//! aether_governor.rs
//!
//! Provenance: Lean 4 -> C -> Rust
//! Source: HeytingLean.Bridge.Sharma.AetherGovernor

fn clamp(x: f64, lo: f64, hi: f64) -> f64 {
    x.max(lo).min(hi)
}

/// (Lean: govError)
pub fn governor_error(r_target: f64, delta: f64, epsilon: f64) -> f64 {
    delta / epsilon - r_target
}

/// (Lean: govStep)
pub fn governor_step(
    epsilon: f64,
    e_prev: f64,
    delta: f64,
    dt: f64,
    alpha: f64,
    beta: f64,
    eps_min: f64,
    eps_max: f64,
    r_target: f64,
) -> f64 {
    let e = governor_error(r_target, delta, epsilon);
    let d_error = (e - e_prev) / dt;
    let adjustment = alpha * e + beta * d_error;
    clamp(epsilon + adjustment, eps_min, eps_max)
}

/// (Lean: hft_gain_margin_refined)
pub fn gain_margin_refined(dt: f64) -> bool {
    dt >= 1.0 && (0.01 + 0.05 / dt) < 1.0
}

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

    #[test]
    fn test_gain_margin_refined() {
        assert!(gain_margin_refined(1.0));
        assert!(!gain_margin_refined(0.001));
    }
}