use crate::{
    disk::{error::DiskError, Disk, DiskAPI},
    erasure::{ReadAt, Writer},
    error::{Error, Result},
    io::{FileReader, FileWriter},
    store_api::BitrotAlgorithm,
};
use blake2::Blake2b512;
use blake2::Digest as _;
use highway::{HighwayHash, HighwayHasher, Key};
use lazy_static::lazy_static;
use sha2::{digest::core_api::BlockSizeUser, Digest, Sha256};
use std::{any::Any, collections::HashMap, io::Cursor, sync::Arc};
use tokio::io::{AsyncReadExt as _, AsyncWriteExt};
use tracing::{error, info};

lazy_static! {
    static ref BITROT_ALGORITHMS: HashMap<BitrotAlgorithm, &'static str> = {
        let mut m = HashMap::new();
        m.insert(BitrotAlgorithm::SHA256, "sha256");
        m.insert(BitrotAlgorithm::BLAKE2b512, "blake2b");
        m.insert(BitrotAlgorithm::HighwayHash256, "highwayhash256");
        m.insert(BitrotAlgorithm::HighwayHash256S, "highwayhash256S");
        m
    };
}

// const MAGIC_HIGHWAY_HASH256_KEY: &[u8] = &[
//     0x4b, 0xe7, 0x34, 0xfa, 0x8e, 0x23, 0x8a, 0xcd, 0x26, 0x3e, 0x83, 0xe6, 0xbb, 0x96, 0x85, 0x52, 0x04, 0x0f, 0x93, 0x5d, 0xa3,
//     0x9f, 0x44, 0x14, 0x97, 0xe0, 0x9d, 0x13, 0x22, 0xde, 0x36, 0xa0,
// ];
const MAGIC_HIGHWAY_HASH256_KEY: &[u64; 4] = &[3, 4, 2, 1];

#[derive(Clone, Debug)]
pub enum Hasher {
    SHA256(Sha256),
    HighwayHash256(HighwayHasher),
    BLAKE2b512(Blake2b512),
}

impl Hasher {
    pub fn update(&mut self, data: impl AsRef<[u8]>) {
        match self {
            Hasher::SHA256(core_wrapper) => {
                core_wrapper.update(data);
            }
            Hasher::HighwayHash256(highway_hasher) => {
                highway_hasher.append(data.as_ref());
            }
            Hasher::BLAKE2b512(core_wrapper) => {
                core_wrapper.update(data);
            }
        }
    }

    pub fn finalize(self) -> Vec<u8> {
        match self {
            Hasher::SHA256(core_wrapper) => core_wrapper.finalize().to_vec(),
            Hasher::HighwayHash256(highway_hasher) => highway_hasher
                .finalize256()
                .iter()
                .flat_map(|&n| n.to_le_bytes()) // 使用小端字节序转换
                .collect(),
            Hasher::BLAKE2b512(core_wrapper) => core_wrapper.finalize().to_vec(),
        }
    }

    pub fn size(&self) -> usize {
        match self {
            Hasher::SHA256(_) => Sha256::output_size(),
            Hasher::HighwayHash256(_) => 32,
            Hasher::BLAKE2b512(_) => Blake2b512::output_size(),
        }
    }

    pub fn block_size(&self) -> usize {
        match self {
            Hasher::SHA256(_) => Sha256::block_size(),
            Hasher::HighwayHash256(_) => 64,
            Hasher::BLAKE2b512(_) => 64,
        }
    }

    pub fn reset(&mut self) {
        match self {
            Hasher::SHA256(core_wrapper) => core_wrapper.reset(),
            Hasher::HighwayHash256(highway_hasher) => {
                let key = Key(*MAGIC_HIGHWAY_HASH256_KEY);
                *highway_hasher = HighwayHasher::new(key);
            }
            Hasher::BLAKE2b512(core_wrapper) => core_wrapper.reset(),
        }
    }
}

