//! Deterministic byte-stability for the `state.ncl` renderer (O1.5 / D9).
//!
//! The renderer is invoked twice on the same input; the two outputs MUST
//! be byte-identical. Failure would indicate a non-deterministic source
//! such as iteration over an unordered collection or use of a clock.

use std::path::{Path, PathBuf};
use std::process::Command;

use ontoref_ontology::render::render_state_ncl;
use ontoref_ontology::types::StateConfig;

/// Project root that holds the `.ontoref/` spine.
///
/// Walks up from this crate until it finds the directory containing `.ontoref/`.
/// Post-ADR-048 (constellation) the spine sits at the constellation parent,
/// outside `code/`; pre-ADR-048 it was inside the workspace. Searching ancestors
/// resolves it under either layout instead of hard-coding a hop count.
fn workspace_root() -> PathBuf {
    PathBuf::from(env!("CARGO_MANIFEST_DIR"))
        .ancestors()
        .find(|dir| dir.join(".ontoref").is_dir())
        .map(Path::to_path_buf)
        .expect("a `.ontoref/` spine must exist in an ancestor of CARGO_MANIFEST_DIR")
}

fn nickel_export_state(path: &Path) -> StateConfig {
    let output = Command::new("nickel")
        .arg("export")
        .arg("--format")
        .arg("json")
        .arg(path)
        .output()
        .expect("nickel binary must be on PATH for this test");
    assert!(output.status.success(), "nickel export failed");
    serde_json::from_slice(&output.stdout).expect("StateConfig parse")
}

#[test]
fn repeated_render_produces_identical_bytes() {
    let root = workspace_root();
    let source = ontoref_ontology::layout::resolve_section(&root, "ontology/state.ncl");
    let state = nickel_export_state(&source);

    let first = render_state_ncl(&state);
    let second = render_state_ncl(&state);
    let third = render_state_ncl(&state);

    assert_eq!(first, second, "render is not deterministic across two calls");
    assert_eq!(second, third, "render is not deterministic across three calls");
}