use core::marker::PhantomData;

use crate::Node;

pub struct ComposeNode<'n, Inter, First, Second> {
	first: &'n First,
	second: &'n Second,
	_phantom: PhantomData<&'n Input>,
	_phantom2: PhantomData<Inter>,
}

impl<'n, Input: 'n, Inter: 'n, First, Second> Node<'n, Input> for ComposeNode<'n, Input, Inter, First, Second>
where
	First: Node<'n, Input, Output = Inter>,
	Second: Node<'n, Inter>, /*+ Node<<First as Node<Input>>::Output<'n>>*/
{
	type Output = <Second as Node<'n, Inter>>::Output;

	fn eval(&'n self, input: Input) -> Self::Output {
		// evaluate the first node with the given input
		// and then pipe the result from the first computation
		// into the second node
		let arg: Inter = self.first.eval(input);
		self.second.eval(arg)
	}
}

impl<'n, Input, Inter, FIRST, SECOND> ComposeNode<'n, Input, Inter, FIRST, SECOND>
where
	FIRST: Node<'n, Input>,
{
	pub const fn new(first: &'n FIRST, second: &'n SECOND) -> Self {
		ComposeNode::<'n, Input, Inter, FIRST, SECOND> {
			first,
			second,
			_phantom: PhantomData,
			_phantom2: PhantomData,
		}
	}
}

#[repr(C)]
pub struct ComposeNodeOwned<'n, Input, Inter, FIRST, SECOND> {
	first: FIRST,
	second: SECOND,
	_phantom: PhantomData<&'n Input>,
	_phantom2: PhantomData<Inter>,
}

impl<'n, Input: 'n, Inter: 'n, First, Second> Node<'n, Input> for ComposeNodeOwned<'n, Input, Inter, First, Second>
where
	First: Node<'n, Input, Output = Inter>,
	Second: Node<'n, Inter>,
{
	type Output = <Second as Node<'n, Inter>>::Output;

	fn eval(&'n self, input: Input) -> Self::Output {
		// evaluate the first node with the given input
		// and then pipe the result from the first computation
		// into the second node
		let arg: Inter = self.first.eval(input);
		self.second.eval(arg)
	}
}

impl<'n, Input, Inter, First: 'n, Second> ComposeNodeOwned<'n, Input, Inter, First, Second>
where
	First: Node<'n, Input, Output = Inter>,
{
	#[cfg(feature = "nightly")]
	pub const fn new(first: First, second: Second) -> Self {
		ComposeNodeOwned::<'n, Input, Inter, First, Second> {
			first,
			second,
			_phantom: PhantomData,
			_phantom2: PhantomData,
		}
	}
	#[cfg(not(feature = "nightly"))]
	pub fn new(first: First, second: Second) -> Self {
		ComposeNodeOwned::<'n, Input, Inter, First, Second> {
			first,
			second,
			_phantom: PhantomData,
			_phantom2: PhantomData,
		}
	}
}

pub trait After<I>: Sized {
	fn after<'n, First: Node<'n, I>>(&'n self, first: &'n First) -> ComposeNode<'n, I, <First as Node<'n, I>>::Output, First, Self> {
		ComposeNode::new(first, self)
	}
}
impl<Second: for<'n> Node<'n, I>, I> After<I> for Second {}