impl BitrotAlgorithm {
    pub fn new_hasher(&self) -> Hasher {
        match self {
            BitrotAlgorithm::SHA256 => Hasher::SHA256(Sha256::new()),
            BitrotAlgorithm::HighwayHash256 | BitrotAlgorithm::HighwayHash256S => {
                let key = Key(*MAGIC_HIGHWAY_HASH256_KEY);
                Hasher::HighwayHash256(HighwayHasher::new(key))
            }
            BitrotAlgorithm::BLAKE2b512 => Hasher::BLAKE2b512(Blake2b512::new()),
        }
    }

    pub fn available(&self) -> bool {
        BITROT_ALGORITHMS.get(self).is_some()
    }

    pub fn string(&self) -> String {
        BITROT_ALGORITHMS.get(self).map_or("".to_string(), |s| s.to_string())
    }
}

#[derive(Debug)]
pub struct BitrotVerifier {
    _algorithm: BitrotAlgorithm,
    _sum: Vec<u8>,
}

impl BitrotVerifier {
    pub fn new(algorithm: BitrotAlgorithm, checksum: &[u8]) -> BitrotVerifier {
        BitrotVerifier {
            _algorithm: algorithm,
            _sum: checksum.to_vec(),
        }
    }
}

pub fn bitrot_algorithm_from_string(s: &str) -> BitrotAlgorithm {
    for (k, v) in BITROT_ALGORITHMS.iter() {
        if *v == s {
            return k.clone();
        }
    }

    BitrotAlgorithm::HighwayHash256S
}

pub type BitrotWriter = Box<dyn Writer + Send + 'static>;

// pub async fn new_bitrot_writer(
//     disk: DiskStore,
//     orig_volume: &str,
//     volume: &str,
//     file_path: &str,
//     length: usize,
//     algo: BitrotAlgorithm,
//     shard_size: usize,
// ) -> Result<BitrotWriter> {
//     if algo == BitrotAlgorithm::HighwayHash256S {
//         return Ok(Box::new(
//             StreamingBitrotWriter::new(disk, orig_volume, volume, file_path, length, algo, shard_size).await?,
//         ));
//     }
//     Ok(Box::new(WholeBitrotWriter::new(disk, volume, file_path, algo, shard_size)))
// }

pub type BitrotReader = Box<dyn ReadAt + Send>;

// #[allow(clippy::too_many_arguments)]
// pub fn new_bitrot_reader(
//     disk: DiskStore,
//     data: &[u8],
//     bucket: &str,
//     file_path: &str,
//     till_offset: usize,
//     algo: BitrotAlgorithm,
//     sum: &[u8],
//     shard_size: usize,
// ) -> BitrotReader {
//     if algo == BitrotAlgorithm::HighwayHash256S {
//         return Box::new(StreamingBitrotReader::new(disk, data, bucket, file_path, algo, till_offset, shard_size));
//     }
//     Box::new(WholeBitrotReader::new(disk, bucket, file_path, algo, till_offset, sum))
// }

pub async fn close_bitrot_writers(writers: &mut [Option<BitrotWriter>]) -> Result<()> {
    for w in writers.iter_mut().flatten() {
        w.close().await?;
    }

    Ok(())
}

// pub fn bitrot_writer_sum(w: &BitrotWriter) -> Vec<u8> {
//     if let Some(w) = w.as_any().downcast_ref::<WholeBitrotWriter>() {
//         return w.hash.clone().finalize();
//     }

//     Vec::new()
// }

pub fn bitrot_shard_file_size(size: usize, shard_size: usize, algo: BitrotAlgorithm) -> usize {
    if algo != BitrotAlgorithm::HighwayHash256S {
        return size;
    }
    size.div_ceil(shard_size) * algo.new_hasher().size() + size
}

pub async fn bitrot_verify(
    r: FileReader,
    want_size: usize,
    part_size: usize,
    algo: BitrotAlgorithm,
    _want: Vec<u8>,
    mut shard_size: usize,
) -> Result<()> {
    // if algo != BitrotAlgorithm::HighwayHash256S {
    //     let mut h = algo.new_hasher();
    //     h.update(r.get_ref());
    //     let hash = h.finalize();
    //     if hash != want {
    //         info!("bitrot_verify except: {:?}, got: {:?}", want, hash);
    //         return Err(Error::new(DiskError::FileCorrupt));
    //     }

