# Copyright (c) The mmMamba team and The HuggingFace Inc. team. All rights reserved.
#
# This code is based on transformers/src/transformers/models/llama/modeling_llama.py
#
# 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.
import math
import queue
import threading
import warnings
from typing import List, Optional, Tuple, Union

import torch
import torch.nn.functional as F
import torch.utils.checkpoint
from einops import rearrange
from torch import nn
from torch.nn import CrossEntropyLoss
from transformers.activations import ACT2FN
from transformers.modeling_outputs import (BaseModelOutputWithPast,
                                           CausalLMOutputWithPast)
from transformers.modeling_utils import PreTrainedModel
from transformers.utils import (add_start_docstrings,
                                add_start_docstrings_to_model_forward, logging,
                                replace_return_docstrings)
from fused_norm_gate import FusedRMSNormSwishGate

from mamba_ssm.ops.triton.ssd_combined import mamba_chunk_scan_combined
from mamba_ssm.ops.triton.selective_state_update import selective_state_update
from causal_conv1d import causal_conv1d_fn, causal_conv1d_update


try:
    from transformers.generation.streamers import BaseStreamer
except:  # noqa # pylint: disable=bare-except
    BaseStreamer = None

from .configuration_mmMamba import mmMambaConfig

logger = logging.get_logger(__name__)

_CONFIG_FOR_DOC = 'mmMambaConfig'

flash_attn_func, flash_attn_varlen_func = None, None
pad_input, index_first_axis, unpad_input = None, None, None
try:
    from flash_attn import flash_attn_func as _flash_attn_func
    from flash_attn import flash_attn_varlen_func as _flash_attn_varlen_func
    from flash_attn.bert_padding import index_first_axis as _index_first_axis
    from flash_attn.bert_padding import pad_input as _pad_input
    from flash_attn.bert_padding import unpad_input as _unpad_input

    flash_attn_func, flash_attn_varlen_func = _flash_attn_func, _flash_attn_varlen_func
    pad_input, index_first_axis, unpad_input = _pad_input, _index_first_axis, _unpad_input
    has_flash_attn = True
except:
    has_flash_attn = False

try:
    from flash_attn import flash_attn_with_kvcache
except ImportError:
    flash_attn_with_kvcache = None

try:
    from flash_attn.layers.rotary import RotaryEmbedding
except ImportError:
    RotaryEmbedding = None

import torch.nn.functional as F

def _update_kv_cache(kv, inference_params, layer_idx):
    """kv: (batch_size, seqlen, 2, nheads, head_dim) or (batch_size, 1, 2, nheads, head_dim)"""
    # Pre-allocate memory for key-values for inference.
    num_heads, head_dim = kv.shape[-2:]
    assert layer_idx in inference_params.key_value_memory_dict
    kv_cache, _ = inference_params.key_value_memory_dict[layer_idx]
    # Adjust key and value for inference
    batch_start = inference_params.batch_size_offset
    batch_end = batch_start + kv.shape[0]
    sequence_start = inference_params.seqlen_offset
    sequence_end = sequence_start + kv.shape[1]
    assert batch_end <= kv_cache.shape[0]
    assert sequence_end <= kv_cache.shape[1]
    assert kv_cache is not None
    kv_cache[batch_start:batch_end, sequence_start:sequence_end, ...] = kv
    return kv_cache[batch_start:batch_end, :sequence_end, ...]

def _import_flash_attn():
    global flash_attn_func, flash_attn_varlen_func
    global pad_input, index_first_axis, unpad_input
    try:
        from flash_attn import flash_attn_func as _flash_attn_func
        from flash_attn import \
            flash_attn_varlen_func as _flash_attn_varlen_func
        from flash_attn.bert_padding import \
            index_first_axis as _index_first_axis
        from flash_attn.bert_padding import pad_input as _pad_input
        from flash_attn.bert_padding import unpad_input as _unpad_input
        flash_attn_func, flash_attn_varlen_func = _flash_attn_func, _flash_attn_varlen_func
        pad_input, index_first_axis, unpad_input = _pad_input, _index_first_axis, _unpad_input
    except ImportError:
        raise ImportError('flash_attn is not installed.')


# Copied from transformers.models.llama.modeling_llama.LlamaRMSNorm with Llama->mmMamba
class mmMambaRMSNorm(nn.Module):
    def __init__(self, hidden_size, eps=1e-6):
        """
        mmMambaRMSNorm is equivalent to T5LayerNorm
        """
        super().__init__()
        self.weight = nn.Parameter(torch.ones(hidden_size))
        self.variance_epsilon = eps

    def forward(self, hidden_states):
        input_dtype = hidden_states.dtype
        hidden_states = hidden_states.to(torch.float32)
        variance = hidden_states.pow(2).mean(-1, keepdim=True)
        hidden_states = hidden_states * torch.rsqrt(variance + self.variance_epsilon)
        return self.weight * hidden_states.to(input_dtype)


# Copied from transformers.model.llama.modeling_llama.LlamaRotaryEmbedding with Llama->mmMamba
class mmMambaRotaryEmbedding(nn.Module):
    def __init__(self, dim, max_position_embeddings=2048, base=10000, device=None):
        super().__init__()

        self.dim = dim
        self.max_position_embeddings = max_position_embeddings
        self.base = base
        inv_freq = 1.0 / (self.base ** (torch.arange(0, self.dim, 2).float().to(device) / self.dim))
        self.register_buffer('inv_freq', inv_freq, persistent=False)

