# Copyright 2019 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.
# ==============================================================================
"""Test configs for lstm."""
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function

import tensorflow.compat.v1 as tf
from tensorflow.lite.testing.zip_test_utils import create_tensor_data
from tensorflow.lite.testing.zip_test_utils import ExtraTocoOptions
from tensorflow.lite.testing.zip_test_utils import make_zip_of_tests
from tensorflow.lite.testing.zip_test_utils import register_make_test_function
from tensorflow.python.ops import rnn


@register_make_test_function()
def make_lstm_tests(options):
  """Make a set of tests to do basic Lstm cell."""

  test_parameters = [
      {
          "dtype": [tf.float32],
          "num_batchs": [1],
          "time_step_size": [1],
          "input_vec_size": [3],
          "num_cells": [4],
          "split_tflite_lstm_inputs": [False],
      },
  ]

  def build_graph(parameters):
    """Build a simple graph with BasicLSTMCell."""

    num_batchs = parameters["num_batchs"]
    time_step_size = parameters["time_step_size"]
    input_vec_size = parameters["input_vec_size"]
    num_cells = parameters["num_cells"]
    inputs_after_split = []
    for i in range(time_step_size):
      one_timestamp_input = tf.compat.v1.placeholder(
          dtype=parameters["dtype"],
          name="split_{}".format(i),
          shape=[num_batchs, input_vec_size])
      inputs_after_split.append(one_timestamp_input)
    # Currently lstm identifier has a few limitations: only supports
    # forget_bias == 0, inner state activation == tanh.
    # TODO(zhixianyan): Add another test with forget_bias == 1.
    # TODO(zhixianyan): Add another test with relu as activation.
    lstm_cell = tf.compat.v1.nn.rnn_cell.BasicLSTMCell(
        num_cells, forget_bias=0.0, state_is_tuple=True)
    cell_outputs, _ = rnn.static_rnn(
        lstm_cell, inputs_after_split, dtype=tf.float32)
    out = cell_outputs[-1]
    return inputs_after_split, [out]

  def build_inputs(parameters, sess, inputs, outputs):
    """Feed inputs, assign variables, and freeze graph."""

    with tf.compat.v1.variable_scope("", reuse=True):
      kernel = tf.get_variable("rnn/basic_lstm_cell/kernel")
      bias = tf.get_variable("rnn/basic_lstm_cell/bias")
      kernel_values = create_tensor_data(parameters["dtype"],
                                         [kernel.shape[0], kernel.shape[1]], -1,
                                         1)
      bias_values = create_tensor_data(parameters["dtype"], [bias.shape[0]], 0,
                                       1)
      sess.run(tf.group(kernel.assign(kernel_values), bias.assign(bias_values)))

    num_batchs = parameters["num_batchs"]
    time_step_size = parameters["time_step_size"]
    input_vec_size = parameters["input_vec_size"]
    input_values = []
    for _ in range(time_step_size):
      tensor_data = create_tensor_data(parameters["dtype"],
                                       [num_batchs, input_vec_size], 0, 1)
      input_values.append(tensor_data)
    out = sess.run(outputs, feed_dict=dict(zip(inputs, input_values)))
    return input_values, out

  # TODO(zhixianyan): Automatically generate rnn_states for lstm cell.
  extra_toco_options = ExtraTocoOptions()
  extra_toco_options.rnn_states = (
      "{state_array:rnn/BasicLSTMCellZeroState/zeros,"
      "back_edge_source_array:rnn/basic_lstm_cell/Add_1,size:4},"
      "{state_array:rnn/BasicLSTMCellZeroState/zeros_1,"
      "back_edge_source_array:rnn/basic_lstm_cell/Mul_2,size:4}")

  make_zip_of_tests(
      options,
      test_parameters,
      build_graph,
      build_inputs,
      extra_toco_options,
      use_frozen_graph=True)