    //     return Ok(());
    // }
    let mut h = algo.new_hasher();
    let mut hash_buf = vec![0; h.size()];
    let mut left = want_size;

    if left != bitrot_shard_file_size(part_size, shard_size, algo.clone()) {
        info!(
            "bitrot_shard_file_size failed, left: {}, part_size: {}, shard_size: {}, algo: {:?}",
            left, part_size, shard_size, algo
        );
        return Err(Error::new(DiskError::FileCorrupt));
    }

    let mut r = r;

    while left > 0 {
        h.reset();
        let n = r.read_exact(&mut hash_buf).await?;
        left -= n;

        if left < shard_size {
            shard_size = left;
        }

        let mut buf = vec![0; shard_size];
        let read = r.read_exact(&mut buf).await?;
        h.update(buf);
        left -= read;
        let hash = h.clone().finalize();
        if h.clone().finalize() != hash_buf[0..n] {
            info!("bitrot_verify except: {:?}, got: {:?}", hash_buf[0..n].to_vec(), hash);
            return Err(Error::new(DiskError::FileCorrupt));
        }
    }

    Ok(())
}

// pub struct WholeBitrotWriter {
//     disk: DiskStore,
//     volume: String,
//     file_path: String,
//     _shard_size: usize,
//     pub hash: Hasher,
// }

// impl WholeBitrotWriter {
//     pub fn new(disk: DiskStore, volume: &str, file_path: &str, algo: BitrotAlgorithm, shard_size: usize) -> Self {
//         WholeBitrotWriter {
//             disk,
//             volume: volume.to_string(),
//             file_path: file_path.to_string(),
//             _shard_size: shard_size,
//             hash: algo.new_hasher(),
//         }
//     }
// }

// #[async_trait::async_trait]
// impl Writer for WholeBitrotWriter {
//     fn as_any(&self) -> &dyn Any {
//         self
//     }

//     async fn write(&mut self, buf: &[u8]) -> Result<()> {
//         let mut file = self.disk.append_file(&self.volume, &self.file_path).await?;
//         let _ = file.write(buf).await?;
//         self.hash.update(buf);

//         Ok(())
//     }
// }

// #[derive(Debug)]
// pub struct WholeBitrotReader {
//     disk: DiskStore,
//     volume: String,
//     file_path: String,
//     _verifier: BitrotVerifier,
//     till_offset: usize,
//     buf: Option<Vec<u8>>,
// }

// impl WholeBitrotReader {
//     pub fn new(disk: DiskStore, volume: &str, file_path: &str, algo: BitrotAlgorithm, till_offset: usize, sum: &[u8]) -> Self {
//         Self {
//             disk,
//             volume: volume.to_string(),
//             file_path: file_path.to_string(),
//             _verifier: BitrotVerifier::new(algo, sum),
//             till_offset,
//             buf: None,
//         }
//     }
// }

// #[async_trait::async_trait]
// impl ReadAt for WholeBitrotReader {
//     async fn read_at(&mut self, offset: usize, length: usize) -> Result<(Vec<u8>, usize)> {
//         if self.buf.is_none() {
//             let buf_len = self.till_offset - offset;
//             let mut file = self
//                 .disk
//                 .read_file_stream(&self.volume, &self.file_path, offset, length)
//                 .await?;
//             let mut buf = vec![0u8; buf_len];
//             file.read_at(offset, &mut buf).await?;
//             self.buf = Some(buf);
//         }

//         if let Some(buf) = &mut self.buf {
//             if buf.len() < length {
//                 return Err(Error::new(DiskError::LessData));
//             }

