import gc
from pathlib import Path
from tempfile import NamedTemporaryFile, TemporaryDirectory

from CSXCAD import ContinuousStructure
from openEMS.openEMS import openEMS

ACCESSOR = {"Material": "GetEpsilon", "Excitation": "GetEnabled",
            "ProbeBox": "GetProbeType", "LumpedElement": "GetResistance"}

def build_model():
    csx = ContinuousStructure()
    csx.AddMaterial("substrate")
    csx.AddMetal("ground").AddBox([0, 0, 0], [20, 20, 0.1])
    csx.AddMetal("trace").AddBox([0, 0, 0.1], [1, 1, 0.2])
    for n in (1, 2):
        le = csx.AddLumpedElement(f"port_resist_{n}", ny="z", caps=True, R=50)
        le.AddBox([0, 0, 0], [1, 1, 1])
        csx.AddExcitation(f"port_excite_{n}", exc_type=0, exc_val=(1.0, 0.0, 0.0))
        csx.AddProbe(f"port_ut_{n}", 0)
        csx.AddProbe(f"port_it_{n}", 1)
    grid = csx.GetGrid()
    grid.SetDeltaUnit(1e-3)
    for axis in "xyz":
        grid.AddLine(axis, [-5.0, 0.0, 5.0, 10.0, 15.0])
    return csx

def reload_roundtrip(model_xml):
    """Load a saved model into an openEMS object, wrap its CSX properties, write back."""
    loader = openEMS()
    loader.ReadFromXML(str(model_xml))
    csx = loader.GetCSX()
    for j in range(csx.GetQtyProperties()):
        csx.GetProperty(j)
    with NamedTemporaryFile(suffix=".xml") as tmp:
        csx.Write2XML(tmp.name)
        loader.Write2XML(tmp.name)

with TemporaryDirectory() as d:
    d = Path(d)
    xml = d / "structure.xml"
    model_xml = d / "model.xml"
    for i in range(50):
        csx = build_model()
        csx.Write2XML(str(xml))
        fdtd = openEMS(NrTS=300, EndCriteria=1e-3)
        fdtd.SetCSX(csx)                 # the FDTD owns the CSX
        fdtd.SetBoundaryCond(["PML_8"] * 6)
        fdtd.SetGaussExcite(2.5e9, 0.5e9)
        fdtd.Write2XML(str(model_xml))
        reload_roundtrip(model_xml)
        del fdtd                         # frees the CSX and all its properties
        gc.collect()

        csx2 = ContinuousStructure()
        csx2.ReadFromXML(str(xml))
        for j in range(csx2.GetQtyProperties()):
            prop = csx2.GetProperty(j)
            type_str = prop.GetTypeString()
            if type_str not in ACCESSOR:
                continue
            expected = {"Material": "CSPropMaterial", "Excitation": "CSPropExcitation",
                        "ProbeBox": "CSPropProbeBox", "LumpedElement": "CSPropLumpedElement"}[type_str]
            if type(prop).__name__ != expected:
                print(f"iteration {i}: property {j} ({prop.GetName()!r}) is a live "
                      f"{type_str} but was returned as a {type(prop).__name__}")
                getattr(prop, ACCESSOR[type_str])()   # <- crashes here
        del csx2
    else:
        print("no stale wrapper in 50 iterations")