# coding=utf-8
# Adapted from
# https://github.com/huggingface/transformers/blob/19e6e80e10118f855137b90740936c0b11ac397f/src/transformers/models/qwen2_vl/modeling_qwen2_vl.py
# Copyright 2024 The Qwen team.
# Copyright 2023 The vLLM team.
# Copyright 2022 EleutherAI and the HuggingFace Inc. team. All rights reserved.
#
# This code is based on EleutherAI's GPT-NeoX library and the GPT-NeoX
# and OPT implementations in this library. It has been modified from its
# original forms to accommodate minor architectural differences compared
# to GPT-NeoX and OPT used by the Meta AI team that trained the model.
#
# 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.
"""Inference-only Qwen2-VL model compatible with HuggingFace weights."""
from functools import lru_cache, partial
from typing import (Any, Callable, Iterable, List, Literal, Mapping, Optional,
                    Tuple, Type, TypedDict, Union)

import torch
import torch.nn as nn
import torch.nn.functional as F
from einops import rearrange, repeat
from PIL import Image
from transformers.image_utils import (get_image_size,
                                      infer_channel_dimension_format,
                                      to_numpy_array)
from transformers.models.qwen2_vl.image_processing_qwen2_vl import (
    make_batched_images, make_batched_videos, smart_resize)

import vllm.envs as envs
from vllm.attention import AttentionMetadata
from vllm.attention.selector import (_Backend, backend_name_to_enum,
                                     get_global_forced_attn_backend)
from vllm.config import CacheConfig, MultiModalConfig
from vllm.distributed import get_pp_group, parallel_state
from vllm.distributed import utils as dist_utils
from vllm.inputs import INPUT_REGISTRY, InputContext, LLMInputs
from vllm.logger import init_logger
from vllm.model_executor import SamplingMetadata
from vllm.model_executor.layers.activation import QuickGELU
from vllm.model_executor.layers.linear import (ColumnParallelLinear,
                                               RowParallelLinear)
from vllm.model_executor.layers.logits_processor import LogitsProcessor
from vllm.model_executor.layers.quantization import QuantizationConfig
from vllm.model_executor.layers.sampler import Sampler, SamplerOutput
from vllm.model_executor.layers.vocab_parallel_embedding import ParallelLMHead
from vllm.model_executor.model_loader.weight_utils import default_weight_loader
from vllm.model_executor.models.qwen2 import Qwen2Model
from vllm.multimodal import (MULTIMODAL_REGISTRY, MultiModalDataDict,
                             MultiModalInputs)
from vllm.multimodal.base import MultiModalData
from vllm.multimodal.image import cached_get_image_processor
from vllm.platforms import current_platform
from vllm.sequence import IntermediateTensors, SequenceData
from vllm.transformers_utils.configs.qwen2vl import (Qwen2VLConfig,
                                                     Qwen2VLVisionConfig)
from vllm.transformers_utils.processor import get_processor
from vllm.utils import is_cpu

from .interfaces import SupportsMultiModal, SupportsPP
from .utils import (PPMissingLayer, is_pp_missing_parameter,
                    make_empty_intermediate_tensors_factory)

logger = init_logger(__name__)

# === Vision Inputs === #


class Qwen2VLImagePixelInputs(TypedDict):
    type: Literal["pixel_values"]
    data: torch.Tensor
    """Shape: 
    `(num_patches, num_channels * patch_size * patch_size)`
    """

    image_grid_thw: torch.Tensor
    """Shape: `(num_images, 3)`
    This should be in `(grid_t, grid_h, grid_w)` format.
    """


class Qwen2VLImageEmbeddingInputs(TypedDict):
    type: Literal["image_embeds"]
    data: torch.Tensor
    """Shape: `(batch_size * num_images, image_feature_size, hidden_size)`
    `hidden_size` must match the hidden size of language model backbone.
    """


