#========================================================================
# 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 ccpi.optimisation.operators import LinearOperator
from ccpi.astra.processors import AstraForwardProjectorMC, AstraBackProjectorMC
from ccpi.astra.operators import AstraProjectorSimple


class AstraProjectorMC(LinearOperator):
    """ASTRA Multichannel projector"""
    def __init__(self, geomv, geomp, device):
        super(AstraProjectorMC, self).__init__()
        
        # Store volume and sinogram geometries.
        self.sinogram_geometry = geomp
        self.volume_geometry = geomv
        
        self.fp = AstraForwardProjectorMC(volume_geometry=geomv,
                                        sinogram_geometry=geomp,
                                        proj_id=None,
                                        device=device)
        
        self.bp = AstraBackProjectorMC(volume_geometry=geomv,
                                        sinogram_geometry=geomp,
                                        proj_id=None,
                                        device=device)
                
        # Initialise empty for singular value.
        self.s1 = None    
        self.device = device
    
    def direct(self, IM, out=None):
        self.fp.set_input(IM)
        
        if out is None:
            return self.fp.get_output()
        else:
            out.fill(self.fp.get_output())
    
    def adjoint(self, DATA, out=None):
        self.bp.set_input(DATA)
        
        if out is None:
            return self.bp.get_output()
        else:
            out.fill(self.bp.get_output())    
    
    def domain_geometry(self):
        return self.volume_geometry
    
    def range_geometry(self):
        return self.sinogram_geometry 
    
    def calculate_norm(self):
        
        igtmp = self.volume_geometry.clone()
        igtmp.shape = self.volume_geometry.shape[1:]
        igtmp.dimension_labels = ['horizontal_y', 'horizontal_x']
        igtmp.channels = 1

        agtmp = self.sinogram_geometry.clone()
        agtmp.shape = self.sinogram_geometry.shape[1:]
        agtmp.dimension_labels = ['angle', 'horizontal']
        agtmp.channels = 1        
        
        Atmp = AstraProjectorSimple(igtmp, agtmp, device = self.device)
                  
        return Atmp.norm()    
    


if __name__  == '__main__':
    
    from ccpi.framework import ImageGeometry, AcquisitionGeometry
    import numpy as np
    
    N = 30
    angles = np.linspace(0, np.pi, 180)
    ig = ImageGeometry(N, N, channels = 5)
    ag = AcquisitionGeometry('parallel','2D', angles, pixel_num_h = N, channels = 5)
    
    A = AstraProjectorMC(ig, ag, 'gpu')
    print(A.norm())
    
    
    
    

