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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 smallvec::SmallVec;
use snarkvm_fields::PrimeField;

use core::fmt::Debug;

pub trait SpongeParameters<const RATE: usize, const CAPACITY: usize> {}

/// The interface for a cryptographic sponge.
/// A sponge can `absorb` or take in inputs and later `squeeze` or output bytes or field elements.
/// The outputs are dependent on previous `absorb` and `squeeze` calls.
pub trait AlgebraicSponge<F: PrimeField, const RATE: usize, const CAPACITY: usize>: Clone + Debug {
    /// Parameters used by the sponge.
    type Parameters: SpongeParameters<RATE, CAPACITY>;

    /// Initialize a new instance of the sponge.
    fn with_parameters(params: &Self::Parameters) -> Self;

    /// Absorb an input into the sponge.
    fn absorb(&mut self, input: &[F]);

    /// Squeeze `num_elements` field elements from the sponge.
    fn squeeze_field_elements(&mut self, num_elements: usize) -> SmallVec<[F; 10]>;
}

pub trait DefaultCapacityAlgebraicSponge<F: PrimeField, const RATE: usize>: AlgebraicSponge<F, RATE, 1> {
    fn sample_parameters() -> Self::Parameters;

    fn with_default_parameters() -> Self {
        Self::with_parameters(&Self::sample_parameters())
    }
}

/// The mode structure for duplex sponges
#[derive(PartialEq, Eq, Clone, Debug)]
pub enum DuplexSpongeMode {
    /// The sponge is currently absorbing data.
    Absorbing {
        /// next position of the state to be XOR-ed when absorbing.
        next_absorb_index: usize,
    },
    /// The sponge is currently squeezing data out.
    Squeezing {
        /// next position of the state to be outputted when squeezing.
        next_squeeze_index: usize,
    },
}