//             return Ok((buf.drain(0..length).collect::<Vec<_>>(), length));
//         }

//         Err(Error::new(DiskError::LessData))
//     }
// }

// struct StreamingBitrotWriter {
//     hasher: Hasher,
//     tx: Sender<Option<Vec<u8>>>,
//     task: Option<JoinHandle<()>>,
// }

// impl StreamingBitrotWriter {
//     pub async fn new(
//         disk: DiskStore,
//         orig_volume: &str,
//         volume: &str,
//         file_path: &str,
//         length: usize,
//         algo: BitrotAlgorithm,
//         shard_size: usize,
//     ) -> Result<Self> {
//         let hasher = algo.new_hasher();
//         let (tx, mut rx) = mpsc::channel::<Option<Vec<u8>>>(10);

//         let total_file_size = length.div_ceil(shard_size) * hasher.size() + length;
//         let mut writer = disk.create_file(orig_volume, volume, file_path, total_file_size).await?;

//         let task = spawn(async move {
//             loop {
//                 if let Some(Some(buf)) = rx.recv().await {
//                     writer.write(&buf).await.unwrap();
//                     continue;
//                 }

//                 break;
//             }
//         });

//         Ok(StreamingBitrotWriter {
//             hasher,
//             tx,
//             task: Some(task),
//         })
//     }
// }

// #[async_trait::async_trait]
// impl Writer for StreamingBitrotWriter {
//     fn as_any(&self) -> &dyn Any {
//         self
//     }

//     async fn write(&mut self, buf: &[u8]) -> Result<()> {
//         if buf.is_empty() {
//             return Ok(());
//         }
//         self.hasher.reset();
//         self.hasher.update(buf);
//         let hash_bytes = self.hasher.clone().finalize();
//         let _ = self.tx.send(Some(hash_bytes)).await?;
//         let _ = self.tx.send(Some(buf.to_vec())).await?;

//         Ok(())
//     }

//     async fn close(&mut self) -> Result<()> {
//         let _ = self.tx.send(None).await?;
//         if let Some(task) = self.task.take() {
//             let _ = task.await; // 等待任务完成
//         }
//         Ok(())
//     }
// }

// #[derive(Debug)]
// struct StreamingBitrotReader {
//     disk: DiskStore,
//     _data: Vec<u8>,
//     volume: String,
//     file_path: String,
//     till_offset: usize,
//     curr_offset: usize,
//     hasher: Hasher,
//     shard_size: usize,
//     buf: Vec<u8>,
//     hash_bytes: Vec<u8>,
// }

// impl StreamingBitrotReader {
//     pub fn new(
//         disk: DiskStore,
//         data: &[u8],
//         volume: &str,
//         file_path: &str,
//         algo: BitrotAlgorithm,
//         till_offset: usize,
//         shard_size: usize,
//     ) -> Self {
//         let hasher = algo.new_hasher();
//         Self {
//             disk,
//             _data: data.to_vec(),
//             volume: volume.to_string(),
//             file_path: file_path.to_string(),
//             till_offset: till_offset.div_ceil(shard_size) * hasher.size() + till_offset,
//             curr_offset: 0,
//             hash_bytes: Vec::with_capacity(hasher.size()),
//             hasher,
//             shard_size,
//             buf: Vec::new(),
//         }
//     }
// }

// #[async_trait::async_trait]
// impl ReadAt for StreamingBitrotReader {
//     async fn read_at(&mut self, offset: usize, length: usize) -> Result<(Vec<u8>, usize)> {
//         if offset % self.shard_size != 0 {
//             return Err(Error::new(DiskError::Unexpected));
//         }
//         if self.buf.is_empty() {
//             self.curr_offset = offset;
//             let stream_offset = (offset / self.shard_size) * self.hasher.size() + offset;
//             let buf_len = self.till_offset - stream_offset;
//             let mut file = self.disk.read_file(&self.volume, &self.file_path).await?;
//             let mut buf = vec![0u8; buf_len];
//             file.read_at(stream_offset, &mut buf).await?;
//             self.buf = buf;
//         }
//         if offset != self.curr_offset {
//             return Err(Error::new(DiskError::Unexpected));
//         }

