import torch
from transformers.models.bert.modeling_bert import BertPreTrainedModel, BertPooler
from codes.Component import EdgeEncoding, TransformerEncoder


BertLayerNorm = torch.nn.LayerNorm

class BaseModel(BertPreTrainedModel):
    data = None

    def __init__(self, config):
        super(BaseModel, self).__init__(config)
        self.config = config

        self.embeddings = EdgeEncoding(config)
        self.encoder = TransformerEncoder(config)
        self.pooler = BertPooler(config)

        self.init_weights()

    def get_input_embeddings(self):
        return self.embeddings.raw_feature_embeddings

    def set_input_embeddings(self, value):
        self.embeddings.raw_feature_embeddings = value

    def _prune_heads(self, heads_to_prune):
        for layer, heads in heads_to_prune.items():
            self.encoder.layer[layer].attention.prune_heads(heads)

    def setting_preparation(self, input_ids=None, attention_mask=None, token_type_ids=None, position_ids=None, head_mask=None, inputs_embeds=None, encoder_hidden_states=None, encoder_attention_mask=None,):

        if input_ids is not None and inputs_embeds is not None:
            raise ValueError("You cannot specify both input_ids and inputs_embeds at the same time")
        elif input_ids is not None:
            input_shape = input_ids.size()
        elif inputs_embeds is not None:
            input_shape = inputs_embeds.size()[:-1]
        else:
            raise ValueError("You have to specify either input_ids or inputs_embeds")

        device = input_ids.device if input_ids is not None else inputs_embeds.device

        if attention_mask is None:
            attention_mask = torch.ones(input_shape, device=device)
        if token_type_ids is None:
            token_type_ids = torch.zeros(input_shape, dtype=torch.long, device=device)

        if attention_mask.dim() == 3:
            extended_attention_mask = attention_mask[:, None, :, :]
        elif attention_mask.dim() == 2:
            if self.config.is_decoder:
                batch_size, seq_length = input_shape
                seq_ids = torch.arange(seq_length, device=device)
                causal_mask = seq_ids[None, None, :].repeat(batch_size, seq_length, 1) <= seq_ids[None, :, None]
                causal_mask = causal_mask.to(torch.long)  # not converting to long will cause errors with pytorch version < 1.3
                extended_attention_mask = causal_mask[:, None, :, :] * attention_mask[:, None, None, :]
            else:
                extended_attention_mask = attention_mask[:, None, None, :]
        else:
            raise ValueError(
                "Wrong shape for input_ids (shape {}) or attention_mask (shape {})".format(
                    input_shape, attention_mask.shape
                )
            )

        extended_attention_mask = extended_attention_mask.to(dtype=next(self.parameters()).dtype)  # fp16 compatibility
        extended_attention_mask = (1.0 - extended_attention_mask) * -10000.0

        if self.config.is_decoder and encoder_hidden_states is not None:
            encoder_batch_size, encoder_sequence_length, _ = encoder_hidden_states.size()
            encoder_hidden_shape = (encoder_batch_size, encoder_sequence_length)
            if encoder_attention_mask is None:
                encoder_attention_mask = torch.ones(encoder_hidden_shape, device=device)

            if encoder_attention_mask.dim() == 3:
                encoder_extended_attention_mask = encoder_attention_mask[:, None, :, :]
            elif encoder_attention_mask.dim() == 2:
                encoder_extended_attention_mask = encoder_attention_mask[:, None, None, :]
            else:
                raise ValueError(
                    "Wrong shape for encoder_hidden_shape (shape {}) or encoder_attention_mask (shape {})".format(
                        encoder_hidden_shape, encoder_attention_mask.shape
                    )
                )

            encoder_extended_attention_mask = encoder_extended_attention_mask.to(dtype=next(self.parameters()).dtype)  # fp16 compatibility
            encoder_extended_attention_mask = (1.0 - encoder_extended_attention_mask) * -10000.0
        else:
            encoder_extended_attention_mask = None

        if head_mask is not None:
            if head_mask.dim() == 1:
                head_mask = head_mask.unsqueeze(0).unsqueeze(0).unsqueeze(-1).unsqueeze(-1)
                head_mask = head_mask.expand(self.config.num_hidden_layers, -1, -1, -1, -1)
            elif head_mask.dim() == 2:
                head_mask = (
                    head_mask.unsqueeze(1).unsqueeze(-1).unsqueeze(-1)
                )  # We can specify head_mask for each layer
            head_mask = head_mask.to(dtype=next(self.parameters()).dtype)
        else:
            head_mask = [None] * self.config.num_hidden_layers

        return token_type_ids, extended_attention_mask, encoder_extended_attention_mask, head_mask


    def forward(self, init_pos_ids, hop_dis_ids, time_dis_ids, head_mask=None):
        if head_mask is None:
            head_mask = [None] * self.config.num_hidden_layers

        embedding_output = self.embeddings(init_pos_ids=init_pos_ids,
                                           hop_dis_ids=hop_dis_ids, time_dis_ids=time_dis_ids)
        encoder_outputs = self.encoder(embedding_output, head_mask=head_mask) #这里的输出是tuple，因为在某些设定下要输出别的信息（中间分析用）
        sequence_output = encoder_outputs[0]
        pooled_output = self.pooler(sequence_output)
        outputs = (sequence_output, pooled_output,) + encoder_outputs[1:]
        return outputs

    def run(self):
        pass