#!/usr/bin/env python3

'''
/**
 * @file imagej_tiff_saver.py
 * @brief save tiffs for imagej (1.52d+) - with stacks and hyperstacks
 * @par <b>License</b>:
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/
'''

__copyright__ = "Copyright 2018, Elphel, Inc."
__license__   = "GPL-3.0+"
__email__     = "oleg@elphel.com"

'''
Usage example:
  import imagej_tiffwriter
  import numpy as np

  # have a few images in the form of numpy arrays
  # make sure to stack them as:
  #   - (t,z,h,w,c)
  #   - (z,h,w,c)
  #   - (h,w,c)
  #   - (h,w)

  imagej_tiffwriter.save(path,images)

'''

from PIL import Image, TiffImagePlugin
import numpy as np
import math

# DO NOT USE?
# thing is the old ImageJs <1.52d poorly handle tags directories or something like that
def __get_IJ_IFD(t,z,c):

  ifd = TiffImagePlugin.ImageFileDirectory_v2()

  ijheader = [
    'ImageJ=',
    'hyperstack=true',
    'images='+str(t*z*c),
    'channels='+str(c),
    'slices='+str(z),
    'frames='+str(t),
    'loop=false'
  ]

  ifd[270] = ("\n".join(ijheader)+"\n")

  #is_hyperstack = 'true' if len(shape)>1 else 'false'
  #if (len(shape)>0):

  return ifd


#def save(path,images,force_stack=False,force_hyperstack=False):
def save(path,images):

  # Got images, analyze shape:
  #   - possible formats (c == depth):
  #     -- (t,z,h,w,c)
  #     -- (t,h,w,c), t or z does not matter
  #     -- (h,w,c)
  #     -- (h,w)


  # 0 or 1 images.shapes are not handled
  #
  # save single channel image in the form of numpy array
  #   -
  if   len(images.shape)==2:
    # (h,w) -> (h,w,c=1)
    image = Image.fromarray(images)
    image.save(path)

  elif len(images.shape)>2:

    h,w,c  = images.shape[-3:]

    if len(images.shape)==3:
      images = np.reshape(images,(1,h,w,c))

    z = images.shape[-4]

    if len(images.shape)==4:
      images = np.reshape(images,(1,z,h,w,c))

    t  = images.shape[-5]

    c_axis = len(images.shape)-1

    if c>1:
      channels = np.squeeze(np.split(images,c,axis=c_axis))
    else:
      channels = np.squeeze(images,axis=c_axis)


    split_channels = np.concatenate(channels,axis=-3)
    images_flat = np.reshape(split_channels,(-1,h,w))

    imlist = []
    for i in range(images_flat.shape[0]):
      imlist.append(Image.fromarray(images_flat[i]))

    imlist[0].save(path,save_all=True,append_images=imlist[1:])
    # thing is the old ImageJs <1.52d poorly handle tags directories or something like that
    #imlist[0].save(path,save_all=True,append_images=imlist[1:],tiffinfo=__get_IJ_IFD(t,z,c))

# Testing
if __name__ == "__main__":

  def hamming_window(x,N):
    y = 0.54 - 0.46*math.cos(2*math.pi*x/(N-1))
    return y

  hw = hamming_window

  NT = 5
  NC = 2
  NZ = 3
  NX = 512
  NY = 512

  images = np.empty((NT,NZ,NY,NX,NC))

  import time
  print(str(time.time())+": Generating test images")
  for t in range(NT):
    for z in range(NZ):
      for c in range(NC):
        images[t,z,:,:,c] = np.array([[(255-t*25)*hw(i,512)*hw(j,512) for i in range(NX)] for j in range(NY)],np.float32)
  print(str(time.time())+": Test images generated")
  print("Images shape: "+str(images.shape))

  v = save("result_2.tiff",images)