//         self.hash_bytes = self.buf.drain(0..self.hash_bytes.capacity()).collect();
//         let buf = self.buf.drain(0..length).collect::<Vec<_>>();
//         self.hasher.reset();
//         self.hasher.update(&buf);
//         let actual = self.hasher.clone().finalize();
//         if actual != self.hash_bytes {
//             return Err(Error::new(DiskError::FileCorrupt));
//         }

//         let readed_len = buf.len();
//         self.curr_offset += readed_len;

//         Ok((buf, readed_len))
//     }
// }

pub struct BitrotFileWriter {
    inner: Option<FileWriter>,
    hasher: Hasher,
    _shard_size: usize,
    inline: bool,
    inline_data: Vec<u8>,
}

impl BitrotFileWriter {
    pub async fn new(
        disk: Arc<Disk>,
        volume: &str,
        path: &str,
        inline: bool,
        algo: BitrotAlgorithm,
        _shard_size: usize,
    ) -> Result<Self> {
        let inner = if !inline {
            Some(disk.create_file("", volume, path, 0).await?)
        } else {
            None
        };

        let hasher = algo.new_hasher();

        Ok(Self {
            inner,
            inline,
            inline_data: Vec::new(),
            hasher,
            _shard_size,
        })
    }

    // pub fn writer(&self) -> &FileWriter {
    //     &self.inner
    // }

    pub fn inline_data(&self) -> &[u8] {
        &self.inline_data
    }
}

#[async_trait::async_trait]
impl Writer for BitrotFileWriter {
    fn as_any(&self) -> &dyn Any {
        self
    }

    async fn write(&mut self, buf: &[u8]) -> Result<()> {
        if buf.is_empty() {
            return Ok(());
        }
        self.hasher.reset();
        self.hasher.update(buf);
        let hash_bytes = self.hasher.clone().finalize();

        if let Some(f) = self.inner.as_mut() {
            f.write_all(&hash_bytes).await?;
            f.write_all(buf).await?;
        } else {
            self.inline_data.extend_from_slice(&hash_bytes);
            self.inline_data.extend_from_slice(buf);
        }

        Ok(())
    }
    async fn close(&mut self) -> Result<()> {
        if self.inline {
            return Ok(());
        }

        if let Some(f) = self.inner.as_mut() {
            f.shutdown().await?;
        }

        Ok(())
    }
}

pub async fn new_bitrot_filewriter(
    disk: Arc<Disk>,
    volume: &str,
    path: &str,
    inline: bool,
    algo: BitrotAlgorithm,
    shard_size: usize,
) -> Result<BitrotWriter> {
    let w = BitrotFileWriter::new(disk, volume, path, inline, algo, shard_size).await?;

    Ok(Box::new(w))
}

struct BitrotFileReader {
    disk: Arc<Disk>,
    data: Option<Vec<u8>>,
    volume: String,
    file_path: String,
    reader: Option<FileReader>,
    till_offset: usize,
    curr_offset: usize,
    hasher: Hasher,
    shard_size: usize,
    // buf: Vec<u8>,
    hash_bytes: Vec<u8>,
    read_buf: Vec<u8>,
}

fn ceil(a: usize, b: usize) -> usize {
    a.div_ceil(b)
}

impl BitrotFileReader {
    pub fn new(
        disk: Arc<Disk>,
        data: Option<Vec<u8>>,
        volume: String,
        file_path: String,
        algo: BitrotAlgorithm,
        till_offset: usize,
        shard_size: usize,
    ) -> Self {
        let hasher = algo.new_hasher();
        Self {
            disk,
            data,
            volume,
            file_path,
            till_offset: ceil(till_offset, shard_size) * hasher.size() + till_offset,
            curr_offset: 0,
            hash_bytes: vec![0u8; hasher.size()],
            hasher,
            shard_size,
            // buf: Vec::new(),
            read_buf: Vec::new(),
            reader: None,
        }
    }
}