        # Build here to make `torch.jit.trace` work.
        self._set_cos_sin_cache(
            seq_len=max_position_embeddings, device=self.inv_freq.device, dtype=torch.get_default_dtype()
        )

    def _set_cos_sin_cache(self, seq_len, device, dtype):
        self.max_seq_len_cached = seq_len
        t = torch.arange(self.max_seq_len_cached, device=device).to(dtype=self.inv_freq.dtype)

        freqs = torch.einsum('i,j->ij', t, self.inv_freq)
        # Different from paper, but it uses a different permutation in order to obtain the same calculation
        emb = torch.cat((freqs, freqs), dim=-1)
        self.register_buffer('cos_cached', emb.cos().to(dtype), persistent=False)
        self.register_buffer('sin_cached', emb.sin().to(dtype), persistent=False)

    def forward(self, x, seq_len=None):
        # x: [bs, num_attention_heads, seq_len, head_size]
        if seq_len > self.max_seq_len_cached:
            self._set_cos_sin_cache(seq_len=seq_len, device=x.device, dtype=torch.float32)

        return (
            self.cos_cached[:seq_len].to(dtype=x.dtype),
            self.sin_cached[:seq_len].to(dtype=x.dtype),
        )


# Copied from transformers.model.llama.modeling_llama.LlamaLinearScalingRotaryEmbedding with Llama->mmMamba
class mmMambaLinearScalingRotaryEmbedding(mmMambaRotaryEmbedding):
    """mmMambaRotaryEmbedding extended with linear scaling. Credits to the Reddit user /u/kaiokendev"""

    def __init__(self, dim, max_position_embeddings=2048, base=10000, device=None, scaling_factor=1.0):
        self.scaling_factor = scaling_factor
        super().__init__(dim, max_position_embeddings, base, device)

    def _set_cos_sin_cache(self, seq_len, device, dtype):
        self.max_seq_len_cached = seq_len
        t = torch.arange(self.max_seq_len_cached, device=device).to(dtype=self.inv_freq.dtype)
        t = t / self.scaling_factor

        freqs = torch.einsum('i,j->ij', t, self.inv_freq)
        # Different from paper, but it uses a different permutation in order to obtain the same calculation
        emb = torch.cat((freqs, freqs), dim=-1)
        self.register_buffer('cos_cached', emb.cos().to(dtype), persistent=False)
        self.register_buffer('sin_cached', emb.sin().to(dtype), persistent=False)


# Copied from transformers.model.llama.modeling_llama.LlamaDynamicNTKScalingRotaryEmbedding with Llama->mmMamba
class mmMambaDynamicNTKScalingRotaryEmbedding(mmMambaRotaryEmbedding):
    """mmMambaRotaryEmbedding extended with Dynamic NTK scaling.
    Credits to the Reddit users /u/bloc97 and /u/emozilla.
    """

    def __init__(self, dim, max_position_embeddings=2048, base=10000, device=None, scaling_factor=1.0):
        self.scaling_factor = scaling_factor
        super().__init__(dim, max_position_embeddings, base, device)

    def _set_cos_sin_cache(self, seq_len, device, dtype):
        self.max_seq_len_cached = seq_len

        if seq_len > self.max_position_embeddings:
            base = self.base * (
                (self.scaling_factor * seq_len / self.max_position_embeddings) - (self.scaling_factor - 1)
            ) ** (self.dim / (self.dim - 2))
            inv_freq = 1.0 / (base ** (torch.arange(0, self.dim, 2).float().to(device) / self.dim))
            self.register_buffer('inv_freq', inv_freq, persistent=False)

        t = torch.arange(self.max_seq_len_cached, device=device).to(dtype=self.inv_freq.dtype)

        freqs = torch.einsum('i,j->ij', t, self.inv_freq)
        # Different from paper, but it uses a different permutation in order to obtain the same calculation
        emb = torch.cat((freqs, freqs), dim=-1)
        self.register_buffer('cos_cached', emb.cos().to(dtype), persistent=False)
        self.register_buffer('sin_cached', emb.sin().to(dtype), persistent=False)



class mmMambaMLP(nn.Module):
    def __init__(self, config):
        super().__init__()
        self.config = config
        self.hidden_size = config.hidden_size
        self.intermediate_size = config.intermediate_size
        self.w1 = nn.Linear(self.hidden_size, self.intermediate_size, bias=False)
        self.w3 = nn.Linear(self.hidden_size, self.intermediate_size, bias=False)
        self.w2 = nn.Linear(self.intermediate_size, self.hidden_size, bias=False)
        self.act_fn = ACT2FN[config.hidden_act]

    def forward(self, x):
        down_proj = self.w2(self.act_fn(self.w1(x)) * self.w3(x))

        return down_proj


# Copied from transformers.model.llama.modeling_llama.repeat_kv
def repeat_kv(hidden_states: torch.Tensor, n_rep: int) -> torch.Tensor:
    """
    This is the equivalent of torch.repeat_interleave(x, dim=1, repeats=n_rep). The hidden states go from (batch,
    num_key_value_heads, seqlen, head_dim) to (batch, num_attention_heads, seqlen, head_dim)
    """
    batch, num_key_value_heads, slen, head_dim = hidden_states.shape
    if n_rep == 1:
        return hidden_states
    hidden_states = hidden_states[:, :, None, :, :].expand(batch, num_key_value_heads, n_rep, slen, head_dim)
    return hidden_states.reshape(batch, num_key_value_heads * n_rep, slen, head_dim)

def repeat_kv2(hidden_states: torch.Tensor, n_rep: int) -> torch.Tensor:
    """
    This is the equivalent of torch.repeat_interleave(x, dim=1, repeats=n_rep). The hidden states go from (batch,
    num_key_value_heads, seqlen, head_dim) to (batch, num_attention_heads, seqlen, head_dim)
    """
    batch, num_key_value_heads, head_dim = hidden_states.shape
    if n_rep == 1:
        return hidden_states
    hidden_states = hidden_states[:, :, None,  :].expand(batch, num_key_value_heads, n_rep, head_dim)
    return hidden_states.reshape(batch, num_key_value_heads * n_rep, head_dim)


class MHA_LM(nn.Module):
    """Multi-headed attention from 'Attention Is All You Need' paper"""

    def __init__(self, config: mmMambaConfig, layer_idx: int):
        super().__init__()
        self.config = config
        self.layer_idx = layer_idx#-------------------------
        self.hidden_size = config.hidden_size
        self.num_heads = config.num_attention_heads
        self.head_dim = self.hidden_size // self.num_heads
        self.num_key_value_heads = config.num_key_value_heads
        self.num_key_value_groups = self.num_heads // self.num_key_value_heads
        self.max_position_embeddings = config.max_position_embeddings
        self.is_causal = True
        self.rotary_emb_dim = self.head_dim
        self.softmax_scale = None
        self.causal = True
        
