'''
Description  :  
Author       : Boxin Zhang
Version      : 0.2.5
Copyright (c) 2024 by KVCache.AI, All Rights Reserved. 
'''
import torch
from torch import nn
from ktransformers.models.modeling_deepseek import DeepseekV2Attention, apply_rotary_pos_emb
from ktransformers.models.modeling_qwen2_moe import Qwen2MoeAttention
from ktransformers.models.modeling_qwen3_moe import Qwen3MoeAttention
from typing import Optional, Tuple
from ktransformers.operators.base_operator import BaseInjectedModule
from ktransformers.util.custom_loader import GGUFLoader
import logging
from transformers.configuration_utils import PretrainedConfig
from flashinfer import BatchMLAPagedAttentionWrapper
from ktransformers.operators.flashinfer_batch_prefill_wrapper import flashInferAttn
from ktransformers.models.custom_cache import KDeepSeekV3Cache, KGQACache
logger = logging.getLogger("attention")

# Copied from transformers.models.llama.modeling_llama.rotate_half
def rotate_half(x):
    """Rotates half the hidden dims of the input."""
    x1 = x[..., : x.shape[-1] // 2]
    x2 = x[..., x.shape[-1] // 2 :]
    return torch.cat((-x2, x1), dim=-1)

class flashinfer_attn(BaseInjectedModule, DeepseekV2Attention):
    def __init__(self,
                 key: str,
                 gguf_loader : GGUFLoader,
                 config: PretrainedConfig,
                 orig_module: nn.Module,
                 prefill_device: str = "cuda",
                 generate_device: str = "cuda",
                 chunck_size: int = 1000,
                 **kwargs):
        BaseInjectedModule.__init__(self, key, gguf_loader, config, orig_module, prefill_device, **kwargs)
        self.orig_module.__init__(orig_module.config,
            orig_module.layer_idx)
        self.chunck_size = chunck_size # TODO, generate chunck_size automatically.


    def get_absorbed(self) -> Tuple[torch.Tensor, torch.Tensor]:
        if not (hasattr(self, 'q_absorb') and hasattr(self, 'out_absorb')):
            kv_b_proj = self.kv_b_proj.weight.view(self.num_heads, -1, self.kv_lora_rank)
            q_absorb = kv_b_proj[:, :self.qk_nope_head_dim, :].reshape(-1, self.kv_lora_rank)
            out_absorb = kv_b_proj[:, self.qk_nope_head_dim:, :].reshape(-1, self.kv_lora_rank)
            self.q_absorb = nn.Linear(self.kv_lora_rank, self.num_heads * self.qk_nope_head_dim, 
                                      bias=False, dtype=q_absorb.dtype, device=q_absorb.device)
            self.q_absorb.weight.data = q_absorb
            self.out_absorb = nn.Linear(self.kv_lora_rank, self.num_heads * self.v_head_dim, 
                                        bias=False, dtype=out_absorb.dtype, device=out_absorb.device)
            self.out_absorb.weight.data = out_absorb
            #del self.orig_module.kv_b_proj
        q_absorb = self.q_absorb.weight.view(self.num_heads, self.qk_nope_head_dim, self.kv_lora_rank)
        out_absorb = self.out_absorb.weight.view(self.num_heads, self.v_head_dim, self.kv_lora_rank)
        return q_absorb, out_absorb
    

    def forward(self,
                hidden_states: torch.Tensor,
                kv_cache: KDeepSeekV3Cache,
                position_ids: torch.Tensor,
                wrapper: BatchMLAPagedAttentionWrapper,
                num_tokens_tensors: torch.Tensor,
                page_idx: torch.Tensor,
                page_offset: torch.Tensor,
                ):
        q_len, _ = hidden_states.size()

        if self.q_lora_rank is None:
            q = self.q_proj(hidden_states, num_tokens_tensors)
        else:
            q = self.q_b_proj(self.q_a_layernorm(self.q_a_proj(hidden_states, num_tokens_tensors), num_tokens_tensors), num_tokens_tensors)
        q = q.view(q_len, self.num_heads, self.q_head_dim)
        q_nope, q_pe = torch.split(
            q, [self.qk_nope_head_dim, self.qk_rope_head_dim], dim=-1
        )

        compressed_kv = self.kv_a_proj_with_mqa(hidden_states, num_tokens_tensors)
        compressed_kv, k_pe = torch.split(
            compressed_kv, [self.kv_lora_rank, self.qk_rope_head_dim], dim=-1
        )
        compressed_kv = compressed_kv.contiguous()
        compressed_kv = self.kv_a_layernorm(compressed_kv, num_tokens_tensors)
        k_pe = k_pe.view(q_len, 1, self.qk_rope_head_dim)
        compressed_kv = compressed_kv.view(q_len, 1, self.kv_lora_rank)
        
        cos, sin = self.rotary_emb(q_pe, position_ids.unsqueeze(0))
        q_pe, k_pe = apply_rotary_pos_emb(q_pe.unsqueeze(0), k_pe.unsqueeze(0), cos, sin, unsqueeze_dim=2)
        q_pe = q_pe.squeeze(0)
        if kv_cache is not None:
            
