import sys
import copy
import torch

def _check_model_old_version(model):
    if hasattr(model.WN[0], 'res_layers') or hasattr(model.WN[0], 'cond_layers'):
        return True
    else:
        return False


def _update_model_res_skip(old_model, new_model):
    for idx in range(0, len(new_model.WN)):
        wavenet = new_model.WN[idx]
        n_channels = wavenet.n_channels
        n_layers = wavenet.n_layers
        wavenet.res_skip_layers = torch.nn.ModuleList()
        for i in range(0, n_layers):
            if i < n_layers - 1:
                res_skip_channels = 2*n_channels
            else:
                res_skip_channels = n_channels
            res_skip_layer = torch.nn.Conv1d(n_channels, res_skip_channels, 1)
            skip_layer = torch.nn.utils.remove_weight_norm(wavenet.skip_layers[i])
            if i < n_layers - 1:
                res_layer = torch.nn.utils.remove_weight_norm(wavenet.res_layers[i])
                res_skip_layer.weight = torch.nn.Parameter(torch.cat([res_layer.weight, skip_layer.weight]))
                res_skip_layer.bias = torch.nn.Parameter(torch.cat([res_layer.bias, skip_layer.bias]))
            else:
                res_skip_layer.weight = torch.nn.Parameter(skip_layer.weight)
                res_skip_layer.bias = torch.nn.Parameter(skip_layer.bias)
            res_skip_layer = torch.nn.utils.weight_norm(res_skip_layer, name='weight')
            wavenet.res_skip_layers.append(res_skip_layer)
        del wavenet.res_layers
        del wavenet.skip_layers

def _update_model_cond(old_model, new_model):
    for idx in range(0, len(new_model.WN)):
        wavenet = new_model.WN[idx]
        n_channels = wavenet.n_channels
        n_layers = wavenet.n_layers
        n_mel_channels = wavenet.cond_layers[0].weight.shape[1]
        cond_layer = torch.nn.Conv1d(n_mel_channels, 2*n_channels*n_layers, 1)
        cond_layer_weight = []
        cond_layer_bias = []
        for i in range(0, n_layers):
            _cond_layer = torch.nn.utils.remove_weight_norm(wavenet.cond_layers[i])
            cond_layer_weight.append(_cond_layer.weight)
            cond_layer_bias.append(_cond_layer.bias)
        cond_layer.weight = torch.nn.Parameter(torch.cat(cond_layer_weight))
        cond_layer.bias = torch.nn.Parameter(torch.cat(cond_layer_bias))
        cond_layer = torch.nn.utils.weight_norm(cond_layer, name='weight')
        wavenet.cond_layer = cond_layer
        del wavenet.cond_layers

def update_model(old_model):
    if not _check_model_old_version(old_model):
        return old_model
    new_model = copy.deepcopy(old_model)
    if hasattr(old_model.WN[0], 'res_layers'):
        _update_model_res_skip(old_model, new_model)
    if hasattr(old_model.WN[0], 'cond_layers'):
        _update_model_cond(old_model, new_model)
    return new_model

if __name__ == '__main__':
    old_model_path = sys.argv[1]
    new_model_path = sys.argv[2]
    model = torch.load(old_model_path, map_location='cpu')
    model['model'] = update_model(model['model'])
    torch.save(model, new_model_path)