# Copyright (c) Microsoft Corporation.
# Licensed under the MIT license.

"""Module of the distributed inference benchmark."""

import os
import time

import torch
import torch.nn.functional as F
import torch.distributed as dist

from superbench.common.utils import logger
from superbench.benchmarks import DistributedImpl, DistributedBackend, BenchmarkRegistry, ReturnCode, Precision
from superbench.benchmarks.micro_benchmarks import MicroBenchmarkWithInvoke
from superbench.benchmarks.context import Enum
from superbench.benchmarks.reducer import ReduceType


class ComputationKernelType(Enum):
    """The Enum class representing different computation kernel type."""
    ADDMM = 'addmm'
    MATMUL = 'matmul'
    MUL = 'mul'


class CommunicationKernelType(Enum):
    """The Enum class representing different communication kernel type."""
    ALLGATHER = 'allgather'
    ALLREDUCE = 'allreduce'
    ALLTOALL = 'alltoall'


class ActivationKernelType(Enum):
    """The Enum class representing different activation kernel type."""
    RELU = 'relu'
    SIGMOID = 'sigmoid'
    TANH = 'tanh'


class DistInferenceModel(torch.nn.Module):
    """The model class for distributed inference benchmark."""
    def __init__(
        self, input_size, hidden_size, num_layers, computation, communication, activation, precision, num_ranks, device
    ):
        """Constructor.

        Args:
            input_size (int): input data dimension.
            hidden_size (int): hidden layer dimension.
            num_layers (int): number of layers in the model.
            computation (ComputationKernelType): type of computation kernel of this model.
            communication (CommunicationKernelType): type of communication kernel of this model.
            activation (ActivationKernelType): type of activation kernel of this model.
            precision (Precision): data type of this model.
            num_ranks (int): number of ranks in this model runs.
            device (torch.device): device this model runs on.
        """
        super().__init__()
        self.input_size = input_size
        self.hidden_size = hidden_size
        self.num_layers = num_layers
        self.weights = torch.rand(
            self.input_size, self.hidden_size, dtype=getattr(torch, precision.value), device=device
        )
        self.bias = torch.rand(self.hidden_size, dtype=getattr(torch, precision.value), device=device)
        self.num_ranks = num_ranks
        self.step_times = []

        self.__init_computation_kernels(computation)
        self.__init_communication_kernels(communication)
        self.__init_activation_kernels(activation)

    def __init_computation_kernels(self, computation):
        """Select computation kernel according to option.

        Args:
            computation (ComputationKernelType): the type of the computation kernel to run.
        """
        self.computation_kernel = None
        if computation == ComputationKernelType.ADDMM:
            self.computation_kernel = lambda x: torch.addmm(self.bias, x, self.weights)
        elif computation == ComputationKernelType.MATMUL:
            self.computation_kernel = lambda x: torch.matmul(x, self.weights)
        elif computation == ComputationKernelType.MUL:
            self.computation_kernel = lambda x: torch.mul(x, x)

    def __init_communication_kernels(self, communication):
        """Select communication kernel according to option.

        Args:
            communication (CommunicationKernelType): the type of the communication kernel to run.
        """
        self.communication_kernel = None
        if communication == CommunicationKernelType.ALLGATHER:
            self.communication_kernel = self.__all_gather_wrapper
        elif communication == CommunicationKernelType.ALLREDUCE:
            self.communication_kernel = self.__all_reduce_wrapper
        elif communication == CommunicationKernelType.ALLTOALL:
            self.communication_kernel = self.__all_to_all_wrapper

    def __init_activation_kernels(self, activation):
        """Select activation kernel according to option.

        Args:
            activation (ActivationKernelType): the type of the activation kernel to run.
        """
        self.activation_kernel = None
        if activation == ActivationKernelType.RELU:
            self.activation_kernel = F.relu
        elif activation == ActivationKernelType.SIGMOID:
            self.activation_kernel = F.sigmoid
        elif activation == ActivationKernelType.TANH:
            self.activation_kernel = F.tanh

    def __all_gather_wrapper(self, x):
        """All-gather wrapper with output initialization.

        Args:
            x (Tensor): input.

