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

#[cfg(feature = "std")]
use zeroize::Zeroize;

#[cfg(feature = "borsh")]
use borsh::{BorshSerialize, BorshDeserialize};
#[cfg(feature = "serde")]
use serde::{Serialize, Deserialize};

use scale::{Encode, Decode, MaxEncodedLen};
use scale_info::TypeInfo;

#[cfg(test)]
use sp_io::TestExternalities;

#[cfg(test)]
use frame_support::{pallet_prelude::*, Identity, traits::StorageInstance};

use sp_core::{ConstU32, bounded::BoundedVec};
pub use sp_application_crypto as crypto;

mod amount;
pub use amount::*;

mod block;
pub use block::*;

mod networks;
pub use networks::*;

mod balance;
pub use balance::*;

mod account;
pub use account::*;

mod constants;
pub use constants::*;

mod dex;
#[allow(unused_imports)]
pub use dex::*;

pub type BlockNumber = u64;
pub type Header = sp_runtime::generic::Header<BlockNumber, sp_runtime::traits::BlakeTwo256>;

#[cfg(feature = "borsh")]
pub fn borsh_serialize_bounded_vec<W: borsh::io::Write, T: BorshSerialize, const B: u32>(
  bounded: &BoundedVec<T, ConstU32<B>>,
  writer: &mut W,
) -> Result<(), borsh::io::Error> {
  borsh::BorshSerialize::serialize(bounded.as_slice(), writer)
}

#[cfg(feature = "borsh")]
pub fn borsh_deserialize_bounded_vec<R: borsh::io::Read, T: BorshDeserialize, const B: u32>(
  reader: &mut R,
) -> Result<BoundedVec<T, ConstU32<B>>, borsh::io::Error> {
  let vec: Vec<T> = borsh::BorshDeserialize::deserialize_reader(reader)?;
  vec.try_into().map_err(|_| borsh::io::Error::other("bound exceeded"))
}

pub const MAX_ADDRESS_LEN: u32 = 512;

#[derive(Clone, PartialEq, Eq, Debug, Encode, Decode, MaxEncodedLen, TypeInfo)]
#[cfg_attr(feature = "borsh", derive(BorshSerialize, BorshDeserialize))]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
pub struct ExternalAddress(
  #[cfg_attr(
    feature = "borsh",
    borsh(
      serialize_with = "borsh_serialize_bounded_vec",
      deserialize_with = "borsh_deserialize_bounded_vec"
    )
  )]
  BoundedVec<u8, ConstU32<{ MAX_ADDRESS_LEN }>>,
);
#[cfg(feature = "std")]
impl Zeroize for ExternalAddress {
  fn zeroize(&mut self) {
    self.0.as_mut().zeroize()
  }
}

impl ExternalAddress {
  #[cfg(feature = "std")]
  pub fn new(address: Vec<u8>) -> Result<ExternalAddress, &'static str> {
    Ok(ExternalAddress(address.try_into().map_err(|_| "address length exceeds {MAX_ADDRESS_LEN}")?))
  }

  #[cfg(feature = "std")]
  pub fn consume(self) -> Vec<u8> {
    self.0.into_inner()
  }
}

impl AsRef<[u8]> for ExternalAddress {
  fn as_ref(&self) -> &[u8] {
    self.0.as_ref()
  }
}

/// Lexicographically reverses a given byte array.
pub fn reverse_lexicographic_order<const N: usize>(bytes: [u8; N]) -> [u8; N] {
  let mut res = [0u8; N];
  for (i, byte) in bytes.iter().enumerate() {
    res[i] = !*byte;
  }
  res
}

#[test]
fn test_reverse_lexicographic_order() {
  TestExternalities::default().execute_with(|| {
    use rand_core::{RngCore, OsRng};

    struct Storage;
    impl StorageInstance for Storage {
      fn pallet_prefix() -> &'static str {
        "LexicographicOrder"
      }

      const STORAGE_PREFIX: &'static str = "storage";
    }
    type Map = StorageMap<Storage, Identity, [u8; 8], (), OptionQuery>;

    struct StorageReverse;
    impl StorageInstance for StorageReverse {
      fn pallet_prefix() -> &'static str {
        "LexicographicOrder"
      }

      const STORAGE_PREFIX: &'static str = "storagereverse";
    }
    type MapReverse = StorageMap<StorageReverse, Identity, [u8; 8], (), OptionQuery>;

    // populate the maps
    let mut amounts = vec![];
    for _ in 0 .. 100 {
      amounts.push(OsRng.next_u64());
    }

    let mut amounts_sorted = amounts.clone();
    amounts_sorted.sort();
    for a in amounts {
      Map::set(a.to_be_bytes(), Some(()));
      MapReverse::set(reverse_lexicographic_order(a.to_be_bytes()), Some(()));
    }

    // retrive back and check whether they are sorted as expected
    let total_size = amounts_sorted.len();
    let mut map_iter = Map::iter_keys();
    let mut reverse_map_iter = MapReverse::iter_keys();
    for i in 0 .. amounts_sorted.len() {
      let first = map_iter.next().unwrap();
      let second = reverse_map_iter.next().unwrap();

      assert_eq!(u64::from_be_bytes(first), amounts_sorted[i]);
      assert_eq!(
        u64::from_be_bytes(reverse_lexicographic_order(second)),
        amounts_sorted[total_size - (i + 1)]
      );
    }
  });
}