Qwen2VLImageInputs = Union[Qwen2VLImagePixelInputs,
                           Qwen2VLImageEmbeddingInputs]


class Qwen2VLVideoInputs(TypedDict):
    pixel_values_videos: torch.Tensor
    """Shape: 
    `(num_patches, 
      num_channels * temporal_patch_size * patch_size * patch_size)`
    """

    video_grid_thw: torch.Tensor
    """Shape: `(num_videos, 3)`
    
    This should be in `(grid_t, grid_h, grid_w)` format.
    """


# === Vision Encoder === #


class Qwen2VisionMLP(nn.Module):

    def __init__(
        self,
        in_features: int,
        hidden_features: int = None,
        act_layer: Type[nn.Module] = QuickGELU,
        quant_config: Optional[QuantizationConfig] = None,
    ):
        super().__init__()
        self.fc1 = ColumnParallelLinear(in_features,
                                        hidden_features,
                                        quant_config=quant_config)
        self.act = act_layer()
        self.fc2 = RowParallelLinear(hidden_features,
                                     in_features,
                                     quant_config=quant_config)

    def forward(self, x: torch.Tensor) -> torch.Tensor:
        x_parallel, _ = self.fc1(x)
        x_parallel = self.act(x_parallel)
        x, _ = self.fc2(x_parallel)
        return x


def rotate_half(x: torch.Tensor, interleaved: bool = False) -> torch.Tensor:
    if not interleaved:
        x1, x2 = x.chunk(2, dim=-1)
        return torch.cat((-x2, x1), dim=-1)
    else:
        x1, x2 = x[..., ::2], x[..., 1::2]
        return rearrange(torch.stack((-x2, x1), dim=-1),
                         "... d two -> ... (d two)",
                         two=2)


def apply_rotary_emb_torch(x: torch.Tensor,
                           cos: torch.Tensor,
                           sin: torch.Tensor,
                           interleaved: bool = False) -> torch.Tensor:
    """
    x: (batch_size, seqlen, nheads, headdim)
    cos, sin: (seqlen, rotary_dim / 2) or (batch_size, seqlen, rotary_dim / 2)
    """
    ro_dim = cos.shape[-1] * 2
    assert ro_dim <= x.shape[-1]
    cos = repeat(
        cos,
        "... d -> ... 1 (2 d)" if not interleaved else "... d -> ... 1 (d 2)")
    sin = repeat(
        sin,
        "... d -> ... 1 (2 d)" if not interleaved else "... d -> ... 1 (d 2)")
    return torch.cat(
        [
            x[..., :ro_dim] * cos +
            rotate_half(x[..., :ro_dim], interleaved) * sin, x[..., ro_dim:]
        ],
        dim=-1,
    )


def apply_rotary_pos_emb_vision(t: torch.Tensor,
                                freqs: torch.Tensor) -> torch.Tensor:
    t_ = t.float()
    cos = freqs.cos()
    sin = freqs.sin()
    output = apply_rotary_emb_torch(t_, cos, sin).type_as(t)
    return output


class Qwen2VisionAttention(nn.Module):

    def __init__(
        self,
        embed_dim: Optional[int] = None,
        num_heads: Optional[int] = None,
        projection_size: Optional[int] = None,
        quant_config: Optional[QuantizationConfig] = None,
    ) -> None:
        super().__init__()
        # Per attention head and per partition values.
        world_size = parallel_state.get_tensor_model_parallel_world_size()
        self.hidden_size_per_attention_head = dist_utils.divide(
            projection_size, num_heads)
        self.num_attention_heads_per_partition = dist_utils.divide(
            num_heads, world_size)

        self.qkv = ColumnParallelLinear(input_size=embed_dim,
                                        output_size=3 * projection_size,
                                        quant_config=quant_config)
        self.proj = RowParallelLinear(input_size=projection_size,
                                      output_size=embed_dim,
                                      quant_config=quant_config)

