use nu_plugin::{MsgPackSerializer, Plugin, PluginCommand, SimplePluginCommand, serve_plugin};
use nu_protocol::{LabeledError, Signature, Type, Value};

struct MyPlugin;

impl Plugin for MyPlugin {
    fn version(&self) -> String {
        env!("CARGO_PKG_VERSION").into()
    }

    fn commands(&self) -> Vec<Box<dyn nu_plugin::PluginCommand<Plugin = Self>>> {
        vec![Box::new(MyCommand)]
    }
}

struct MyCommand;

impl SimplePluginCommand for MyCommand {
    type Plugin = MyPlugin;

    fn name(&self) -> &str {
        "mynu"
    }

    fn signature(&self) -> nu_protocol::Signature {
        Signature::build(PluginCommand::name(self)).input_output_type(Type::String, Type::String)
    }

    fn description(&self) -> &str {
        "A learning rust plugin"
    }

    fn run(
        &self,
        _plugin: &Self::Plugin,
        _engine: &nu_plugin::EngineInterface,
        _call: &nu_plugin::EvaluatedCall,
        input: &nu_protocol::Value,
    ) -> Result<nu_protocol::Value, nu_protocol::LabeledError> {
        match input {
            Value::String { val, .. } => {
                Ok(Value::string(format!("Hello, {}!", val), input.span()))
            }
            _ => Err(LabeledError::new("Expected String input").into()),
        }
    }
}

fn main() {
    serve_plugin(&MyPlugin {}, MsgPackSerializer)
}