#[async_trait::async_trait]
impl ReadAt for BitrotFileReader {
    // 读取数据
    async fn read_at(&mut self, offset: usize, length: usize) -> Result<(Vec<u8>, usize)> {
        if offset % self.shard_size != 0 {
            error!(
                "BitrotFileReader read_at offset % self.shard_size != 0 , {} % {} = {}",
                offset,
                self.shard_size,
                offset % self.shard_size
            );
            return Err(Error::new(DiskError::Unexpected));
        }

        if self.reader.is_none() {
            self.curr_offset = offset;
            let stream_offset = (offset / self.shard_size) * self.hasher.size() + offset;

            if let Some(data) = self.data.clone() {
                self.reader = Some(Box::new(Cursor::new(data)));
            } else {
                self.reader = Some(
                    self.disk
                        .read_file_stream(&self.volume, &self.file_path, stream_offset, self.till_offset - stream_offset)
                        .await?,
                );
            }
        }

        if offset != self.curr_offset {
            error!("BitrotFileReader read_at offset != self.curr_offset, {} != {}", offset, self.curr_offset);
            return Err(Error::new(DiskError::Unexpected));
        }

        let reader = self.reader.as_mut().unwrap();
        // let mut hash_buf = self.hash_bytes;

        self.hash_bytes.clear();
        self.hash_bytes.resize(self.hasher.size(), 0u8);

        reader.read_exact(&mut self.hash_bytes).await?;

        self.read_buf.clear();
        self.read_buf.resize(length, 0u8);

        reader.read_exact(&mut self.read_buf).await?;

        self.hasher.reset();
        self.hasher.update(&self.read_buf);
        let actual = self.hasher.clone().finalize();
        if actual != self.hash_bytes {
            error!(
                "BitrotFileReader read_at actual != self.hash_bytes, {:?} != {:?}",
                actual, self.hash_bytes
            );
            return Err(Error::new(DiskError::FileCorrupt));
        }

        let readed_len = self.read_buf.len();
        self.curr_offset += readed_len;

        Ok((self.read_buf.clone(), readed_len))

        // let stream_offset = (offset / self.shard_size) * self.hasher.size() + offset;
        // let buf_len = self.hasher.size() + length;

        // self.read_buf.clear();
        // self.read_buf.resize(buf_len, 0u8);

        // self.inner.read_at(stream_offset, &mut self.read_buf).await?;

        // let hash_bytes = &self.read_buf.as_slice()[0..self.hash_bytes.capacity()];

        // self.hash_bytes.clone_from_slice(hash_bytes);
        // let buf = self.read_buf.as_slice()[self.hash_bytes.capacity()..self.hash_bytes.capacity() + length].to_vec();

        // self.hasher.reset();
        // self.hasher.update(&buf);
        // let actual = self.hasher.clone().finalize();

        // if actual != self.hash_bytes {
        //     return Err(Error::new(DiskError::FileCorrupt));
        // }

        // let readed_len = buf.len();
        // self.curr_offset += readed_len;

        // Ok((buf, readed_len))
    }
}

pub fn new_bitrot_filereader(
    disk: Arc<Disk>,
    data: Option<Vec<u8>>,
    volume: String,
    file_path: String,
    till_offset: usize,
    algo: BitrotAlgorithm,
    shard_size: usize,
) -> BitrotReader {
    Box::new(BitrotFileReader::new(disk, data, volume, file_path, algo, till_offset, shard_size))
}

#[cfg(test)]
mod test {
    use std::collections::HashMap;

    use hex_simd::decode_to_vec;

    use crate::{
        disk::error::DiskError,
        error::{Error, Result},
        store_api::BitrotAlgorithm,
    };

