use polars::prelude::*;
use polars_lazy::frame::LazyCsvReader;

fn read_csv(path: PlRefPath) -> Result<LazyFrame, PolarsError> {
    let schema = Schema::from_iter(vec![
        Field::new("Title".into(), DataType::String),
        Field::new("RoleType".into(), DataType::String),
        Field::new("Name".into(), DataType::String),
        Field::new("Shares".into(), DataType::String),
        Field::new("Note".into(), DataType::String),
    ]);

    let lf = LazyCsvReader::new(path).with_has_header(true).with_schema(Some(Arc::new(schema))).finish()?;
    let with_song_id = lf.with_columns([col("RoleType").eq(lit("ASCAP")).cast(DataType::Int64).cum_sum(false).alias("SongID")]);
    Ok(with_song_id)
}

fn main() -> Result<(), PolarsError> {
    let path: PlRefPath = PlRefPath::new("ASCAP_CATALOG.csv");
    let name: &str = "REBERGEN WILLEM";

    let lf = read_csv(path)?;

    let writer_is_name = col("RoleType").eq(lit("W")).and(col("Name").str().contains_literal(lit(name)));

    let song_titles = lf.filter(writer_is_name)
        .unique(None, UniqueKeepStrategy::Any)
        .sort(["Title"], Default::default())
        .select([col("SongID"), col("Title")])
        .collect()?;

    println!("{}", song_titles);

    Ok(())
}