# Copyright 2017 The TensorFlow 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.
# ==============================================================================

from __future__ import absolute_import
from __future__ import division
from __future__ import print_function

import time

import tensorflow.compat.v1 as tf  # pylint: disable=g-bad-import-order
from absl import logging
from official.r1.mnist import mnist

BATCH_SIZE = 100


def dummy_input_fn():
  image = tf.random.uniform([BATCH_SIZE, 784])
  labels = tf.random.uniform([BATCH_SIZE, 1], maxval=9, dtype=tf.int32)
  return image, labels


def make_estimator():
  data_format = 'channels_last'
  if tf.test.is_built_with_cuda():
    data_format = 'channels_first'
  return tf.estimator.Estimator(
      model_fn=mnist.model_fn, params={
          'data_format': data_format
      })


class Tests(tf.test.TestCase):
  """Run tests for MNIST model.

  MNIST uses contrib and will not work with TF 2.0.  All tests are disabled if
  using TF 2.0.
  """

  def test_mnist(self):
    classifier = make_estimator()
    classifier.train(input_fn=dummy_input_fn, steps=2)
    eval_results = classifier.evaluate(input_fn=dummy_input_fn, steps=1)

    loss = eval_results['loss']
    global_step = eval_results['global_step']
    accuracy = eval_results['accuracy']
    self.assertEqual(loss.shape, ())
    self.assertEqual(2, global_step)
    self.assertEqual(accuracy.shape, ())

    input_fn = lambda: tf.random.uniform([3, 784])
    predictions_generator = classifier.predict(input_fn)
    for _ in range(3):
      predictions = next(predictions_generator)
      self.assertEqual(predictions['probabilities'].shape, (10,))
      self.assertEqual(predictions['classes'].shape, ())

  def mnist_model_fn_helper(self, mode, multi_gpu=False):
    features, labels = dummy_input_fn()
    image_count = features.shape[0]
    spec = mnist.model_fn(features, labels, mode, {
        'data_format': 'channels_last',
        'multi_gpu': multi_gpu
    })

    if mode == tf.estimator.ModeKeys.PREDICT:
      predictions = spec.predictions
      self.assertAllEqual(predictions['probabilities'].shape, (image_count, 10))
      self.assertEqual(predictions['probabilities'].dtype, tf.float32)
      self.assertAllEqual(predictions['classes'].shape, (image_count,))
      self.assertEqual(predictions['classes'].dtype, tf.int64)

    if mode != tf.estimator.ModeKeys.PREDICT:
      loss = spec.loss
      self.assertAllEqual(loss.shape, ())
      self.assertEqual(loss.dtype, tf.float32)

    if mode == tf.estimator.ModeKeys.EVAL:
      eval_metric_ops = spec.eval_metric_ops
      self.assertAllEqual(eval_metric_ops['accuracy'][0].shape, ())
      self.assertAllEqual(eval_metric_ops['accuracy'][1].shape, ())
      self.assertEqual(eval_metric_ops['accuracy'][0].dtype, tf.float32)
      self.assertEqual(eval_metric_ops['accuracy'][1].dtype, tf.float32)

  def test_mnist_model_fn_train_mode(self):
    self.mnist_model_fn_helper(tf.estimator.ModeKeys.TRAIN)

  def test_mnist_model_fn_train_mode_multi_gpu(self):
    self.mnist_model_fn_helper(tf.estimator.ModeKeys.TRAIN, multi_gpu=True)

  def test_mnist_model_fn_eval_mode(self):
    self.mnist_model_fn_helper(tf.estimator.ModeKeys.EVAL)

  def test_mnist_model_fn_predict_mode(self):
    self.mnist_model_fn_helper(tf.estimator.ModeKeys.PREDICT)


class Benchmarks(tf.test.Benchmark):
  """Simple speed benchmarking for MNIST."""

  def benchmark_train_step_time(self):
    classifier = make_estimator()
    # Run one step to warmup any use of the GPU.
    classifier.train(input_fn=dummy_input_fn, steps=1)

    have_gpu = tf.test.is_gpu_available()
    num_steps = 1000 if have_gpu else 100
    name = 'train_step_time_%s' % ('gpu' if have_gpu else 'cpu')

    start = time.time()
    classifier.train(input_fn=dummy_input_fn, steps=num_steps)
    end = time.time()

    wall_time = (end - start) / num_steps
    self.report_benchmark(
        iters=num_steps,
        wall_time=wall_time,
        name=name,
        extras={
            'examples_per_sec': BATCH_SIZE / wall_time
        })


if __name__ == '__main__':
  logging.set_verbosity(logging.ERROR)
  tf.disable_v2_behavior()
  tf.test.main()
