# SPDX-License-Identifier: Apache-2.0
# Copyright 2018-2021 The glTF-Blender-IO authors.


import bpy
import typing
from io_scene_gltf2.io.com import gltf2_io
from io_scene_gltf2.blender.exp.gltf2_blender_gather_cache import cached
from io_scene_gltf2.blender.exp import gltf2_blender_gather_nodes
from io_scene_gltf2.blender.exp import gltf2_blender_gather_joints
from io_scene_gltf2.blender.exp import gltf2_blender_gather_skins
from io_scene_gltf2.io.exp.gltf2_io_user_extensions import export_user_extensions

@cached
def gather_animation_channel_target(obj_uuid: int,
                                    channels: typing.Tuple[bpy.types.FCurve],
                                    bake_bone: typing.Union[str, None],
                                    bake_channel: typing.Union[str, None],
                                    driver_obj_uuid,
                                    export_settings
                                    ) -> gltf2_io.AnimationChannelTarget:

        blender_object = export_settings['vtree'].nodes[obj_uuid].blender_object

        animation_channel_target = gltf2_io.AnimationChannelTarget(
            extensions=__gather_extensions(channels, blender_object, export_settings, bake_bone),
            extras=__gather_extras(channels, blender_object, export_settings, bake_bone),
            node=__gather_node(channels, obj_uuid, export_settings, bake_bone, driver_obj_uuid),
            path=__gather_path(channels, blender_object, export_settings, bake_bone, bake_channel)
        )

        export_user_extensions('gather_animation_channel_target_hook',
                               export_settings,
                               animation_channel_target,
                               channels,
                               blender_object,
                               bake_bone,
                               bake_channel)

        return animation_channel_target

def __gather_extensions(channels: typing.Tuple[bpy.types.FCurve],
                        blender_object: bpy.types.Object,
                        export_settings,
                        bake_bone: typing.Union[str, None]
                        ) -> typing.Any:
    return None


def __gather_extras(channels: typing.Tuple[bpy.types.FCurve],
                    blender_object: bpy.types.Object,
                    export_settings,
                    bake_bone: typing.Union[str, None]
                    ) -> typing.Any:
    return None


def __gather_node(channels: typing.Tuple[bpy.types.FCurve],
                  obj_uuid: str,
                  export_settings,
                  bake_bone: typing.Union[str, None],
                  driver_obj_uuid
                  ) -> gltf2_io.Node:

    blender_object = export_settings['vtree'].nodes[obj_uuid].blender_object

    if driver_obj_uuid is not None:
        return export_settings['vtree'].nodes[driver_obj_uuid].node

    if blender_object.type == "ARMATURE":
        # TODO: get joint from fcurve data_path and gather_joint

        if bake_bone is not None:
            blender_bone = blender_object.pose.bones[bake_bone]
        else:
            blender_bone = blender_object.path_resolve(channels[0].data_path.rsplit('.', 1)[0])

        if isinstance(blender_bone, bpy.types.PoseBone):
            return gltf2_blender_gather_joints.gather_joint_vnode(export_settings['vtree'].nodes[obj_uuid].bones[blender_bone.name], export_settings)

    return export_settings['vtree'].nodes[obj_uuid].node


def __gather_path(channels: typing.Tuple[bpy.types.FCurve],
                  blender_object: bpy.types.Object,
                  export_settings,
                  bake_bone: typing.Union[str, None],
                  bake_channel: typing.Union[str, None]
                  ) -> str:
    if bake_channel is None:
        # Note: channels has some None items only for SK if some SK are not animated
        target = [c for c in channels if c is not None][0].data_path.split('.')[-1]
    else:
        target = bake_channel
    path = {
        "delta_location": "translation",
        "delta_rotation_euler": "rotation",
        "location": "translation",
        "rotation_axis_angle": "rotation",
        "rotation_euler": "rotation",
        "rotation_quaternion": "rotation",
        "scale": "scale",
        "value": "weights"
    }.get(target)

    if target is None:
        return None

    return path