"""Small opaque PBR materials, generated without external assets."""
import unreal

from pathlib import Path

from .paths import GENERATED, PROJECT, slug


def color(name, rgb=(0.15, 0.5, 0.8), roughness=0.55, metallic=0.0):
    path = f"{GENERATED}/Materials/M_{slug(name)}"
    material = unreal.load_asset(path)
    if material is None:
        material = unreal.AssetToolsHelpers.get_asset_tools().create_asset(
            "M_" + name, GENERATED + "/Materials", unreal.Material, unreal.MaterialFactoryNew())
    if not isinstance(material, unreal.Material):
        raise TypeError(f"{path} nie jest materialem.")
    lib = unreal.MaterialEditingLibrary
    lib.delete_all_material_expressions(material)
    material.set_editor_property("used_with_skeletal_mesh", True)
    base = lib.create_material_expression(material, unreal.MaterialExpressionConstant3Vector, -300, 0)
    base.set_editor_property("constant", unreal.LinearColor(*rgb, 1.0))
    lib.connect_material_property(base, "", unreal.MaterialProperty.MP_BASE_COLOR)
    for offset, value, prop in [(160, roughness, unreal.MaterialProperty.MP_ROUGHNESS),
                                (280, metallic, unreal.MaterialProperty.MP_METALLIC)]:
        node = lib.create_material_expression(material, unreal.MaterialExpressionConstant, -300, offset)
        node.set_editor_property("r", float(value))
        lib.connect_material_property(node, "", prop)
    lib.recompile_material(material)
    unreal.EditorAssetLibrary.save_loaded_asset(material)
    return material


def assign(actor, material, slot=None):
    """Set a material on an actor and all attached meshes; slot=None replaces every slot."""
    components = [component for part in [actor, *actor.get_attached_actors(True, True)]
                  for component in part.get_components_by_class(unreal.MeshComponent)
                  if component.get_num_materials() > 0]
    if not components:
        raise TypeError("Material mozna przypisac do aktora z siatka.")
    for component in components:
        for index in range(component.get_num_materials()) if slot is None else [slot]:
            component.set_material(index, material)


def texture_set(name, *, base_color, normal=None, roughness=None, metallic=None, emissive=None, tiling=1):
    """Create one atlas material from adjacent PBR textures (PNG/JPEG).

    tiling repeats the textures: one number, or (u, v) for separate directions.
    """
    slug(name)
    u_tiling, v_tiling = tiling if isinstance(tiling, (tuple, list)) else (tiling, tiling)
    if u_tiling <= 0 or v_tiling <= 0:
        raise ValueError("tiling musi byc dodatnie.")
    tools = unreal.AssetToolsHelpers.get_asset_tools()
    path = f"{GENERATED}/Materials/M_{name}"
    material = unreal.load_asset(path)
    if material is None:
        material = tools.create_asset("M_" + name, GENERATED + "/Materials",
                                      unreal.Material, unreal.MaterialFactoryNew())
    lib = unreal.MaterialEditingLibrary
    lib.delete_all_material_expressions(material)
    material.set_editor_property("used_with_skeletal_mesh", True)
    coordinates = lib.create_material_expression(material, unreal.MaterialExpressionTextureCoordinate, -600, 0)
    coordinates.set_editor_property("u_tiling", float(u_tiling))
    coordinates.set_editor_property("v_tiling", float(v_tiling))
    entries = [("BaseColor", base_color, unreal.MaterialProperty.MP_BASE_COLOR, "RGB", "color"),
               ("Normal", normal, unreal.MaterialProperty.MP_NORMAL, "RGB", "normal"),
               ("Roughness", roughness, unreal.MaterialProperty.MP_ROUGHNESS, "R", "linear"),
               ("Metallic", metallic, unreal.MaterialProperty.MP_METALLIC, "R", "linear"),
               ("Emissive", emissive, unreal.MaterialProperty.MP_EMISSIVE_COLOR, "RGB", "color")]
    for index, (label, filename, prop, channel, role) in enumerate(entries):
        if filename is None:
            if label in {"Roughness", "Metallic"}:
                node = lib.create_material_expression(material, unreal.MaterialExpressionConstant, -300, index * 180)
                node.set_editor_property("r", 0.6 if label == "Roughness" else 0.0)
                lib.connect_material_property(node, "", prop)
            continue
        source = Path(filename).expanduser()
        source = (source if source.is_absolute() else PROJECT / source).resolve()
        if not source.is_file():
            raise FileNotFoundError(source)
        task = unreal.AssetImportTask()
        task.filename = str(source)
        task.destination_path = f"{GENERATED}/Materials/Textures/{name}"
        task.destination_name = "T_" + label
        task.automated = True
        task.replace_existing = True
        task.save = True
        task.set_editor_property("async_", False)
        tools.import_asset_tasks([task])
        textures = [obj for obj in task.get_objects() if isinstance(obj, unreal.Texture2D)]
        if len(textures) != 1:
            raise RuntimeError("Nie mozna zaimportowac tekstury " + str(source))
        texture = textures[0]
        texture.set_editor_property("srgb", role == "color")
        texture.set_editor_property("compression_settings", unreal.TextureCompressionSettings.TC_NORMALMAP
                                    if role == "normal" else unreal.TextureCompressionSettings.TC_MASKS
                                    if role == "linear" else unreal.TextureCompressionSettings.TC_DEFAULT)
        unreal.EditorAssetLibrary.save_loaded_asset(texture)
        node = lib.create_material_expression(material, unreal.MaterialExpressionTextureSample, -300, index * 180)
        node.set_editor_property("texture", texture)
        node.set_editor_property("sampler_type", unreal.MaterialSamplerType.SAMPLERTYPE_NORMAL
                                 if role == "normal" else unreal.MaterialSamplerType.SAMPLERTYPE_MASKS
                                 if role == "linear" else unreal.MaterialSamplerType.SAMPLERTYPE_COLOR)
        lib.connect_material_expressions(coordinates, "", node, "UVs")
        lib.connect_material_property(node, channel, prop)
    lib.recompile_material(material)
    unreal.EditorAssetLibrary.save_loaded_asset(material)
    return material