# 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
#
# https://www.apache.org/licenses/LICENSE-2.0
#
# 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.

model = models.InceptionV1()
model.load_graphdef()

def render_activation_grid_very_naive(img, model, layer="mixed4d", W=42, n_steps=256):
  
  # Get the activations
  with tf.Graph().as_default(), tf.Session() as sess:
    t_input = tf.placeholder("float32", [None, None, None, 3])
    T = render.import_model(model, t_input, t_input)
    acts = T(layer).eval({t_input: img[None]})[0]
  acts_flat = acts.reshape([-1] + [acts.shape[2]])
  
  # Render an image for each activation vector
  param_f = lambda: param.image(W, batch=acts_flat.shape[0])
  obj = objectives.Objective.sum(
      [objectives.direction(layer, v, batch=n)
       for n,v in enumerate(acts_flat)
      ])
  thresholds=(n_steps//2, n_steps)
  vis_imgs = render.render_vis(model, obj, param_f, thresholds=thresholds)[-1]
  
  # Combine the images and display the resulting grid
  vis_imgs_ = vis_imgs.reshape(list(acts.shape[:2]) + [W, W, 3])
  vis_imgs_cropped = vis_imgs_[:, :, 2:-2, 2:-2, :]
  show(np.hstack(np.hstack(vis_imgs_cropped)))
  return vis_imgs_cropped

def render_activation_grid_less_naive(img, model, layer="mixed4d", W=42,
                                 n_groups=6, subsample_factor=1, n_steps=256):
  
  # Get the activations
  with tf.Graph().as_default(), tf.Session() as sess:
    t_input = tf.placeholder("float32", [None, None, None, 3])
    T = render.import_model(model, t_input, t_input)
    acts = T(layer).eval({t_input: img[None]})[0]
  acts_flat = acts.reshape([-1] + [acts.shape[2]])
  N = acts_flat.shape[0]
  
  # The trick to avoiding "decoherence" is to recognize images that are
  # for similar activation vectors and 
  if n_groups > 0:
    reducer = ChannelReducer(n_groups, "NMF")
    groups = reducer.fit_transform(acts_flat)
    groups /= groups.max(0)
  else:
    groups = np.zeros([])
    
  print(groups.shape)

  
  # The key trick to increasing memory efficiency is random sampling.
  # Even though we're visualizing lots of images, we only run a small
  # subset through the network at once. In order to do this, we'll need
  # to hold tensors in a tensorflow graph around the visualization process.
  
  with tf.Graph().as_default() as graph, tf.Session() as sess:
    
    
    # Using the groups, create a paramaterization of images that
    # partly shares paramters between the images for similar activation
    # vectors. Each one still has a full set of unique parameters, and could
    # optimize to any image. We're just making it easier to find solutions
    # where things are the same.
    group_imgs_raw = param.fft_image([n_groups, W, W, 3])
    unique_imgs_raw = param.fft_image([N, W, W, 3])
    opt_imgs = param.to_valid_rgb(tf.stack([
            0.7*unique_imgs_raw[i] + 
            0.5*sum(groups[i, j] * group_imgs_raw[j] for j in range(n_groups))
            for i in range(N) ]),
            decorrelate=True)
    
    # Construct a random batch to optimize this step
    batch_size = 64
    rand_inds = tf.random_uniform([batch_size], 0, N, dtype=tf.int32)
    pres_imgs = tf.gather(opt_imgs, rand_inds)
    pres_acts = tf.gather(acts_flat, rand_inds)
    obj = objectives.Objective.sum(
      [objectives.direction(layer, pres_acts[n], batch=n)
       for n in range(batch_size)
      ])
    
    # Actually do the optimization...
    T = render.make_vis_T(model, obj, param_f=pres_imgs)
    tf.global_variables_initializer().run()
    
    for i in range(n_steps):
      T("vis_op").run()
      if (i+1) % (n_steps//2) == 0:
        show(pres_imgs.eval()[::4])
    
    vis_imgs = opt_imgs.eval()
    
  # Combine the images and display the resulting grid
  print("")
  vis_imgs_ = vis_imgs.reshape(list(acts.shape[:2]) + [W, W, 3])
  vis_imgs_cropped = vis_imgs_[:, :, 2:-2, 2:-2, :]
  show(np.hstack(np.hstack(vis_imgs_cropped)))
  return vis_imgs_cropped