# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
from collections.abc import Iterable

import torch
import torch.distributed as dist
from torch import nn
from transformers import GptOssConfig

from vllm.compilation.decorators import support_torch_compile
from vllm.config import CacheConfig, VllmConfig
from vllm.distributed import (
    get_dp_group,
    get_ep_group,
    get_pcp_group,
    get_pp_group,
    get_tensor_model_parallel_rank,
    get_tensor_model_parallel_world_size,
    tensor_model_parallel_all_gather,
)
from vllm.model_executor.layers.attention import Attention
from vllm.model_executor.layers.fused_moe import FusedMoE
from vllm.model_executor.layers.fused_moe.config import FusedMoEParallelConfig
from vllm.model_executor.layers.layernorm import RMSNorm
from vllm.model_executor.layers.linear import QKVParallelLinear, RowParallelLinear
from vllm.model_executor.layers.logits_processor import LogitsProcessor
from vllm.model_executor.layers.quantization import QuantizationConfig
from vllm.model_executor.layers.rotary_embedding import get_rope
from vllm.model_executor.layers.utils import rocm_unquantized_gemm
from vllm.model_executor.layers.vocab_parallel_embedding import (
    ParallelLMHead,
    VocabParallelEmbedding,
)
from vllm.model_executor.model_loader.weight_utils import default_weight_loader
from vllm.model_executor.models.utils import sequence_parallel_chunk
from vllm.platforms import current_platform
from vllm.sequence import IntermediateTensors
from vllm.utils.math_utils import cdiv
from vllm.v1.attention.backend import AttentionType

from .interfaces import SupportsEagle3, SupportsLoRA, SupportsPP
from .utils import (
    AutoWeightsLoader,
    WeightsMapper,
    extract_layer_index,
    is_pp_missing_parameter,
    make_empty_intermediate_tensors_factory,
    make_layers,
    maybe_prefix,
)


class OAIAttention(nn.Module):
    def __init__(
        self,
        config: GptOssConfig,
        quant_config: QuantizationConfig | None = None,
        cache_config: CacheConfig | None = None,
        prefix: str = "",
    ):
        super().__init__()
        self.layer_idx = extract_layer_index(prefix)
        self.head_dim = config.head_dim
        self.num_attention_heads = config.num_attention_heads
        self.num_key_value_heads = config.num_key_value_heads
        self.hidden_size = config.hidden_size

        self.rotary_emb = get_rope(
            self.head_dim,
            max_position=config.max_position_embeddings,
            dtype=torch.float32,
            rope_parameters={
                "rope_theta": config.rope_parameters["rope_theta"],
                "rope_type": "yarn",
                "factor": config.rope_parameters["factor"],
                "original_max_position_embeddings": config.rope_parameters[
                    "original_max_position_embeddings"
                ],
                "beta_fast": config.rope_parameters["beta_fast"],
                "beta_slow": config.rope_parameters["beta_slow"],
                "truncate": config.rope_parameters.get("truncate", True),
            },
            is_neox_style=True,
        )

        tp_size = get_tensor_model_parallel_world_size()

        self.sinks = torch.nn.Parameter(
            torch.empty(config.num_attention_heads // tp_size, requires_grad=False)
        )

        self.q_size = self.num_attention_heads * self.head_dim // tp_size
        self.kv_size = self.num_key_value_heads * self.head_dim // tp_size
        self.scaling = self.head_dim**-0.5

        self.qkv_proj = QKVParallelLinear(
            hidden_size=self.hidden_size,
            head_size=self.head_dim,
            total_num_heads=self.num_attention_heads,
            total_num_kv_heads=self.num_key_value_heads,
            quant_config=quant_config,
            prefix=f"{prefix}.qkv_proj",
        )

        self.o_proj = RowParallelLinear(
            input_size=self.num_attention_heads * self.head_dim,
            output_size=self.hidden_size,
            quant_config=quant_config,
            prefix=f"{prefix}.o_proj",
        )

        self.num_local_attention_heads = config.num_attention_heads // tp_size
        self.num_local_key_value_heads = config.num_key_value_heads // tp_size

