# coding=utf-8
# Copyright 2018 The Google AI Language Team Authors.
#
# 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 unittest
import shutil

from transformers import is_torch_available

if is_torch_available():
    from transformers import (GPT2Config, GPT2Model, GPT2_PRETRAINED_MODEL_ARCHIVE_MAP,
                                    GPT2LMHeadModel, GPT2DoubleHeadsModel)

from .modeling_common_test import (CommonTestCases, ids_tensor)
from .configuration_common_test import ConfigTester
from .utils import require_torch, slow, torch_device


@require_torch
class GPT2ModelTest(CommonTestCases.CommonModelTester):

    all_model_classes = (GPT2Model, GPT2LMHeadModel, GPT2DoubleHeadsModel) if is_torch_available() else ()

    class GPT2ModelTester(object):

        def __init__(self,
                     parent,
                     batch_size=13,
                     seq_length=7,
                     is_training=True,
                     use_token_type_ids=True,
                     use_input_mask=True,
                     use_labels=True,
                     use_mc_token_ids=True,
                     vocab_size=99,
                     hidden_size=32,
                     num_hidden_layers=5,
                     num_attention_heads=4,
                     intermediate_size=37,
                     hidden_act="gelu",
                     hidden_dropout_prob=0.1,
                     attention_probs_dropout_prob=0.1,
                     max_position_embeddings=512,
                     type_vocab_size=16,
                     type_sequence_label_size=2,
                     initializer_range=0.02,
                     num_labels=3,
                     num_choices=4,
                     scope=None,
                     ):
            self.parent = parent
            self.batch_size = batch_size
            self.seq_length = seq_length
            self.is_training = is_training
            self.use_token_type_ids = use_token_type_ids
            self.use_input_mask = use_input_mask
            self.use_labels = use_labels
            self.use_mc_token_ids = use_mc_token_ids
            self.vocab_size = vocab_size
            self.hidden_size = hidden_size
            self.num_hidden_layers = num_hidden_layers
            self.num_attention_heads = num_attention_heads
            self.intermediate_size = intermediate_size
            self.hidden_act = hidden_act
            self.hidden_dropout_prob = hidden_dropout_prob
            self.attention_probs_dropout_prob = attention_probs_dropout_prob
            self.max_position_embeddings = max_position_embeddings
            self.type_vocab_size = type_vocab_size
            self.type_sequence_label_size = type_sequence_label_size
            self.initializer_range = initializer_range
            self.num_labels = num_labels
            self.num_choices = num_choices
            self.scope = scope

        def prepare_config_and_inputs(self):
            input_ids = ids_tensor([self.batch_size, self.seq_length], self.vocab_size)

            input_mask = None
            if self.use_input_mask:
                input_mask = ids_tensor([self.batch_size, self.seq_length], vocab_size=2)

            token_type_ids = None
            if self.use_token_type_ids:
                token_type_ids = ids_tensor([self.batch_size, self.seq_length], self.type_vocab_size)

            mc_token_ids = None
            if self.use_mc_token_ids:
                mc_token_ids = ids_tensor([self.batch_size, self.num_choices], self.seq_length)

            sequence_labels = None
            token_labels = None
            choice_labels = None
            if self.use_labels:
                sequence_labels = ids_tensor([self.batch_size], self.type_sequence_label_size)
                token_labels = ids_tensor([self.batch_size, self.seq_length], self.num_labels)
                choice_labels = ids_tensor([self.batch_size], self.num_choices)

            config = GPT2Config(
                vocab_size_or_config_json_file=self.vocab_size,
                n_embd=self.hidden_size,
                n_layer=self.num_hidden_layers,
                n_head=self.num_attention_heads,
                # intermediate_size=self.intermediate_size,
                # hidden_act=self.hidden_act,
                # hidden_dropout_prob=self.hidden_dropout_prob,
                # attention_probs_dropout_prob=self.attention_probs_dropout_prob,
                n_positions=self.max_position_embeddings,
                n_ctx=self.max_position_embeddings
                # type_vocab_size=self.type_vocab_size,
                # initializer_range=self.initializer_range
            )

            head_mask = ids_tensor([self.num_hidden_layers, self.num_attention_heads], 2)

            return config, input_ids, input_mask, head_mask, token_type_ids, mc_token_ids, sequence_labels, token_labels, choice_labels

        def check_loss_output(self, result):
            self.parent.assertListEqual(
                list(result["loss"].size()),
                [])