        if (self.head_dim * self.num_heads) != self.hidden_size:
            raise ValueError(
                f"hidden_size must be divisible by num_heads (got `hidden_size`: {self.hidden_size}"
                f" and `num_heads`: {self.num_heads})."
            )

        self.wqkv = nn.Linear(
            self.hidden_size,
            (self.num_heads + 2 * self.num_key_value_heads) * self.head_dim,
            bias=False,
        )

        self.wo = nn.Linear(self.num_heads * self.head_dim, self.hidden_size, bias=False)
        self.rotary_emb = RotaryEmbedding(
                self.head_dim,
                base=self.config.rope_theta,
                interleaved=False,
                device=self.wo.weight.device, 
                )

    def _shape(self, tensor: torch.Tensor, seq_len: int, bsz: int):
        return tensor.view(bsz, seq_len, self.num_heads, self.head_dim).transpose(1, 2).contiguous()

    def _update_kv_cache(self, kv, inference_params):
        """kv: (batch_size, seqlen, 2, nheads, head_dim) or (batch_size, 1, 2, nheads, head_dim)"""
        assert self.layer_idx is not None, "Generation requires layer_idx in the constructor"
        return _update_kv_cache(kv, inference_params, self.layer_idx)

    def _apply_rotary_update_kvcache_attention(self, q, kv, inference_params):
        """
        Fast path that combine 3 steps: apply rotary to Q and K, update kv cache, and apply attention.
        q: (batch_size, seqlen_q, nheads, head_dim)
        kv: (batch_size, seqlen_k, 2, nheads_kv, head_dim)
        """
        assert inference_params is not None and inference_params.seqlen_offset > 0
        if self.rotary_emb_dim > 0:
            self.rotary_emb._update_cos_sin_cache(
                inference_params.max_seqlen, device=q.device, dtype=q.dtype
            )
            rotary_cos, rotary_sin = self.rotary_emb._cos_cached, self.rotary_emb._sin_cached
        else:
            rotary_cos, rotary_sin = None, None
        batch = q.shape[0]
        kv_cache, _ = inference_params.key_value_memory_dict[self.layer_idx]
        kv_cache = kv_cache[:batch]
        cache_seqlens = (
            inference_params.lengths_per_sample[:batch]
            if inference_params.lengths_per_sample is not None
            else inference_params.seqlen_offset
        )
        assert flash_attn_with_kvcache is not None, "flash_attn must be installed"
        context = flash_attn_with_kvcache(
            q,
            kv_cache[:, :, 0],
            kv_cache[:, :, 1],
            kv[:, :, 0],
            kv[:, :, 1],
            rotary_cos=rotary_cos,
            rotary_sin=rotary_sin,
            cache_seqlens=cache_seqlens,
            softmax_scale=self.softmax_scale,
            causal=self.causal,
            rotary_interleaved=self.rotary_emb.interleaved if self.rotary_emb_dim > 0 else False,
        )
        return context

    def _update_kvcache_attention(self, q, kv, inference_params):
        """Write kv to inference_params, then do attention"""
        if (
            inference_params.seqlen_offset == 0
            or flash_attn_with_kvcache is None
        ):
            # TODO: this only uses seqlen_offset and not lengths_per_sample.
            kv = self._update_kv_cache(kv, inference_params)
            k, v = kv.unbind(dim=-3)
            #k = torch.repeat_interleave(k, dim=2, repeats=self.num_heads // self.num_key_value_heads)
            #v = torch.repeat_interleave(v, dim=2, repeats=self.num_heads // self.num_key_value_heads)
            attn_output = flash_attn_func(
                q, k, v, 0.0, softmax_scale=None, causal=self.causal
            )
            return attn_output
        else:
            batch = q.shape[0]
            kv_cache, _ = inference_params.key_value_memory_dict[self.layer_idx]
            kv_cache = kv_cache[:batch]
            cache_seqlens = (
                inference_params.lengths_per_sample[:batch]
                if inference_params.lengths_per_sample is not None
                else inference_params.seqlen_offset
            )
            return flash_attn_with_kvcache(
                q,
                kv_cache[:, :, 0],
                kv_cache[:, :, 1],
                kv[:, :, 0],
                kv[:, :, 1],
                cache_seqlens=cache_seqlens,
                softmax_scale=self.softmax_scale,
                causal=self.causal,
            )
            
    def forward(
        self,
        hidden_states: torch.Tensor,
        inference_params = None,
        output_attentions: bool = False,
        cache_position: Optional[torch.LongTensor] = None,#------------------------------------------------------------------------
        use_cache: bool = False,
        **kwargs,
    ) -> Tuple[torch.Tensor, Optional[torch.Tensor], Optional[Tuple[torch.Tensor]]]:
        if inference_params is not None and self.layer_idx not in inference_params.key_value_memory_dict:
            inference_params.key_value_memory_dict[self.layer_idx] = self.allocate_inference_cache(
                hidden_states.shape[0], inference_params.max_seqlen, dtype=hidden_states.dtype
            )
        seqlen_offset = (
            0
            if inference_params is None
            else (
                inference_params.lengths_per_sample
                if inference_params.lengths_per_sample is not None
                else inference_params.seqlen_offset
            )
        )

        bsz, q_len, _ = hidden_states.size()
        rotary_max_seqlen = inference_params.max_seqlen if inference_params is not None else None

        qkv = self.wqkv(hidden_states)
        qkv = rearrange(
            qkv,
            "b q (h gs d) -> b q h gs d",
            gs=2 + self.num_key_value_groups,
            d=self.head_dim,
        )

        q = qkv[..., : self.num_key_value_groups, :]
        q = rearrange(q, "b q h gs d -> b q (h gs) d")
        kv = qkv[..., self.num_key_value_groups:, :].transpose(2,3)
        
