"""Empty both Unreal maps before a build, and verify they really are empty.

    <engine>/UnrealEditor-Cmd <uproject> -run=pythonscript \
        -script=<repo>/Tools/unreal/ue_recreate_maps.py -nullrhi -unattended -nopause -stdout

Why this does not delete the `.umap` files: `LevelEditorSubsystem.new_level()` refuses a path whose
package is still in memory, and `EditorAssetLibrary.delete_asset()` leaves the file on disk with the package
still registered, so deleting and recreating in one session always returns False. Measured:

    new_level fresh            -> True
    delete_asset               -> True
    disk file still present    -> True
    new_level again            -> False

What does work, and is what the maps actually need, is clearing every actor and saving: the builders stage
everything they use, so a level with no actors is the blank slate. Anything an experiment left behind - an
actor from a probe, a duplicated vehicle, a stale shot camera - is gone, which is the failure this step
exists to prevent.

Both maps are emptied and saved, and the script reports the actor count it left behind.

Result: /tmp/gigline/recreate-maps.txt
"""

import os

import unreal

MAPS = ("/Game/Hollywood/DemoMap", "/Game/Test/ReviewMap")
RESULT = "/tmp/gigline/recreate-maps.txt"
lines = []


def log(message):
    lines.append(str(message))
    unreal.log(str(message))


def make_writable(path):
    """A .umap under Content/ that is read-only cannot be saved; LFS checks it out that way."""
    disk = os.path.join(unreal.Paths.project_content_dir(),
                        path.replace("/Game/", "") + ".umap")
    try:
        mode = os.stat(disk).st_mode & 0o777
        if not mode & 0o200:
            os.chmod(disk, 0o644)
            log(f"{path}: chmod u+w ({oct(mode)} -> 0o644)")
    except FileNotFoundError:
        pass


def main():
    les = unreal.get_editor_subsystem(unreal.LevelEditorSubsystem)
    for path in MAPS:
        make_writable(path)
        if not les.load_level(path):
            log(f"{path}: could not load, and new_level cannot replace an in-memory package")
            continue
        removed = 0
        for actor in list(unreal.EditorLevelLibrary.get_all_level_actors()):
            try:
                unreal.EditorLevelLibrary.destroy_actor(actor)
                removed += 1
            except Exception:  # noqa: BLE001
                pass
        left = len(unreal.EditorLevelLibrary.get_all_level_actors())
        saved = unreal.EditorLoadingAndSavingUtils.save_map(
            unreal.EditorLevelLibrary.get_editor_world(), path)
        log(f"{path}: cleared {removed} actors, {left} left, save_map {saved}")
    empty = all(" 0 left" in line for line in lines)
    lines.append(f"VERDICT: {'PASS' if empty else 'FAIL'}")
    log(f"maps emptied: {'yes' if empty else 'no'}")


try:
    main()
except Exception as exc:  # noqa: BLE001
    import traceback
    log(f"FAILED: {type(exc).__name__}: {exc}")
    log(traceback.format_exc())
    lines.append("VERDICT: FAIL")

with open(RESULT, "w") as handle:
    handle.write("\n".join(lines) + "\n")