// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you 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 crate::utils::wait_for_future;
use datafusion::arrow::pyarrow::ToPyArrow;
use datafusion::arrow::record_batch::RecordBatch;
use datafusion::physical_plan::SendableRecordBatchStream;
use futures::StreamExt;
use pyo3::prelude::*;
use pyo3::{pyclass, pymethods, PyObject, PyResult, Python};

#[pyclass(name = "RecordBatch", module = "datafusion", subclass)]
pub struct PyRecordBatch {
    batch: RecordBatch,
}

#[pymethods]
impl PyRecordBatch {
    fn to_pyarrow(&self, py: Python) -> PyResult<PyObject> {
        self.batch.to_pyarrow(py)
    }
}

impl From<RecordBatch> for PyRecordBatch {
    fn from(batch: RecordBatch) -> Self {
        Self { batch }
    }
}

#[pyclass(name = "RecordBatchStream", module = "datafusion", subclass)]
pub struct PyRecordBatchStream {
    stream: SendableRecordBatchStream,
}

impl PyRecordBatchStream {
    pub fn new(stream: SendableRecordBatchStream) -> Self {
        Self { stream }
    }
}

#[pymethods]
impl PyRecordBatchStream {
    fn next(&mut self, py: Python) -> PyResult<Option<PyRecordBatch>> {
        let result = self.stream.next();
        match wait_for_future(py, result) {
            None => Ok(None),
            Some(Ok(b)) => Ok(Some(b.into())),
            Some(Err(e)) => Err(e.into()),
        }
    }

    fn __next__(&mut self, py: Python) -> PyResult<Option<PyRecordBatch>> {
        self.next(py)
    }

    fn __iter__(slf: PyRef<'_, Self>) -> PyRef<'_, Self> {
        slf
    }
}