# Copyright (c) 2024 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
# Copyright (c) 2024 Arc Institute. All rights reserved.
# Copyright (c) 2024 Michael Poli. All rights reserved.
# Copyright (c) 2024 Stanford University. 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.


import torch

from nemo.collections.llm.gpt.model.base import GPTConfig
from nemo.lightning.pytorch.callbacks.flops_callback import FLOPsMeasurementCallback


class MockDataModule:
    def __init__(self, global_batch_size, vocab_size):
        self.global_batch_size = global_batch_size
        self.tokenizer = self
        self.vocab_size = vocab_size


def test_flops_measurement_callback_bert():
    model_config = GPTConfig(
        seq_length=128,
        hidden_size=768,
        num_layers=12,
        ffn_hidden_size=3072,
        num_attention_heads=12,
        moe_router_topk=0,
        num_query_groups=12,
    )

    train_step_time = 1.23
    global_batch_size = 1
    num_devices = torch.distributed.get_world_size() if torch.distributed.is_initialized() else 1
    model_name = "bert"
    data_module = MockDataModule(global_batch_size=global_batch_size, vocab_size=100)
    callback = FLOPsMeasurementCallback(model_config, data_module, model_name)
    total_flops, flops_per_gpu = callback.eval_model_flops()

    expected_total_flops = 84146651135.99998
    expected_flops_per_gpu = expected_total_flops / num_devices

    assert total_flops == expected_total_flops
    assert flops_per_gpu == expected_flops_per_gpu

    tflops_per_sec_per_gpu = callback.eval_tflops_per_sec_per_gpu(train_step_time)
    expected_tflops_per_sec_per_gpu = expected_flops_per_gpu / (1e12 * train_step_time)
    assert tflops_per_sec_per_gpu[0] == expected_tflops_per_sec_per_gpu