#![cfg_attr(not(feature = "std"), no_std)]

use ghost_traits::hashing::GhostHasher;
use sp_core::H256;
use sp_io::hashing::{blake2_256, keccak_256, sha2_256};

pub mod bounded_bitmap;
pub mod hash_chain;
pub mod merkle_tree;
pub mod networks;
pub mod utxo;
pub mod lcg;

pub type AuthIndexU8 = u8;
pub type AuthIndexU16 = u16;
pub type AuthIndexU32 = u32;
pub type AuthIndexU64 = u64;
pub type AuthIndexU128 = u128;

pub type BitmapChunkU8 = u8;
pub type BitmapChunkU16 = u16;
pub type BitmapChunkU32 = u32;
pub type BitmapChunkU64 = u64;
pub type BitmapChunkU128 = u128;

pub type DkgIndexU8 = u8;
pub type DkgIndexU16 = u16;
pub type DkgIndexU32 = u32;
pub type DkgIndexU64 = u64;
pub type DkgIndexU128 = u128;

pub type NetworkIdU8 = u8;
pub type NetworkIdU16 = u16;
pub type NetworkIdU32 = u32;
pub type NetworkIdU64 = u64;
pub type NetworkIdU128 = u128;

pub fn get_byzantium_quorum_threshold<I>(value: I) -> I
where
    I: num_traits::PrimInt,
{
    let zero = I::zero();
    let one = I::one();
    let three = one + one + one;

    if value == zero { return zero; }

    let f = (value - one) / three;
    value - f
}

macro_rules! impl_ghost_hasher {
    (
        struct $name:ident;
        hash_type: $hash_type:ty;
        hash_bytes_len: $hash_bytes_len:expr;
        fn hash($data:ident) -> $hash_res:expr
    ) => {
        pub struct $name;

        impl GhostHasher for $name {
            type Hash = $hash_type;
            type HashBytes = [u8; $hash_bytes_len];

            fn hash($data: &[u8]) -> Self::Hash {
                $hash_res
            }

            fn hash_len() -> usize {
                $hash_bytes_len
            }

            fn empty() -> Self::Hash {
                <$hash_type>::zero()
            }

            fn combine_hashes(left: Self::Hash, right: Self::Hash) -> Self::Hash {
                let mut combined = [0u8; $hash_bytes_len * 2];
                combined[..$hash_bytes_len].copy_from_slice(left.as_ref());
                combined[$hash_bytes_len..].copy_from_slice(right.as_ref());
                Self::hash(&combined)
            }

            fn combine_hashes_prefixed(p: u8, l: Self::Hash, r: Self::Hash) -> Self::Hash {
                let mut combined = [p; $hash_bytes_len * 2 + 1];
                combined[1..1 + $hash_bytes_len].copy_from_slice(l.as_ref());
                combined[1 + $hash_bytes_len..].copy_from_slice(r.as_ref());
                Self::hash(&combined)
            }
        }
    };
}

impl_ghost_hasher!(
    struct SubstrateBlake2Hasher;
    hash_type: H256;
    hash_bytes_len: 32;
    fn hash(data) -> H256::from(blake2_256(data))
);

impl_ghost_hasher!(
    struct SubstrateKeccakHasher;
    hash_type: H256;
    hash_bytes_len: 32;
    fn hash(data) -> H256::from(keccak_256(data))
);

impl_ghost_hasher!(
    struct UtxoSha2Hasher;
    hash_type: H256;
    hash_bytes_len: 32;
    fn hash(data) -> {
        let first_pass: [u8; 32] = sha2_256(data);
        let second_pass: [u8; 32] = sha2_256(&first_pass);

        H256::from(second_pass)
    }
);

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_bft_threshold_standard_paper_cases() {
        // Lower boundaries (f increases here)
        assert_eq!(get_byzantium_quorum_threshold(1u32), 1);
        assert_eq!(get_byzantium_quorum_threshold(4u32), 3);
        assert_eq!(get_byzantium_quorum_threshold(7u32), 5);
        assert_eq!(get_byzantium_quorum_threshold(10u32), 7);

        // Upper boundaries (max nodes for a given 'f')
        assert_eq!(get_byzantium_quorum_threshold(3u32), 3);
        assert_eq!(get_byzantium_quorum_threshold(6u32), 5);
        assert_eq!(get_byzantium_quorum_threshold(9u32), 7);
    }

    #[test]
    fn test_bft_threshold_zero_nodes() {
        assert_eq!(get_byzantium_quorum_threshold(0u32), 0);
    }

    #[test]
    fn test_bft_threshold_integer_boundaries() {
        let max_val = usize::MAX;
        let expected_f = (max_val - 1) / 3;
        let expected_honest = max_val - expected_f;

        assert_eq!(get_byzantium_quorum_threshold(max_val), expected_honest);
    }

    #[test]
    fn test_bft_threshold_different_types() {
        assert_eq!(get_byzantium_quorum_threshold(4u8), 3u8);
        assert_eq!(get_byzantium_quorum_threshold(4u64), 3u64);
        assert_eq!(get_byzantium_quorum_threshold(4usize), 3usize);
    }
}