        if (
            inference_params is None
            or inference_params.seqlen_offset == 0
            or (self.rotary_emb_dim == 0 or self.rotary_emb_dim % 16 != 0)
        ):
            if self.rotary_emb_dim > 0:
                q, kv = self.rotary_emb(
                    q, kv, seqlen_offset=seqlen_offset, max_seqlen=rotary_max_seqlen
                )
            if inference_params is None:
                k, v = kv.unbind(dim=-3)
                k = torch.repeat_interleave(k, dim=2, repeats=self.num_heads // self.num_key_value_heads)
                v = torch.repeat_interleave(v, dim=2, repeats=self.num_heads // self.num_key_value_heads)
                context = F.scaled_dot_product_attention(
                    q.transpose(1, 2), k.transpose(1, 2), v.transpose(1, 2), is_causal=True, scale=None
                ).transpose(1, 2)
            else:
                context = self._update_kvcache_attention(q, kv, inference_params)
        else:
            context = self._apply_rotary_update_kvcache_attention(q, kv, inference_params)
        context = rearrange(context, "... h d -> ... (h d)")
        out = self.wo(context)
        return out
    
    def allocate_inference_cache(self, batch_size, max_seqlen, dtype=None):
        dtype = self.wo.weight.dtype if dtype is None else dtype
        device = self.wo.weight.device
        kv_cache = torch.empty(
            batch_size, max_seqlen, 2, self.num_key_value_heads, self.head_dim, dtype=dtype, device=device,
        )
        return kv_cache, None

    
class Mamba2_LM(nn.Module):
    """
    LoLCATs attention implementation initialized from a 
    `LlamaAttention` or `MistralAttention` object (base_attn)

    Most of the arguments are directly tied to argparse args
    - For now we don't support padding.
    """
    def __init__(self, config: mmMambaConfig, layer_idx: Optional[int] = None,
                 elementwise_affine: Optional[bool] = True,
                 norm_eps: float = 1e-5,
                 ):
        super().__init__()
        self.config = config
        self.hidden_size = config.hidden_size
        self.num_heads = config.num_attention_heads
        self.head_dim = self.hidden_size // self.num_heads
        self.num_key_value_heads = config.num_key_value_heads
        self.num_key_value_groups = self.num_heads // self.num_key_value_heads
        self.max_position_embeddings = config.max_position_embeddings
        self.layer_idx = layer_idx
        self.bias = False
        self.chunk_size = 128
        conv_bias = True
        self.conv_bias = conv_bias
        self.d_conv = 2
        self.activation="silu"
        self.max_position_embeddings = config.max_position_embeddings
        self.rope_theta = config.rope_theta

        self.wvkqgdt = nn.Linear(
            self.hidden_size,
            (self.num_heads + 2 * self.num_key_value_heads + self.num_heads) * self.head_dim + self.num_heads,
            bias=self.bias
        )
        self.o_proj = nn.Linear(self.num_heads * self.head_dim, self.hidden_size, bias=False)

        self.device = self.wvkqgdt.weight.device
        self.dtype = self.wvkqgdt.weight.dtype

        conv_dim = self.num_heads * self.head_dim + 2 * self.num_key_value_heads * self.head_dim
            
        self.conv1d = nn.Conv1d(
            in_channels=conv_dim,
            out_channels=conv_dim,
            bias=self.conv_bias,
            kernel_size=self.d_conv,
            groups=conv_dim,
            padding=self.d_conv - 1,
            device=self.device, 
            dtype=self.dtype
        )
        with torch.no_grad():
            self.conv1d.weight.zero_()  
            self.conv1d.weight[:, 0, 1] = 1 
            self.conv1d.bias.zero_()  

        # Activation after conv
        if self.activation == "identity":
            self.act = nn.Identity()
        elif self.activation in ["silu", "swish"]:
            self.act = nn.SiLU()
        else:
            raise ValueError(f"Unknown activation {self.activation}")
        
        self.g_norm_swish_gate = FusedRMSNormSwishGate(hidden_size=self.head_dim, elementwise_affine=elementwise_affine, eps=norm_eps).to(self.dtype).to(self.device)

        dt = torch.exp(
            torch.rand(self.num_heads, dtype=self.dtype, device=self.device) * (math.log(0.1) - math.log(0.001))
            + math.log(0.001)
        )
        dt = torch.clamp(dt, min=0.001)
        # Inverse of softplus: https://github.com/pytorch/pytorch/issues/72759
        inv_dt = dt + torch.log(-torch.expm1(-dt))
        self.dt_bias = nn.Parameter(inv_dt)
        self.dt_bias._no_weight_decay = True
        
        A_log_bias = torch.zeros(self.num_heads, dtype=self.dtype, device=self.device)
        self.A_log_bias = nn.Parameter(A_log_bias)
        self.A_log_bias._no_weight_decay = True

    def forward(self,
                hidden_states: torch.Tensor,
                inference_params = None,
                output_attentions: bool = False,
                use_cache: bool = True,
                **kwargs,
               ) -> Tuple[torch.Tensor, Optional[torch.Tensor], Optional[Tuple[torch.Tensor]]]:
        hidden_states = hidden_states.to(self.dtype)
        vkqgdt = self.wvkqgdt(hidden_states)
        vkq, g, dt = torch.split(
                vkqgdt,
                [
                    (2*self.num_key_value_heads+self.num_heads) * self.head_dim,
                    self.num_heads * self.head_dim,
                    self.num_heads,
                ],
                dim=2,
            )
        batch, seqlen, _ = hidden_states.shape
        conv_state, ssm_state = None, None
        if inference_params is not None:
            conv_state, ssm_state = self._get_states_from_cache(inference_params, batch)

        if use_cache and inference_params.seqlen_offset==0:
            vkq, new_conv_states = causal_conv1d_fn(
                vkq.transpose(1, 2),
                rearrange(self.conv1d.weight, "d 1 w -> d w"),
                self.conv1d.bias,
                initial_states=None,
                return_final_states=True,
                activation=None if self.activation == "identity" else self.activation,
            )

            v, k, q = torch.split(
                vkq,
                [
                    self.num_key_value_heads * self.head_dim,
                    self.num_key_value_heads * self.head_dim,
                    self.num_heads * self.head_dim,
                ],
                dim=1,
            )

            v = rearrange(v, "b (h n) l -> b h l n", h=self.num_key_value_heads)
            k = rearrange(k, "b (h n) l -> b h l n", h=self.num_key_value_heads)
            q = rearrange(q, "b (h n) l -> b l h n", h=self.num_heads)
            k = repeat_kv(k, self.num_key_value_groups).transpose(1, 2)
            v = repeat_kv(v, self.num_key_value_groups).transpose(1, 2)
                