        # Detect attention implementation.
        selected_backend: Optional[_Backend] = get_global_forced_attn_backend()
        if selected_backend is None:
            backend_by_env_var: Optional[str] = envs.VLLM_ATTENTION_BACKEND
            if backend_by_env_var is not None:
                selected_backend = backend_name_to_enum(backend_by_env_var)
        if selected_backend is None:
            # For Volta and Turing GPUs, use xformers instead.
            device_available = current_platform.has_device_capability(80)
            if device_available:
                from transformers.utils import is_flash_attn_2_available

                if is_flash_attn_2_available():
                    self._use_flash_attn = True
                else:
                    logger.warning(
                        "Current Qwen2-VL implementation has a bug with "
                        "`vllm-flash-attn` inside vision module, so we use "
                        "xformers backend instead. You can run `pip install "
                        "flash-attn to use flash-attention backend.")
                    self._use_flash_attn = False
            else:
                self._use_flash_attn = False
        else:
            if selected_backend == _Backend.FLASH_ATTN:
                self._use_flash_attn = True
            elif selected_backend == _Backend.XFORMERS:
                self._use_flash_attn = False
            else:
                raise RuntimeError(
                    f"Qwen2-VL does not support {selected_backend} backend now."
                )

    def forward(
        self,
        x: torch.Tensor,
        cu_seqlens: torch.Tensor,
        rotary_pos_emb: torch.Tensor = None,
    ) -> torch.Tensor:
        # [s, b, c] --> [s, b, head * 3 * head_dim]
        x, _ = self.qkv(x)

        # [s, b, head * 3 * head_dim] --> [s, b, head, 3 * head_dim]
        new_x_shape = x.size()[:-1] + (
            self.num_attention_heads_per_partition,
            3 * self.hidden_size_per_attention_head,
        )
        x = x.view(*new_x_shape)

        # [s, b, head, 3 * head_dim] --> 3 [s, b, head, head_dim]
        q, k, v = dist_utils.split_tensor_along_last_dim(x, 3)
        batch_size = q.shape[1]

        q, k, v = [
            rearrange(x, "s b ... -> b s ...").contiguous() for x in (q, k, v)
        ]
        if rotary_pos_emb is not None:
            q = apply_rotary_pos_emb_vision(q, rotary_pos_emb)
            k = apply_rotary_pos_emb_vision(k, rotary_pos_emb)

        if self._use_flash_attn:
            # from vllm_flash_attn.flash_attn_interface import (
            #   flash_attn_varlen_func)
            from flash_attn import flash_attn_varlen_func

            q, k, v = [rearrange(x, "b s ... -> (b s) ...") for x in [q, k, v]]

            max_seqlen = (cu_seqlens[1:] - cu_seqlens[:-1]).max().item()
            output = flash_attn_varlen_func(q,
                                            k,
                                            v,
                                            cu_seqlens_q=cu_seqlens,
                                            cu_seqlens_k=cu_seqlens,
                                            max_seqlen_q=max_seqlen,
                                            max_seqlen_k=max_seqlen,
                                            dropout_p=0,
                                            causal=False)

            context_layer = rearrange(output,
                                      "(b s) ... -> b s ...",
                                      b=batch_size)
        elif is_cpu():
            seq_length = q.size(1)
            q, k, v = [rearrange(x, "b s h d -> b h s d") for x in [q, k, v]]
            attention_mask = torch.zeros([1, seq_length, seq_length],
                                         device=q.device,
                                         dtype=torch.bool)
            for i in range(1, len(cu_seqlens)):
                attention_mask[..., cu_seqlens[i - 1]:cu_seqlens[i],
                               cu_seqlens[i - 1]:cu_seqlens[i]] = True
            output = F.scaled_dot_product_attention(q,
                                                    k,
                                                    v,
                                                    attention_mask,
                                                    dropout_p=0.0)
            context_layer = rearrange(output, "b h s d -> b s h d ")
        else:
            from xformers import ops as xops
            from xformers.ops.fmha.attn_bias import BlockDiagonalMask

