// Copyright 2022 RisingWave Labs
//
// 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 risingwave_common::array::DataChunk;
use risingwave_pb::data::PbDataChunk;
use tokio::sync::OnceCell;

#[derive(Debug, Clone)]
pub(super) struct DataChunkInChannel {
    data_chunk: DataChunk,
    /// If the data chunk is only needed to transfer locally,
    /// this field should not be initialized.
    prost_data_chunk: OnceCell<PbDataChunk>,
}

impl DataChunkInChannel {
    pub fn new(data_chunk: DataChunk) -> Self {
        Self {
            data_chunk,
            prost_data_chunk: OnceCell::new(),
        }
    }

    pub async fn to_protobuf(&self) -> PbDataChunk {
        let prost_data_chunk = self
            .prost_data_chunk
            .get_or_init(|| async {
                let res = self.data_chunk.clone().compact_vis();
                res.to_protobuf()
            })
            .await;
        prost_data_chunk.clone()
    }

    pub fn into_data_chunk(self) -> DataChunk {
        self.data_chunk
    }

    pub fn cardinality(&self) -> usize {
        self.data_chunk.cardinality()
    }
}
