# Copyright (c) Microsoft Corporation.
# Licensed under the MIT license.
import os
import logging
import torch
import numpy as np
from .shape_dependency import ChannelDependency, GroupDependency, CatPaddingDependency, InputChannelDependency
from .utils import get_module_by_name
# logging.basicConfig(level = logging.DEBUG)
_logger = logging.getLogger(__name__)


def fix_mask_conflict(masks, model=None, dummy_input=None, traced=None):
    """
    MaskConflict fix the mask conflict for the channel dependencies
    and group dependency.

    Parameters
    ----------
    masks : dict/str
        A dict object that stores the masks or the path of the mask file
    model : torch.nn.Module
        model to fix the mask conflict
    dummy_input : torch.Tensor
        input example to trace the model
    traced : torch._C.torch.jit.TopLevelTracedModule
        the traced model of the target model, is this parameter is not None,
        we donnot use the model and dummpy_input to get the trace graph.
    """
    if isinstance(masks, str):
        # if the input is the path of the mask_file
        assert os.path.exists(masks)
        masks = torch.load(masks)
    assert len(masks) > 0,  'Mask tensor cannot be empty'
    # if the user uses the model and dummy_input to trace the model, we
    # should get the traced model handly, so that, we only trace the
    # model once, GroupMaskConflict and ChannelMaskConflict will reuse
    # this traced model.
    if traced is None:
        assert model is not None and dummy_input is not None
        training = model.training
        model.eval()
        # We need to trace the model in eval mode
        traced = torch.jit.trace(model, dummy_input)
        model.train(training)

    fix_group_mask = GroupMaskConflict(masks, model, dummy_input, traced)
    masks = fix_group_mask.fix_mask()
    fix_channel_mask = ChannelMaskConflict(masks, model, dummy_input, traced)
    masks = fix_channel_mask.fix_mask()
    padding_cat_mask = CatMaskPadding(masks, model, dummy_input, traced)
    masks = padding_cat_mask.fix_mask()
    return masks, fix_channel_mask.conv_prune_dim


class MaskFix:
    def __init__(self, masks, model=None, dummy_input=None, traced=None):
        # check if the parameters are valid
        parameter_valid = False
        if traced is not None:
            parameter_valid = True
        elif (model is not None) and (dummy_input is not None):
            parameter_valid = True
        if not parameter_valid:
            raise Exception('The input parameters is invalid!')
        self.model = model
        self.dummy_input = dummy_input
        self.traced = traced
        self.masks = masks

    def fix_mask(self):
        raise NotImplementedError

    def export(self, path):
        """
        Export the masks after fixing the conflict to file.
        """
        torch.save(self.masks, path)


class CatMaskPadding(MaskFix):
    def __init__(self, masks, model, dummy_input=None, traced=None):
        """
        CatMaskPadding find the layers whose output tensor is passed
        to the same cat operation. The cat operation concatnates the
        masks of the input tensors as the output mask, so when some
        of the input layers of the cat operation are not pruned, we still
        need to pass the masks of these non-pruned layers(the mask are
        all ones) to the cat operation to ensure the shape of the output
        mask is right.

        Parameters
        ----------
        masks : dict
            a dict object that stores the masks
        model : torch.nn.Module
            model to fix the mask conflict
        dummy_input : torch.Tensor
            input example to trace the model
        traced : torch._C.torch.jit.TopLevelTracedModule
            the traced model of the target model, is this parameter is not None,
            we donnot use the model and dummpy_input to get the trace graph.
        """
        super(CatMaskPadding, self).__init__(masks, model, dummy_input, traced)

    def fix_mask(self):
        cat_padding_depen = CatPaddingDependency(
            self.model, self.dummy_input, self.traced)
        name_to_module = {}
        for name, module in self.model.named_modules():
            name_to_module[name] = module
        depen = cat_padding_depen.dependency_sets
        for layers in depen:
            device = None
            count = 0
            for layer in layers:
                if layer in self.masks:
                    count += 1
                    if device is None:
                        device = self.masks[layer]['weight'].device
            if count == 0:
                # no layer is pruned
                continue
            elif count == len(layers):
                # all the layers have been pruned
                continue
            # pad the mask for the non-pruned layers
            for layer in layers:
                if layer in self.masks:
                    continue

                module = name_to_module[layer]
                w_shape = module.weight.data.size()
                w_mask = torch.ones(w_shape).to(device)
                b_mask = None
                if hasattr(module, 'bias') and module.bias is not None:
                    # module.bias may be None
                    b_shape = module.bias.data.size()
                    b_mask = torch.ones(b_shape).to(device)
                self.masks[layer] = {'weight': w_mask, 'bias': b_mask}

        return self.masks


class GroupMaskConflict(MaskFix):
    def __init__(self, masks, model=None, dummy_input=None, traced=None):
        """
        GroupMaskConflict fix the mask conflict between the layers that
        has group dependecy with each other.

