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use crate::{syscall_bn254_add, syscall_bn254_double, utils::AffinePoint};

/// The number of limbs in [Bn254AffinePoint].
pub const N: usize = 16;

/// An affine point on the Bn254 curve.
#[derive(Copy, Clone)]
#[repr(align(4))]
pub struct Bn254AffinePoint(pub [u32; N]);

impl AffinePoint<N> for Bn254AffinePoint {
    /// The generator has been taken from py_pairing python library by the Ethereum Foundation:
    ///
    /// https://github.com/ethereum/py_pairing/blob/5f609da/py_ecc/bn128/bn128_field_elements.py
    const GENERATOR: [u32; N] = [1, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0];

    fn new(limbs: [u32; N]) -> Self {
        Self(limbs)
    }

    fn limbs_ref(&self) -> &[u32; N] {
        &self.0
    }

    fn limbs_mut(&mut self) -> &mut [u32; N] {
        &mut self.0
    }

    fn add_assign(&mut self, other: &Self) {
        let a = self.limbs_mut();
        let b = other.limbs_ref();
        unsafe {
            syscall_bn254_add(a, b);
        }
    }

    fn double(&mut self) {
        let a = self.limbs_mut();
        unsafe {
            syscall_bn254_double(a);
        }
    }
}