        def create_and_check_gpt2_model(self, config, input_ids, input_mask, head_mask, token_type_ids, *args):
            model = GPT2Model(config=config)
            model.to(torch_device)
            model.eval()

            model(input_ids, token_type_ids=token_type_ids, head_mask=head_mask)
            model(input_ids, token_type_ids=token_type_ids)
            sequence_output, presents = model(input_ids)

            result = {
                "sequence_output": sequence_output,
                "presents": presents,
            }
            self.parent.assertListEqual(
                list(result["sequence_output"].size()),
                [self.batch_size, self.seq_length, self.hidden_size])
            self.parent.assertEqual(len(result["presents"]), config.n_layer)

        def create_and_check_lm_head_model(self, config, input_ids, input_mask, head_mask, token_type_ids, *args):
            model = GPT2LMHeadModel(config)
            model.to(torch_device)
            model.eval()

            loss, lm_logits, _ = model(input_ids, token_type_ids=token_type_ids, labels=input_ids)

            result = {
                "loss": loss,
                "lm_logits": lm_logits
            }

            self.parent.assertListEqual(
                list(result["loss"].size()),
                [])
            self.parent.assertListEqual(
                list(result["lm_logits"].size()),
                [self.batch_size, self.seq_length, self.vocab_size])

        def create_and_check_double_lm_head_model(self, config, input_ids, input_mask, head_mask, token_type_ids, mc_token_ids, *args):
            model = GPT2DoubleHeadsModel(config)
            model.to(torch_device)
            model.eval()


            multiple_choice_inputs_ids = input_ids.unsqueeze(1).expand(-1, self.num_choices, -1).contiguous()
            multiple_choice_input_mask = input_mask.unsqueeze(1).expand(-1, self.num_choices, -1).contiguous()
            multiple_choice_token_type_ids = token_type_ids.unsqueeze(1).expand(-1, self.num_choices, -1).contiguous()

            inputs = {'input_ids': multiple_choice_inputs_ids,
                      'mc_token_ids': mc_token_ids,
                      'attention_mask': multiple_choice_input_mask,
                      'token_type_ids': multiple_choice_token_type_ids,
                      'lm_labels': multiple_choice_inputs_ids}

            loss, lm_logits, mc_logits, _ = model(**inputs)

            result = {
                "loss": loss,
                "lm_logits": lm_logits,
                "mc_logits": mc_logits
            }

            self.parent.assertListEqual(
                list(result["loss"].size()),
                [])
            self.parent.assertListEqual(
                list(result["lm_logits"].size()),
                [self.batch_size, self.num_choices, self.seq_length, self.vocab_size])
            self.parent.assertListEqual(
                list(result["mc_logits"].size()),
                [self.batch_size, self.num_choices])

        def prepare_config_and_inputs_for_common(self):
            config_and_inputs = self.prepare_config_and_inputs()

            (config, input_ids, input_mask, head_mask, token_type_ids,
             mc_token_ids, sequence_labels, token_labels, choice_labels) = config_and_inputs

            inputs_dict = {
                'input_ids': input_ids,
                'token_type_ids': token_type_ids,
                'head_mask': head_mask
            }

            return config, inputs_dict

    def setUp(self):
        self.model_tester = GPT2ModelTest.GPT2ModelTester(self)
        self.config_tester = ConfigTester(self, config_class=GPT2Config, n_embd=37)

    def test_config(self):
        self.config_tester.run_common_tests()

    def test_gpt2_model(self):
        config_and_inputs = self.model_tester.prepare_config_and_inputs()
        self.model_tester.create_and_check_gpt2_model(*config_and_inputs)

    def test_gpt2_lm_head_model(self):
        config_and_inputs = self.model_tester.prepare_config_and_inputs()
        self.model_tester.create_and_check_lm_head_model(*config_and_inputs)

    def test_gpt2_double_lm_head_model(self):
        config_and_inputs = self.model_tester.prepare_config_and_inputs()
        self.model_tester.create_and_check_double_lm_head_model(*config_and_inputs)

    @slow
    def test_model_from_pretrained(self):
        cache_dir = "/tmp/transformers_test/"
        for model_name in list(GPT2_PRETRAINED_MODEL_ARCHIVE_MAP.keys())[:1]:
            model = GPT2Model.from_pretrained(model_name, cache_dir=cache_dir)
            shutil.rmtree(cache_dir)
            self.assertIsNotNone(model)


if __name__ == "__main__":
    unittest.main()
