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// Copyright (C) 2019-2021 Aleo Systems Inc.
// This file is part of the snarkVM library.

// The snarkVM library is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// The snarkVM library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with the snarkVM library. If not, see <https://www.gnu.org/licenses/>.

use snarkvm_fields::{field, Zero};
use snarkvm_utilities::biginteger::{BigInteger256, BigInteger384};

use crate::{
    bls12_377::{g1::Bls12_377G1Parameters, Fq, Fq2, Fr},
    traits::{ModelParameters, ShortWeierstrassParameters},
};

#[derive(Clone, Default, PartialEq, Eq)]
pub struct Bls12_377G2Parameters;

impl ModelParameters for Bls12_377G2Parameters {
    type BaseField = Fq2;
    type ScalarField = Fr;
}

impl ShortWeierstrassParameters for Bls12_377G2Parameters {
    /// AFFINE_GENERATOR_COEFFS = (G2_GENERATOR_X, G2_GENERATOR_Y)
    const AFFINE_GENERATOR_COEFFS: (Self::BaseField, Self::BaseField) = (G2_GENERATOR_X, G2_GENERATOR_Y);
    /// COEFF_A = [0, 0]
    const COEFF_A: Fq2 = field!(Fq2, Bls12_377G1Parameters::COEFF_A, Bls12_377G1Parameters::COEFF_A,);
    // As per https://eprint.iacr.org/2012/072.pdf,
    // this curve has b' = b/i, where b is the COEFF_B of G1, and x^6 -i is
    // the irreducible poly used to extend from Fp2 to Fp12.
    // In our case, i = u (App A.3, T_6).
    /// COEFF_B = [0,
    /// 155198655607781456406391640216936120121836107652948796323930557600032281009004493664981332883744016074664192874906]
    const COEFF_B: Fq2 = field!(
        Fq2,
        field!(Fq, BigInteger384([0, 0, 0, 0, 0, 0])),
        field!(
            Fq,
            BigInteger384([
                9255502405446297221,
                10229180150694123945,
                9215585410771530959,
                13357015519562362907,
                5437107869987383107,
                16259554076827459,
            ])
        ),
    );
    /// COFACTOR =
    /// 7923214915284317143930293550643874566881017850177945424769256759165301436616933228209277966774092486467289478618404761412630691835764674559376407658497
    const COFACTOR: &'static [u64] = &[
        0x0000000000000001,
        0x452217cc90000000,
        0xa0f3622fba094800,
        0xd693e8c36676bd09,
        0x8c505634fae2e189,
        0xfbb36b00e1dcc40c,
        0xddd88d99a6f6a829,
        0x26ba558ae9562a,
    ];
    /// COFACTOR_INV = COFACTOR^{-1} mod r
    /// = 6764900296503390671038341982857278410319949526107311149686707033187604810669
    const COFACTOR_INV: Fr = field!(
        Fr,
        BigInteger256([
            15499857013495546999,
            4613531467548868169,
            14546778081091178013,
            549402535258503313,
        ])
    );

    #[inline(always)]
    fn mul_by_a(_: &Self::BaseField) -> Self::BaseField {
        Self::BaseField::zero()
    }
}

pub const G2_GENERATOR_X: Fq2 = field!(Fq2, G2_GENERATOR_X_C0, G2_GENERATOR_X_C1);
pub const G2_GENERATOR_Y: Fq2 = field!(Fq2, G2_GENERATOR_Y_C0, G2_GENERATOR_Y_C1);

///
/// G2_GENERATOR_X_C0 =
/// 170590608266080109581922461902299092015242589883741236963254737235977648828052995125541529645051927918098146183295
///
/// See `snarkvm_algorithms::hash_to_curve::tests::bls12_377` for tests.
///
pub const G2_GENERATOR_X_C0: Fq = field!(
    Fq,
    BigInteger384::new([
        1394603105513884269,
        11069732150289508451,
        4261960060090787184,
        13457254148541472797,
        3177258746859163322,
        82258727112085846
    ])
);

///
/// G2_GENERATOR_X_C1 =
/// 83407003718128594709087171351153471074446327721872642659202721143408712182996929763094113874399921859453255070254
///
/// See `snarkvm_algorithms::hash_to_curve::tests::bls12_377` for tests.
///
pub const G2_GENERATOR_X_C1: Fq = field!(
    Fq,
    BigInteger384::new([
        12672065269715576738,
        3451530808602826578,
        9486610028138952262,
        5031487885431614078,
        9858745210421513581,
        63301617551232910
    ])
);

///
/// G2_GENERATOR_Y_C0 =
/// 1843833842842620867708835993770650838640642469700861403869757682057607397502738488921663703124647238454792872005
///
/// See `snarkvm_algorithms::hash_to_curve::tests::bls12_377` for tests.
///
pub const G2_GENERATOR_Y_C0: Fq = field!(
    Fq,
    BigInteger384::new([
        1855632670224768760,
        2989378521406112342,
        9748867374972564648,
        3204895972998458874,
        16520689795595505429,
        61918742406142643
    ])
);

///
/// G2_GENERATOR_Y_C1 =
/// 33145532013610981697337930729788870077912093258611421158732879580766461459275194744385880708057348608045241477209
///
/// See `snarkvm_algorithms::hash_to_curve::tests::bls12_377` for tests.
///
pub const G2_GENERATOR_Y_C1: Fq = field!(
    Fq,
    BigInteger384::new([
        1532128906028652860,
        14539073382194201855,
        10828918286556702479,
        14664598863867299115,
        483199896405477997,
        73741830940675480
    ])
);