )
              (AtLabel "t")
          ],
          [ExTermination],
          Just
            ( Program
                ( ExApplication
                    ExTermination
                    ( BiTau
                        AtRho
                        ( ExFormation
                            [ BiTau (AtLabel "x") (ExDispatch ExThis (AtLabel "t")),
                              BiVoid (AtLabel "t")
                            ]
                        )
                    )
                )
            )
        )
      ]

  describe "replace program fast: Program => ([Expression], [Expression]) => Program" $
    test
      replaceProgramFast
      [ ( "Q -> [[^ -> ?, @ -> ?, D> -> ?]] => [[ !B1, !a -> ?, !B2 ]] => [[ !B1, !a -> $, !B2 ]] => Q -> [[ ^ -> $, @ -> $, D> -> $ ]]",
          Program (ExFormation [BiVoid AtRho, BiVoid AtPhi, BiVoid AtDelta]),
          [ExFormation [BiVoid AtRho], ExFormation [BiVoid AtPhi], ExFormation [BiVoid AtDelta]],
          [ExFormation [BiTau AtRho ExThis], ExFormation [BiTau AtPhi ExThis], ExFormation [BiTau AtDelta ExThis]],
          Just (Program (ExFormation [BiTau AtRho ExThis, BiTau AtPhi ExThis, BiTau AtDelta ExThis]))
        ),
        ( "Q -> [[ ^ -> ? ]] => [[ !B1, !a -> ?, !B2 ]] => [[ !B1, !a -> [[ !a -> ? ]], !B2 ]] => Q -> [[ ^ -> [[ ^ -> [[ ^ -> [[ ^ -> ? ]] ]] ]] ]]",
          Program (ExFormation [BiVoid AtRho]),
          [ExFormation [BiVoid AtRho]],
          [ExFormation [BiTau AtRho (ExFormation [BiVoid AtRho])]],
          Just (Program (ExFormation [BiTau AtRho (ExFormation [BiTau AtRho (ExFormation [BiTau AtRho (ExFormation [BiVoid AtRho])])])]))
        ),
        ( "Q -> [[ ^ -> T ]](^ -> [[ ^ -> $]]).@ => [[ !B1, !a -> ?, !B2 ]] => [[ !B1, !a -> $, !B2 ]] => Q -> [[ ^ -> $ ]].@",
          Program (ExDispatch (ExApplication (ExFormation [BiTau AtRho ExTermination]) (BiTau AtRho (ExFormation [BiTau AtRho ExThis]))) AtPhi),
          [ExFormation [BiTau AtRho ExTermination], ExFormation [BiTau AtRho ExThis]],
          [ExFormation [BiTau AtRho ExGlobal], ExFormation [BiVoid AtPhi]],
          Just (Program (ExDispatch (ExApplication (ExFormation [BiTau AtRho ExGlobal]) (BiTau AtRho (ExFormation [BiVoid AtPhi]))) AtPhi))
        )
      ]