//! Encodings
use super::*;
use ext::*;
use std::{fmt, error};
use bytes::{
    Buf,
    Bytes,
};
use std::io;
use tokio::io::{
    AsyncRead, AsyncWrite,
    AsyncReadExt, AsyncWriteExt,
};
use serde::{
    Serialize,
    de::DeserializeOwned
};
use cryptohelpers::{
    sha256,
    rsa,
};

/// Size of buffer to use when copying a stream.
pub const STREAMING_BUFFER_SIZE: usize = 4096;

pub mod ser;

/// Copy `from` to `to`, transforming the data with the provided key and IV.
///
/// # Stream cipher usage
/// The copy is buffered by `STREAMING_BUFFER_SIZE` bytes, and the cipher applied to each read buffer.
/// If the buffer cannot be filled (because the stream reached EOF before filling it), then only the full portion of the buffer is transformed and written.
#[inline] pub async fn cc20_copy_stream<F, T, K>(from: &mut F, to: &mut T, keys: K, decrypt: bool) -> io::Result<(usize, usize)>
where K: key::CC20Key,
      F: AsyncRead + Unpin + ?Sized,
      T: AsyncWrite + Unpin + ?Sized
{
    if decrypt {
	ser::cha_copy::<F, T, STREAMING_BUFFER_SIZE, true>(from, to, keys.key(), keys.iv()).await
    } else {
	ser::cha_copy::<F, T, STREAMING_BUFFER_SIZE, false>(from, to, keys.key(), keys.iv()).await
    }
}