# Copyright (c) 2025 Huawei Technologies Co., Ltd. All Rights Reserved.
# Copyright 2024 The Qwen team.
# Copyright 2023 The vLLM team.
# Copyright 2022 EleutherAI and the HuggingFace Inc. team. All rights reserved. Copyright 2022 EleutherAI and the HuggingFace Inc. team. All rights reserved.
#
# 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,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# Adapted from vllm/model_executor/models/qwen3_moe.py
# This file is a part of the vllm-ascend project.

from typing import Optional

import torch
from torch import nn
from transformers import PretrainedConfig
from vllm.compilation.decorators import support_torch_compile
from vllm.config import CacheConfig, CompilationLevel, VllmConfig
from vllm.distributed import get_tensor_model_parallel_world_size
from vllm.distributed.parallel_state import (get_dp_group, get_ep_group,
                                             get_tp_group)
from vllm.forward_context import get_forward_context
from vllm.model_executor.layers.fused_moe.layer import FusedMoE
from vllm.model_executor.layers.layernorm import RMSNorm
from vllm.model_executor.layers.linear import ReplicatedLinear
from vllm.model_executor.layers.logits_processor import LogitsProcessor
from vllm.model_executor.layers.quantization import QuantizationConfig
from vllm.model_executor.layers.vocab_parallel_embedding import (
    ParallelLMHead, VocabParallelEmbedding)
from vllm.model_executor.models.interfaces import (MixtureOfExperts,
                                                   SupportsLoRA, SupportsPP)
from vllm.model_executor.models.qwen3_moe import (Qwen3MoeAttention,
                                                  Qwen3MoeDecoderLayer,
                                                  Qwen3MoeForCausalLM,
                                                  Qwen3MoeMLP, Qwen3MoeModel,
                                                  Qwen3MoeSparseMoeBlock)
from vllm.model_executor.models.utils import (
    PPMissingLayer, extract_layer_index,
    make_empty_intermediate_tensors_factory, make_layers, maybe_prefix)

from vllm_ascend.ops.fused_moe import AscendFusedMoE
from vllm_ascend.utils import vllm_version_is


class CustomSparseMoeBlock(Qwen3MoeSparseMoeBlock):

    def __init__(
        self,
        config: PretrainedConfig,
        quant_config: Optional[QuantizationConfig] = None,
        prefix: str = "",
    ):
        nn.Module.__init__(self)
        self.tp_size = get_tensor_model_parallel_world_size()
        if self.tp_size > config.num_experts:
            raise ValueError(
                f"Tensor parallel size {self.tp_size} is greater than "
                f"the number of experts {config.num_experts}.")

        self.gate = ReplicatedLinear(
            config.hidden_size,
            config.num_experts,
            bias=False,
            quant_config=None,
            prefix=f"{prefix}.gate",
        )

        self.experts = AscendFusedMoE(
            num_experts=config.num_experts,
            top_k=config.num_experts_per_tok,
            hidden_size=config.hidden_size,
            intermediate_size=config.moe_intermediate_size,
            reduce_results=False,
            renormalize=config.norm_topk_prob,
            quant_config=quant_config,
            prefix=f"{prefix}.experts",
        )

        self.top_k = config.num_experts_per_tok

        self.dp_size = get_dp_group().world_size

        self.tp_group = get_tp_group().device_group
        self.tp_rank = get_tp_group().rank_in_group
        self.ep_group = get_ep_group()

        self.params_dtype = torch.get_default_dtype()

    def forward(
        self,
        hidden_states,
        attn_metadata=None,
    ):
        if attn_metadata is None:
            attn_metadata = get_forward_context().attn_metadata
        # when profile runs, force experts to load balanced tokens
        # to avoid high memory consumption on a single rank.
        enable_force_load_balance = get_forward_context().in_profile_run
        is_prefill = get_forward_context().with_prefill

        # router_logits: (num_tokens, n_experts)
        router_logits, _ = self.gate(hidden_states)

        hidden_states = self.experts(
            hidden_states=hidden_states,
            router_logits=router_logits,
            is_prefill=is_prefill,
            top_k=self.top_k,
            enable_force_load_balance=enable_force_load_balance,
            shared_experts=None,
        )

        return hidden_states


class CustomQwen3MoeDecoderLayer(Qwen3MoeDecoderLayer):

    def __init__(
        self,
        config: PretrainedConfig,
        cache_config: Optional[CacheConfig] = None,
        quant_config: Optional[QuantizationConfig] = None,
        vllm_config: Optional[VllmConfig] = None,
        prefix: str = "",
    ) -> None:

        nn.Module.__init__(self)
        self.hidden_size = config.hidden_size
        rope_theta = getattr(config, "rope_theta", 10000)
        rope_scaling = getattr(config, "rope_scaling", None)
        max_position_embeddings = getattr(config, "max_position_embeddings",
                                          8192)
        self.self_attn = Qwen3MoeAttention(
            hidden_size=self.hidden_size,
            num_heads=config.num_attention_heads,
            num_kv_heads=config.num_key_value_heads,
            rope_theta=rope_theta,
            rope_scaling=rope_scaling,
            max_position_embeddings=max_position_embeddings,
            rms_norm_eps=config.rms_norm_eps,
            qkv_bias=getattr(config, 'attention_bias', False),
            head_dim=getattr(config, 'head_dim', None),
            cache_config=cache_config,
            quant_config=quant_config,
            prefix=f"{prefix}.self_attn",
        )

