# ========================================================================
# Copyright 2019 Science Technology Facilities Council
# Copyright 2019 University of Manchester
#
# This work is part of the Core Imaging Library developed by Science Technology
# Facilities Council and University of Manchester
#
# 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.txt
#
# 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.
#
# =========================================================================

from cil.framework import DataOrder
from cil.optimisation.operators import LinearOperator, ChannelwiseOperator
from src.operators.UfoStandardProjector import UfoStandardProjector
from src.operators.UfoStackedProjector import UfoStackedProjector

class ProjectionOperator(LinearOperator):
    """Ufo projector modified to use DataSet and geometry."""

    def __init__(self, geomv, geomp, stacked=True, precision_mode='single', stack_num=2):

        super(ProjectionOperator, self).__init__(domain_geometry=geomv, range_geometry=geomp)

        DataOrder.check_order_for_engine('astra', geomv)
        DataOrder.check_order_for_engine('astra', geomp)

        self.volume_geometry = geomv
        self.sinogram_geometry = geomp

        sinogram_geometry_sc = geomp.subset(channel=0)
        volume_geometry_sc = geomv.subset(channel=0)

        if stacked==True:
            operator = UfoStackedProjector(volume_geometry_sc, sinogram_geometry_sc, precision_mode, stack_num)
        else:
            operator = UfoStandardProjector(volume_geometry_sc, sinogram_geometry_sc)

        if geomp.channels > 1:
            operator_full = ChannelwiseOperator(operator, self.sinogram_geometry.channels, dimension='prepend')
            self.operator = operator_full
        else:
            self.operator = operator

    def direct(self, IM, out=None):
        return self.operator.direct(IM, out=out)

    def adjoint(self, DATA, out=None):
        return self.operator.adjoint(DATA, out=out)

    def calculate_norm(self):
        return self.operator.norm()

    def domain_geometry(self):
        return self.volume_geometry

    def range_geometry(self):
        return self.sinogram_geometry