//! Chunk-boundary invariance: the same input stream fed into two
//! decoders — one in arbitrary chunks, one all-at-once — must produce
//! the same command sequence.

#![no_main]

use donglora_protocol::Command;
use donglora_protocol::framing::CobsDecoder;
use libfuzzer_sys::fuzz_target;

fn drain(stream: &[u8], chunk_sched: &[u8]) -> Vec<Command> {
    let mut out: Vec<Command> = Vec::new();
    let mut decoder = CobsDecoder::new();
    let mut cursor = 0;
    let mut idx = 0;
    while cursor < stream.len() {
        let split = if idx < chunk_sched.len() {
            ((chunk_sched[idx] as usize) % 64) + 1
        } else {
            16
        };
        idx += 1;
        let end = (cursor + split).min(stream.len());
        decoder.feed(&stream[cursor..end], |c| out.push(c));
        cursor = end;
    }
    out
}

fuzz_target!(|data: &[u8]| {
    let split = 32.min(data.len());
    let (sched, stream) = data.split_at(split);

    let whole: Vec<Command> = {
        let mut v = Vec::new();
        CobsDecoder::new().feed(stream, |c| v.push(c));
        v
    };
    let chunked = drain(stream, sched);
    assert_eq!(whole, chunked);
});