# Copyright 2018 The glTF-Blender-IO authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import bpy

from io_scene_gltf2.io.com import gltf2_io
from io_scene_gltf2.blender.exp import gltf2_blender_gather_nodes
from io_scene_gltf2.blender.exp import gltf2_blender_gather_animations
from io_scene_gltf2.blender.exp.gltf2_blender_gather_cache import cached
from io_scene_gltf2.blender.exp import gltf2_blender_generate_extras
from io_scene_gltf2.blender.exp import gltf2_blender_export_keys


def gather_gltf2(export_settings):
    """
    Gather glTF properties from the current state of blender.

    :return: list of scene graphs to be added to the glTF export
    """
    scenes = []
    animations = []  # unfortunately animations in gltf2 are just as 'root' as scenes.
    for blender_scene in bpy.data.scenes:
        scenes.append(__gather_scene(blender_scene, export_settings))
        if export_settings[gltf2_blender_export_keys.ANIMATIONS]:
            animations += __gather_animations(blender_scene, export_settings)

    return scenes, animations


@cached
def __gather_scene(blender_scene, export_settings):
    scene = gltf2_io.Scene(
        extensions=None,
        extras=__gather_extras(blender_scene, export_settings),
        name=blender_scene.name,
        nodes=[]
    )

    for blender_object in blender_scene.objects:
        if blender_object.parent is None:
            node = gltf2_blender_gather_nodes.gather_node(blender_object, export_settings)
            if node is not None:
                scene.nodes.append(node)

    return scene


def __gather_animations(blender_scene, export_settings):
    animations = []
    for blender_object in blender_scene.objects:
        animations += gltf2_blender_gather_animations.gather_animations(blender_object, export_settings)
    return animations


def __gather_extras(blender_object, export_settings):
    if export_settings[gltf2_blender_export_keys.EXTRAS]:
        return gltf2_blender_generate_extras.generate_extras(blender_object)
    return None