            A = -torch.exp(self.A_log_bias.float())

            y, new_ssm_states = mamba_chunk_scan_combined(
                x = v,
                #x = v / F.softplus(A_log).to(v.dtype).unsqueeze(-1),
                dt=dt,
                dt_softplus=True,
                A=A,
                B=k,
                C=q,
                chunk_size=self.chunk_size,
                dt_bias=self.dt_bias,
                initial_states=None, # currently not supported by mamba_ssm.utils.generation
                return_final_states=True,
            )

            conv_state.copy_(new_conv_states)
            ssm_state.copy_(new_ssm_states)

        elif use_cache and inference_params.seqlen_offset>0:
            
            vkq = causal_conv1d_update(
                vkq.transpose(1, 2).squeeze(-1),
                conv_state,
                self.conv1d.weight.squeeze(1),
                self.conv1d.bias,
                self.activation,
            )

            v, k, q = torch.split(
                vkq,
                [
                    self.num_key_value_heads * self.head_dim,
                    self.num_key_value_heads * self.head_dim,
                    self.num_heads * self.head_dim,
                ],
                dim=1,
            )

            v = rearrange(v, "b (h n) -> b h n", h=self.num_key_value_heads)
            k = rearrange(k, "b (h n) -> b h n", h=self.num_key_value_heads)
            q = rearrange(q, "b (h n) -> b h n", h=self.num_heads)
            k = repeat_kv2(k, self.num_key_value_groups)
            v = repeat_kv2(v, self.num_key_value_groups)

            dt = dt.transpose(1, 2).squeeze(-1)
            dt = dt[:, :, None].expand(-1, -1, self.head_dim)
            dt_bias = self.dt_bias[:, None, ...].expand(-1, self.head_dim)
            A = -torch.exp(self.A_log_bias.float())
            A = A[:, None, ...][:, :, None].expand(-1, self.head_dim, self.head_dim).to(dtype=torch.float32)
            D = torch.zeros((self.num_heads, self.head_dim), dtype=A.dtype, device=A.device)

            y = selective_state_update(
                ssm_state,
                v,
                dt,
                A=A,
                B=k,
                C=q,
                D=D,
                dt_bias=dt_bias,
                dt_softplus=True,
            )
            
        else:
            vkq = causal_conv1d_fn(
                vkq.transpose(1, 2),
                rearrange(self.conv1d.weight, "d 1 w -> d w"),
                self.conv1d.bias,
                initial_states=None,
                return_final_states=False,
                activation=None if self.activation == "identity" else self.activation,
            )

            v, k, q = torch.split(
                vkq,
                [
                    self.num_key_value_heads * self.head_dim,
                    self.num_key_value_heads * self.head_dim,
                    self.num_heads * self.head_dim,
                ],
                dim=1,
            )

            v = rearrange(v, "b (h n) l -> b h l n", h=self.num_key_value_heads)
            k = rearrange(k, "b (h n) l -> b h l n", h=self.num_key_value_heads)
            q = rearrange(q, "b (h n) l -> b l h n", h=self.num_heads)
            k = repeat_kv(k, self.num_key_value_groups).transpose(1, 2)
            v = repeat_kv(v, self.num_key_value_groups).transpose(1, 2)
                
            A = -torch.exp(self.A_log_bias.float())

            y = mamba_chunk_scan_combined(
                x = v,
                dt=dt,
                dt_softplus=True,
                A=A,
                B=k,
                C=q,
                chunk_size=self.chunk_size,
                dt_bias=self.dt_bias,
                initial_states=None, # currently not supported by mamba_ssm.utils.generation
                return_final_states=False,
            )
        
        g = rearrange(g, 'b l (h d) -> b l h d', h=self.num_heads)
        y_true = self.g_norm_swish_gate(y, g)
        y_true = y_true.view(batch, seqlen, self.hidden_size)
        y_true = self.o_proj(y_true)

        return y_true
        
    def _get_states_from_cache(self, inference_params, batch_size, initialize_states=False):
        device = self.conv1d.weight.device
        dtype = self.conv1d.weight.dtype
        assert self.layer_idx is not None
        if self.layer_idx not in inference_params.key_value_memory_dict:
            batch_shape = (batch_size,)
            conv_state = torch.zeros(
                batch_size, 2*self.hidden_size, self.d_conv-1, device=device, dtype=dtype
            )
            ssm_state = torch.zeros(
                batch_size, self.num_heads, self.head_dim, self.head_dim, device=device, dtype=dtype
            )
            inference_params.key_value_memory_dict[self.layer_idx] = (conv_state, ssm_state)
        else:
            conv_state, ssm_state = inference_params.key_value_memory_dict[self.layer_idx]
            # TODO: What if batch size changes between generation, and we reuse the same states?
            if initialize_states:
                conv_state.zero_()
                ssm_state.zero_()
        return conv_state, ssm_state

            
    def allocate_inference_cache(self, batch_size, max_seqlen, dtype=None, **kwargs):
        device = self.conv1d.weight.device
        dtype = self.conv1d.weight.dtype
        conv_state = torch.zeros(
            batch_size, 2*self.hidden_size, self.d_conv-1, device=device, dtype=dtype
        )

