use extension_traits::extension;
use opendal::{Buffer, Error, ErrorKind, FuturesAsyncReader, Operator};

#[extension(pub trait OperatorExt)]
impl Operator {
    async fn read_if_exists(&self, path: &str) -> Result<Option<Buffer>, Error> {
        match self.read(path).await {
            Ok(buffer) => Ok(Some(buffer)),
            Err(error) if matches!(error.kind(), ErrorKind::NotFound) => Ok(None),
            Err(error) => Err(error),
        }
    }

    async fn async_reader_if_exists(
        &self,
        path: &str,
    ) -> Result<Option<FuturesAsyncReader>, Error> {
        let reader = self.reader(path).await?;
        match reader.into_futures_async_read(..).await {
            Ok(reader) => Ok(Some(reader)),
            Err(error) if matches!(error.kind(), ErrorKind::NotFound) => Ok(None),
            Err(error) => Err(error),
        }
    }
}