            seqlens = (cu_seqlens[1:] - cu_seqlens[:-1]).tolist()
            attn_bias = BlockDiagonalMask.from_seqlens(q_seqlen=seqlens,
                                                       kv_seqlen=None)

            context_layer = xops.memory_efficient_attention_forward(
                q, k, v, attn_bias=attn_bias, p=0, scale=None)
        context_layer = rearrange(context_layer,
                                  "b s h d -> s b (h d)").contiguous()

        output, _ = self.proj(context_layer)
        return output


class Qwen2VisionBlock(nn.Module):

    def __init__(
        self,
        dim: int,
        num_heads: int,
        mlp_ratio: float,
        act_layer: Type[nn.Module] = QuickGELU,
        norm_layer: Type[nn.Module] = None,
        quant_config: Optional[QuantizationConfig] = None,
    ) -> None:
        super().__init__()
        if norm_layer is None:
            norm_layer = partial(nn.LayerNorm, eps=1e-6)
        self.norm1 = norm_layer(dim)
        self.norm2 = norm_layer(dim)
        mlp_hidden_dim = int(dim * mlp_ratio)

        self.attn = Qwen2VisionAttention(embed_dim=dim,
                                         num_heads=num_heads,
                                         projection_size=dim,
                                         quant_config=quant_config)
        self.mlp = Qwen2VisionMLP(dim,
                                  mlp_hidden_dim,
                                  act_layer=act_layer,
                                  quant_config=quant_config)

    def forward(self, x: torch.Tensor, cu_seqlens: torch.Tensor,
                rotary_pos_emb: torch.Tensor) -> torch.Tensor:
        x = x + self.attn(self.norm1(x),
                          cu_seqlens=cu_seqlens,
                          rotary_pos_emb=rotary_pos_emb)
        x = x + self.mlp(self.norm2(x))
        return x


class Qwen2VisionPatchEmbed(nn.Module):

    def __init__(
        self,
        patch_size: int = 14,
        temporal_patch_size: int = 2,
        in_chans: int = 3,
        embed_dim: int = 1152,
    ) -> None:
        super().__init__()
        self.patch_size = patch_size
        self.temporal_patch_size = temporal_patch_size
        self.embed_dim = embed_dim

        kernel_size = [temporal_patch_size, patch_size, patch_size]
        self.proj = nn.Conv3d(in_chans,
                              embed_dim,
                              kernel_size=kernel_size,
                              stride=kernel_size,
                              bias=False)

    def forward(self, x: torch.Tensor) -> torch.Tensor:
        L, C = x.shape
        x = x.view(L, -1, self.temporal_patch_size, self.patch_size,
                   self.patch_size)
        x = self.proj(x).view(L, self.embed_dim)
        return x


class Qwen2VisionPatchMerger(nn.Module):

    def __init__(
        self,
        d_model: int,
        context_dim: int,
        norm_layer: Type[nn.Module] = None,
        spatial_merge_size: int = 2,
        quant_config: Optional[QuantizationConfig] = None,
    ) -> None:
        super().__init__()
        self.hidden_size = context_dim * (spatial_merge_size**2)
        if norm_layer is None:
            norm_layer = partial(nn.LayerNorm, eps=1e-6)
        self.ln_q = norm_layer(context_dim)
        self.mlp = nn.ModuleList([
            ColumnParallelLinear(self.hidden_size,
                                 self.hidden_size,
                                 bias=True,
                                 quant_config=quant_config),
            nn.GELU(),
            RowParallelLinear(self.hidden_size,
                              d_model,
                              bias=True,
                              quant_config=quant_config),
        ])

    def forward(self, x: torch.Tensor) -> torch.Tensor:
        x = self.ln_q(x)
        x = x.view(-1, self.hidden_size)

