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# <pep8 compliant>

# This file defines a set of methods that are useful for various
# Relative Keying Set (RKS) related operations, such as: callbacks
# for polling, iterator callbacks, and also generate callbacks.
# All of these can be used in conjunction with the others.

__all__ = [
    "path_add_property",
    "RKS_POLL_selected_objects",
    "RKS_POLL_selected_bones",
    "RKS_POLL_selected_items",
    "RKS_ITER_selected_item",
    "RKS_GEN_available",
    "RKS_GEN_location",
    "RKS_GEN_rotation",
    "RKS_GEN_scaling",
]

import bpy

###########################
# General Utilities


# Append the specified property name on the the existing path
def path_add_property(path, prop):
    if path:
        return path + "." + prop
    else:
        return prop

###########################
# Poll Callbacks


# selected objects (active object must be in object mode)
def RKS_POLL_selected_objects(ksi, context):
    ob = context.active_object
    if ob:
        return ob.mode == 'OBJECT'
    else:
        return bool(context.selected_objects)


# selected bones
def RKS_POLL_selected_bones(ksi, context):
    # we must be in Pose Mode, and there must be some bones selected
    ob = context.active_object
    if ob and ob.mode == 'POSE':
        if context.active_pose_bone or context.selected_pose_bones:
            return True

    # nothing selected
    return False


# selected bones or objects
def RKS_POLL_selected_items(ksi, context):
    return RKS_POLL_selected_bones(ksi, context) or RKS_POLL_selected_objects(ksi, context)

###########################
# Iterator Callbacks


# all selected objects or pose bones, depending on which we've got
def RKS_ITER_selected_item(ksi, context, ks):
    ob = context.active_object
    if ob and ob.mode == 'POSE':
        for bone in context.selected_pose_bones:
            ksi.generate(context, ks, bone)
    else:
        for ob in context.selected_objects:
            ksi.generate(context, ks, ob)


# all select objects only
def RKS_ITER_selected_objects(ksi, context, ks):
    for ob in context.selected_objects:
        ksi.generate(context, ks, ob)

###########################
# Generate Callbacks


# 'Available' F-Curves
def RKS_GEN_available(ksi, context, ks, data):
    # try to get the animation data associated with the closest
    # ID-block to the data (neither of which may exist/be easy to find)
    id_block = data.id_data
    adt = getattr(id_block, "animation_data", None)

    # there must also be an active action...
    if adt is None or adt.action is None:
        return

    # if we haven't got an ID-block as 'data', try to restrict
    # paths added to only those which branch off from here
    # i.e. for bones
    if id_block != data:
        basePath = data.path_from_id()
    else:
        basePath = None  # this is not needed...

    # for each F-Curve, include a path to key it
    # NOTE: we don't need to set the group settings here
    for fcu in adt.action.fcurves:
        if basePath:
            if basePath in fcu.data_path:
                ks.paths.add(id_block, fcu.data_path, index=fcu.array_index)
        else:
            ks.paths.add(id_block, fcu.data_path, index=fcu.array_index)

# ------


# get ID block and based ID path for transform generators
# private function
def get_transform_generators_base_info(data):
    # ID-block for the data
    id_block = data.id_data

    # get base path and grouping method/name
    if isinstance(data, bpy.types.ID):
        # no path in this case
        path = ""

        # data on ID-blocks directly should get grouped by the KeyingSet
        grouping = None
    else:
        # get the path to the ID-block
        path = data.path_from_id()

        # try to use the name of the data element to group the F-Curve
        # else fallback on the KeyingSet name
        grouping = getattr(data, "name", None)

    # return the ID-block and the path
    return id_block, path, grouping


# Location
def RKS_GEN_location(ksi, context, ks, data):
    # get id-block and path info
    id_block, base_path, grouping = get_transform_generators_base_info(data)

    # add the property name to the base path
    path = path_add_property(base_path, "location")

    # add Keying Set entry for this...
    if grouping:
        ks.paths.add(id_block, path, group_method='NAMED', group_name=grouping)
    else:
        ks.paths.add(id_block, path)


# Rotation
def RKS_GEN_rotation(ksi, context, ks, data):
    # get id-block and path info
    id_block, base_path, grouping = get_transform_generators_base_info(data)

    # add the property name to the base path
    #   rotation mode affects the property used
    if data.rotation_mode == 'QUATERNION':
        path = path_add_property(base_path, "rotation_quaternion")
    elif data.rotation_mode == 'AXIS_ANGLE':
        path = path_add_property(base_path, "rotation_axis_angle")
    else:
        path = path_add_property(base_path, "rotation_euler")

    # add Keying Set entry for this...
    if grouping:
        ks.paths.add(id_block, path, group_method='NAMED', group_name=grouping)
    else:
        ks.paths.add(id_block, path)


# Scaling
def RKS_GEN_scaling(ksi, context, ks, data):
    # get id-block and path info
    id_block, base_path, grouping = get_transform_generators_base_info(data)

    # add the property name to the base path
    path = path_add_property(base_path, "scale")

    # add Keying Set entry for this...
    if grouping:
        ks.paths.add(id_block, path, group_method='NAMED', group_name=grouping)
    else:
        ks.paths.add(id_block, path)
