#!/usr/bin/env python
#
# dials.util.image.py
#
#  Copyright (C) 2013 Diamond Light Source
#
#  Author: James Parkhurst
#
#  This code is distributed under the BSD license, a copy of which is
#  included in the root directory of this package.

from __future__ import division

class reader:
  """A class to read the CBF files used in DIALS"""
  def __init__(self):
    pass

  def read_file(self, filename):
    """Read the CBF file"""
    import pycbf
    self.cbf_handle = pycbf.cbf_handle_struct()
    self.cbf_handle.read_file(filename, pycbf.MSG_DIGEST)
    self.cbf_handle.rewind_datablock()

  def get_data(self):
    """Get the gain array from the file"""
    import numpy
    from scitbx.array_family import flex

    # Select the first datablock and rewind all the categories
    self.cbf_handle.select_datablock(0)
    self.cbf_handle.select_category(0)
    self.cbf_handle.select_column(2)
    self.cbf_handle.select_row(0)

    # Check the type of the element to ensure it's a binary
    # otherwise raise an exception
    type = self.cbf_handle.get_typeofvalue()
    if type.find('bnry') > -1:

      # Read the image data into an array
      image_string = self.cbf_handle.get_integerarray_as_string()
      image = flex.int(numpy.fromstring(image_string, numpy.int32))

      # Get the array parameters
      parameters = self.cbf_handle.get_integerarrayparameters_wdims()
      image_size = (parameters[10], parameters[9])

      # Resize the image
      image.reshape(flex.grid(*image_size))

    else:
      raise TypeError('Can\'t find image')

    # Return the image
    return image


if __name__ == '__main__':
  import sys
  import numpy
  handle = reader()
  handle.read_file(sys.argv[1])
  image = handle.get_data()