        mlp_fc1, mlp_act, mlp_fc2 = self.mlp
        x_parallel, _ = mlp_fc1(x)
        x_parallel = mlp_act(x_parallel)
        out, _ = mlp_fc2(x_parallel)
        return out


class Qwen2VisionRotaryEmbedding(nn.Module):

    def __init__(self, dim: int, theta: float = 10000.0) -> None:
        super().__init__()
        self.dim = dim
        self.theta = theta
        inv_freq = 1.0 / (theta
                          **(torch.arange(0, dim, 2, dtype=torch.float) / dim))
        self.register_buffer("inv_freq", inv_freq, persistent=False)
        self._seq_len_cached = 0
        self._freqs_cached = None

    def update_freqs_cache(self, seqlen: int) -> None:
        if seqlen > self._seq_len_cached:
            seqlen *= 2
            self._seq_len_cached = seqlen
            self.inv_freq = 1.0 / (self.theta**(torch.arange(
                0, self.dim, 2, dtype=torch.float, device=self.inv_freq.device)
                                                / self.dim))
            seq = torch.arange(seqlen,
                               device=self.inv_freq.device,
                               dtype=self.inv_freq.dtype)
            freqs = torch.outer(seq, self.inv_freq)
            self._freqs_cached = freqs

    def forward(self, seqlen: int) -> torch.Tensor:
        self.update_freqs_cache(seqlen)
        return self._freqs_cached[:seqlen]


class Qwen2VisionTransformer(nn.Module):

    def __init__(
        self,
        vision_config: Qwen2VLVisionConfig,
        norm_eps: float = 1e-6,
        quant_config: Optional[QuantizationConfig] = None,
    ) -> None:
        super().__init__()

        patch_size: int = vision_config.patch_size
        temporal_patch_size: int = vision_config.temporal_patch_size
        spatial_merge_size: int = vision_config.spatial_merge_size
        in_chans: int = vision_config.in_chans
        hidden_size: int = vision_config.hidden_size
        embed_dim: int = vision_config.embed_dim
        depth: int = vision_config.depth
        num_heads: int = vision_config.num_heads
        mlp_ratio: float = vision_config.mlp_ratio

        self.spatial_merge_size = spatial_merge_size

        self.patch_embed = Qwen2VisionPatchEmbed(
            patch_size=patch_size,
            temporal_patch_size=temporal_patch_size,
            in_chans=in_chans,
            embed_dim=embed_dim,
        )

        norm_layer = partial(nn.LayerNorm, eps=norm_eps)
        head_dim = embed_dim // num_heads
        self.rotary_pos_emb = Qwen2VisionRotaryEmbedding(head_dim // 2)

        self.blocks = nn.ModuleList([
            Qwen2VisionBlock(
                dim=embed_dim,
                num_heads=num_heads,
                mlp_ratio=mlp_ratio,
                norm_layer=norm_layer,
                quant_config=quant_config,
            ) for _ in range(depth)
        ])
        self.merger = Qwen2VisionPatchMerger(
            d_model=hidden_size,
            context_dim=embed_dim,
            norm_layer=norm_layer,
            quant_config=quant_config,
        )

    @property
    def dtype(self) -> torch.dtype:
        return self.blocks[0].mlp.fc2.weight.dtype

    @property
    def device(self) -> torch.device:
        return self.blocks[0].mlp.fc2.weight.device

