from typing import Dict, List

import torch

from ..sharding_strategy import OperationData, OperationDataType
from .node_handler import ModuleHandler
from .registry import operator_registry
from .strategy import BatchNormStrategyGenerator, StrategyGenerator

__all__ = ['BatchNormModuleHandler']


@operator_registry.register(torch.nn.BatchNorm1d)
@operator_registry.register(torch.nn.BatchNorm2d)
@operator_registry.register(torch.nn.BatchNorm3d)
class BatchNormModuleHandler(ModuleHandler):
    """
    A BatchNormModuleHandler which deals with the sharding strategies for nn.BatchNormXd module.
    """

    def get_strategy_generator(self) -> List[StrategyGenerator]:
        op_data_mapping = self.get_operation_data_mapping()
        generators = []
        generators.append(BatchNormStrategyGenerator(op_data_mapping, self.device_mesh))
        return generators

    def get_operation_data_mapping(self) -> Dict[str, OperationData]:
        # use transposed shape for strategies
        # the strategies will be transformed back to its original shape in self.post_process
        physical_input_operand = OperationData(name=str(self.node.args[0]),
                                               type=OperationDataType.ARG,
                                               data=self.node.args[0]._meta_data)
        physical_other_operand = OperationData(name="weight",
                                               type=OperationDataType.PARAM,
                                               data=self.named_parameters['weight'],
                                               logical_shape=self.named_parameters['weight'].shape)
        physical_output = OperationData(name=str(self.node), type=OperationDataType.OUTPUT, data=self.node._meta_data)

        physical_running_mean_operand = OperationData(name="running_mean",
                                                      type=OperationDataType.BUFFER,
                                                      data=self.named_buffers['running_mean'],
                                                      logical_shape=self.named_buffers['running_mean'].shape)

        physical_running_var_operand = OperationData(name="running_var",
                                                     type=OperationDataType.BUFFER,
                                                     data=self.named_buffers['running_var'],
                                                     logical_shape=self.named_buffers['running_var'].shape)

        physical_num_batches_tracked_operand = OperationData(
            name="num_batches_tracked",
            type=OperationDataType.BUFFER,
            data=self.named_buffers['num_batches_tracked'],
            logical_shape=self.named_buffers['num_batches_tracked'].shape)

        mapping = {
            "input": physical_input_operand,
            "other": physical_other_operand,
            "output": physical_output,
            "running_mean": physical_running_mean_operand,
            "running_var": physical_running_var_operand,
            "num_batches_tracked": physical_num_batches_tracked_operand
        }

        if self.named_parameters['bias'] is not None:
            physical_bias_operand = OperationData(name="bias",
                                                  type=OperationDataType.PARAM,
                                                  data=self.named_parameters['bias'])
            mapping['bias'] = physical_bias_operand
        return mapping
