//! P1 regression test: per-backtest sim parameter arrays. With uniform
//! config across N backtests, all N must produce the same market_target
//! decision (proves the per-backtest indexing reduces correctly to the
//! pre-refactor scalar-broadcast semantics).
//!
//! Pair: the independence test (proving DIFFERENT per-backtest configs
//! produce different outputs) lands alongside the P2 inflight-limits
//! kernel where the read_first_inflight_arrival_ts helper exists.

use anyhow::Result;
use ml_backtesting::sim::{BatchedSimConfig, LobSimCuda, UniformSimParams};
use ml_core::device::MlDevice;

#[test]
#[ignore = "requires CUDA"]
fn parallel_sim_equivalence_with_uniform_config() -> Result<()> {
    let dev = match MlDevice::cuda(0) {
        Ok(d) => d,
        Err(e) => {
            eprintln!("skipping: cuda device unavailable ({e})");
            return Ok(());
        }
    };
    let mut sim = LobSimCuda::new(8, &dev)?;
    sim.broadcast_alpha(&[0.8, 0.8, 0.8, 0.8, 0.8])?;
    let cfg = BatchedSimConfig::from_uniform(
        8,
        &UniformSimParams {
            target_annual_vol_units: 50.0,
            annualisation_factor:    825.0,
            max_lots:                5,
            latency_ns:              0,
            kelly_frac_floor:        0.20,
            sharpe_weight_floor:     0.10,
            threshold:               0.0,
            cost_per_lot_per_side:   0.0,
        },
    );
    sim.step_decision_with_latency(0, &cfg)?;
    let first = sim.read_market_target(0)?;
    for b in 1..8 {
        let got = sim.read_market_target(b)?;
        assert_eq!(
            got, first,
            "backtest {b} differs from backtest 0 under uniform config: {got:?} vs {first:?}"
        );
    }
    // And the uniform-config result must equal the result we'd get from
    // a single-backtest sim (preserves pre-refactor behaviour).
    assert_eq!(first.0, 0, "uniform config with p_h=0.8 should produce a buy; got side={}", first.0);
    assert!(first.1 >= 1, "uniform-config size {} < 1", first.1);
    Ok(())
}