        # `mlp_only_layers` in the config.
        layer_idx = extract_layer_index(prefix)
        mlp_only_layers = ([] if not hasattr(config, "mlp_only_layers") else
                           config.mlp_only_layers)
        self.use_aclgraph = (vllm_config is not None
                             and vllm_config.compilation_config.level
                             == CompilationLevel.PIECEWISE
                             and not vllm_config.model_config.enforce_eager)
        if (layer_idx not in mlp_only_layers) and (
                config.num_experts > 0 and
            (layer_idx + 1) % config.decoder_sparse_step == 0):
            if not self.use_aclgraph:
                # FIXME: custom sparse moe block doesn't work with aclgraph.
                self.mlp = CustomSparseMoeBlock(config=config,
                                                quant_config=quant_config,
                                                prefix=f"{prefix}.mlp")
            else:
                if vllm_version_is("0.10.2"):
                    self.mlp = Qwen3MoeSparseMoeBlock(
                        config=config,
                        quant_config=quant_config,
                        prefix=f"{prefix}.mlp")
                else:
                    self.mlp = Qwen3MoeSparseMoeBlock(vllm_config=vllm_config,
                                                      prefix=f"{prefix}.mlp")
        else:
            self.mlp = Qwen3MoeMLP(hidden_size=config.hidden_size,
                                   intermediate_size=config.intermediate_size,
                                   hidden_act=config.hidden_act,
                                   quant_config=quant_config,
                                   prefix=f"{prefix}.mlp")
        self.input_layernorm = RMSNorm(config.hidden_size,
                                       eps=config.rms_norm_eps)
        self.post_attention_layernorm = RMSNorm(config.hidden_size,
                                                eps=config.rms_norm_eps)


@support_torch_compile
class CustomQwen3MoeModel(Qwen3MoeModel):

    def __init__(self, *, vllm_config: VllmConfig, prefix: str = ""):
        nn.Module.__init__(self)
        config = vllm_config.model_config.hf_config
        cache_config = vllm_config.cache_config
        quant_config = vllm_config.quant_config

        parallel_config = vllm_config.parallel_config
        eplb_config = parallel_config.eplb_config
        self.num_redundant_experts = eplb_config.num_redundant_experts
        self.padding_idx = config.pad_token_id
        self.vocab_size = config.vocab_size
        self.config = config
        self.embed_tokens = VocabParallelEmbedding(
            config.vocab_size,
            config.hidden_size,
            prefix=f"{prefix}.embed_tokens")
        self.start_layer, self.end_layer, self.layers = make_layers(
            config.num_hidden_layers,
            lambda prefix: CustomQwen3MoeDecoderLayer(
                config=config,
                cache_config=cache_config,
                quant_config=quant_config,
                vllm_config=vllm_config,
                prefix=prefix),
            prefix=f"{prefix}.layers",
        )
        self.norm = RMSNorm(config.hidden_size, eps=config.rms_norm_eps)
        self.make_empty_intermediate_tensors = (
            make_empty_intermediate_tensors_factory(
                ["hidden_states", "residual"], config.hidden_size))


class CustomQwen3MoeForCausalLM(Qwen3MoeForCausalLM):

    def __init__(self, *, vllm_config: VllmConfig, prefix: str = ""):
        nn.Module.__init__(self)
        SupportsPP.__init__(self)
        SupportsLoRA.__init__(self)
        MixtureOfExperts.__init__(self)
        config = vllm_config.model_config.hf_config
        quant_config = vllm_config.quant_config
        self.config = config
        self.quant_config = quant_config
        self.model = CustomQwen3MoeModel(vllm_config=vllm_config,
                                         prefix=maybe_prefix(prefix, "model"))
        self.lm_head = ParallelLMHead(config.vocab_size,
                                      config.hidden_size,
                                      quant_config=quant_config,
                                      prefix=maybe_prefix(prefix, "lm_head"))
        if self.config.tie_word_embeddings:
            self.lm_head.weight = self.model.embed_tokens.weight
        self.logits_processor = LogitsProcessor(config.vocab_size)
        self.make_empty_intermediate_tensors = (
            self.model.make_empty_intermediate_tensors)

        # Set MoE hyperparameters
        self.expert_weights: list[torch.Tensor] = []

        self.moe_layers: list[FusedMoE] = []
        example_layer = None
        for layer in self.model.layers:
            if isinstance(layer, PPMissingLayer):
                continue

            assert isinstance(layer, Qwen3MoeDecoderLayer)
            if isinstance(layer.mlp, Qwen3MoeSparseMoeBlock):
                example_layer = layer.mlp
                self.moe_layers.append(layer.mlp.experts)

        if example_layer is None:
            raise RuntimeError("No Qwen3MoE layer found in the model.layers.")

        self.num_moe_layers = len(self.moe_layers)
        self.num_expert_groups = 1
        self.num_shared_experts = 0
