use async_std::{prelude::*,stream,task};
use length_prefixed_stream::decode;
use futures::{stream::TryStreamExt};
type Error = Box<dyn std::error::Error+Send+Sync+'static>;

#[test] fn simple_0() -> Result<(),Error> {
  task::block_on(async {
    let input = stream::from_iter(vec![
      Ok(vec![6,97,98,99]),
      Ok(vec![100,101]),
      Ok(vec![102,4,65,66]),
      Ok(vec![67,68]),
    ]).into_async_read();
    let mut decoder = decode(input);
    let mut observed = vec![];
    while let Some(chunk) = decoder.next().await {
      observed.push(chunk?);
    }
    assert_eq![observed, vec![
      vec![97,98,99,100,101,102],
      vec![65,66,67,68],
    ]];
    Ok(())
  })
}

#[test] fn simple_1() -> Result<(),Error> {
  task::block_on(async {
    let input = stream::from_iter(vec![
      Ok(vec![3,10,20,30,5]),
      Ok(vec![11,12,13,14,15]),
      Ok(vec![1,6,3,103]),
      Ok(vec![102,101]),
    ]).into_async_read();
    let mut decoder = decode(input);
    let mut observed = vec![];
    while let Some(chunk) = decoder.next().await {
      observed.push(chunk?);
    }
    assert_eq![observed, vec![
      vec![10,20,30],
      vec![11,12,13,14,15],
      vec![6],
      vec![103,102,101],
    ]];
    Ok(())
  })
}

#[test] fn multibyte_msg_len() -> Result<(),Error> {
  task::block_on(async {
    let input = stream::from_iter(vec![
      Ok(vec![4,200,201,202,203,144]), // encode(400) = [144,3]
      Ok([vec![3],(0..200).collect()].concat()),
      Ok((200..395).map(|c| (c%256) as u8).collect()),
      Ok([(395..400).map(|c| (c%256) as u8).collect(),vec![5,99]].concat()),
      Ok(vec![98,97,96]),
      Ok(vec![95,4,150,150,150,150,1]),
      Ok(vec![55]),
    ]).into_async_read();
    let mut decoder = decode(input);
    let mut observed = vec![];
    while let Some(chunk) = decoder.next().await {
      observed.push(chunk?);
    }
    assert_eq![observed, vec![
      vec![200,201,202,203],
      (0..400).map(|c| (c%256) as u8).collect(),
      vec![99,98,97,96,95],
      vec![150,150,150,150],
      vec![55],
    ]];
    Ok(())
  })
}