"""
Two-sided twins of the Kazah Tender's materials (module of the import runner, see import_assets.py). Milestone M3.

Why: the Kazah model is a single-sided shell. Seen from the pilot's eye (DESIGN_UE.md section 4.6) every hull and canopy-frame
face is a back face and is culled, so the cockpit view showed no canopy frame at all. A flying Tender (AKazahTender::InitFleet)
swaps each material of its body, canopy lid, canopy glass, hatch lid and cockpit interior for the twin made here.

Makes, under /Game/Vehicles/Kazah/Materials, for every MI_<name> made by assets_10_kazah_materials.py:
  MI_<name>_2S   an instance whose PARENT is MI_<name> (so colours and every later change follow it), with the base property
                 override "two sided" switched on.

Runs after assets_10 (module order is by file name). Safe to re-run: the twins are rebuilt every time (cheap).
"""
import unreal

MAT_DIR = "/Game/Vehicles/Kazah/Materials"
SUFFIX = "_2S"


def run(ctx):
    MEL, EAL = ctx.mel, ctx.eal
    if not EAL.does_directory_exist(MAT_DIR):
        raise RuntimeError("no %s - assets_10_kazah_materials.py has to run first" % MAT_DIR)
    made = 0
    for path in sorted(EAL.list_assets(MAT_DIR, recursive=False, include_folder=False)):
        name = path.split("/")[-1].split(".")[0]
        if not name.startswith("MI_") or name.endswith(SUFFIX):
            continue
        parent = EAL.load_asset(MAT_DIR + "/" + name)
        if not isinstance(parent, unreal.MaterialInstanceConstant):
            continue
        twin = ctx.get_or_create(MAT_DIR, name + SUFFIX, unreal.MaterialInstanceConstant, unreal.MaterialInstanceConstantFactoryNew())
        twin.set_editor_property("parent", parent)
        overrides = twin.get_editor_property("base_property_overrides")
        overrides.set_editor_property("override_two_sided", True)
        overrides.set_editor_property("two_sided", True)
        twin.set_editor_property("base_property_overrides", overrides)
        MEL.update_material_instance(twin)
        EAL.save_loaded_asset(twin)
        made += 1
        ctx.log("two-sided twin %s%s" % (name, SUFFIX))
    if made == 0:
        raise RuntimeError("no MI_* instances in %s" % MAT_DIR)
    ctx.log("%d two-sided Kazah material twins" % made)