            # page_idx, page_offset = kv_cache.get_page_table(position_ids, q_indptr, kv_indptr, kv_indices)
            cache_kwargs = {"sin": sin, "cos": cos, "page_idx": page_idx, "page_offset": page_offset}  # Specific to RoPE models
            compressed_kv_with_k_pe = kv_cache.update(compressed_kv.unsqueeze(0), k_pe, self.layer_idx, page_idx, page_offset, cache_kwargs)
            compressed_kv = compressed_kv_with_k_pe [:, :, :, :self.kv_lora_rank].view(-1, kv_cache.page_size, self.kv_lora_rank)
            k_pe = compressed_kv_with_k_pe [:, :, :, self.kv_lora_rank:].view(-1, kv_cache.page_size, self.qk_rope_head_dim)
            
        q_absorb, out_absorb = self.get_absorbed()
        q_nope = q_nope.transpose(0, 1) # q_len is 1, no GPU overhead, same below
        q_nope = torch.matmul(q_nope, q_absorb) # batched MM
        q_nope = q_nope.transpose(0, 1)
        # q_nope.squeeze_(1)
        # q_pe.squeeze_(1)

        attn_output = wrapper.run(q_nope, q_pe, compressed_kv, k_pe).view(q_len, self.num_heads, self.kv_lora_rank)
        attn_output = attn_output.transpose(0, 1)
        attn_output = torch.matmul(attn_output, out_absorb.mT) # [self.num_heads, q_len, self.v_head_dim]
        attn_output = attn_output.transpose(0, 1)
        attn_output = attn_output.reshape(q_len, self.num_heads * self.v_head_dim)
        attn_output = self.o_proj(attn_output, num_tokens_tensors)
        return attn_output

class KQwen2MoeAttention(BaseInjectedModule, Qwen2MoeAttention):
    def __init__(self,
                 key: str,
                 gguf_loader : GGUFLoader,
                 config: PretrainedConfig,
                 orig_module: nn.Module,
                 prefill_device: str = "cuda",
                 generate_device: str = "cuda",
                 chunck_size: int = 1000,
                 **kwargs):
        BaseInjectedModule.__init__(self, key, gguf_loader, config, orig_module, prefill_device, **kwargs)
        self.orig_module.__init__(orig_module.config,
            orig_module.layer_idx)
        self.chunck_size = chunck_size # TODO, generate chunck_size automatically.


    # Copied from transformers.models.mistral.modeling_mistral.apply_rotary_pos_emb
    def apply_rotary_pos_emb(self, q, k, cos, sin, position_ids=None, unsqueeze_dim=1):
        """Applies Rotary Position Embedding to the query and key tensors.

        Args:
            q (`torch.Tensor`): The query tensor.
            k (`torch.Tensor`): The key tensor.
            cos (`torch.Tensor`): The cosine part of the rotary embedding.
            sin (`torch.Tensor`): The sine part of the rotary embedding.
            position_ids (`torch.Tensor`):
                Deprecated and unused.
            unsqueeze_dim (`int`, *optional*, defaults to 1):
                The 'unsqueeze_dim' argument specifies the dimension along which to unsqueeze cos[position_ids] and
                sin[position_ids] so that they can be properly broadcasted to the dimensions of q and k. For example, note
                that cos[position_ids] and sin[position_ids] have the shape [batch_size, seq_len, head_dim]. Then, if q and
                k have the shape [batch_size, heads, seq_len, head_dim], then setting unsqueeze_dim=1 makes
                cos[position_ids] and sin[position_ids] broadcastable to the shapes of q and k. Similarly, if q and k have
                the shape [batch_size, seq_len, heads, head_dim], then set unsqueeze_dim=2.
        Returns:
            `tuple(torch.Tensor)` comprising of the query and key tensors rotated using the Rotary Position Embedding.
        """
        cos = cos.unsqueeze(unsqueeze_dim)
        sin = sin.unsqueeze(unsqueeze_dim)
        q_embed = (q * cos) + (rotate_half(q) * sin)
        k_embed = (k * cos) + (rotate_half(k) * sin)
        return q_embed, k_embed


    def forward(self,
                hidden_states: torch.Tensor,
                kv_cache: KGQACache,
                position_ids: torch.Tensor,
                wrapper: flashInferAttn,
                bsz_tensors: torch.Tensor,
                page_idx: torch.Tensor,
                page_offset: torch.Tensor,
                ):
        q_len, _ = hidden_states.size()

        query_states = self.q_proj(hidden_states, bsz_tensors)
        key_states = self.k_proj(hidden_states, bsz_tensors)
        value_states = self.v_proj(hidden_states, bsz_tensors)


        query_states = query_states.view(q_len, self.num_heads, self.head_dim)
        key_states = key_states.view(q_len, self.num_key_value_heads, self.head_dim)
        value_states = value_states.view(q_len, self.num_key_value_heads, self.head_dim)
        
        cos, sin = self.rotary_emb(value_states.unsqueeze(0), position_ids.unsqueeze(0))
        query_states, key_states = self.apply_rotary_pos_emb(query_states.unsqueeze(0), key_states.unsqueeze(0), cos, sin, unsqueeze_dim=2)