        # Only apply sliding window to every other layer
        sliding_window = config.sliding_window if self.layer_idx % 2 == 0 else None
        self.attn = Attention(
            self.num_local_attention_heads,
            self.head_dim,
            self.scaling,
            num_kv_heads=self.num_local_key_value_heads,
            cache_config=cache_config,
            quant_config=quant_config,
            per_layer_sliding_window=sliding_window,
            attn_type=AttentionType.DECODER,
            prefix=f"{prefix}.attn",
            sinks=self.sinks,
        )

    def forward(
        self, hidden_states: torch.Tensor, positions: torch.Tensor
    ) -> torch.Tensor:
        qkv, _ = self.qkv_proj(hidden_states)
        q, k, v = qkv.split([self.q_size, self.kv_size, self.kv_size], dim=-1)
        q, k = self.rotary_emb(positions, q, k)
        v = v.contiguous()
        attn_output = self.attn(q, k, v)
        output, _ = self.o_proj(attn_output)
        return output


class MLPBlock(torch.nn.Module):
    def __init__(
        self,
        vllm_config: VllmConfig,
        layer_idx: int,
        prefix: str = "",
    ):
        super().__init__()

        config = vllm_config.model_config.hf_config
        quant_config = vllm_config.quant_config
        parallel_config = vllm_config.parallel_config

        self.is_sequence_parallel = parallel_config.use_sequence_parallel_moe

        self.layer_idx = layer_idx
        self.num_experts = config.num_local_experts
        self.hidden_size = config.hidden_size
        self.experts_per_token = config.num_experts_per_tok
        self.world_size = dist.get_world_size() if dist.is_initialized() else 1
        self.router = torch.nn.Linear(config.hidden_size, config.num_local_experts)
        assert config.intermediate_size % self.world_size == 0
        self.experts = FusedMoE(
            num_experts=config.num_local_experts,
            top_k=config.num_experts_per_tok,
            hidden_size=config.hidden_size,
            intermediate_size=config.intermediate_size,
            reduce_results=True,
            renormalize=True,
            quant_config=quant_config,
            prefix=f"{prefix}.experts",
            apply_router_weight_on_input=False,
            has_bias=True,
            activation="swigluoai",
            is_sequence_parallel=self.is_sequence_parallel,
        )

    def forward(self, x: torch.Tensor) -> torch.Tensor:
        num_tokens = x.shape[0]
        if self.is_sequence_parallel:
            x = sequence_parallel_chunk(x)

        if current_platform.is_rocm():
            g = rocm_unquantized_gemm(
                self, x[:, : self.hidden_size], self.router.weight, self.router.bias
            )
        else:
            g = self.router(x)
        x = self.experts(hidden_states=x, router_logits=g)[:, : self.hidden_size]

        if self.is_sequence_parallel:
            x = tensor_model_parallel_all_gather(x.contiguous(), 0)
            x = x[:num_tokens]
        return x


class TransformerBlock(torch.nn.Module):
    def __init__(
        self,
        vllm_config: VllmConfig,
        quant_config: QuantizationConfig,
        prefix: str = "",
    ):
        super().__init__()

        config = vllm_config.model_config.hf_config
        cache_config = vllm_config.cache_config

        self.layer_idx = extract_layer_index(prefix)
        self.attn = OAIAttention(
            config,
            prefix=f"{prefix}.attn",
            quant_config=quant_config,
            cache_config=cache_config,
        )
        self.mlp = MLPBlock(vllm_config, self.layer_idx, prefix=f"{prefix}.mlp")
        self.input_layernorm = RMSNorm(config.hidden_size, eps=1e-5)
        self.post_attention_layernorm = RMSNorm(config.hidden_size, eps=1e-5)

    def forward(
        self,
        hidden_states: torch.Tensor,
        positions: torch.Tensor,
        residual: torch.Tensor | None,
    ) -> torch.Tensor:
        # Self Attention
        if residual is None:
            residual = hidden_states
            hidden_states = self.input_layernorm(hidden_states)
        else:
            hidden_states, residual = self.input_layernorm(hidden_states, residual)
        hidden_states = self.attn(hidden_states, positions)

        # Fully Connected
        hidden_states, residual = self.post_attention_layernorm(hidden_states, residual)
        output = self.mlp(hidden_states)
        return output, residual


