# Copyright 2024 Bytedance Ltd. and/or its affiliates
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
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# To support different vLLM versions, we add the model into SUPPORTED_MOE_MODELS separately to avoid triggering unsupported issues.
SUPPORTED_MOE_MODELS = []

try:
    from vllm.model_executor.models.deepseek_v2 import DeepseekV2ForCausalLM, DeepseekV3ForCausalLM
    SUPPORTED_MOE_MODELS.append(DeepseekV2ForCausalLM)
    SUPPORTED_MOE_MODELS.append(DeepseekV3ForCausalLM)
except ImportError:
    pass

try:
    from vllm.model_executor.models.mixtral import MixtralForCausalLM
    SUPPORTED_MOE_MODELS.append(MixtralForCausalLM)
except ImportError:
    pass

try:
    from vllm.model_executor.models.qwen2_moe import Qwen2MoeForCausalLM
    SUPPORTED_MOE_MODELS.append(Qwen2MoeForCausalLM)
except ImportError:
    pass

try:
    from vllm.model_executor.models.qwen3_moe import Qwen3MoeForCausalLM
    SUPPORTED_MOE_MODELS.append(Qwen3MoeForCausalLM)
except ImportError:
    pass


def patch_vllm_moe_model_weight_loader(model):
    # this is a work around to load the weight of vllm fused moe model
    # it is from a bug from vllm 0.8.2
    # all the weights are supposed to have a weight_loader, but the moe weights
    # do not have a weight_loader, so we need to patch it
    # (True, 'model.embed_tokens.weight')
    # (True, 'model.layers.0.self_attn.qkv_proj.weight')
    # (True, 'model.layers.0.self_attn.qkv_proj.bias')
    # (True, 'model.layers.0.self_attn.o_proj.weight')
    # (True, 'model.layers.0.mlp.gate.weight')
    # (True, 'model.layers.0.mlp.shared_expert.gate_up_proj.weight')
    # (True, 'model.layers.0.mlp.shared_expert.down_proj.weight')
    # (False, 'model.layers.0.mlp.shared_expert_gate.weight')   use default
    # (False, 'model.layers.0.input_layernorm.weight')          use default
    # (False, 'model.layers.0.post_attention_layernorm.weight') use default
    # (False, 'model.layers.0.mlp.experts.w13_weight')          use mlp.experts.weight_loader
    # (False, 'model.layers.0.mlp.experts.w2_weight')          use mlp.experts.weight_loader

    # Define MLP attribute mapping for different model types
    MLP_ATTR_MAPPING = {
        MixtralForCausalLM: "block_sparse_moe",
    }
    DEFAULT_MLP_ATTR = "mlp"

    if not isinstance(model, tuple(SUPPORTED_MOE_MODELS)):
        return

    for layer in model.model.layers:
        mlp_attr = MLP_ATTR_MAPPING.get(type(model), DEFAULT_MLP_ATTR)
        mlp = getattr(layer, mlp_attr)

        param_dict = dict(mlp.named_parameters())
        for name, param in param_dict.items():
            if "w13_weight" in name or "w2_weight" in name:
                param.weight_loader = mlp.experts.weight_loader