        ssm_state = torch.zeros(
            batch_size, self.num_heads, self.head_dim, self.head_dim, device=device, dtype=dtype
        )
        return conv_state, ssm_state
    

mmMamba_ATTENTION_CLASSES = {
    'mha': MHA_LM,
    "mamba2":Mamba2_LM
}


# Modified from transformers.model.llama.modeling_llama.LlamaDecoderLayer
class mmMambaDecoderLayer(nn.Module):
    def __init__(self, config: mmMambaConfig, layer_idx: int):
        super().__init__()
        self.hidden_size = config.hidden_size
        self.layer_idx = layer_idx
        self.attention = mmMamba_ATTENTION_CLASSES[config.layers_block_type[layer_idx-8]](config=config, layer_idx=layer_idx) 

        self.feed_forward = mmMambaMLP(config)
        self.attention_norm = mmMambaRMSNorm(config.hidden_size, eps=config.rms_norm_eps)
        self.ffn_norm = mmMambaRMSNorm(config.hidden_size, eps=config.rms_norm_eps)
        

    def forward(
        self,
        hidden_states: torch.Tensor,
        inference_params = None,
        output_attentions: Optional[bool] = False,
        use_cache: Optional[bool] = True,
        **kwargs,
    ) -> Tuple[torch.FloatTensor, Optional[Tuple[torch.FloatTensor, torch.FloatTensor]]]:
        """
        Args:
            hidden_states (`torch.FloatTensor`): input to the layer of shape `(batch, seq_len, embed_dim)`
            output_attentions (`bool`, *optional*):
                Whether or not to return the attentions tensors of all attention layers. See `attentions` under
                returned tensors for more detail.
            use_cache (`bool`, *optional*):
                If set to `True`, `past_key_values` key value states are returned and can be used to speed up decoding
                (see `past_key_values`).
        """
        #start_time = time.time()
        residual = hidden_states

        hidden_states = self.attention_norm(hidden_states)

        # Self Attention
        hidden_states = self.attention(
            hidden_states=hidden_states,
            inference_params=inference_params,
            output_attentions=output_attentions,
            use_cache=use_cache,
            **kwargs,
        )
        hidden_states = residual + hidden_states

        # Fully Connected
        residual = hidden_states
        hidden_states = self.ffn_norm(hidden_states)
        hidden_states = self.feed_forward(hidden_states)
        hidden_states = residual + hidden_states


        outputs = (hidden_states,)

        if output_attentions:
            outputs += self_attn_weights

        #end_time = time.time()
        #print("language_model_time:", end_time-start_time)
        return outputs
    
    def allocate_inference_cache(self, batch_size, max_seqlen, dtype=None, **kwargs):
        return self.attention.allocate_inference_cache(batch_size, max_seqlen, dtype=dtype, **kwargs)


mmMamba_START_DOCSTRING = r"""
    This model inherits from [`PreTrainedModel`]. Check the superclass documentation for the generic methods the
    library implements for all its model (such as downloading or saving, resizing the input embeddings, pruning heads
    etc.)
    This model is also a PyTorch [torch.nn.Module](https://pytorch.org/docs/stable/nn.html#torch.nn.Module) subclass.
    Use it as a regular PyTorch Module and refer to the PyTorch documentation for all matter related to general usage
    and behavior.
    Parameters:
        config ([`mmMambaConfig`]):
            Model configuration class with all the parameters of the model. Initializing with a config file does not
            load the weights associated with the model, only the configuration. Check out the
            [`~PreTrainedModel.from_pretrained`] method to load the model weights.
"""


# Copied from transformers.models.llama.modeling_llama.LlamaPreTrainedModel with Llama->mmMamba
@add_start_docstrings(
    'The bare mmMamba Model outputting raw hidden-states without any specific head on top.',
    mmMamba_START_DOCSTRING,
)
class mmMambaPreTrainedModel(PreTrainedModel):
    config_class = mmMambaConfig
    base_model_prefix = 'model'
    supports_gradient_checkpointing = True
    _no_split_modules = ['mmMambaDecoderLayer']
    _skip_keys_device_placement = 'past_key_values'
    _supports_flash_attn_2 = True

    def _init_weights(self, module):
        std = self.config.initializer_range
        if isinstance(module, nn.Linear):
            module.weight.data.normal_(mean=0.0, std=std)
            if module.bias is not None:
                module.bias.data.zero_()
        elif isinstance(module, nn.Embedding):
            module.weight.data.normal_(mean=0.0, std=std)
            if module.padding_idx is not None:
                module.weight.data[module.padding_idx].zero_()


mmMamba_INPUTS_DOCSTRING = r"""
    Args:
        input_ids (`torch.LongTensor` of shape `(batch_size, sequence_length)`):
            Indices of input sequence tokens in the vocabulary. Padding will be ignored by default should you provide
            it.
            Indices can be obtained using [`AutoTokenizer`]. See [`PreTrainedTokenizer.encode`] and
            [`PreTrainedTokenizer.__call__`] for details.
            [What are input IDs?](../glossary#input-ids)
        inputs_embeds (`torch.FloatTensor` of shape `(batch_size, sequence_length, hidden_size)`, *optional*):
            Optionally, instead of passing `input_ids` you can choose to directly pass an embedded representation. This
            is useful if you want more control over how to convert `input_ids` indices into associated vectors than the
            model's internal embedding lookup matrix.
        use_cache (`bool`, *optional*):
            If set to `True`, `past_key_values` key value states are returned and can be used to speed up decoding (see
            `past_key_values`).
        output_attentions (`bool`, *optional*):
            Whether or not to return the attentions tensors of all attention layers. See `attentions` under returned
            tensors for more detail.
        output_hidden_states (`bool`, *optional*):
            Whether or not to return the hidden states of all layers. See `hidden_states` under returned tensors for
            more detail.
        return_dict (`bool`, *optional*):
            Whether or not to return a [`~utils.ModelOutput`] instead of a plain tuple.
"""