    def rot_pos_emb(self, grid_thw: torch.Tensor) -> torch.Tensor:
        pos_ids = []
        for t, h, w in grid_thw:
            hpos_ids = torch.arange(h).unsqueeze(1).expand(-1, w)
            wpos_ids = torch.arange(w).unsqueeze(0).expand(h, -1)
            hpos_ids = hpos_ids.reshape(
                h // self.spatial_merge_size,
                self.spatial_merge_size,
                w // self.spatial_merge_size,
                self.spatial_merge_size,
            ).permute(0, 2, 1, 3).flatten()
            wpos_ids = wpos_ids.reshape(
                h // self.spatial_merge_size,
                self.spatial_merge_size,
                w // self.spatial_merge_size,
                self.spatial_merge_size,
            ).permute(0, 2, 1, 3).flatten()
            pos_ids.append(
                torch.stack([hpos_ids, wpos_ids], dim=-1).repeat(t, 1))
        pos_ids = torch.cat(pos_ids, dim=0)
        max_grid_size = grid_thw[:, 1:].max()
        rotary_pos_emb_full = self.rotary_pos_emb(max_grid_size)
        rotary_pos_emb = rotary_pos_emb_full[pos_ids].flatten(1)
        return rotary_pos_emb

    def forward(
        self,
        x: torch.Tensor,
        grid_thw: torch.Tensor,
    ) -> torch.Tensor:
        # patchify
        x = x.to(device=self.device, dtype=self.dtype)
        x = self.patch_embed(x)

        # compute position embedding
        rotary_pos_emb = self.rot_pos_emb(grid_thw)

        # compute cu_seqlens
        cu_seqlens = torch.repeat_interleave(grid_thw[:, 1] * grid_thw[:, 2],
                                             grid_thw[:, 0]).cumsum(
                                                 dim=0, dtype=torch.int32)
        cu_seqlens = F.pad(cu_seqlens, (1, 0), "constant", 0)

        # transformers
        x = x.unsqueeze(1)
        for blk in self.blocks:
            x = blk(x, cu_seqlens=cu_seqlens, rotary_pos_emb=rotary_pos_emb)

        # adapter
        x = self.merger(x)
        return x


# === Vision input helpers === #

cached_get_processor = lru_cache(get_processor)


def mm_input_mapper_for_qwen2_vl(
    ctx: InputContext,
    data: MultiModalData[object],
    data_type_key: str,
) -> MultiModalInputs:
    """Input mapper for Qwen2-VL."""
    if data_type_key == "image" and isinstance(data, dict):
        return MultiModalInputs({
            "image_embeds": data.get("image_embeds"),
            "image_grid_thw": data.get("image_grid_thw"),
        })
    model_config = ctx.model_config
    image_processor = cached_get_image_processor(
        model_config.model, trust_remote_code=model_config.trust_remote_code)
    if image_processor is None:
        raise RuntimeError("No HuggingFace processor is available "
                           "to process the image object")

    images = None
    videos = None
    if data_type_key == "image":
        images = data
    else:
        assert data_type_key == "video"
        videos = data

    try:
        batch_data = image_processor \
            .preprocess(images=images, videos=videos, return_tensors="pt") \
            .data
    except Exception:
        logger.error("Failed to process image (%s)", data)
        raise

    return MultiModalInputs(batch_data)


image_input_mapper_for_qwen2_vl = partial(mm_input_mapper_for_qwen2_vl,
                                          data_type_key="image")
video_input_mapper_for_qwen2_vl = partial(mm_input_mapper_for_qwen2_vl,
                                          data_type_key="video")


def _get_vision_info(
    image_processor,
    height: int,
    width: int,
    min_pixels: int,
    max_pixels: int,
    do_resize: bool = True,
    data_type_key: str = "image",
    mm_count: int = 1,
):
    """Get information (resized height / width and number of vision tokens)
    of input image / video frame."""

