"""Refine forward evaluation of the saved corrected initial data.

This is convergence evidence, not a validated continuum existence certificate.
Run nonlinear_demo.py first to regenerate the input amplitude corrections.
"""
from pathlib import Path
import json
import time
import numpy as np
from nonlinear_demo import Galerkin

ROOT = Path(__file__).resolve().parents[1]

def main() -> None:
    path = ROOT / 'data/nonlinear_demo.json'
    if not path.exists():
        raise FileNotFoundError('Run src/nonlinear_demo.py first.')
    raw = json.loads(path.read_text())
    case = next(r for r in raw['results'] if abs(r['epsilon'] - .4) < 1e-12)
    a = np.array(raw['base_amplitudes']) * np.exp(case['theta'])
    signs, delta = np.array(raw['chiralities']), raw['delta']
    times = [0., .12, .25]
    target = np.array([0., 0., delta**2])
    checks = []
    for cutoff in (3, 4, 5):
        start = time.perf_counter()
        sim = Galerkin(cutoff, 1., .0005)
        values, _ = sim.integrate(sim.initial(a, signs, delta, .4), times)
        checks.append({'K': cutoff, 'grid': sim.n, 'dt': sim.dt,
                       'helicity_residual_max': float(np.max(abs(values[:, 1] - target))),
                       'seconds': time.perf_counter() - start})
    output = {'checks': checks,
              'warning': 'Forward convergence evidence only; no interval PDE certificate.'}
    (ROOT / 'data/refinement_comparison.json').write_text(json.dumps(output, indent=2))
    print(json.dumps(output, indent=2))

if __name__ == '__main__':
    main()