use std::io::BufWriter;
use std::sync::Arc;
use arrow::array::{ArrayRef, RecordBatch, StringViewArray};
use parquet::arrow::ArrowWriter;
use parquet::file::properties::WriterProperties;

fn main() {

    let output= std::fs::File::create("output.parquet").unwrap();
    let mut output = BufWriter::new(output);

    let batch = make_batch('a');
    let props = WriterProperties::builder()
        .set_max_row_group_size(1)
        .set_statistics_truncate_length(Some(64))
        .build();

    let mut writer = ArrowWriter::try_new(&mut output, batch.schema(), Some(props)).unwrap();
    writer.write(&batch).unwrap();

    for char in ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j'] {
        let batch = make_batch(char);
        writer.write(&batch).unwrap();
    }
    writer.close().unwrap();
}

// Makes a batch with long string values for testing purposes.
fn make_batch(val: char) -> RecordBatch {
    let col = Arc::new(StringViewArray::from_iter_values(
        [val.to_string().repeat(100000)]
    )) as ArrayRef;
    RecordBatch::try_from_iter([("col", col)]).unwrap()
}