        Return:
            Tensor after all-gather.
        """
        output = torch.empty([x.shape[0] * self.num_ranks] + list(x.shape[1:]), dtype=x.dtype, device=x.device)
        dist.all_gather_into_tensor(output, x)
        return output

    def __all_reduce_wrapper(self, x):
        """All-reduce wrapper.

        Args:
            x (Tensor): input.

        Return:
            Tensor after all-reduce.
        """
        dist.all_reduce(x)
        return x

    def __all_to_all_wrapper(self, x):
        """All-to-all wrapper with output initialization.

        Args:
            x (Tensor): input.

        Return:
            Tensor after all-to-all.
        """
        output = torch.empty_like(x)
        dist.all_to_all_single(output, x)
        return output

    def forward(self, x):
        """Do forward loops.

        Args:
            x (Tensor): input.

        Return:
            Tensor after the whole inference process.
        """
        activation_out = None
        for i in range(self.num_layers):
            computation_out = self.computation_kernel(x)
            communication_out = self.communication_kernel(computation_out)
            activation_out = self.activation_kernel(communication_out)
        return activation_out


class DistInference(MicroBenchmarkWithInvoke):
    """The base class of micro-benchmarks."""
    def __init__(self, name, parameters=''):
        """Constructor.

        Args:
            name (str): benchmark name.
            parameters (str): benchmark parameters.
        """
        super().__init__(name, parameters)
        self.__world_size = 1
        self.__local_rank = 0
        torch.backends.cudnn.benchmark = True
        self.__device = None

        # For cpp impl path
        self._bin_name = 'dist_inference'

    def __timer(self):
        """Returns the current time which ensures all previous CUDA events have been finished.

        If there is no GPU present, this defaults to `time.time()`; otherwise it will
        synchronize CUDA before measuring the time.

        Return:
            Current time in second.
        """
        torch.cuda.synchronize()
        return time.time()

    def add_parser_arguments(self):
        """Add the specified arguments."""
        super().add_parser_arguments()

        self._parser.add_argument(
            '--use_pytorch',
            action='store_true',
            required=False,
            help='Whether to use pytorch implementation. If not, cpp implementation will be used.',
        )
        self._parser.add_argument(
            '--batch_size',
            type=int,
            default=64,
            required=False,
            help='Batch size.',
        )
        self._parser.add_argument(
            '--input_size',
            type=int,
            default=1024,
            required=False,
            help='Input dimension size.',
        )
        self._parser.add_argument(
            '--hidden_size',
            type=int,
            default=1024,
            required=False,
            help='Hidden size.',
        )
        self._parser.add_argument(
            '--alpha',
            type=float,
            default=1.0,
            required=False,
            help='Coefficient alpha in D = alpha*(A*B) + beta*(C).',
        )
        self._parser.add_argument(
            '--beta',
            type=float,
            default=1.0,
            required=False,
            help='Coefficient beta in D = alpha*(A*B) + beta*(C).',
        )
        self._parser.add_argument(
            '--num_layers',
            type=int,
            default=1,
            required=False,
            help='Number of compute-communicate-activate layers.',
        )
        self._parser.add_argument(
            '--computation_kernel',
            type=ComputationKernelType,
            default=ComputationKernelType.MATMUL,
            required=False,
            help='Computation kernel type. E.g. {}.'.format(' '.join(ComputationKernelType.get_values())),
        )
        self._parser.add_argument(
            '--communication_kernel',
            type=CommunicationKernelType,
            default=CommunicationKernelType.ALLREDUCE,
            required=False,
            help='Communication kernel type. E.g. {}.'.format(' '.join(CommunicationKernelType.get_values())),
        )
        self._parser.add_argument(
            '--activation_kernel',
            type=ActivationKernelType,
            default=ActivationKernelType.RELU,
            required=False,
            help='Activation kernel type. E.g. {}.'.format(' '.join(ActivationKernelType.get_values())),
        )
        self._parser.add_argument(
            '--precision',
            type=Precision,
            default=Precision.FLOAT32,
            required=False,
            help='Model precision. E.g. {}.'.format(' '.join(Precision.get_values())),
        )
        self._parser.add_argument(
            '--num_warmup',
            type=int,
            default=50,
            required=False,
            help='Number of warmup steps.',
        )
        self._parser.add_argument(
            '--num_steps',
            type=int,
            default=10000,
            required=False,
            help='Number of test steps.',
        )
        self._parser.add_argument(
            '--distributed_impl',
            type=DistributedImpl,
            default=DistributedImpl.DDP,
            required=False,
            help='Distributed implementations. E.g. {}.'.format(' '.join(DistributedImpl.get_values())),
        )
        self._parser.add_argument(
            '--distributed_backend',
            type=DistributedBackend,
            default=DistributedBackend.NCCL,
            required=False,
            help='Distributed backends. E.g. {}.'.format(' '.join(DistributedBackend.get_values())),
        )
        self._parser.add_argument(
            '--use_cuda_graph',
            action='store_true',
            required=False,
            help='Whether to launch kernels in CUDA graph mode.',
        )