@support_torch_compile
class GptOssModel(nn.Module):
    def __init__(
        self,
        *,
        vllm_config: VllmConfig,
        prefix: str = "",
    ):
        super().__init__()
        self.config = vllm_config.model_config.hf_config
        self.quant_config = vllm_config.quant_config
        self.parallel_config = vllm_config.parallel_config
        self.config.hidden_size = self.config.hidden_size
        self.embedding = VocabParallelEmbedding(
            self.config.vocab_size,
            self.config.hidden_size,
        )
        self.start_layer, self.end_layer, self.layers = make_layers(
            self.config.num_hidden_layers,
            lambda prefix: TransformerBlock(
                vllm_config,
                prefix=prefix,
                quant_config=self.quant_config,
            ),
            prefix=f"{prefix}.layers",
        )
        self.norm = RMSNorm(self.config.hidden_size, eps=1e-5)
        self.make_empty_intermediate_tensors = make_empty_intermediate_tensors_factory(
            ["hidden_states", "residual"], self.config.hidden_size
        )
        self.aux_hidden_state_layers = tuple[int, ...]()

    def embed_input_ids(self, input_ids: torch.Tensor) -> torch.Tensor:
        return self.embedding(input_ids)

    def forward(
        self,
        input_ids: torch.Tensor | None,
        positions: torch.Tensor,
        intermediate_tensors: IntermediateTensors | None = None,
        inputs_embeds: torch.Tensor | None = None,
    ) -> torch.Tensor:
        if get_pp_group().is_first_rank:
            if inputs_embeds is not None:
                x = inputs_embeds
            else:
                x = self.embed_input_ids(input_ids)

            residual = None
        else:
            assert intermediate_tensors is not None
            x = intermediate_tensors["hidden_states"]
            residual = intermediate_tensors["residual"]

        aux_hidden_states = []
        for i in range(self.start_layer, self.end_layer):
            layer = self.layers[i]
            if i in self.aux_hidden_state_layers:
                aux_hidden_states.append(x if residual is None else x + residual)
            x, residual = layer(x, positions, residual)
        if not get_pp_group().is_last_rank:
            return IntermediateTensors({"hidden_states": x, "residual": residual})
        x, _ = self.norm(x, residual)

        if len(aux_hidden_states) > 0:
            return x, aux_hidden_states
        return x

    def _load_weights_mxfp4(
        self,
        ep_rank_end: int,
        ep_rank_start: int,
        heads_per_rank: int,
        head_start: int,
        weights: Iterable[tuple[str, torch.Tensor]],
        stacked_params_mapping: list[tuple[str, ...]],
    ) -> set[str]:
        params_dict = dict(self.named_parameters())
        loaded_params: set[str] = set()

        mxfp4_block = 32
        use_ep = self.parallel_config.enable_expert_parallel
        num_experts = self.config.num_local_experts

        # In MoE, we need to flatten the tensor parallel size across the data
        # parallel size when EP is disabled.
        tp_size, tp_rank = FusedMoEParallelConfig.flatten_tp_across_dp_and_pcp(
            tp_size=get_tensor_model_parallel_world_size(),
            dp_size=get_dp_group().world_size,
            dp_rank=get_dp_group().rank_in_group,
            pcp_size=get_pcp_group().world_size,
            pcp_rank=get_pcp_group().rank_in_group,
        )

        intermediate_size = self.config.intermediate_size
        intermediate_size_block = intermediate_size // mxfp4_block
        per_rank_intermediate_size_block = cdiv(intermediate_size_block, tp_size)
        per_rank_intermediate_size = per_rank_intermediate_size_block * mxfp4_block

        # Calculate common slicing bounds for current rank
        tp_rank_start = tp_rank * per_rank_intermediate_size
        tp_rank_end = min((tp_rank + 1) * per_rank_intermediate_size, intermediate_size)

        for name, weight in weights:
            # Skip layers on other devices.
            if is_pp_missing_parameter(name, self):
                continue

            if ".w13_weight_scale" in name:
                # Handle MLP gate and up projection weights scale
                if use_ep:
                    narrow_weight = weight[ep_rank_start:ep_rank_end, ...]
                else:
                    narrow_weight = weight[:, 2 * tp_rank_start : 2 * tp_rank_end, ...]

