from transformers import PreTrainedModel
from transformers.modeling_outputs import CausalLMOutputWithPast
from torch import nn

class DolphyBlock(nn.Module):
    def __init__(self, config):
        super().__init__()
        self.attn = nn.Linear(config.hidden_size, config.hidden_size)  # placeholder
        self.mlp = nn.Linear(config.hidden_size, config.hidden_size)   # placeholder

    def forward(self, x):
        x = self.attn(x)
        x = self.mlp(x)
        return x

class DolphyModel(nn.Module):
    def __init__(self, config):
        super().__init__()
        self.embed_tokens = nn.Embedding(config.vocab_size, config.hidden_size)
        self.layers = nn.ModuleList([DolphyBlock(config) for _ in range(config.num_hidden_layers)])
        self.norm = nn.LayerNorm(config.hidden_size)

    def forward(self, input_ids):
        x = self.embed_tokens(input_ids)
        for layer in self.layers:
            x = layer(x)
        return self.norm(x)

class Dolphy1ForCausalLM(PreTrainedModel):
    _auto_class = True

    def __init__(self, config):
        super().__init__(config)
        self.model = DolphyModel(config)
        self.lm_head = nn.Linear(config.hidden_size, config.vocab_size, bias=False)

    def forward(self, input_ids, attention_mask=None, **kwargs):
        hidden_states = self.model(input_ids)
        logits = self.lm_head(hidden_states)
        return CausalLMOutputWithPast(logits=logits)