//! A whole `kestrove-nmh` connection as the app's Broker sees it: length-prefixed frames, outer
//! JSON, and the pairing / open / msg handlers (src/broker.rs). The input is the byte stream the
//! browser side sends; replies go to a sink. Each frame must get exactly one well-formed reply.
#![no_main]
use std::io::{self, Read, Write};
use std::sync::{Arc, OnceLock};

use kestrove_desktop::broker::{Broker, PairingStore, PairingView, SaveView, Ui};
use kestrove_desktop::framing::read_json;
use kv_ffi::VaultCore;
use libfuzzer_sys::fuzz_target;

struct NoUi;
impl Ui for NoUi {
    fn pairing_requested(&self, _: &PairingView) {}
    fn save_requested(&self, _: &SaveView) {}
}

struct Duplex<'a> {
    input: &'a [u8],
    output: Vec<u8>,
}
impl Read for Duplex<'_> {
    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
        self.input.read(buf)
    }
}
impl Write for Duplex<'_> {
    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
        self.output.write(buf)
    }
    fn flush(&mut self) -> io::Result<()> {
        Ok(())
    }
}

fn broker() -> &'static Arc<Broker> {
    static B: OnceLock<Arc<Broker>> = OnceLock::new();
    B.get_or_init(|| {
        Broker::new(
            VaultCore::new_in_memory(),
            Arc::new(NoUi),
            PairingStore::in_memory(),
        )
    })
}

fuzz_target!(|data: &[u8]| {
    let mut io = Duplex {
        input: data,
        output: Vec::new(),
    };
    let _ = broker().serve(&mut io);
    let mut replies = io.output.as_slice();
    while let Some(v) = read_json(&mut replies).expect("app replies are valid frames") {
        assert!(
            v.get("t").and_then(|t| t.as_str()).is_some(),
            "reply without t: {v}"
        );
    }
});