"""Current eight-branch execution regression.

The deleted high_stiffness_explicit_rk45.xml is not reconstructed or renamed.
Per the user decision on 2026-09-12, exercise the corrected eight-branch JSON
through the real XML/native path. This does not claim the former RK45 coverage.
"""
from __future__ import annotations

import json
import math
import unittest
from xml.etree import ElementTree as ET

from app.main import run_system_xml_simulation
from app.simulation.native_codegen.input import load_input
from app.simulation.paths import CURRENT_MQL8_PROJECT_PATH


class CurrentMql8SimulationTests(unittest.TestCase):
    def test_corrected_eight_branch_runs_its_complete_saved_configuration(self):
        original = CURRENT_MQL8_PROJECT_PATH.read_bytes()
        project = json.loads(original)
        settings = project["simulation"]
        xml, document = load_input(CURRENT_MQL8_PROJECT_PATH)
        self.assertEqual(len(document.components), len(project["nodes"]))
        self.assertEqual(len(document.connections), len(project["edges"]))
        self.assertEqual(ET.fromstring(xml).get("unitSystem"), "SI")
        result = run_system_xml_simulation(xml, cancel_check=lambda: False)

        self.assertTrue(result["success"], result["message"])
        self.assertEqual(result["status"], "completed")
        self.assertFalse(result["partial"])
        self.assertEqual(result["simulatedUntil"], settings["t_stop"])
        integration = result["diagnostics"]["integration"]
        self.assertEqual(integration["method"], settings["method"])
        self.assertEqual(integration["rtol"], 1e-8)
        self.assertEqual(result["diagnostics"]["native"]["backend"], "native-c")
        # The current case includes a mechanical transition over the complete 10 s.
        self.assertGreaterEqual(integration["totals"]["stateTransitionCount"], 1)
        self.assertGreaterEqual(integration["totals"]["solverStartCount"], 2)

        series = result["series"]
        times = series["time"]
        self.assertEqual(times[0], settings["t_start"])
        self.assertEqual(times[-1], settings["t_stop"])
        self.assertTrue(all(a < b for a, b in zip(times, times[1:])))
        # Keep every requested output point, in addition to inserted event points.
        step = settings["step"]
        actual_grid = {round(t / step) for t in times if abs(t / step - round(t / step)) < 1e-8}
        expected_grid = set(range(round(settings["t_start"] / step), round(settings["t_stop"] / step) + 1))
        self.assertTrue(expected_grid.issubset(actual_grid))
        for key, values in series.items():
            self.assertEqual(len(values), len(times), key)
            self.assertTrue(all(math.isfinite(value) for value in values), key)
        self.assertEqual(CURRENT_MQL8_PROJECT_PATH.read_bytes(), original)


if __name__ == "__main__":
    unittest.main()