exon 0.32.4

// Copyright 2023 WHERE TRUE Technologies.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use std::sync::Arc;

use datafusion::{
    datasource::physical_plan::{FileMeta, FileOpenFuture, FileOpener},
    error::DataFusionError,
};
use exon_sam::{BatchReader, SAMConfig};
use futures::{StreamExt, TryStreamExt};
use tokio_util::io::StreamReader;

/// A file opener for SAM files.
pub struct SAMOpener {
    config: Arc<SAMConfig>,
}

impl SAMOpener {
    /// Create a new SAM file opener.
    pub fn new(config: Arc<SAMConfig>) -> Self {
        Self { config }
    }
}

impl FileOpener for SAMOpener {
    fn open(&self, file_meta: FileMeta) -> datafusion::error::Result<FileOpenFuture> {
        let config = Arc::clone(&self.config);

        Ok(Box::pin(async move {
            let get_result = config.object_store.get(file_meta.location()).await?;

            let stream_reader = Box::pin(get_result.into_stream().map_err(DataFusionError::from));

            let stream_reader = StreamReader::new(stream_reader);
            let batch_reader = BatchReader::new(stream_reader, config).await?;

            let batch_stream = batch_reader.into_stream();

            Ok(batch_stream.boxed())
        }))
    }
}