    // use super::{bitrot_writer_sum, new_bitrot_reader};

    #[test]
    fn bitrot_self_test() -> Result<()> {
        let mut checksums = HashMap::new();
        checksums.insert(
            BitrotAlgorithm::SHA256,
            "a7677ff19e0182e4d52e3a3db727804abc82a5818749336369552e54b838b004",
        );
        checksums.insert(BitrotAlgorithm::BLAKE2b512, "e519b7d84b1c3c917985f544773a35cf265dcab10948be3550320d156bab612124a5ae2ae5a8c73c0eea360f68b0e28136f26e858756dbfe7375a7389f26c669");
        checksums.insert(
            BitrotAlgorithm::HighwayHash256,
            "c81c2386a1f565e805513d630d4e50ff26d11269b21c221cf50fc6c29d6ff75b",
        );
        checksums.insert(
            BitrotAlgorithm::HighwayHash256S,
            "c81c2386a1f565e805513d630d4e50ff26d11269b21c221cf50fc6c29d6ff75b",
        );

        let iter = [
            BitrotAlgorithm::SHA256,
            BitrotAlgorithm::BLAKE2b512,
            BitrotAlgorithm::HighwayHash256,
        ];

        for algo in iter.iter() {
            if !algo.available() || *algo != BitrotAlgorithm::HighwayHash256 {
                continue;
            }
            let checksum = decode_to_vec(checksums.get(algo).unwrap()).unwrap();

            let mut h = algo.new_hasher();
            let mut msg = Vec::with_capacity(h.size() * h.block_size());
            let mut sum = Vec::with_capacity(h.size());

            for _ in (0..h.size() * h.block_size()).step_by(h.size()) {
                h.update(&msg);
                sum = h.finalize();
                msg.extend(sum.clone());
                h = algo.new_hasher();
            }

            if checksum != sum {
                return Err(Error::new(DiskError::FileCorrupt));
            }
        }

        Ok(())
    }

    // #[tokio::test]
    // async fn test_all_bitrot_algorithms() -> Result<()> {
    //     for algo in BITROT_ALGORITHMS.keys() {
    //         test_bitrot_reader_writer_algo(algo.clone()).await?;
    //     }

    //     Ok(())
    // }

    // async fn test_bitrot_reader_writer_algo(algo: BitrotAlgorithm) -> Result<()> {
    //     let temp_dir = TempDir::new().unwrap().path().to_string_lossy().to_string();
    //     fs::create_dir_all(&temp_dir)?;
    //     let volume = "testvol";
    //     let file_path = "testfile";

    //     let ep = Endpoint::try_from(temp_dir.as_str())?;
    //     let opt = DiskOption::default();
    //     let disk = new_disk(&ep, &opt).await?;
    //     disk.make_volume(volume).await?;
    //     let mut writer = new_bitrot_writer(disk.clone(), "", volume, file_path, 35, algo.clone(), 10).await?;

    //     writer.write(b"aaaaaaaaaa").await?;
    //     writer.write(b"aaaaaaaaaa").await?;
    //     writer.write(b"aaaaaaaaaa").await?;
    //     writer.write(b"aaaaa").await?;

    //     let sum = bitrot_writer_sum(&writer);
    //     writer.close().await?;

    //     let mut reader = new_bitrot_reader(disk, b"", volume, file_path, 35, algo, &sum, 10);
    //     let read_len = 10;
    //     let mut result: Vec<u8>;
    //     (result, _) = reader.read_at(0, read_len).await?;
    //     assert_eq!(result, b"aaaaaaaaaa");
    //     (result, _) = reader.read_at(10, read_len).await?;
    //     assert_eq!(result, b"aaaaaaaaaa");
    //     (result, _) = reader.read_at(20, read_len).await?;
    //     assert_eq!(result, b"aaaaaaaaaa");
    //     (result, _) = reader.read_at(30, read_len / 2).await?;
    //     assert_eq!(result, b"aaaaa");

    //     Ok(())
    // }
}