                param = params_dict[name]
                weight_loader = getattr(param, "weight_loader", default_weight_loader)
                weight_loader(
                    param,
                    narrow_weight,
                    weight_name=name,
                    shard_id=None,
                    expert_id=None,
                )
                loaded_params.add(name)
                continue
            elif ".w2_weight_scale" in name:
                # Handle MLP down projection weights
                if use_ep:
                    narrow_weight = weight[ep_rank_start:ep_rank_end, ...]
                else:
                    narrow_weight = weight[
                        ..., tp_rank_start // mxfp4_block : tp_rank_end // mxfp4_block
                    ]

                param = params_dict[name]
                weight_loader = getattr(param, "weight_loader", default_weight_loader)
                weight_loader(
                    param,
                    narrow_weight,
                    weight_name=name,
                    shard_id=None,
                    expert_id=None,
                )
                loaded_params.add(name)
                continue
            elif ".w13_weight" in name:
                # Handle MLP gate and up projection weights
                # flat weight from (E, 2 * N, block_size, entry_per_block)
                # to (E, 2 * N, -1), shouldn't trigger copy for contiguous
                weight = weight.view(
                    num_experts, 2 * intermediate_size, -1
                ).contiguous()

                # Extract gate and up projection parts
                # since the weight is shuffled, we can slice directly
                if use_ep:
                    narrow_weight = weight[ep_rank_start:ep_rank_end, ...]
                else:
                    narrow_weight = weight[:, 2 * tp_rank_start : 2 * tp_rank_end, ...]

                param = params_dict[name]
                weight_loader = getattr(param, "weight_loader", default_weight_loader)
                weight_loader(
                    param,
                    narrow_weight,
                    weight_name=name,
                    shard_id=None,
                    expert_id=None,
                )
                loaded_params.add(name)
                continue
            elif ".w2_weight" in name:
                # Handle MLP down projection weights
                # same flatten here, but since 2 mx4 value are packed in 1
                # uint8, divide by 2
                weight = weight.view(
                    num_experts, -1, intermediate_size // 2
                ).contiguous()
                if use_ep:
                    narrow_weight = weight[ep_rank_start:ep_rank_end, ...]
                else:
                    narrow_weight = weight[..., tp_rank_start // 2 : tp_rank_end // 2]

                param = params_dict[name]
                weight_loader = getattr(param, "weight_loader", default_weight_loader)
                weight_loader(
                    param,
                    narrow_weight,
                    weight_name=name,
                    shard_id=None,
                    expert_id=None,
                )
                loaded_params.add(name)
                continue
            elif ".w13_bias" in name:
                # Handle MLP gate and up projection biases
                # Extract gate and up projection bias parts
                if use_ep:
                    narrow_weight = weight[ep_rank_start:ep_rank_end, ...]
                else:
                    narrow_weight = weight[:, 2 * tp_rank_start : 2 * tp_rank_end]

                param = params_dict[name]
                weight_loader = getattr(param, "weight_loader", default_weight_loader)
                weight_loader(
                    param,
                    narrow_weight,
                    weight_name=name,
                    shard_id=None,
                    expert_id=None,
                )
                loaded_params.add(name)
                continue
            elif ".w2_bias" in name:
                # Handle MLP down projection bias
                param = params_dict[name]
                weight_loader = getattr(param, "weight_loader", default_weight_loader)
                if use_ep:
                    weight = weight[ep_rank_start:ep_rank_end, ...]
                else:
                    # (only load on rank 0 to avoid duplication)
                    if tp_rank != 0:
                        weight.zero_()
                weight_loader(
                    param, weight, weight_name=name, shard_id=None, expert_id=None
                )
                loaded_params.add(name)
                continue
            elif "sinks" in name:
                # Handle attention sinks (distributed across ranks)
                param = params_dict[name]
                narrow_weight = weight.narrow(0, head_start, heads_per_rank)
                param.data.copy_(narrow_weight)
                loaded_params.add(name)
                continue
            for param_name, weight_name, shard_id in stacked_params_mapping:
                if weight_name not in name:
                    continue
                name = name.replace(weight_name, param_name)
                param = params_dict[name]
                weight_loader = getattr(param, "weight_loader", default_weight_loader)
                if weight_loader == default_weight_loader:
                    weight_loader(param, weight)
                else:
                    weight_loader(param, weight, shard_id)
                break
            else:
                # Handle all other weights with potential renaming
                if name not in params_dict:
                    continue
                param = params_dict[name]
                weight_loader = getattr(param, "weight_loader", default_weight_loader)
                weight_loader(param, weight)
            loaded_params.add(name)
        return loaded_params

    def _load_weights_other(
        self,
        ep_rank_end: int,
        ep_rank_start: int,
        heads_per_rank: int,
        head_start: int,
        weights: Iterable[tuple[str, torch.Tensor]],
        stacked_params_mapping: list[tuple[str, ...]],
    ) -> set[str]:
        params_dict = dict(self.named_parameters())
        loaded_params: set[str] = set()

