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

module BuilderSpec where

import Ast
import Builder
import Control.Monad
import Data.Map.Strict qualified as Map
import Matcher
import Test.Hspec (Example (Arg), Expectation, Spec, SpecWith, anyException, describe, it, shouldBe, shouldThrow, shouldSatisfy)
import Data.Either (isLeft)

test :: (Show a, Eq a) => (a -> Subst -> Either String (a, a)) -> [(String, a, [(String, MetaValue)], Either String (a, a))] -> SpecWith (Arg Expectation)
test function useCases =
  forM_ useCases $ \(desc, expr, mp, res) ->
    it desc $ function expr (Subst (Map.fromList mp)) `shouldBe` res

spec :: Spec
spec = do
  describe "buildExpression" $
    test
      buildExpression
      [ ( "Q.!a => (!a >> x) => Q.x",
          ExDispatch ExGlobal (AtMeta "a"),
          [("a", MvAttribute (AtLabel "x"))],
          Right (ExDispatch ExGlobal (AtLabel "x"), defaultScope)
        ),
        ( "Q.c(!a -> !e) => (!a >> x, !e >> $.y.z) => Q.c(x -> $.y.z)",
          ExApplication (ExDispatch ExGlobal (AtLabel "c")) (BiTau (AtMeta "a") (ExMeta "e")),
          [("a", MvAttribute (AtLabel "x")), ("e", MvExpression (ExDispatch (ExDispatch ExThis (AtLabel "y")) (AtLabel "z")) defaultScope)],
          Right (ExApplication (ExDispatch ExGlobal (AtLabel "c")) (BiTau (AtLabel "x") (ExDispatch (ExDispatch ExThis (AtLabel "y")) (AtLabel "z"))), defaultScope)
        ),
        ( "[[!a -> $.x, !B]] => (!a >> y, !B >> [[b -> ?, L> Func]]) => [[y -> $.x, b -> ?, L> Func]]",
          ExFormation [BiTau (AtMeta "a") (ExDispatch ExThis (AtLabel "x")), BiMeta "B"],
          [("a", MvAttribute (AtLabel "y")), ("B", MvBindings [BiVoid (AtLabel "b"), BiLambda "Func"])],
          Right
            ( ExFormation
                [ BiTau (AtLabel "y") (ExDispatch ExThis (AtLabel "x")),
                  BiVoid (AtLabel "b"),
                  BiLambda "Func"
                ],
              defaultScope
            )
        ),
        ( "Q * !t => (!t >> [.a, .b, (~1 -> $.x)]) => Q.a.b(~1 -> $.x)",
          ExMetaTail ExGlobal "t",
          [("t", MvTail [TaDispatch (AtLabel "a"), TaDispatch (AtLabel "b"), TaApplication (BiTau (AtAlpha 1) (ExDispatch ExThis (AtLabel "x")))])],
          Right (ExApplication (ExDispatch (ExDispatch ExGlobal (AtLabel "a")) (AtLabel "b")) (BiTau (AtAlpha 1) (ExDispatch ExThis (AtLabel "x"))), defaultScope)
        ),
        ( "Q.!a => () => X",
          ExDispatch ExGlobal (AtMeta "a"),
          [],
          Left "meta 'a' is either does not exist or refers to an inappropriate term"
        ),
        ( "!e0(!a1 -> !e1, !a2 => !e2) => (!e0 >> [[]], !a1 >> x, !e1 >> Q, !a2 >> y, !e2 >> $) => [[]](x -> Q, y -> $)",
          ExApplication (ExApplication (ExMeta "e0") (BiTau (AtMeta "a1") (ExMeta "e1"))) (BiTau (AtMeta "a2") (ExMeta "e2")),
          [ ("e0", MvExpression (ExFormation []) defaultScope),
            ("a1", MvAttribute (AtLabel "x")),
            ("e1", MvExpression ExGlobal defaultScope),
            ("a2", MvAttribute (AtLabel "y")),
            ("e2", MvExpression ExThis defaultScope)
          ],
          Right (ExApplication (ExApplication (ExFormation []) (BiTau (AtLabel "x") ExGlobal)) (BiTau (AtLabel "y") ExThis), defaultScope)
        ),
        ( "⟦!a ↦ ∅, !B⟧.!a => (!a >> t, !B >> ⟦ x ↦ ξ.t ⟧ ) => ⟦ t ↦ ∅, x ↦ ξ.t ⟧.t",
          ExDispatch (ExFormation [BiVoid (AtMeta "a"), BiMeta "B"]) (AtMeta "a"),
          [ ("a", MvAttribute (AtLabel "t")),
            ("B", MvBindings [BiTau (AtLabel "x") (ExDispatch ExThis (AtLabel "t"))])
          ],
          Right
            ( ExDispatch
                ( ExFormation
                    [ BiVoid (AtLabel "t"),
                      BiTau (AtLabel "x") (ExDispatch ExThis (AtLabel "t"))
                    ]
                )
                (AtLabel "t"),
              defaultScope
            )
        )
      ]

  describe "buildExpressions" $ do
    it "!e => [(!e >> Q.x), (!e >> $.y)] => [Q.x, $.y]" $ do
      built <-
        buildExpressions
          (ExMeta "e")
          [ substSingle "e" (MvExpression (ExDispatch ExGlobal (AtLabel "x")) defaultScope),
            substSingle "e" (MvExpression (ExDispatch ExThis (AtLabel "y")) defaultScope)
          ]
      built `shouldBe` [(ExDispatch ExGlobal (AtLabel "x"), defaultScope), (ExDispatch ExThis (AtLabel "y"), defaultScope)]
    it "!e => [(!e1 >> Q.x)] => X" $
      buildExpressions
        (ExMeta "e")
        [substSingle "e1" (MvExpression (ExDispatch ExGlobal (AtLabel "x")) defaultScope)]
        `shouldThrow` anyException
  
  describe "build with duplicate attributes in bindings" $ do
    it "build binding with duplicates" $
      buildBinding (BiMeta "B") (substSingle "B" (MvBindings [BiVoid AtRho, BiVoid AtRho])) `shouldSatisfy` isLeft
    it "build formation with duplicates" $
      buildExpression (ExMeta "e") (substSingle "e" (MvExpression (ExFormation [BiVoid AtRho, BiVoid AtRho]) ExThis)) `shouldSatisfy` isLeft