nu-command 0.29.0

use crate::prelude::*;
use nu_data::base::select_fields;
use nu_engine::WholeStreamCommand;
use nu_errors::ShellError;
use nu_protocol::{ReturnSuccess, Signature, SyntaxShape, TaggedDictBuilder, UntaggedValue, Value};
use nu_source::Tagged;

use super::support::{rotate, Direction};

pub struct SubCommand;

#[derive(Deserialize)]
pub struct Arguments {
    by: Option<Tagged<u64>>,
    opposite: bool,
    #[serde(rename(deserialize = "cells-only"))]
    cells_only: bool,
}

impl Arguments {
    fn direction(&self) -> Direction {
        if self.opposite {
            return Direction::Left;
        }

        Direction::Right
    }

    fn move_headers(&self) -> bool {
        !self.cells_only
    }
}

#[async_trait]
impl WholeStreamCommand for SubCommand {
    fn name(&self) -> &str {
        "roll column"
    }

    fn signature(&self) -> Signature {
        Signature::build("roll column")
            .optional("by", SyntaxShape::Int, "the number of times to roll")
            .switch("opposite", "roll in the opposite direction", Some('o'))
            .switch("cells-only", "only roll the cells", Some('c'))
    }

    fn usage(&self) -> &str {
        "Rolls the table columns"
    }

    async fn run(&self, args: CommandArgs) -> Result<OutputStream, ShellError> {
        roll(args).await
    }
}

pub async fn roll(args: CommandArgs) -> Result<OutputStream, ShellError> {
    let (args, input) = args.process().await?;

    Ok(input
        .map(move |value| {
            futures::stream::iter({
                let tag = value.tag();

                roll_by(value, &args)
                    .unwrap_or_else(|| vec![UntaggedValue::nothing().into_value(tag)])
                    .into_iter()
                    .map(ReturnSuccess::value)
            })
        })
        .flatten()
        .to_output_stream())
}

fn roll_by(value: Value, options: &Arguments) -> Option<Vec<Value>> {
    let tag = value.tag();
    let direction = options.direction();

    if value.is_row() {
        if options.move_headers() {
            let columns = value.data_descriptors();

            if let Some(fields) = rotate(columns, &options.by, direction) {
                return Some(vec![select_fields(&value, &fields, &tag)]);
            }
        } else {
            let columns = value.data_descriptors();
            let values_rotated = rotate(
                value
                    .row_entries()
                    .map(|(_, value)| value)
                    .map(Clone::clone)
                    .collect::<Vec<_>>(),
                &options.by,
                direction,
            );

            if let Some(ref values) = values_rotated {
                let mut out = TaggedDictBuilder::new(&tag);

                for (k, v) in columns.iter().zip(values.iter()) {
                    out.insert_value(k, v.clone());
                }

                return Some(vec![out.into_value()]);
            }
        }
        None
    } else if value.is_table() {
        rotate(
            value.table_entries().map(Clone::clone).collect(),
            &options.by,
            direction,
        )
    } else {
        Some(vec![value])
    }
}