//! Token-balance gate for master/spec.md form-only blocks.
//!
//! The mini-spec is the experimental treatment; if the JSON-cohort's
//! form-only scaffolding is meaningfully longer than the AIL-cohort's
//! (or vice versa), the experiment is biased before the model ever
//! sees the prompts. This test catches gross imbalance.

use std::path::PathBuf;
use xmodel_render::splitter::{self, Form, Segment};

fn master_dir() -> PathBuf {
    let manifest = PathBuf::from(env!("CARGO_MANIFEST_DIR"));
    manifest.parent().unwrap().join("master")
}

#[test]
fn form_only_block_token_totals_within_five_percent() {
    let spec_text = std::fs::read_to_string(master_dir().join("spec.md"))
        .expect("master/spec.md must exist");
    let segments = splitter::split(&spec_text);

    let mut json_buf = String::new();
    let mut ail_buf = String::new();
    for seg in &segments {
        if let Segment::FormOnly { form, body } = seg {
            match form {
                Form::Json => json_buf.push_str(body),
                Form::Ail => ail_buf.push_str(body),
            }
        }
    }

    let bpe = tiktoken_rs::cl100k_base().expect("cl100k_base tokenizer should load");
    let json_count = bpe.encode_with_special_tokens(&json_buf).len();
    let ail_count = bpe.encode_with_special_tokens(&ail_buf).len();
    assert!(json_count > 0, "JSON-form blocks produced zero tokens");
    assert!(ail_count > 0, "AIL-form blocks produced zero tokens");

    let max = json_count.max(ail_count) as f64;
    let diff = (json_count as i64 - ail_count as i64).unsigned_abs() as f64;
    let ratio = diff / max;
    assert!(
        ratio <= 0.05,
        "form-only block token imbalance: json={json_count}, ail={ail_count}, ratio={ratio:.4} > 0.05",
    );
}