use super::tests::*;
use super::*;

pub trait FunctorTestSuite<'a>: WeakFunctor<'a> + Eqr<'a> {
    fn sample<A: 'a, F: FnMut(&'a dyn Fn(A) -> Self::F<A>)>(f: F);
}

pub fn functor_follows_laws<'a, T: Functor<'a> + FunctorTestSuite<'a>>() -> R {
    let mut res = R::default();
    T::sample(|pa| {
        res += fmap_respects_identity::<T, _>(|| pa(2));
    });
    T::sample(|pa| {
        res += fmap_respects_composition::<T, _, _, _>(|x| x + 5, |x| x + 3, || pa(2));
    });
    res
}

pub fn applicative_follows_laws<'a, T: Applicative<'a> + FunctorTestSuite<'a>>() -> R {
    let mut res = functor_follows_laws::<T>();
    T::sample(|pa| {
        res += seq_respects_identity::<T, _>(|| pa(2));
    });
    T::sample(|pa| {
        T::sample(|pg| {
            T::sample(|pf| {
                res += seq_respects_composition::<T, _, _, _, _, _>(
                    || pf(|x| x + 5),
                    || pg(|x| x + 3),
                    || pa(2),
                );
            })
        })
    });
    res += seq_is_homomorphic::<T, _, _>(|x| x + 3, || 2);
    T::sample(|pf| {
        res += seq_respects_interchange::<T, _, _, _>(|| pf(|x| x + 3), || 2);
    });
    T::sample(|pa| {
        T::sample(|pf| {
            res += seq_can_be_expressed_via_la2::<T, _, _, _>(|| pf(|x| x + 3), || pa(2));
        })
    });
    T::sample(|pa| {
        res += fmap_can_be_expressed_via_seq::<T, _, _>(|x| x + 3, || pa(2));
    });
    T::sample(|pa| {
        T::sample(|pb| {
            res += discard_can_be_expressed_via_seq_or_la2::<T, _, _>(|| pa(2), || pb(2));
        })
    });
    res
}

pub fn monad_follows_laws<'a, T: Monad<'a> + FunctorTestSuite<'a>>() -> R {
    let mut res = applicative_follows_laws::<T>();
    T::sample(|pa| {
        res += bind_respects_left_identity::<T, _, _>(|x| pa(x + 3), || 2);
    });
    T::sample(|pa| {
        res += bind_respects_right_identity::<T, _>(|| pa(2));
    });
    T::sample(|pa| {
        T::sample(|pg| {
            T::sample(|pf| {
                res += bind_is_associative::<T, _, _, _>(|x| pf(x + 5), |x| pg(x + 3), || pa(2));
            })
        })
    });
    T::sample(|pa| {
        T::sample(|pf| {
            seq_can_be_expressed_via_bind::<T, _, _, _>(|| pf(|x| x + 3), || pa(2));
        })
    });
    T::sample(|pa| {
        res += fmap_can_be_expressed_via_bind::<T, _, _>(|x| x + 3, || pa(2));
    });
    res
}