    if do_resize:
        resized_height, resized_width = smart_resize(
            height=height,
            width=width,
            factor=image_processor.patch_size * image_processor.merge_size,
            min_pixels=min_pixels,
            max_pixels=max_pixels,
        )
    else:
        resized_height, resized_width = height, width

    if data_type_key == "image":
        grid_t = mm_count
    else:
        assert data_type_key == "video"
        grid_t = max(mm_count // image_processor.temporal_patch_size, 1)

    grid_h = resized_height // image_processor.patch_size
    grid_w = resized_width // image_processor.patch_size
    vision_tokens = grid_t * grid_h * grid_w
    llm_num_vision_tokens = (vision_tokens // image_processor.merge_size //
                             image_processor.merge_size)

    return resized_height, resized_width, llm_num_vision_tokens


def _get_max_image_info(
    image_processor,
    data_type_key: str = "image",
    mm_count: int = 1,
):
    return _get_vision_info(
        image_processor,
        height=9999999,
        width=9999999,

        # Limit min / max pixels.
        min_pixels=max(image_processor.min_pixels, 28 * 28),
        max_pixels=min(image_processor.max_pixels, 1280 * 28 * 28),
        data_type_key=data_type_key,
        mm_count=mm_count,
    )


def get_max_qwen2_vl_mm_tokens(ctx: InputContext, data_type_key: str) -> int:
    image_processor = cached_get_image_processor(ctx.model_config.model)
    max_resized_height, max_resized_width, max_llm_image_tokens = \
        _get_max_image_info(image_processor, data_type_key=data_type_key,
                            mm_count=1)
    return max_llm_image_tokens


get_max_qwen2_vl_image_tokens = partial(get_max_qwen2_vl_mm_tokens,
                                        data_type_key="image")
get_max_qwen2_vl_video_tokens = partial(get_max_qwen2_vl_mm_tokens,
                                        data_type_key="video")


def dummy_data_for_qwen2_vl(
    ctx: InputContext, seq_len: int, mm_counts: Mapping[str, int]
) -> Tuple[SequenceData, Optional[MultiModalDataDict]]:
    image_processor = cached_get_image_processor(ctx.model_config.model)

    num_images = mm_counts["image"]
    max_resized_height, max_resized_width, max_llm_image_tokens = \
        _get_max_image_info(image_processor, data_type_key="image",
                            mm_count=num_images)
    if seq_len - max_llm_image_tokens - 2 < 0:
        raise RuntimeError(
            f"Qwen2-VL cannot process {num_images} images in a prompt, "
            "please increase max_model_len or reduce image limit by "
            "--limit-mm-per-prompt.")

    # Check video counts.
    num_videos = mm_counts["video"]
    max_resized_height, max_resized_width, max_llm_video_tokens = \
        _get_max_image_info(image_processor, data_type_key="video",
                            mm_count=num_videos)
    if seq_len - max_llm_video_tokens - 2 < 0:
        raise RuntimeError(
            f"Qwen2-VL cannot process {num_images} videos in a prompt, "
            "please increase max_model_len or reduce video limit by "
            "--limit-mm-per-prompt.")

    hf_config = ctx.get_hf_config(Qwen2VLConfig)

    dummy_seqdata = SequenceData.from_token_counts(
        (hf_config.vision_start_token_id, 1),
        (hf_config.image_token_id, max_llm_image_tokens),
        (hf_config.vision_end_token_id, 1),
        (0, seq_len - max_llm_image_tokens - 2),
    )

    dummy_image = Image.new("RGB", (max_resized_width, max_resized_height),
                            color=0)

    return dummy_seqdata, {
        "image": dummy_image if num_images == 1 else [dummy_image] * num_images
    }


def _get_llm_num_vision_tokens(
    mm_inputs: list,
    data_type_key: str,
    image_processor,
):
    """Get number of vision tokens of multimodal inputs.

    This method is derived from `transformers.models.qwen2_vl.
    image_processing_qwen2_vl.Qwen2VLImageProcessor._preprocess`.
    """
    image = to_numpy_array(mm_inputs[0])
    input_data_format = infer_channel_dimension_format(image)
    height, width = get_image_size(image, channel_dim=input_data_format)
    _, _, llm_num_vision_tokens = _get_vision_info(
        image_processor,
        height=height,
        width=width,
        min_pixels=image_processor.min_pixels,
        max_pixels=image_processor.max_pixels,
        do_resize=image_processor.do_resize,
        data_type_key=data_type_key,
        mm_count=len(mm_inputs),
    )
    return llm_num_vision_tokens


def _expand_pad_tokens(inputs: list, token_id: int, make_batched_fn: Callable,
                       data_type_key: str, image_processor: Any,
                       prompt_token_ids: List[int]) -> List[int]:
    """
    Expand pad tokens for multi-modal inputs (e.g., images or videos).

