//! Rustler boundary for the core conical eclipse-shadow geometry.
//!
//! Pure glue: decode the satellite/Sun vectors, call the relocated
//! `sidereon_core::astro::events::eclipse` functions, encode the result. No shadow
//! formula lives here. The core now rejects degenerate input, surfaced here as
//! the shared `:invalid_input` atom.

use crate::errors;
use rustler::{Atom, NifResult};
use sidereon_core::astro::events::eclipse::{self, EclipseStatus};

mod atoms {
    rustler::atoms! {
        sunlit,
        penumbra,
        umbra
    }
}

type Vec3 = (f64, f64, f64);

pub(crate) fn shadow_fraction_impl(sat: Vec3, sun: Vec3) -> NifResult<f64> {
    eclipse::shadow_fraction([sat.0, sat.1, sat.2], [sun.0, sun.1, sun.2])
        .map_err(errors::invalid_input)
}

pub(crate) fn status_impl(sat: Vec3, sun: Vec3) -> NifResult<Atom> {
    let status = eclipse::status([sat.0, sat.1, sat.2], [sun.0, sun.1, sun.2])
        .map_err(errors::invalid_input)?;
    Ok(match status {
        EclipseStatus::Sunlit => atoms::sunlit(),
        EclipseStatus::Penumbra => atoms::penumbra(),
        EclipseStatus::Umbra => atoms::umbra(),
    })
}