use crate::func::*;

pub trait ApplicativeLA2ViaSeq: ApplicativeSeq {
    fn _la2_via_seq<'a, A: 'a, B: 'a, C: 'a>(
        f: impl 'a + FnOnce(A, B) -> C,
        fa: Self::F<'a, A>,
        fb: Self::F<'a, B>,
    ) -> Self::F<'a, C>
    where
        Self: 'a;
}

impl<T: ApplicativeSeq> ApplicativeLA2ViaSeq for T {
    fn _la2_via_seq<'a, A: 'a, B: 'a, C: 'a>(
        f: impl 'a + FnOnce(A, B) -> C,
        fa: Self::F<'a, A>,
        fb: Self::F<'a, B>,
    ) -> Self::F<'a, C>
    where
        Self: 'a,
    {
        Self::seq(Self::fmap(|a| |b| f(a, b), fa), fb)
    }
}

pub trait ApplicativeSeqViaLA2: ApplicativeLA2 {
    fn _seq_via_la2<'a, A: 'a, B: 'a>(
        ff: Self::F<'a, impl 'a + FnOnce(A) -> B>,
        fa: Self::F<'a, A>,
    ) -> Self::F<'a, B>
    where
        Self: 'a;
}

impl<T: ApplicativeLA2> ApplicativeSeqViaLA2 for T {
    fn _seq_via_la2<'a, A: 'a, B: 'a>(
        ff: Self::F<'a, impl 'a + FnOnce(A) -> B>,
        fa: Self::F<'a, A>,
    ) -> Self::F<'a, B>
    where
        Self: 'a,
    {
        Self::la2(|f, a| f(a), ff, fa)
    }
}

pub trait ApplicativeTupleViaLA2: ApplicativeLA2 {
    fn _tuple_via_la2<'a, A: 'a, B: 'a>(
        fab: (Self::F<'a, A>, Self::F<'a, B>),
    ) -> Self::F<'a, (A, B)>
    where
        Self: 'a;
}

impl<T: ApplicativeLA2> ApplicativeTupleViaLA2 for T {
    fn _tuple_via_la2<'a, A: 'a, B: 'a>(
        (fa, fb): (Self::F<'a, A>, Self::F<'a, B>),
    ) -> Self::F<'a, (A, B)>
    where
        Self: 'a,
    {
        Self::la2(|a, b| (a, b), fa, fb)
    }
}