"""Creates /Game/Maps/L_Gym if it does not exist: a flat floor, a player start and daylight. Idempotent.

Step 1 wants an empty gym; step 3 extends this script with the greybox sections from Movement.md (stairs, slopes,
gaps, ledges, doorways, beams, corridor, surfaces, arena). Run headless:
  UnrealEditor-Cmd.exe Salty.uproject -run=pythonscript -script=Scripts/Authoring/create_gym.py
or from the editor's Python console. Never hand-edit the .umap; rerun this.
"""
import unreal

LEVEL_PATH = "/Game/Maps/L_Gym"
FLOOR_HALF_SIZE_CM = 5000.0   # a 100 m square; the cube mesh is 100 cm, so scale = size / 100
CUBE = "/Engine/BasicShapes/Cube.Cube"
FLOOR_MATERIAL = "/Game/LevelPrototyping/Materials/MI_PrototypeGrid_Gray.MI_PrototypeGrid_Gray"

level_subsystem = unreal.get_editor_subsystem(unreal.LevelEditorSubsystem)
actor_subsystem = unreal.get_editor_subsystem(unreal.EditorActorSubsystem)
asset_lib = unreal.EditorAssetLibrary


def spawn(actor_class, label, location=unreal.Vector(0, 0, 0), rotation=unreal.Rotator(0, 0, 0)):
    actor = actor_subsystem.spawn_actor_from_class(actor_class, location, rotation)
    actor.set_actor_label(label)
    return actor


def find_actor(label):
    for actor in actor_subsystem.get_all_level_actors():
        if actor.get_actor_label() == label:
            return actor
    return None


def ensure_floor():
    if find_actor("Gym_Floor"):
        return
    floor = spawn(unreal.StaticMeshActor, "Gym_Floor", unreal.Vector(0, 0, -50))
    mesh = unreal.load_asset(CUBE)
    component = floor.static_mesh_component
    component.set_editor_property("mobility", unreal.ComponentMobility.STATIC)
    component.set_static_mesh(mesh)
    scale = FLOOR_HALF_SIZE_CM * 2.0 / 100.0
    floor.set_actor_scale3d(unreal.Vector(scale, scale, 1.0))
    material = unreal.load_asset(FLOOR_MATERIAL) if asset_lib.does_asset_exist(FLOOR_MATERIAL) else None
    if material:
        component.set_material(0, material)


def ensure_daylight():
    sun = find_actor("Gym_Sun")
    if not sun:
        sun = spawn(unreal.DirectionalLight, "Gym_Sun", unreal.Vector(0, 0, 500))
        sun.light_component.set_editor_property("intensity", 10.0)
        sun.light_component.set_editor_property("atmosphere_sun_light", True)
    # Always re-applied, with keyword arguments: positional unreal.Rotator is (roll, pitch, yaw), and the first
    # version of this script pitched the sun 30 degrees upward, which lit the gym as night.
    sun.set_actor_rotation(unreal.Rotator(roll=0.0, pitch=-45.0, yaw=30.0), False)
    if not find_actor("Gym_Sky"):
        spawn(unreal.SkyAtmosphere, "Gym_Sky", unreal.Vector(0, 0, 0))
    if not find_actor("Gym_SkyLight"):
        sky_light = spawn(unreal.SkyLight, "Gym_SkyLight", unreal.Vector(0, 0, 500))
        sky_light.light_component.set_editor_property("real_time_capture", True)
    if not find_actor("Gym_Fog"):
        spawn(unreal.ExponentialHeightFog, "Gym_Fog", unreal.Vector(0, 0, 0))


def ensure_player_starts():
    # Two starts so two PIE clients on a dedicated server both spawn without a collision warning.
    for index, y in enumerate((-150, 150)):
        label = f"Gym_PlayerStart_{index}"
        if not find_actor(label):
            spawn(unreal.PlayerStart, label, unreal.Vector(0, y, 100))


def main():
    if asset_lib.does_asset_exist(LEVEL_PATH):
        unreal.log(f"{LEVEL_PATH} exists; loading it to top up missing actors")
        level_subsystem.load_level(LEVEL_PATH)
    else:
        unreal.log(f"creating {LEVEL_PATH}")
        level_subsystem.new_level(LEVEL_PATH, False)  # not world-partitioned: the gym is small and hand-laid
    ensure_floor()
    ensure_daylight()
    ensure_player_starts()
    level_subsystem.save_current_level()
    unreal.log(f"{LEVEL_PATH} saved")


main()