imports :: GHC.RenamedSource -> DetailsMap
imports src@(_, imps, _, _) =
    everything (<|>) ie src ++ mapMaybe (imp . GHC.unLoc) imps
  where
    ie term = case cast term of
        (Just (GHC.IEVar v)) -> pure $ var v
        (Just (GHC.IEThingAbs t)) -> pure $ typ t
        (Just (GHC.IEThingAll t)) -> pure $ typ t
        (Just (GHC.IEThingWith t _ vs _fls)) ->
          [typ t] ++ map var vs
        _ -> empty
    typ (GHC.L sspan name) = (sspan, RtkType name)
    var (GHC.L sspan name) = (sspan, RtkVar name)
    imp idecl | not . GHC.ideclImplicit $ idecl =
        let (GHC.L sspan name) = GHC.ideclName idecl
        in Just (sspan, RtkModule name)
    imp _ = Nothing

-- | Check whether token stream span matches GHC source span.
--
-- Currently, it is implemented as checking whether "our" span is contained
-- in GHC span. The reason for that is because GHC span are generally wider
-- and may spread across couple tokens. For example, @(>>=)@ consists of three
-- tokens: @(@, @>>=@, @)@, but GHC source span associated with @>>=@ variable
-- contains @(@ and @)@. Similarly, qualified identifiers like @Foo.Bar.quux@
-- are tokenized as @Foo@, @.@, @Bar@, @.@, @quux@ but GHC source span
-- associated with @quux@ contains all five elements.
imports :: GHC.RenamedSource -> DetailsMap
imports src@(_, imps, _, _) =
    everything (<|>) ie src ++ mapMaybe (imp . GHC.unLoc) imps
  where
    ie term = case cast term of
        (Just (GHC.IEVar v)) -> pure $ var v
        (Just (GHC.IEThingAbs t)) -> pure $ typ t
        (Just (GHC.IEThingAll t)) -> pure $ typ t
        (Just (GHC.IEThingWith t _ vs _fls)) ->
          [typ t] ++ map var vs
        _ -> empty
    typ (GHC.L sspan name) = (sspan, RtkType name)
    var (GHC.L sspan name) = (sspan, RtkVar name)
    imp idecl | not . GHC.ideclImplicit $ idecl =
        let (GHC.L sspan name) = GHC.ideclName idecl
        in Just (sspan, RtkModule name)
    imp _ = Nothing

-- | Check whether token stream span matches GHC source span.
--
-- Currently, it is implemented as checking whether "our" span is contained
-- in GHC span. The reason for that is because GHC span are generally wider
-- and may spread across couple tokens. For example, @(>>=)@ consists of three
-- tokens: @(@, @>>=@, @)@, but GHC source span associated with @>>=@ variable
-- contains @(@ and @)@. Similarly, qualified identifiers like @Foo.Bar.quux@
-- are tokenized as @Foo@, @.@, @Bar@, @.@, @quux@ but GHC source span
-- associated with @quux@ contains all five elements.
imports src@(_, imps, _, _) =
    everything (<|>) ie src ++ mapMaybe (imp . GHC.unLoc) imps
  where
    ie term = case cast term of
        (Just (GHC.IEVar v)) -> pure $ var v
        (Just (GHC.IEThingAbs t)) -> pure $ typ t
        (Just (GHC.IEThingAll t)) -> pure $ typ t
        (Just (GHC.IEThingWith t _ vs _fls)) ->
          [typ t] ++ map var vs
        _ -> empty
    typ (GHC.L sspan name) = (sspan, RtkType name)
    var (GHC.L sspan name) = (sspan, RtkVar name)
    imp idecl | not . GHC.ideclImplicit $ idecl =
        let (GHC.L sspan name) = GHC.ideclName idecl
        in Just (sspan, RtkModule name)
    imp _ = Nothing

-- | Check whether token stream span matches GHC source span.
--
-- Currently, it is implemented as checking whether "our" span is contained
-- in GHC span. The reason for that is because GHC span are generally wider
-- and may spread across couple tokens. For example, @(>>=)@ consists of three
-- tokens: @(@, @>>=@, @)@, but GHC source span associated with @>>=@ variable
-- contains @(@ and @)@. Similarly, qualified identifiers like @Foo.Bar.quux@
-- are tokenized as @Foo@, @.@, @Bar@, @.@, @quux@ but GHC source span
-- associated with @quux@ contains all five elements.