        use_ep = self.parallel_config.enable_expert_parallel

        # In MoE, we need to flatten the tensor parallel size across the data
        # parallel size when EP is disabled.
        tp_size, tp_rank = FusedMoEParallelConfig.flatten_tp_across_dp_and_pcp(
            tp_size=get_tensor_model_parallel_world_size(),
            dp_size=get_dp_group().world_size,
            dp_rank=get_dp_group().rank_in_group,
            pcp_size=get_pcp_group().world_size,
            pcp_rank=get_pcp_group().rank_in_group,
        )

        intermediate_size = self.config.intermediate_size
        per_rank_intermediate_size = cdiv(intermediate_size, tp_size)
        # Calculate common slicing bounds for current rank
        tp_rank_start = tp_rank * per_rank_intermediate_size
        tp_rank_end = min((tp_rank + 1) * per_rank_intermediate_size, intermediate_size)

        for name, weight in weights:
            # Skip layers on other devices.
            if is_pp_missing_parameter(name, self):
                continue

            if ".w13_weight" in name:
                # Handle MLP gate and up projection weights
                # Extract gate and up projection parts
                if use_ep:
                    narrow_weight = weight[ep_rank_start:ep_rank_end, ...]
                else:
                    narrow_weight = weight[:, :, 2 * tp_rank_start : 2 * tp_rank_end]

                narrow_weight = narrow_weight.permute(0, 2, 1).contiguous()
                param = params_dict[name]

                param.copy_(narrow_weight)
                loaded_params.add(name)
                continue
            elif ".w2_weight" in name:
                # Handle MLP down projection weights
                if use_ep:
                    narrow_weight = weight[ep_rank_start:ep_rank_end, ...]
                else:
                    narrow_weight = weight[:, tp_rank_start:tp_rank_end, :]
                narrow_weight = narrow_weight.permute(0, 2, 1).contiguous()
                param = params_dict[name]

                param.copy_(narrow_weight)
                loaded_params.add(name)
                continue
            elif ".w13_bias" in name:
                # Handle MLP gate and up projection biases
                # Extract gate and up projection bias parts
                if use_ep:
                    narrow_weight = weight[ep_rank_start:ep_rank_end, ...]
                else:
                    narrow_weight = weight[:, 2 * tp_rank_start : 2 * tp_rank_end]

                param = params_dict[name]
                param.copy_(narrow_weight)
                loaded_params.add(name)
                continue
            elif ".w2_bias" in name:
                # Handle MLP down projection bias
                if use_ep:
                    weight = weight[ep_rank_start:ep_rank_end, ...]
                else:
                    # (only load on rank 0 to avoid duplication)
                    if tp_rank != 0:
                        weight.zero_()
                param = params_dict[name]
                param.copy_(weight)
                loaded_params.add(name)
                continue
            elif "sinks" in name:
                # Handle attention sinks (distributed across ranks)
                param = params_dict[name]
                narrow_weight = weight.narrow(0, head_start, heads_per_rank)
                param.data.copy_(narrow_weight)
                loaded_params.add(name)
                continue
            for param_name, weight_name, shard_id in stacked_params_mapping:
                if weight_name not in name:
                    continue
                name = name.replace(weight_name, param_name)
                param = params_dict[name]
                weight_loader = getattr(param, "weight_loader", default_weight_loader)
                if weight_loader == default_weight_loader:
                    weight_loader(param, weight)
                else:
                    weight_loader(param, weight, shard_id)
                break
            else:
                # Handle all other weights with potential renaming
                if name not in params_dict:
                    continue
                param = params_dict[name]
                weight_loader = getattr(param, "weight_loader", default_weight_loader)
                weight_loader(param, weight)
            loaded_params.add(name)
        return loaded_params

    def load_weights(self, weights: Iterable[tuple[str, torch.Tensor]]) -> set[str]:
        stacked_params_mapping = [
            # (param_name, shard_name, shard_id)
            (".qkv_proj", ".q_proj", "q"),
            (".qkv_proj", ".k_proj", "k"),
            (".qkv_proj", ".v_proj", "v"),
        ]

        tp_rank = get_tensor_model_parallel_rank()
        tp_size = get_tensor_model_parallel_world_size()

