//! One JSON call over stdin/stdout. Script exception text never leaves this guest.
use sausage_cred_script::{ErrorKind, Limits, evaluate};
use std::io::{Read, Write};
use zeroize::Zeroizing;

#[derive(serde::Deserialize)]
struct Request {
    source: String,
    input: Zeroizing<String>,
    export: Option<String>,
    max_time_ms: u64,
    max_memory_bytes: usize,
}

fn run() -> Result<(), Box<dyn std::error::Error>> {
    let mut wire = Zeroizing::new(String::new());
    std::io::stdin().read_to_string(&mut wire)?;
    let request: Request = serde_json::from_str(&wire)?;
    let result = evaluate(
        &request.source,
        &request.input,
        request.export.as_deref(),
        Limits {
            max_time_ms: Some(request.max_time_ms),
            max_memory_bytes: Some(request.max_memory_bytes),
            ..Limits::default()
        },
    );
    let response = match result {
        Ok(result) => serde_json::json!({"result": result}),
        Err(error) => serde_json::json!({"kind": match error.kind {
            ErrorKind::Limit => "Limit",
            ErrorKind::Syntax => "Syntax",
            ErrorKind::Throw => "Throw",
            ErrorKind::NonJson => "NonJson",
            ErrorKind::Engine => "Engine",
        }}),
    };
    serde_json::to_writer(std::io::stdout().lock(), &response)?;
    std::io::stdout().flush()?;
    Ok(())
}
fn main() {
    if run().is_err() {
        std::process::exit(1);
    }
}

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

    #[test]
    fn request_input_has_zeroizing_ownership() {
        let request: Request = serde_json::from_str(r#"{"source":"export default x=>x","input":"null","export":null,"max_time_ms":100,"max_memory_bytes":8388608}"#).unwrap();
        let _: &Zeroizing<String> = &request.input;
    }
}