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use crypto_bigint::Uint;
use rand_core::CryptoRngCore;

use crate::{
    generate_prime_with_rng, generate_safe_prime_with_rng, is_prime_with_rng,
    is_safe_prime_with_rng,
};

/// Provides a generic way to access methods for random prime number generation
/// and primality checking, wrapping the standalone functions ([`is_prime_with_rng`] etc).
pub trait RandomPrimeWithRng {
    /// Returns a random prime of size `bit_length` using the provided RNG.
    /// If `bit_length` is `None`, the full size of `Uint<L>` is used.
    ///
    /// Panics if `bit_length` is less than 2, or greater than the bit size of the target `Uint`.
    ///
    /// See [`is_prime_with_rng`] for details about the performed checks.
    fn generate_prime_with_rng(rng: &mut impl CryptoRngCore, bit_length: Option<usize>) -> Self;

    /// Returns a random safe prime (that is, such that `(n - 1) / 2` is also prime)
    /// of size `bit_length` using the provided RNG.
    /// If `bit_length` is `None`, the full size of `Uint<L>` is used.
    ///
    /// Panics if `bit_length` is less than 3, or greater than the bit size of the target `Uint`.
    ///
    /// See [`is_prime_with_rng`] for details about the performed checks.
    fn generate_safe_prime_with_rng(
        rng: &mut impl CryptoRngCore,
        bit_length: Option<usize>,
    ) -> Self;

    /// Checks probabilistically if the given number is prime using the provided RNG.
    ///
    /// See [`is_prime_with_rng`] for details about the performed checks.
    fn is_prime_with_rng(&self, rng: &mut impl CryptoRngCore) -> bool;

    /// Checks probabilistically if the given number is a safe prime using the provided RNG.
    ///
    /// See [`is_prime_with_rng`] for details about the performed checks.
    fn is_safe_prime_with_rng(&self, rng: &mut impl CryptoRngCore) -> bool;
}

impl<const L: usize> RandomPrimeWithRng for Uint<L> {
    fn generate_prime_with_rng(rng: &mut impl CryptoRngCore, bit_length: Option<usize>) -> Self {
        generate_prime_with_rng(rng, bit_length)
    }
    fn generate_safe_prime_with_rng(
        rng: &mut impl CryptoRngCore,
        bit_length: Option<usize>,
    ) -> Self {
        generate_safe_prime_with_rng(rng, bit_length)
    }
    fn is_prime_with_rng(&self, rng: &mut impl CryptoRngCore) -> bool {
        is_prime_with_rng(rng, self)
    }
    fn is_safe_prime_with_rng(&self, rng: &mut impl CryptoRngCore) -> bool {
        is_safe_prime_with_rng(rng, self)
    }
}

#[cfg(test)]
mod tests {
    use crypto_bigint::U64;
    use rand_core::OsRng;

    use super::RandomPrimeWithRng;

    #[test]
    fn uint_impl() {
        assert!(!U64::from(15u32).is_prime_with_rng(&mut OsRng));
        assert!(U64::from(19u32).is_prime_with_rng(&mut OsRng));

        assert!(!U64::from(13u32).is_safe_prime_with_rng(&mut OsRng));
        assert!(U64::from(11u32).is_safe_prime_with_rng(&mut OsRng));

        assert!(U64::generate_prime_with_rng(&mut OsRng, Some(10)).is_prime_with_rng(&mut OsRng));
        assert!(U64::generate_safe_prime_with_rng(&mut OsRng, Some(10))
            .is_safe_prime_with_rng(&mut OsRng));
    }
}