    def _preprocess(self):
        """Preprocess/preparation operations before the benchmarking.

        Return:
            True if _preprocess() succeed.
        """
        if not super()._preprocess():
            return False

        if self._args.use_pytorch:
            # Initialize PyTorch if pytorch impl path
            if self._args.distributed_impl != DistributedImpl.DDP:
                return self._set_error_code_and_print_error_msg(
                    ReturnCode.DISTRIBUTED_SETTING_INIT_FAILURE,
                    'Unsupported distributed implementation - model: {}, distributed implementation: {}.'.format(
                        self._name, self._args.distributed_impl
                    )
                )

            try:
                torch.distributed.init_process_group(backend=self._args.distributed_backend.value)
                self.__world_size = int(os.environ['WORLD_SIZE'])
                self.__local_rank = int(os.environ['LOCAL_RANK'])
                assert (torch.cuda.is_available())
            except BaseException as e:
                torch.distributed.destroy_process_group()
                return self._set_error_code_and_print_error_msg(
                    ReturnCode.DISTRIBUTED_SETTING_INIT_FAILURE,
                    'Initialize distributed env failed - benchmark: {}, message: {}.'.format(self._name, str(e))
                )

            torch.cuda.set_device(self.__local_rank)
            self.__device = torch.device('cuda:{}'.format(self.__local_rank))
        else:
            # Assemble commands if cpp impl path
            self.__bin_path = os.path.join(self._args.bin_dir, self._bin_name)

            args = '-m %d -n %d -k %d' % (self._args.hidden_size, self._args.batch_size, self._args.input_size)
            args += ' --alpha %g --beta %g' % (self._args.alpha, self._args.beta)
            args += ' --num_layers %d --num_warmups %d --num_iters %d' % \
                (self._args.num_layers, self._args.num_warmup, self._args.num_steps)
            if self._args.use_cuda_graph:
                args += ' --use_cuda_graph'
            self._commands = ['%s %s' % (self.__bin_path, args)]

        return True

    def _prepare_model(
        self, input_size, hidden_size, num_layers, computation, communication, activation, precision, num_ranks
    ):
        """Prepare model.

        Args:
            input_size (int): input data dimension.
            hidden_size (int): hidden layer dimension.
            num_layers (int): number of layers in the model.
            computation (ComputationKernelType): type of computation kernel of this model.
            communication (CommunicationKernelType): type of communication kernel of this model.
            activation (ActivationKernelType): type of activation kernel of this model.
            precision (Precision): data type of this model.
            num_ranks (int): number of ranks in this model runs.

        Return:
            Model prepared.
        """
        model = DistInferenceModel(
            input_size, hidden_size, num_layers, computation, communication, activation, precision, num_ranks,
            self.__device
        )
        model = model.to(dtype=getattr(torch, precision.value))
        model = model.cuda()
        return model

    def _run_model(self, model, batch_size, input_size, precision, device, num_warmup, num_steps):
        """Run model and collect step times.

        Args:
            model (torch.nn.Module): model to run.
            batch_size (int): batch size of input data.
            input_size (int): input data dimension.
            precision (Precision): data type of this model.
            device (torch.device): device this model runs on.
            num_warmup (int): number of warm-up runs.
            num_steps (int): number of test runs.

