#!/usr/bin/env python3

import os
import sys
from optparse import OptionParser

import numpy as np
import scipy.ndimage

import damask


scriptName = os.path.splitext(os.path.basename(__file__))[0]
scriptID   = ' '.join([scriptName,damask.version])


# --------------------------------------------------------------------
#                                MAIN
# --------------------------------------------------------------------

parser = OptionParser(option_class=damask.extendableOption, usage='%prog options [ASCIItable(s)]', description = """
Average each data block of size 'packing' into single values thus reducing the former grid to grid/packing.

""", version = scriptID)

parser.add_option('-c','--coordinates',
                  dest = 'pos',
                  type = 'string', metavar = 'string',
                  help = 'column label of coordinates [%default]')
parser.add_option('-p','--packing',
                  dest = 'packing',
                  type = 'int', nargs = 3, metavar = 'int int int',
                  help = 'size of packed group [%default]')
parser.add_option('--shift',
                  dest = 'shift',
                  type = 'int', nargs = 3, metavar = 'int int int',
                  help = 'shift vector of packing stencil [%default]')
parser.add_option('-g', '--grid',
                  dest = 'grid',
                  type = 'int', nargs = 3, metavar = 'int int int',
                  help = 'grid in x,y,z (optional)')
parser.add_option('-s', '--size',
                  dest = 'size',
                  type = 'float', nargs = 3, metavar = 'float float float',
                  help = 'size in x,y,z (optional)')
parser.set_defaults(pos     = 'pos',
                    packing = (2,2,2),
                    shift   = (0,0,0),
                   )

(options,filenames) = parser.parse_args()

packing = np.array(options.packing,dtype = int)
shift   = np.array(options.shift,  dtype = int)

prefix = 'averagedDown{}x{}x{}_'.format(*packing)
if any(shift != 0): prefix += 'shift{:+}{:+}{:+}_'.format(*shift)

# --- loop over input files ------------------------------------------------------------------------

if filenames == []: filenames = [None]

for name in filenames:
  try:    table = damask.ASCIItable(name    = name,
                                    outname = os.path.join(os.path.dirname(name),
                                                           prefix+os.path.basename(name)) if name else name,
                                    buffered = False)
  except IOError:
    continue
  damask.util.report(scriptName,name)

# ------------------------------------------ read header ------------------------------------------

  table.head_read()

# ------------------------------------------ sanity checks ----------------------------------------

  errors  = []
  remarks = []
  
  if table.label_dimension(options.pos) != 3:  errors.append('coordinates {} are not a vector.'.format(options.pos))

  if remarks != []: damask.util.croak(remarks)
  if errors  != []:
    damask.util.croak(errors)
    table.close(dismiss = True)
    continue

# ------------------------------------------ assemble header ---------------------------------------

  table.info_append(scriptID + '\t' + ' '.join(sys.argv[1:]))
  table.head_write()

# --------------- figure out size and grid ---------------------------------------------------------

  table.data_readArray()

  if (options.grid is None or options.size is None):
    grid,size,origin = damask.grid_filters.cell_coord0_2_DNA(table.data[:,table.label_indexrange(options.pos)])
  else:
    grid   = np.array(options.grid,'i')
    size   = np.array(options.size,'d')

  packing = np.where(grid == 1,1,packing)                                                           # reset packing to 1 where grid==1
  shift   = np.where(grid == 1,0,shift)                                                             # reset   shift to 0 where grid==1
  packedGrid = np.maximum(np.ones(3,'i'),grid//packing)

  averagedDown = scipy.ndimage.filters.uniform_filter( \
                  np.roll(
                  np.roll(
                  np.roll(table.data.reshape(list(grid)+[table.data.shape[1]],order = 'F'),
                          -shift[0],axis = 0),
                          -shift[1],axis = 1),
                          -shift[2],axis = 2),
                  size = list(packing) + [1],
                  mode = 'wrap',
                  origin = list(-(packing//2)) + [0])\
                  [::packing[0],::packing[1],::packing[2],:].reshape((packedGrid.prod(),table.data.shape[1]),order = 'F')

  
  table.data = averagedDown

#--- generate grid --------------------------------------------------------------------------------

  coords = damask.grid_filters.cell_coord0(packedGrid,size,shift/packedGrid*size+origin)
  table.data[:,table.label_indexrange(options.pos)] = coords.reshape((-1,3))


# ------------------------------------------ output finalization -----------------------------------  
  table.data_writeArray()
  table.close()