        query_states = query_states.view(q_len, self.num_heads, self.head_dim)
        key_states = key_states.view(
            q_len, self.num_key_value_heads, self.head_dim
        )
        value_states = value_states.view(
            q_len, self.num_key_value_heads, self.head_dim
        )

        k_cache = kv_cache.get_k_cache(self.layer_idx)
        v_cache = kv_cache.get_v_cache(self.layer_idx)


        attn_output = wrapper.forward(query_states, k_cache, v_cache, key_states, value_states)
  

        attn_output = self.o_proj(attn_output.view(q_len, self.num_heads * self.head_dim), bsz_tensors)

        return attn_output

class KQwen3MoeAttention(BaseInjectedModule, Qwen3MoeAttention):
    def __init__(self,
                 key: str,
                 gguf_loader : GGUFLoader,
                 config: PretrainedConfig,
                 orig_module: nn.Module,
                 prefill_device: str = "cuda",
                 generate_device: str = "cuda",
                 chunck_size: int = 1000,
                 **kwargs):
        BaseInjectedModule.__init__(self, key, gguf_loader, config, orig_module, prefill_device, **kwargs)
        self.orig_module.__init__(orig_module.config,
            orig_module.layer_idx)
        self.chunck_size = chunck_size # TODO, generate chunck_size automatically.


    # Copied from transformers.models.mistral.modeling_mistral.apply_rotary_pos_emb
    def apply_rotary_pos_emb(self, q, k, cos, sin, position_ids=None, unsqueeze_dim=1):
        """Applies Rotary Position Embedding to the query and key tensors.

        Args:
            q (`torch.Tensor`): The query tensor.
            k (`torch.Tensor`): The key tensor.
            cos (`torch.Tensor`): The cosine part of the rotary embedding.
            sin (`torch.Tensor`): The sine part of the rotary embedding.
            position_ids (`torch.Tensor`):
                Deprecated and unused.
            unsqueeze_dim (`int`, *optional*, defaults to 1):
                The 'unsqueeze_dim' argument specifies the dimension along which to unsqueeze cos[position_ids] and
                sin[position_ids] so that they can be properly broadcasted to the dimensions of q and k. For example, note
                that cos[position_ids] and sin[position_ids] have the shape [batch_size, seq_len, head_dim]. Then, if q and
                k have the shape [batch_size, heads, seq_len, head_dim], then setting unsqueeze_dim=1 makes
                cos[position_ids] and sin[position_ids] broadcastable to the shapes of q and k. Similarly, if q and k have
                the shape [batch_size, seq_len, heads, head_dim], then set unsqueeze_dim=2.
        Returns:
            `tuple(torch.Tensor)` comprising of the query and key tensors rotated using the Rotary Position Embedding.
        """
        cos = cos.unsqueeze(unsqueeze_dim)
        sin = sin.unsqueeze(unsqueeze_dim)
        q_embed = (q * cos) + (rotate_half(q) * sin)
        k_embed = (k * cos) + (rotate_half(k) * sin)
        return q_embed, k_embed


    def forward(self,
                hidden_states: torch.Tensor,
                kv_cache: KGQACache,
                position_ids: torch.Tensor,
                wrapper: flashInferAttn,
                bsz_tensors: torch.Tensor,
                page_idx: torch.Tensor,
                page_offset: torch.Tensor,
                ):
        q_len, _ = hidden_states.size()

        bsz_tensors_q = bsz_tensors * self.num_heads
        bsz_tensors_kv = bsz_tensors * self.num_key_value_heads

        query_states = self.q_norm(self.q_proj(hidden_states, bsz_tensors), bsz_tensors_q)
        key_states = self.k_norm(self.k_proj(hidden_states, bsz_tensors), bsz_tensors_kv)
        value_states = self.v_proj(hidden_states, bsz_tensors)


        query_states = query_states.view(q_len, self.num_heads, self.head_dim)
        key_states = key_states.view(q_len, self.num_key_value_heads, self.head_dim)
        value_states = value_states.view(q_len, self.num_key_value_heads, self.head_dim)
        
        cos, sin = self.rotary_emb(value_states.unsqueeze(0), position_ids.unsqueeze(0))
        query_states, key_states = self.apply_rotary_pos_emb(query_states.unsqueeze(0), key_states.unsqueeze(0), cos, sin, unsqueeze_dim=2)

        query_states = query_states.view(q_len, self.num_heads, self.head_dim)
        key_states = key_states.view(
            q_len, self.num_key_value_heads, self.head_dim
        )
        value_states = value_states.view(
            q_len, self.num_key_value_heads, self.head_dim
        )

        k_cache = kv_cache.get_k_cache(self.layer_idx)
        v_cache = kv_cache.get_v_cache(self.layer_idx)


        attn_output = wrapper.forward(query_states, k_cache, v_cache, key_states, value_states)
  

        attn_output = self.o_proj(attn_output.view(q_len, self.num_heads * self.head_dim), bsz_tensors)

        return attn_output