// 文件创建和清理位于计时之外；同一文件先预热，不把页缓存当作编译器收益。
struct ResourceCase {
    path: String,
    limit: i64,
}

struct ResourceDirectory(std::path::PathBuf);

impl Drop for ResourceDirectory {
    fn drop(&mut self) {
        fs::remove_dir_all(&self.0).unwrap();
    }
}

fn resource_fault(_: impl std::fmt::Display) -> Fault {
    &FaultInfo {
        source: "resource-reference",
        line: 1,
        column: 1,
        message: "resource failure",
    }
}

fn generated_open(values: &[ResourceCase]) -> Result<bool, Fault> {
    values.first().map_or(Ok(true), |value| {
        GENERATED_OPEN(&value.path).map_err(resource_fault)
    })
}

fn reference_open(values: &[ResourceCase]) -> Result<bool, Fault> {
    let Some(value) = values.first() else {
        return Ok(true);
    };
    let file = ReferenceFile::open(&value.path).map_err(resource_fault)?;
    let alias = file.clone();
    alias.close().map_err(resource_fault)?;
    Ok(true)
}

fn generated_read(values: &[ResourceCase]) -> Result<Vec<u8>, Fault> {
    values.first().map_or(Ok(Vec::new()), |value| {
        GENERATED_READ(&value.path, value.limit).map_err(resource_fault)
    })
}

fn reference_read(values: &[ResourceCase]) -> Result<Vec<u8>, Fault> {
    let Some(value) = values.first() else {
        return Ok(Vec::new());
    };
    let file = ReferenceFile::open(&value.path).map_err(resource_fault)?;
    let bytes = file
        .read(value.limit)
        .map_err(resource_fault)?
        .unwrap_or_default();
    file.close().map_err(resource_fault)?;
    Ok(bytes)
}

fn generated_stream(values: &[ResourceCase]) -> Result<i64, Fault> {
    values.first().map_or(Ok(0), |value| {
        GENERATED_STREAM(&value.path, value.limit).map_err(resource_fault)
    })
}

fn reference_stream(values: &[ResourceCase]) -> Result<i64, Fault> {
    values.first().map_or(Ok(0), |value| {
        reference_consume(&value.path, value.limit, false).map_err(resource_fault)
    })
}

fn generated_partial(values: &[ResourceCase]) -> Result<i64, Fault> {
    values.first().map_or(Ok(0), |value| {
        GENERATED_PARTIAL(&value.path, value.limit).map_err(resource_fault)
    })
}

fn reference_partial(values: &[ResourceCase]) -> Result<i64, Fault> {
    values.first().map_or(Ok(0), |value| {
        reference_consume(&value.path, value.limit, true).map_err(resource_fault)
    })
}

fn generated_closed(values: &[ResourceCase]) -> Result<bool, Fault> {
    Ok(values
        .first()
        .is_none_or(|value| GENERATED_CLOSED(&value.path).is_err()))
}

fn reference_closed(values: &[ResourceCase]) -> Result<bool, Fault> {
    let Some(value) = values.first() else {
        return Ok(true);
    };
    let file = ReferenceFile::open(&value.path).map_err(resource_fault)?;
    let stream = ReferenceStream::new(&file, 64).map_err(resource_fault)?;
    file.close().map_err(resource_fault)?;
    Ok(stream.next().unwrap().is_err())
}

fn main() {
    let path =
        std::env::temp_dir().join(format!("dever-resource-performance-{}", std::process::id()));
    fs::create_dir(&path).unwrap();
    let directory = ResourceDirectory(path);
    let path = directory.0.join("input");
    let bytes = (0..65537)
        .map(|index| (index % 251) as u8)
        .collect::<Vec<_>>();
    fs::write(&path, &bytes).unwrap();
    let path = path.to_str().unwrap().to_owned();
    assert_eq!(GENERATED_READ(&path, 1_000_000).unwrap(), bytes);
    for limit in [0, -1, i64::MAX] {
        assert!(GENERATED_READ(&path, limit).is_err());
        assert!(ReferenceFile::open(&path).unwrap().read(limit).is_err());
    }
    let expected: i64 = bytes.iter().map(|byte| i64::from(*byte)).sum();
    for limit in [64, 4096] {
        assert_eq!(GENERATED_STREAM(&path, limit).unwrap(), expected);
        assert_eq!(GENERATED_PARTIAL(&path, limit).unwrap(), expected);
    }
    let closed = GENERATED_CLOSED(&path).unwrap_err();
    assert!(
        closed.to_string().contains("ReadEvent.Failed")
            && format!("{closed:?}").contains("file is closed"),
        "{closed}"
    );
    let file = ReferenceFile::open(&path).unwrap();
    let alias = file.clone();
    assert_eq!(file.read(2).unwrap().unwrap(), bytes[..2]);
    assert_eq!(alias.read(2).unwrap().unwrap(), bytes[2..4]);
    let stream = ReferenceStream::new(&file, 2).unwrap();
    alias.close().unwrap();
    assert!(stream.next().unwrap().is_err());
    assert!(stream.next().is_none());
    println!("case,sample,implementation,elapsed_ns,checksum");
    let values = [ResourceCase {
        path: path.clone(),
        limit: 64,
    }];
    compare(
        "file_open_close",
        &values,
        2000,
        generated_open,
        reference_open,
        |value| u64::from(*value),
    );
    compare(
        "file_read_64",
        &values,
        2000,
        generated_read,
        reference_read,
        |value| value.len() as u64,
    );
    compare(
        "stream_read_64",
        &values,
        50,
        generated_stream,
        reference_stream,
        |value| *value as u64,
    );
    compare(
        "stream_resume_64",
        &values,
        50,
        generated_partial,
        reference_partial,
        |value| *value as u64,
    );
    compare(
        "stream_closed",
        &values,
        2000,
        generated_closed,
        reference_closed,
        |value| u64::from(*value),
    );
    let values = [ResourceCase { path, limit: 4096 }];
    compare(
        "file_read_4096",
        &values,
        1000,
        generated_read,
        reference_read,
        |value| value.len() as u64,
    );
    compare(
        "stream_read_4096",
        &values,
        200,
        generated_stream,
        reference_stream,
        |value| *value as u64,
    );
    compare(
        "stream_resume_4096",
        &values,
        200,
        generated_partial,
        reference_partial,
        |value| *value as u64,
    );
}