use nu_engine::command_prelude::*;

use rand::{thread_rng, RngCore};

#[derive(Clone)]
pub struct SubCommand;

impl Command for SubCommand {
    fn name(&self) -> &str {
        "random binary"
    }

    fn signature(&self) -> Signature {
        Signature::build("random binary")
            .input_output_types(vec![(Type::Nothing, Type::Binary)])
            .allow_variants_without_examples(true)
            .required("length", SyntaxShape::Int, "Length of the output binary.")
            .category(Category::Random)
    }

    fn usage(&self) -> &str {
        "Generate random bytes."
    }

    fn search_terms(&self) -> Vec<&str> {
        vec!["generate", "bytes"]
    }

    fn run(
        &self,
        engine_state: &EngineState,
        stack: &mut Stack,
        call: &Call,
        _input: PipelineData,
    ) -> Result<PipelineData, ShellError> {
        let length = call.req(engine_state, stack, 0)?;
        let mut rng = thread_rng();

        let mut out = vec![0u8; length];
        rng.fill_bytes(&mut out);

        Ok(Value::binary(out, call.head).into_pipeline_data())
    }

    fn examples(&self) -> Vec<Example> {
        vec![Example {
            description: "Generate 16 random bytes",
            example: "random binary 16",
            result: None,
        }]
    }
}

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

    #[test]
    fn test_examples() {
        use crate::test_examples;

        test_examples(SubCommand {})
    }
}