        # Attention heads per rank
        heads_per_rank = self.config.num_attention_heads // tp_size
        head_start = tp_rank * heads_per_rank

        ep_size = get_ep_group().world_size
        ep_rank = get_ep_group().rank
        num_experts = self.config.num_local_experts
        experts_per_rank = num_experts // ep_size
        ep_rank_start = ep_rank * experts_per_rank
        ep_rank_end = (ep_rank + 1) * experts_per_rank

        quant_method = (
            self.config.quantization_config["quant_method"]
            if hasattr(self.config, "quantization_config")
            else None
        )
        if quant_method == "mxfp4":
            return self._load_weights_mxfp4(
                ep_rank_end,
                ep_rank_start,
                heads_per_rank,
                head_start,
                weights,
                stacked_params_mapping,
            )
        else:
            return self._load_weights_other(
                ep_rank_end,
                ep_rank_start,
                heads_per_rank,
                head_start,
                weights,
                stacked_params_mapping,
            )


class GptOssForCausalLM(nn.Module, SupportsPP, SupportsEagle3, SupportsLoRA):
    is_3d_moe_weight: bool = True
    packed_modules_mapping = {"qkv_proj": ["q_proj", "k_proj", "v_proj"]}

    hf_to_vllm_mapper = WeightsMapper(
        orig_to_new_substr={
            ".self_attn.": ".attn.",
        },
        orig_to_new_suffix={
            ".embed_tokens.weight": ".embedding.weight",
            # MoE MXFP4 weights
            ".gate_up_proj_blocks": ".w13_weight",
            ".down_proj_blocks": ".w2_weight",
            ".gate_up_proj_scales": ".w13_weight_scale",
            ".down_proj_scales": ".w2_weight_scale",
            # MoE other weights
            ".gate_up_proj": ".w13_weight",
            ".down_proj": ".w2_weight",
            # MoE Bias
            ".gate_up_proj_bias": ".w13_bias",
            ".down_proj_bias": ".w2_bias",
        },
    )

    def __init__(
        self,
        vllm_config: VllmConfig,
        prefix: str = "",
    ):
        super().__init__()
        self.vllm_config = vllm_config
        self.config = vllm_config.model_config.hf_config

        self.model = GptOssModel(
            vllm_config=vllm_config,
            prefix=maybe_prefix(prefix, "model"),
        )
        self.lm_head = ParallelLMHead(
            self.config.vocab_size,
            self.config.hidden_size,
            prefix=maybe_prefix(prefix, "lm_head"),
        )
        self.logits_processor = LogitsProcessor(self.config.vocab_size)
        self.make_empty_intermediate_tensors = (
            self.model.make_empty_intermediate_tensors
        )

    def set_aux_hidden_state_layers(self, layers: tuple[int, ...]) -> None:
        self.model.aux_hidden_state_layers = layers

    def get_eagle3_aux_hidden_state_layers(self) -> tuple[int, ...]:
        num_layers = len(self.model.layers)
        return (2, num_layers // 2, num_layers - 3)

    def embed_input_ids(self, input_ids: torch.Tensor) -> torch.Tensor:
        return self.model.embed_input_ids(input_ids)

    def forward(
        self,
        input_ids: torch.Tensor | None,
        positions: torch.Tensor,
        intermediate_tensors: IntermediateTensors | None = None,
        inputs_embeds: torch.Tensor | None = None,
    ) -> torch.Tensor:
        return self.model(input_ids, positions, intermediate_tensors, inputs_embeds)

    def compute_logits(self, hidden_states: torch.Tensor) -> torch.Tensor:
        logits = self.logits_processor(self.lm_head, hidden_states)
        return logits

    def get_expert_mapping(self) -> list[tuple[str, str, int, str]]:
        # Params for weights, weight scales, activation scales
        # (param_name, weight_name, expert_id, shard_id)
        return FusedMoE.make_expert_params_mapping(
            self,
            ckpt_gate_proj_name="gate_proj",
            ckpt_down_proj_name="down_proj",
            ckpt_up_proj_name="up_proj",
            num_experts=self.config.num_local_experts,
            num_redundant_experts=0,
        )

    def load_weights(self, weights: Iterable[tuple[str, torch.Tensor]]) -> set[str]:
        loader = AutoWeightsLoader(
            self,
            skip_prefixes=(["lm_head."] if self.config.tie_word_embeddings else None),
        )
        return loader.load_weights(weights, mapper=self.hf_to_vllm_mapper)