        Parameters
        ----------
        masks : dict
            a dict object that stores the masks
        model : torch.nn.Module
            model to fix the mask conflict
        dummy_input : torch.Tensor
            input example to trace the model
        traced : torch._C.torch.jit.TopLevelTracedModule
            the traced model of the target model, is this parameter is not None,
            we donnot use the model and dummpy_input to get the trace graph.
        """
        super(GroupMaskConflict, self).__init__(
            masks, model, dummy_input, traced)

    def fix_mask(self):
        """
        Fix the mask conflict before the mask inference for the layers that
        has group dependencies. This function should be called before the
        mask inference of the 'speedup' module.
        """
        group_depen = GroupDependency(
            self.model, self.dummy_input, self.traced)
        depens = group_depen.dependency
        _logger.info(depens)
        for layername in depens:
            group = depens[layername]
            if layername not in self.masks:
                # this layer not pruned
                continue
            w_mask = self.masks[layername]['weight']
            shape = w_mask.size()
            count = np.prod(shape[1:])
            all_ones = (w_mask.flatten(1).sum(-1) ==
                        count).nonzero().squeeze(1).tolist()
            all_zeros = (w_mask.flatten(1).sum(-1) ==
                         0).nonzero().squeeze(1).tolist()
            if len(all_ones) + len(all_zeros) < w_mask.size(0):
                # In fine-grained pruning, skip this layer
                _logger.info('Layers %s using fine-grained pruning', layername)
                continue
            assert shape[0] % group == 0
            # Find the number of masked filter for each group (mini_masked).
            # Because we have to keep the pruned filter can still
            # be divided into the same number of groups, so we only can
            # prune mini_masked filters for each group.
            step = shape[0] / group
            group_masked = []
            for i in range(group):
                _start = step * i
                _end = step * (i+1)
                _tmp_list = list(
                    filter(lambda x: _start <= x and x < _end, all_zeros))
                group_masked.append(_tmp_list)
            mini_masked = min([len(x) for x in group_masked])
            for gm in group_masked:
                for i in range(mini_masked, len(gm)):
                    # To keep the output channel number still being divisible to
                    # groups, we set the masks of following filters to be zero.
                    pos = gm[i]
                    self.masks[layername]['weight'][pos] = torch.ones(
                        shape[1:])
                    if 'bias' in self.masks[layername] and self.masks[layername]['bias'] is not None:
                        self.masks[layername]['bias'][pos] = 1
        return self.masks


class ChannelMaskConflict(MaskFix):
    def __init__(self, masks, model=None, dummy_input=None, traced=None):
        """
        ChannelMaskConflict fix the mask conflict between the layers that
        has channel dependecy with each other.

        Parameters
        ----------
        masks : dict
            a dict object that stores the masks
        model : torch.nn.Module
            model to fix the mask conflict
        dummy_input : torch.Tensor
            input example to trace the model
        graph : torch._C.torch.jit.TopLevelTracedModule
            the traced graph of the target model, is this parameter is not None,
            we donnot use the model and dummpy_input to get the trace graph.
        """
        super(ChannelMaskConflict, self).__init__(
            masks, model, dummy_input, traced)
        self.conv_prune_dim = detect_mask_prune_dim(masks, model)
        _logger.info('detected conv prune dim: %s', self.conv_prune_dim)

    def fix_mask(self):
        """
        Fix the mask conflict before the mask inference for the layers that
        has shape dependencies. This function should be called before the
        mask inference of the 'speedup' module. Only structured pruning masks
        are supported.
        """
        if self.conv_prune_dim == 0:
            channel_depen = ChannelDependency(
                self.model, self.dummy_input, self.traced)
        else:
            channel_depen = InputChannelDependency(
                self.model, self.dummy_input, self.traced)
        depen_sets = channel_depen.dependency_sets
        sum_idx = (1, 2, 3) if self.conv_prune_dim == 0 else (0, 2, 3)

        (_tmp_name, _tmp_tensor) = list(self.masks.items())[0]
        device = _tmp_tensor['weight'].device

