use bnum::cast::As;
use bnum::types::{I256,I512};
use fixed::{FixedI64,FixedI128};
use typenum::{Sum,Unsigned};

#[derive(Clone,Copy,Debug)]
pub struct Fixed<Int,Frac>{
	bits:Int,
	phantom:std::marker::PhantomData<Frac>,
}
pub type FixedI256<Frac>=Fixed<I256,Frac>;
pub type FixedI512<Frac>=Fixed<I512,Frac>;

impl<Int:From<i128>+std::ops::Shl<u32,Output=Int>,FracDst:Unsigned> From<i128> for Fixed<Int,FracDst>{
	fn from(value:i128)->Self{
		Self{
			bits:Int::from(value)<<FracDst::U32,
			phantom:std::marker::PhantomData,
		}
	}
}

impl<Int:PartialEq,Frac> PartialEq for Fixed<Int,Frac>{
	fn eq(&self,other:&Self)->bool{
		self.bits==other.bits
	}
}
impl<Int:Eq,Frac> Eq for Fixed<Int,Frac>{}

pub trait WideMul<Rhs=Self>{
	type Output;
	fn wide_mul(self,rhs:Rhs)->Self::Output;
}

//going wide from foreign fixed type
impl<A,B> WideMul<FixedI64<B>> for FixedI64<A>
	where
		A:std::ops::Add<B>,
		B:Unsigned,
{
	type Output=FixedI128<Sum<A,B>>;
	fn wide_mul(self,rhs:FixedI64<B>)->Self::Output{
		self.wide_mul(rhs)
	}
}
impl<A,B> WideMul<FixedI128<B>> for FixedI128<A>
	where
		A:std::ops::Add<B>,
		B:Unsigned,
{
	type Output=FixedI256<Sum<A,B>>;
	fn wide_mul(self,rhs:FixedI128<B>)->Self::Output{
		FixedI256{
			bits:I256::from(self.to_bits())*I256::from(rhs.to_bits()),
			phantom:std::marker::PhantomData,
		}
	}
}
//going wider native
impl<A,B> WideMul<FixedI256<B>> for FixedI256<A>
	where
		A:std::ops::Add<B>,
		B:Unsigned,
{
	type Output=FixedI512<Sum<A,B>>;
	fn wide_mul(self,rhs:FixedI256<B>)->Self::Output{
		FixedI512{
			bits:self.bits.as_::<I512>()*rhs.bits.as_::<I512>(),
			phantom:std::marker::PhantomData,
		}
	}
}