siderust 0.12.0

// SPDX-License-Identifier: AGPL-3.0-only
// Copyright (C) 2026 Vallés Puig, Ramon

//! Embedded Sun-Earth Lagrange Chebyshev kernels.
//!
//! The five SCK binary files (`l1.sck`..`l5.sck`) are embedded in
//! [`siderust_archive`] under `src/lagrange/vsop87/` and activated by the
//! `lagrange` feature of that crate (pulled in automatically when this crate
//! is built with `lagrange-centers`).
//!
//! The bytes are lazily parsed on first access so the parsing cost is paid only
//! when the Lagrange API is first called.

use alloc::vec::Vec;
use spin::Once;

use crate::archive::lagrange::vsop87 as sck_data;
use crate::formats::sck::parse_sck;

pub(crate) const NCOEFF: usize = 8;

fn parse_records(bytes: &'static [u8]) -> Vec<f64> {
    parse_sck(bytes)
        .expect("embedded SCK must be valid")
        .records
}

static L1: Once<Vec<f64>> = Once::new();
static L2: Once<Vec<f64>> = Once::new();
static L3: Once<Vec<f64>> = Once::new();
static L4: Once<Vec<f64>> = Once::new();
static L5: Once<Vec<f64>> = Once::new();

/// SHA-256 of the original concatenated f64 payload from which the SCK files were derived.
pub(crate) const CHECKSUM: &str =
    "69c8eddcaeedc6f2e906a2ac5a4a2c2c7d97f491c08ce2b5ac6f4038e1966846";

#[must_use]
pub(crate) fn records_l1() -> &'static [f64] {
    L1.call_once(|| parse_records(sck_data::L1_BYTES))
        .as_slice()
}

#[must_use]
pub(crate) fn records_l2() -> &'static [f64] {
    L2.call_once(|| parse_records(sck_data::L2_BYTES))
        .as_slice()
}

#[must_use]
pub(crate) fn records_l3() -> &'static [f64] {
    L3.call_once(|| parse_records(sck_data::L3_BYTES))
        .as_slice()
}

#[must_use]
pub(crate) fn records_l4() -> &'static [f64] {
    L4.call_once(|| parse_records(sck_data::L4_BYTES))
        .as_slice()
}

#[must_use]
pub(crate) fn records_l5() -> &'static [f64] {
    L5.call_once(|| parse_records(sck_data::L5_BYTES))
        .as_slice()
}