        for dset in depen_sets:
            if len(dset) <= 1:
                continue
            # channel_masks is a list, each element is None or a vector, for example:
            # [[0, 1, 1, 0, 0], [0, 0, 1, 1, 0], None], None means no channel
            # is pruned.
            channel_masks = []
            fine_grained = False
            for name in dset:
                if name in self.masks:
                    _, m = get_module_by_name(self.model, name)
                    assert m is not None
                    mask = self.masks[name]['weight']
                    if type(m).__name__ == 'Conv2d':
                        channel_mask = (mask.abs().sum(sum_idx) != 0).int()
                        channel_masks.append(channel_mask)
                        if (channel_mask.sum() * (mask.numel() / mask.shape[self.conv_prune_dim])).item() != (mask > 0).sum().item():
                            fine_grained = True
                    elif type(m).__name__ == 'Linear':
                        channel_masks.append((mask.abs().sum(0) != 0).int())
                    elif type(m).__name__ == 'BatchNorm2d':
                        channel_masks.append(mask.int())
                    elif type(m).__name__ == 'ConvTranspose2d':
                        # convtranspose have difference memory layout, so that we need create
                        # a tmp_sum_idx for conv_transpose
                        tmp_sum_idx = (
                            0, 2, 3) if self.conv_prune_dim == 0 else (1, 2, 3)
                        channel_mask = (mask.abs().sum(tmp_sum_idx) != 0).int()
                        channel_masks.append(channel_mask)
                        if (channel_mask.sum() * (mask.numel() / mask.shape[1-self.conv_prune_dim])).item() != (mask > 0).sum().item():
                            fine_grained = True
                    else:
                        raise RuntimeError(
                            f'unsupported module type: {type(m).__name__}')
                else:
                    # no mask means not pruned, equivlent to full masks
                    channel_masks.append(None)
            if fine_grained:
                _logger.info(
                    'fine-grained mask detected, skip solving conflict for this set: %s', dset)
                continue
            if all(x is None for x in channel_masks):
                continue
            num_channels_list = [len(x)
                                 for x in channel_masks if x is not None]
            # number of channels in same set should be identical
            assert len(set(num_channels_list)) == 1
            num_channels = num_channels_list[0]

            for i, dim_mask in enumerate(channel_masks):
                if dim_mask is None:
                    channel_masks[i] = torch.ones(num_channels).int().to(device)

            # merge masks with 'or'
            merged_channel_mask = channel_masks[0].clone()
            for i in range(1, len(channel_masks)):
                merged_channel_mask = (
                    (merged_channel_mask + channel_masks[i]) != 0).int()

            merged_index = torch.nonzero(merged_channel_mask, as_tuple=True)[0]

            for name in dset:
                if name not in self.masks:
                    assert all(merged_channel_mask)
                    continue
                orig_mask = self.masks[name]['weight']
                _, m = get_module_by_name(self.model, name)
                new_mask = torch.zeros_like(orig_mask)
                if type(m).__name__ == 'Conv2d':
                    if self.conv_prune_dim == 0:
                        new_mask[merged_index, :, :, :] = 1.
                    else:
                        new_mask[:, merged_index, :, :] = 1.
                elif type(m).__name__ == 'Linear':
                    new_mask[:, merged_index] = 1.
                elif type(m).__name__ == 'BatchNorm2d':
                    new_mask = merged_index.type_as(orig_mask)
                else:
                    raise RuntimeError(
                        f'unsupported module type: {type(m).__name__}')

                self.masks[name]['weight'] = new_mask
                if 'bias' in self.masks[name] and self.masks[name]['bias'] is not None:
                    if type(m).__name__ == 'Conv2d':
                        assert self.conv_prune_dim == 0
                    self.masks[name]['bias'] = merged_channel_mask.type_as(
                        self.masks[name]['bias'])

        return self.masks


def detect_mask_prune_dim(masks, model):
    """
    Detect how the masks of convolutional layers are pruned.

    Parameters
    ----------
    masks: dict
        A dict object that stores the masks.
    model: nn.Module
        Model object which the mask can be applied on.

    Returns:
    -------
        How the masks of convolutional layers are pruned, this depends on pruning algorithms, it should
        return 1 for masks generated by AMCPruner, and returns 0 for masks generated by the rest
        NNI builtin pruners.
        0: filter pruning, prune filters of weights which causes channels of output feature maps are pruned.
        1: channel pruning, prune kernels corresponding to each input channels which causes channels of
           input feature maps are pruned.
    """
    dim0_preserved, dim1_preserved = 0., 0.
    dim0_num, dim1_num = 0., 0.
    for module_name in masks:
        _, m = get_module_by_name(model, module_name)
        if m is None or type(m).__name__ != 'Conv2d':
            continue

        mask = masks[module_name]['weight'].clone()
        assert (mask >= 0).sum() == mask.numel(), \
            "mask values should be greater than or equal to 0."
        mask = (mask > 0).int()
        mask = mask.view(mask.shape[0], mask.shape[1], -1)
        dim0_mask = (mask.sum((1, 2)) > 0).int()
        dim1_mask = (mask.sum((0, 2)) > 0).int()
        dim0_preserved += dim0_mask.sum().item()
        dim1_preserved += dim1_mask.sum().item()
        dim0_num += len(dim0_mask)
        dim1_num += len(dim1_mask)

    if dim0_num == 0 or dim1_num == 0:
        _logger.warning('no multi-dimension masks found.')
        return 0

    dim0_sparsity, dim1_sparsity = 1. - dim0_preserved / \
        dim0_num, 1. - dim1_preserved / dim1_num
    _logger.info('dim0 sparsity: %f', dim0_sparsity)
    _logger.info('dim1 sparsity: %f', dim1_sparsity)

    if dim0_sparsity == dim1_sparsity == 0.:
        _logger.warning('nothing masked.')

    if dim0_sparsity > 0 and dim1_sparsity > 0:
        _logger.warning('both dim0 and dim1 masks found.')

    return 0 if dim0_sparsity >= dim1_sparsity else 1
