nu-command 0.75.0

use crate::help::highlight_search_in_table;
use nu_color_config::StyleComputer;
use nu_engine::{scope::ScopeData, CallExt};
use nu_protocol::{
    ast::Call,
    engine::{Command, EngineState, Stack},
    span, Category, Example, IntoInterruptiblePipelineData, IntoPipelineData, PipelineData,
    ShellError, Signature, Span, Spanned, SyntaxShape, Type, Value,
};
use std::borrow::Cow;

#[derive(Clone)]
pub struct HelpAliases;

impl Command for HelpAliases {
    fn name(&self) -> &str {
        "help aliases"
    }

    fn usage(&self) -> &str {
        "Show help on nushell aliases."
    }

    fn signature(&self) -> Signature {
        Signature::build("help aliases")
            .category(Category::Core)
            .rest(
                "rest",
                SyntaxShape::String,
                "the name of alias to get help on",
            )
            .named(
                "find",
                SyntaxShape::String,
                "string to find in alias names and usage",
                Some('f'),
            )
            .input_output_types(vec![(Type::Nothing, Type::Table(vec![]))])
            .allow_variants_without_examples(true)
    }

    fn examples(&self) -> Vec<Example> {
        vec![
            Example {
                description: "show all aliases",
                example: "help aliases",
                result: None,
            },
            Example {
                description: "show help for single alias",
                example: "help aliases my-alias",
                result: None,
            },
            Example {
                description: "search for string in alias names and usages",
                example: "help aliases --find my-alias",
                result: None,
            },
        ]
    }

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

pub fn help_aliases(
    engine_state: &EngineState,
    stack: &mut Stack,
    call: &Call,
) -> Result<PipelineData, ShellError> {
    let head = call.head;
    let find: Option<Spanned<String>> = call.get_flag(engine_state, stack, "find")?;
    let rest: Vec<Spanned<String>> = call.rest(engine_state, stack, 0)?;

    // 🚩The following two-lines are copied from filters/find.rs:
    let style_computer = StyleComputer::from_config(engine_state, stack);
    // Currently, search results all use the same style.
    // Also note that this sample string is passed into user-written code (the closure that may or may not be
    // defined for "string").
    let string_style = style_computer.compute("string", &Value::string("search result", head));

    if let Some(f) = find {
        let all_cmds_vec = build_help_aliases(engine_state, stack, head);
        let found_cmds_vec =
            highlight_search_in_table(all_cmds_vec, &f.item, &["name", "usage"], &string_style)?;

        return Ok(found_cmds_vec
            .into_iter()
            .into_pipeline_data(engine_state.ctrlc.clone()));
    }

    if rest.is_empty() {
        let found_cmds_vec = build_help_aliases(engine_state, stack, head);

        Ok(found_cmds_vec
            .into_iter()
            .into_pipeline_data(engine_state.ctrlc.clone()))
    } else {
        let mut name = String::new();

        for r in &rest {
            if !name.is_empty() {
                name.push(' ');
            }
            name.push_str(&r.item);
        }

        let alias_id = if let Some(id) = engine_state.find_alias(name.as_bytes(), &[]) {
            id
        } else {
            return Err(ShellError::AliasNotFound(span(
                &rest.iter().map(|r| r.span).collect::<Vec<Span>>(),
            )));
        };

        let alias_expansion = engine_state
            .get_alias(alias_id)
            .iter()
            .map(|span| String::from_utf8_lossy(engine_state.get_span_contents(span)))
            .collect::<Vec<Cow<str>>>()
            .join(" ");

        let alias_usage = engine_state.build_alias_usage(alias_id);

        // TODO: merge this into documentation.rs at some point
        const G: &str = "\x1b[32m"; // green
        const C: &str = "\x1b[36m"; // cyan
        const RESET: &str = "\x1b[0m"; // reset

        let mut long_desc = String::new();

        if let Some((usage, extra_usage)) = alias_usage {
            long_desc.push_str(&usage);
            long_desc.push_str("\n\n");

            if !extra_usage.is_empty() {
                long_desc.push_str(&extra_usage);
                long_desc.push_str("\n\n");
            }
        }

        long_desc.push_str(&format!("{G}Alias{RESET}: {C}{name}{RESET}"));
        long_desc.push_str("\n\n");
        long_desc.push_str(&format!("{G}Expansion{RESET}:\n  {alias_expansion}"));

        let config = engine_state.get_config();
        if !config.use_ansi_coloring {
            long_desc = nu_utils::strip_ansi_string_likely(long_desc);
        }

        Ok(Value::String {
            val: long_desc,
            span: call.head,
        }
        .into_pipeline_data())
    }
}

fn build_help_aliases(engine_state: &EngineState, stack: &Stack, span: Span) -> Vec<Value> {
    let mut scope_data = ScopeData::new(engine_state, stack);
    scope_data.populate_aliases();

    scope_data.collect_aliases(span)
}

#[cfg(test)]
mod test {
    #[test]
    fn test_examples() {
        use super::HelpAliases;
        use crate::test_examples;
        test_examples(HelpAliases {})
    }
}