        Return:
            Model step times collected.
        """
        data = torch.rand(batch_size, input_size, dtype=getattr(torch, precision.value), device=self.__device)

        # warm up
        for i in range(num_warmup):
            model(data)

        # run and collect results
        step_times = [0.] * num_steps
        for i in range(self._args.num_steps):
            start = self.__timer()
            model(data)
            end = self.__timer()
            step_times[i] = (end - start) * 1000

        return step_times

    def _process_data(self, step_times):
        """Process data.

        Args:
            step_times (List[float]): Model step times collected.

        Return:
            True if _process_data succeeds.
        """
        if not self._process_numeric_result('step_times', step_times, reduce_type=ReduceType.MAX, cal_percentile=True):
            return False
        return True

    def _benchmark(self):
        """Implementation for benchmarking.

        Return:
            True if _benchmark succeeds.
        """
        if self._args.use_pytorch:
            # Execute PyTorch model if pytorch impl path
            batch_size = self._args.batch_size
            input_size = self._args.input_size
            hidden_size = self._args.hidden_size
            num_layers = self._args.num_layers
            computation = self._args.computation_kernel
            communication = self._args.communication_kernel
            activation = self._args.activation_kernel
            precision = self._args.precision
            num_warmup = self._args.num_warmup
            num_steps = self._args.num_steps

            if self.__local_rank == 0:
                logger.info(
                    'Distributed Inference - using {} GPUs: '
                    'batch_size={}, input_size={}, hidden_size={}, num_layers={}, '
                    'computation_kernel={}, communication_kernel={}, activation_kernel={}, precision={}, '
                    'num_warmup={} num_steps={}'.format(
                        self.__world_size, batch_size, input_size, hidden_size, num_layers, computation, communication,
                        activation, precision, num_warmup, num_steps
                    )
                )

            # Prepare model
            model = self._prepare_model(
                input_size, hidden_size, num_layers, computation, communication, activation, precision,
                self.__world_size
            )

            # Run model
            step_times = self._run_model(model, batch_size, input_size, precision, self.__device, num_warmup, num_steps)

            # Process data and return
            return self._process_data(step_times)
        else:
            # Execute commands if cpp impl path
            if not super()._benchmark():
                return False
            return True

    def _process_raw_result(self, cmd_idx, raw_output):
        """Function to parse raw results and save the summarized results.

          self._result.add_raw_data() and self._result.add_result() need to be called to save the results.

        Args:
            cmd_idx (int): the index of command corresponding with the raw_output.
            raw_output (str): raw output string of the micro-benchmark.

        Return:
            True if the raw output string is valid and result can be extracted.
        """
        self._result.add_raw_data('raw_output_' + str(cmd_idx), raw_output, self._args.log_raw_data)

        try:
            output_lines = [x.strip() for x in raw_output.strip().splitlines()]
            step_times = []
            for output_line in output_lines:
                if output_line.startswith('Latency of step'):
                    step_times.append(float(output_line.split(' ms')[0].split()[-1]))
            return self._process_numeric_result(
                'step_times', step_times, reduce_type=ReduceType.MAX, cal_percentile=True
            )
        except BaseException as e:
            return self._set_error_code_and_print_error_msg(
                ReturnCode.MICROBENCHMARK_RESULT_PARSING_FAILURE,
                'The result format is invalid - round: {}, benchmark: {}, raw output: {}, message: {}.'.format(
                    self._curr_run_index, self._name, raw_output, str(e)
                )
            )

    def _postprocess(self):
        """Postprocess/cleanup operations after the benchmarking.

        Return:
            True if _postprocess succeeds.
        """
        if not super()._postprocess():
            return False

        if self._args.use_pytorch:
            try:
                torch.distributed.destroy_process_group()
            except BaseException as e:
                return self._set_error_code_and_print_error_msg(
                    ReturnCode.DISTRIBUTED_SETTING_DESTROY_FAILURE,
                    'Post process failed - benchmark: {}, message: {}.'.format(self._name, str(e))
                )

        return True

    def _set_error_code_and_print_error_msg(self, error_code, error_msg):
        """Set error code and print error log upon error.

        Return:
            False, representing error.
        """
        self._result.set_return_code(error_code)
        logger.error(error_msg)
        return False


BenchmarkRegistry.register_benchmark('pytorch-dist-inference', DistInference, parameters='')
