use nu_engine::CallExt;
use nu_protocol::{
    ast::Call,
    engine::{Command, EngineState, Stack},
    Category, Example, PipelineData, ShellError, Signature, Span, SyntaxShape, Value,
};

use super::super::values::{Column, NuDataFrame};

#[derive(Clone)]
pub struct FilterWith;

impl Command for FilterWith {
    fn name(&self) -> &str {
        "dfr filter-with"
    }

    fn usage(&self) -> &str {
        "Filters dataframe using a mask as reference"
    }

    fn signature(&self) -> Signature {
        Signature::build(self.name())
            .required("mask", SyntaxShape::Any, "boolean mask used to filter data")
            .category(Category::Custom("dataframe".into()))
    }

    fn examples(&self) -> Vec<Example> {
        vec![Example {
            description: "Filter dataframe using a bool mask",
            example: r#"let mask = ([true false] | dfr to-df);
    [[a b]; [1 2] [3 4]] | dfr to-df | dfr filter-with $mask"#,
            result: Some(
                NuDataFrame::try_from_columns(vec![
                    Column::new("a".to_string(), vec![Value::test_int(1)]),
                    Column::new("b".to_string(), vec![Value::test_int(2)]),
                ])
                .expect("simple df for test should not fail")
                .into_value(Span::test_data()),
            ),
        }]
    }

    fn run(
        &self,
        engine_state: &EngineState,
        stack: &mut Stack,
        call: &Call,
        input: PipelineData,
    ) -> Result<PipelineData, ShellError> {
        command(engine_state, stack, call, input)
    }
}

fn command(
    engine_state: &EngineState,
    stack: &mut Stack,
    call: &Call,
    input: PipelineData,
) -> Result<PipelineData, ShellError> {
    let mask_value: Value = call.req(engine_state, stack, 0)?;

    let mask_span = mask_value.span()?;
    let mask = NuDataFrame::try_from_value(mask_value)?.as_series(mask_span)?;
    let mask = mask.bool().map_err(|e| {
        ShellError::SpannedLabeledErrorHelp(
            "Error casting to bool".into(),
            e.to_string(),
            mask_span,
            "Perhaps you want to use a series with booleans as mask".into(),
        )
    })?;

    let df = NuDataFrame::try_from_pipeline(input, call.head)?;

    df.as_ref()
        .filter(mask)
        .map_err(|e| {
            ShellError::SpannedLabeledErrorHelp(
                "Error calculating dummies".into(),
                e.to_string(),
                call.head,
                "The only allowed column types for dummies are String or Int".into(),
            )
        })
        .map(|df| PipelineData::Value(NuDataFrame::dataframe_into_value(df, call.head), None))
}

#[cfg(test)]
mod test {
    use super::super::super::test_dataframe::test_dataframe;
    use super::*;

    #[test]
    fn test_examples() {
        test_dataframe(vec![Box::new(FilterWith {})])
    }
}