# Modified from transformers.model.llama.modeling_llama.LlamaModel
@add_start_docstrings(
    'The bare mmMamba Model outputting raw hidden-states without any specific head on top.',
    mmMamba_START_DOCSTRING,
)
class mmMambaModel(mmMambaPreTrainedModel):
    """
    Transformer decoder consisting of *config.num_hidden_layers* layers. Each layer is a [`mmMambaDecoderLayer`]
    Args:
        config: mmMambaConfig
    """

    _auto_class = 'AutoModel'

    def __init__(self, config: mmMambaConfig):
        super().__init__(config)
        self.padding_idx = config.pad_token_id
        self.vocab_size = config.vocab_size
        self.config = config
        self.tok_embeddings = nn.Embedding(config.vocab_size, config.hidden_size, self.padding_idx)

        self.layers = nn.ModuleList([mmMambaDecoderLayer(config, (layer_idx+8)) for layer_idx in range(config.num_hidden_layers)])
        self.norm = mmMambaRMSNorm(config.hidden_size, eps=config.rms_norm_eps)

        self.gradient_checkpointing = False
        # Initialize weights and apply final processing
        self.post_init()

    def get_input_embeddings(self):
        return self.tok_embeddings

    def set_input_embeddings(self, value):
        self.tok_embeddings = value

    @add_start_docstrings_to_model_forward(mmMamba_INPUTS_DOCSTRING)
    def forward(
        self,
        input_ids: torch.LongTensor = None,
        inference_params=None,
        inputs_embeds: Optional[torch.FloatTensor] = None,
        use_cache: Optional[bool] = True,
        output_attentions: Optional[bool] = None,
        output_hidden_states: Optional[bool] = None,
        return_dict: Optional[bool] = None,
    ) -> Union[Tuple, BaseModelOutputWithPast]:
        output_attentions = output_attentions if output_attentions is not None else self.config.output_attentions
        output_hidden_states = (
            output_hidden_states if output_hidden_states is not None else self.config.output_hidden_states
        )
        use_cache = use_cache if use_cache is not None else self.config.use_cache

        return_dict = return_dict if return_dict is not None else self.config.use_return_dict

        if self.config.attn_implementation == 'flash_attention_2':
            _import_flash_attn()

        # retrieve input_ids and inputs_embeds
        if input_ids is not None and inputs_embeds is not None:
            raise ValueError('You cannot specify both input_ids and inputs_embeds at the same time')
        elif input_ids is not None:
            batch_size, seq_length = input_ids.shape[:2]
        elif inputs_embeds is not None:
            batch_size, seq_length = inputs_embeds.shape[:2]
        else:
            raise ValueError('You have to specify either input_ids or inputs_embeds')

        if inputs_embeds is None:
            inputs_embeds = self.tok_embeddings(input_ids)

        # embed positions
        hidden_states = inputs_embeds

        if self.gradient_checkpointing and self.training:
            if use_cache:
                logger.warning_once(
                    '`use_cache=True` is incompatible with gradient checkpointing. Setting `use_cache=False`...'
                )
                use_cache = False

        # decoder layers
        all_hidden_states = () if output_hidden_states else None
        all_self_attns = () if output_attentions else None
        next_decoder_cache = () if use_cache else None

        for idx, decoder_layer in enumerate(self.layers):
            if output_hidden_states:
                all_hidden_states += (hidden_states,)

            if self.gradient_checkpointing and self.training:

                def create_custom_forward(module):
                    def custom_forward(*inputs):
                        # None for past_key_value
                        return module(*inputs, output_attentions, None)

                    return custom_forward

                layer_outputs = torch.utils.checkpoint.checkpoint(
                    create_custom_forward(decoder_layer),
                    hidden_states,
                    inference_params,
                    None,
                )
            else:
                layer_outputs = decoder_layer(
                    hidden_states,
                    inference_params=inference_params,
                    output_attentions=output_attentions,
                    use_cache=use_cache,
                )

            hidden_states = layer_outputs[0]


            if output_attentions:
                all_self_attns += layer_outputs[1]
        
        hidden_states = self.norm(hidden_states)

        # add hidden states from the last decoder layer
        if output_hidden_states:
            all_hidden_states += (hidden_states,)

        next_cache = None 
        if not return_dict:
            return tuple(v for v in [hidden_states, next_cache, all_hidden_states, all_self_attns] if v is not None)
        return BaseModelOutputWithPast(
            last_hidden_state=hidden_states,
            past_key_values=next_cache,
            hidden_states=all_hidden_states,
            attentions=all_self_attns,
        )
            
    def allocate_inference_cache(self, batch_size, max_seqlen, dtype=None, **kwargs):
        return {
            layer.layer_idx: layer.allocate_inference_cache(batch_size, max_seqlen, dtype=dtype, **kwargs)
            for layer in self.layers
        }

# Modified from transformers.model.llama.modeling_llama.LlamaForCausalLM
class mmMambaForCausalLM(mmMambaPreTrainedModel):
    _auto_class = 'AutoModelForCausalLM'

    _tied_weights_keys = ['output.weight']

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

        # Initialize weights and apply final processing
        self.post_init()

    def get_input_embeddings(self):
        return self.model.tok_embeddings

    def set_input_embeddings(self, value):
        self.model.tok_embeddings = value

    def get_output_embeddings(self):
        return self.output

    def set_output_embeddings(self, new_embeddings):
        self.output = new_embeddings

