import math
from types import SimpleNamespace

import unreal

from .camera import look_at

# Calibrated in tools/smoke_basics.py against the fixed exposure from camera.create.
_CUBEMAP_AMBIENT = 30.0
_FOG_LUMINANCE = 30.0


def _setup(actor, component_class, intensity, color):
    light = actor.get_component_by_class(component_class)
    light.set_mobility(unreal.ComponentMobility.MOVABLE)
    light.set_editor_property("intensity", float(intensity))
    light.set_light_color(unreal.LinearColor(*color, 1.0))
    return light


def area(scene, name="Light", location=(200, -200, 350), target=(0, 0, 100),
         intensity=12000, color=(1, 1, 1), size=180):
    actor = scene.spawn(unreal.RectLight, name, location)
    light = _setup(actor, unreal.RectLightComponent, intensity, color)
    light.set_editor_property("source_width", float(size))
    light.set_editor_property("source_height", float(size))
    light.set_editor_property("attenuation_radius", 2000.0)
    look_at(actor, target)
    return actor


def point(scene, name="Point", location=(0, 0, 250), intensity=10000, color=(1, 1, 1)):
    """Bulb shining in all directions."""
    actor = scene.spawn(unreal.PointLight, name, location)
    light = _setup(actor, unreal.PointLightComponent, intensity, color)
    light.set_editor_property("attenuation_radius", 2000.0)
    return actor


def spot(scene, name="Spot", location=(200, -200, 400), target=(0, 0, 100),
         intensity=20000, color=(1, 1, 1), angle=30):
    """Cone of light; angle is measured in degrees from the cone axis."""
    actor = scene.spawn(unreal.SpotLight, name, location)
    light = _setup(actor, unreal.SpotLightComponent, intensity, color)
    light.set_editor_property("attenuation_radius", 2000.0)
    light.set_editor_property("outer_cone_angle", float(angle))
    light.set_editor_property("inner_cone_angle", float(angle) * 0.7)
    look_at(actor, target)
    return actor


def sun(scene, name="Sun", location=(300, -300, 500), target=(0, 0, 0),
        intensity=500, color=(1, 1, 1)):
    """Parallel light for the whole scene; only the location-target direction matters."""
    actor = scene.spawn(unreal.DirectionalLight, name, location)
    light = _setup(actor, unreal.DirectionalLightComponent, intensity, color)
    light.set_atmosphere_sun_light(True)
    look_at(actor, target)
    return actor


def environment(scene, sky=True, sun_intensity=500, sun_angle=45, sun_yaw=-45,
                ambient=1.0, fog=0.0, fog_color=(0.6, 0.7, 0.9)):
    """Add a world around the scene: sky, sun, ambient light and height fog.

    sun_angle is the height above the horizon in degrees (low = sunset), sun_yaw
    its compass direction. sky=False keeps a black background with ambient light.
    The sky is lit only by the sun: for night use sky=False, sun_intensity=0, ambient=0.3.
    Returns .sun (None when sun_intensity=0), usable with shot.light_key.
    """
    for name, value in (("sun_intensity", sun_intensity), ("ambient", ambient), ("fog", fog)):
        if value < 0:
            raise ValueError(f"{name} nie moze byc ujemne.")
    sun_actor = None
    if sun_intensity > 0:
        height, compass = math.radians(sun_angle), math.radians(sun_yaw)
        direction = (math.cos(height) * math.cos(compass), math.cos(height) * math.sin(compass), math.sin(height))
        sun_actor = sun(scene, location=tuple(1000 * value for value in direction), intensity=sun_intensity)
        sun_actor.get_component_by_class(unreal.DirectionalLightComponent).set_atmosphere_sun_light(sky)
    # Also for sky=False: an unlit atmosphere keeps the background black, not white.
    scene.spawn(unreal.SkyAtmosphere, "Sky")
    ambient_actor = scene.spawn(unreal.SkyLight, "Ambient")
    light = ambient_actor.light_component
    light.set_mobility(unreal.ComponentMobility.MOVABLE)
    if sky:
        light.set_editor_property("real_time_capture", True)
        light.set_intensity(float(ambient))
    else:
        light.set_editor_property("source_type", unreal.SkyLightSourceType.SLS_SPECIFIED_CUBEMAP)
        light.set_cubemap(unreal.load_asset("/Engine/MapTemplates/Sky/DaylightAmbientCubemap"))
        light.set_intensity(float(ambient) * _CUBEMAP_AMBIENT)
    if fog > 0:
        component = scene.spawn(unreal.ExponentialHeightFog, "Fog").component
        component.set_fog_density(float(fog))
        component.set_editor_property("fog_inscattering_luminance", unreal.LinearColor(
            *(value * _FOG_LUMINANCE for value in fog_color), 1.0))
    return SimpleNamespace(sun=sun_actor)


def studio(scene, key_color=(1.0, 0.82, 0.65), fill_color=(0.5, 0.7, 1.0)):
    return [area(scene, "Key", (200, -500, 350), color=key_color),
            area(scene, "Fill", (100, 300, 250), intensity=7000, color=fill_color),
            area(scene, "Rim", (-200, 0, 300), intensity=15000)]