# Copyright 2019 The TensorFlow Hub Authors. All Rights Reserved.
#
# 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
#
# 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.
# ==============================================================================

"""
Explanation: Copyright 2019 The TensorFlow Hub Authors.
Licensed under the Apache License, Version 2.0 (the "License");
End of explanation
"""


import tensorflow as tf

import matplotlib.pyplot as plt
import numpy as np
import seaborn as sns
import tensorflow_hub as hub
import tensorflow_datasets as tfds

from tensorflow_datasets.core import SplitGenerator
from tensorflow_datasets.video.bair_robot_pushing import BairRobotPushingSmall

import tempfile
import pathlib

TEST_DIR = pathlib.Path(tempfile.mkdtemp()) / "bair_robot_pushing_small/softmotion30_44k/test/"

# Download the test split to $TEST_DIR
!mkdir -p $TEST_DIR
!wget -nv https://storage.googleapis.com/download.tensorflow.org/data/bair_test_traj_0_to_255.tfrecords -O $TEST_DIR/traj_0_to_255.tfrecords

# Since the dataset builder expects the train and test split to be downloaded,
# patch it so it only expects the test data to be available
builder = BairRobotPushingSmall()
test_generator = SplitGenerator(name='test', gen_kwargs={"filedir": str(TEST_DIR)})
builder._split_generators = lambda _: [test_generator]
builder.download_and_prepare()

"""
Explanation: Video Inbetweening using 3D Convolutions
<table class="tfo-notebook-buttons" align="left">
  <td>
    <a target="_blank" href="https://www.tensorflow.org/hub/tutorials/tweening_conv3d"><img src="https://www.tensorflow.org/images/tf_logo_32px.png" />View on TensorFlow.org</a>
  </td>
  <td>
    <a target="_blank" href="https://colab.research.google.com/github/tensorflow/hub/blob/master/examples/colab/tweening_conv3d.ipynb"><img src="https://www.tensorflow.org/images/colab_logo_32px.png" />Run in Google Colab</a>
  </td>
  <td>
    <a target="_blank" href="https://github.com/tensorflow/hub/blob/master/examples/colab/tweening_conv3d.ipynb"><img src="https://www.tensorflow.org/images/GitHub-Mark-32px.png" />View on GitHub</a>
  </td>
  <td>
    <a href="https://storage.googleapis.com/tensorflow_docs/hub/examples/colab/tweening_conv3d.ipynb"><img src="https://www.tensorflow.org/images/download_logo_32px.png" />Download notebook</a>
  </td>
  <td>
    <a href="https://tfhub.dev/google/tweening_conv3d_bair/1"><img src="https://www.tensorflow.org/images/hub_logo_32px.png" />See TF Hub model</a>
  </td>
</table>

Yunpeng Li, Dominik Roblek, and Marco Tagliasacchi. From Here to There: Video Inbetweening Using Direct 3D Convolutions, 2019.
https://arxiv.org/abs/1905.10240
Current Hub characteristics:
- has models for BAIR Robot pushing videos and KTH action video dataset (though this colab uses only BAIR)
- BAIR dataset already available in Hub. However, KTH videos need to be supplied by the users themselves.
- only evaluation (video generation) for now
- batch size and frame size are hard-coded
Setup
Since tfds.load('bair_robot_pushing_small', split='test') would download a 30GB archive that also contains the training data, we download a separated archive that only contains the 190MB test data. The used dataset has been published by this paper and is licensed as Creative Commons BY 4.0.
End of explanation
"""


# @title Load some example data (BAIR).
batch_size = 16

# If unable to download the dataset automatically due to "not enough disk space", please download manually to Google Drive and
# load using tf.data.TFRecordDataset.
ds = builder.as_dataset(split="test")
test_videos = ds.batch(batch_size)
first_batch = next(iter(test_videos))
input_frames = first_batch['image_aux1'][:, ::15]
input_frames = tf.cast(input_frames, tf.float32)

# @title Visualize loaded videos start and end frames.

print('Test videos shape [batch_size, start/end frame, height, width, num_channels]: ', input_frames.shape)
sns.set_style('white')
plt.figure(figsize=(4, 2*batch_size))

for i in range(batch_size)[:4]:
  plt.subplot(batch_size, 2, 1 + 2*i)
  plt.imshow(input_frames[i, 0] / 255.0)
  plt.title('Video {}: First frame'.format(i))
  plt.axis('off')
  plt.subplot(batch_size, 2, 2 + 2*i)
  plt.imshow(input_frames[i, 1] / 255.0)
  plt.title('Video {}: Last frame'.format(i))
  plt.axis('off')

"""
Explanation: BAIR: Demo based on numpy array inputs
End of explanation
"""


hub_handle = 'https://tfhub.dev/google/tweening_conv3d_bair/1'
module = hub.load(hub_handle).signatures['default']

"""
Explanation: Load Hub Module
End of explanation
"""


filled_frames = module(input_frames)['default'] / 255.0

# Show sequences of generated video frames.

# Concatenate start/end frames and the generated filled frames for the new videos.
generated_videos = np.concatenate([input_frames[:, :1] / 255.0, filled_frames, input_frames[:, 1:] / 255.0], axis=1)

for video_id in range(4):
  fig = plt.figure(figsize=(10 * 2, 2))
  for frame_id in range(1, 16):
    ax = fig.add_axes([frame_id * 1 / 16., 0, (frame_id + 1) * 1 / 16., 1],
                      xmargin=0, ymargin=0)
    ax.imshow(generated_videos[video_id, frame_id])
    ax.axis('off')

"""
Explanation: Generate and show the videos
End of explanation
"""