    def set_decoder(self, decoder):
        self.model = decoder

    def get_decoder(self):
        return self.model

    @add_start_docstrings_to_model_forward(mmMamba_INPUTS_DOCSTRING)
    @replace_return_docstrings(output_type=CausalLMOutputWithPast, config_class=_CONFIG_FOR_DOC)
    def forward(
        self,
        input_ids: torch.LongTensor = None,
        inference_params=None,
        num_last_tokens=0,
        inputs_embeds: Optional[torch.FloatTensor] = None,
        labels: Optional[torch.LongTensor] = None,
        use_cache: Optional[bool] = True,
        output_attentions: Optional[bool] = None,
        output_hidden_states: Optional[bool] = None,
        return_dict: Optional[bool] = None,
    ) -> Union[Tuple, CausalLMOutputWithPast]:
        r"""
        Args:
            labels (`torch.LongTensor` of shape `(batch_size, sequence_length)`, *optional*):
                Labels for computing the masked language modeling loss. Indices should either be in `[0, ...,
                config.vocab_size]` or -100 (see `input_ids` docstring). Tokens with indices set to `-100` are ignored
                (masked), the loss is only computed for the tokens with labels in `[0, ..., config.vocab_size]`.
        Returns:
        Example:
        ```python
        >>> from transformers import AutoTokenizer, mmMambaForCausalLM
        >>> model = mmMambaForCausalLM.from_pretrained(PATH_TO_CONVERTED_WEIGHTS)
        >>> tokenizer = AutoTokenizer.from_pretrained(PATH_TO_CONVERTED_TOKENIZER)
        >>> prompt = "Hey, are you conscious? Can you talk to me?"
        >>> inputs = tokenizer(prompt, return_tensors="pt")
        >>> # Generate
        >>> generate_ids = model.generate(inputs.input_ids, max_length=30)
        >>> tokenizer.batch_decode(generate_ids, skip_special_tokens=True, clean_up_tokenization_spaces=False)[0]
        "Hey, are you conscious? Can you talk to me?\nI'm not conscious, but I can talk to you."
        ```"""

        output_attentions = output_attentions if output_attentions is not None else self.config.output_attentions
        output_hidden_states = (
            output_hidden_states if output_hidden_states is not None else self.config.output_hidden_states
        )
        return_dict = return_dict if return_dict is not None else self.config.use_return_dict

        # decoder outputs consists of (dec_features, layer_state, dec_hidden, dec_attn)
        outputs = self.model(
            input_ids=input_ids,
            inference_params=inference_params,
            inputs_embeds=inputs_embeds,
            use_cache=use_cache,
            output_attentions=output_attentions,
            output_hidden_states=output_hidden_states,
            return_dict=return_dict,
        )

        hidden_states = outputs[0]
        
        if num_last_tokens > 0:
            hidden_states = hidden_states[:, -num_last_tokens:]
            
        logits = self.output(hidden_states)
        logits = logits.float()

        loss = None
        if labels is not None:
            # Shift so that tokens < n predict n
            shift_logits = logits[..., :-1, :].contiguous()
            shift_labels = labels[..., 1:].contiguous()
            # Flatten the tokens
            loss_fct = CrossEntropyLoss()
            shift_logits = shift_logits.view(-1, self.config.vocab_size)
            shift_labels = shift_labels.view(-1)
            # Enable model parallelism
            shift_labels = shift_labels.to(shift_logits.device)
            loss = loss_fct(shift_logits, shift_labels)

        if not return_dict:
            output = (logits,) + outputs[1:]
            return (loss,) + output if loss is not None else output

        device = input_ids.device if input_ids is not None else inputs_embeds.device
        output = CausalLMOutputWithPast(
            loss=loss,
            logits=logits,
            past_key_values=outputs.past_key_values,
            hidden_states=outputs.hidden_states,
            attentions=outputs.attentions,
        )
        output['logits'] = output['logits'].to(device)
        return output
    
    def allocate_inference_cache(self, batch_size, max_seqlen, dtype=None, **kwargs):
        return self.model.allocate_inference_cache(batch_size, max_seqlen, dtype=dtype, **kwargs)

    @staticmethod
    def _reorder_cache(past_key_values, beam_idx):
        reordered_past = ()
        for layer_past in past_key_values:
            reordered_past += (
                tuple(past_state.index_select(0, beam_idx.to(past_state.device)) for past_state in layer_past),
            )
        return reordered_past


    @torch.no_grad()
    def stream_chat(
        self,
        tokenizer,
        query: str,
        history: List[Tuple[str, str]] = [],
        max_new_tokens: int = 1024,
        do_sample: bool = True,
        temperature: float = 0.8,
        top_p: float = 0.8,
        **kwargs,
    ):
        """
        Return a generator in format: (response, history)
        Eg.
        ('你好，有什么可以帮助您的吗', [('你好', '你好，有什么可以帮助您的吗')])
        ('你好，有什么可以帮助您的吗？', [('你好', '你好，有什么可以帮助您的吗？')])
        """
        if BaseStreamer is None:
            raise ModuleNotFoundError(
                'The version of `transformers` is too low. Please make sure '
                'that you have installed `transformers>=4.28.0`.'
            )

        response_queue = queue.Queue(maxsize=20)

        class ChatStreamer(BaseStreamer):
            def __init__(self, tokenizer) -> None:
                super().__init__()
                self.tokenizer = tokenizer
                self.queue = response_queue
                self.query = query
                self.history = history
                self.response = ''
                self.cache = []
                self.received_inputs = False
                self.queue.put((self.response, history + [(self.query, self.response)]))

            def put(self, value):
                if len(value.shape) > 1 and value.shape[0] > 1:
                    raise ValueError('ChatStreamer only supports batch size 1')
                elif len(value.shape) > 1:
                    value = value[0]

                if not self.received_inputs:
                    # The first received value is input_ids, ignore here
                    self.received_inputs = True
                    return

                self.cache.extend(value.tolist())
                token = self.tokenizer.decode(self.cache, skip_special_tokens=True)
                if token.strip() != '<|im_end|>':
                    self.response = self.response + token
                    history = self.history + [(self.query, self.response)]
                    self.queue.put((self.response, history))
                    self.cache = []
                else:
                    self.end()

            def end(self):
                self.queue.put(None)

        def stream_producer():
            return self.chat(
                tokenizer=tokenizer,
                query=query,
                streamer=ChatStreamer(tokenizer=tokenizer),
                history=history,
                max_new_tokens=max_new_tokens,
                do_sample=do_sample,
                temperature=temperature,
                top_p=top_p,
                **kwargs,
            )

        def consumer():
            producer = threading.Thread(target=stream_producer)
            producer.start()
            while True:
                res = response_queue.get()
                if res is None:
                    return
                yield res

        return consumer()