    Args:
        inputs (list): The multi-modal inputs (e.g., images or videos).
        token_id (int): The token ID used to represent the multi-modal input.
        make_batched_fn (Callable): A function to batch the inputs.
        data_type_key (str): The type of the multi-modal input.
        image_processor (Any): The image processor used to process the inputs.
        prompt_token_ids (List[int]): The list of token IDs in the prompt.

    Returns:
        List[int]: The list of token IDs for the multi-modal inputs.
    """
    indices = [
        idx for idx, token in enumerate(prompt_token_ids) if token == token_id
    ]
    inputs = make_batched_fn(inputs)
    assert len(indices) == len(inputs)

    prompt_token_ids_with_data = []
    for cnt, data in enumerate(inputs):
        num_tokens = _get_llm_num_vision_tokens(
            [data] if data_type_key == "image" else data,
            data_type_key=data_type_key,
            image_processor=image_processor,
        )
        if cnt == 0:
            end_idx = indices[cnt]
            non_data_tokens = prompt_token_ids[:end_idx]
        else:
            non_data_tokens = prompt_token_ids[indices[cnt - 1] +
                                               1:indices[cnt]]
        prompt_token_ids_with_data.extend(non_data_tokens)
        prompt_token_ids_with_data.extend(token_id for _ in range(num_tokens))
    prompt_token_ids_with_data.extend(prompt_token_ids[indices[-1] + 1:])
    return prompt_token_ids_with_data


def input_processor_for_qwen2_vl(ctx: InputContext,
                                 llm_inputs: LLMInputs) -> LLMInputs:
    multi_modal_data = llm_inputs.get("multi_modal_data", None)
    if multi_modal_data is None:
        return llm_inputs

    image_inputs = multi_modal_data.get("image", None)
    video_inputs = multi_modal_data.get("video", None)

    processor = cached_get_processor(ctx.model_config.model)
    image_processor = processor.image_processor
    hf_config = ctx.get_hf_config(Qwen2VLConfig)

    # To avoid redundant processing of vision objects (resize, rescale, etc.),
    # we extract code of calculating number of vision tokens from
    # `transformers.models.qwen2_vl.processing_qwen2_vl.Qwen2VLProcessor`.
    #
    # The following code is equivalent to:
    #    prompt = llm_inputs["prompt"]
    #    inputs = processor(text=[prompt],
    #                       images=image_inputs,
    #                       videos=video_inputs,
    #                       padding=True,
    #                       return_tensors="pt")
    #    prompt_token_ids = inputs["input_ids"][0].tolist()

    prompt_token_ids = llm_inputs.get("prompt_token_ids", None)
    if prompt_token_ids is None:
        prompt = llm_inputs["prompt"]
        prompt_token_ids = processor.tokenizer(
            prompt,
            padding=True,
            return_tensors=None,
        )["input_ids"]

    # Expand image pad tokens.

    if image_inputs is not None:
        if isinstance(image_inputs, dict):
            prompt_token_ids_with_image = []
            image_indices = [
                idx for idx, token in enumerate(prompt_token_ids)
                if token == hf_config.image_token_id
            ]
            image_cnt = len(image_indices)
            embed_dim = image_inputs.get('image_embeds').size(0)
            assert embed_dim % image_cnt == 0
            num_pad_tokens = embed_dim // image_cnt
            for idx, token in enumerate(prompt_token_ids):
                if idx in image_indices:
                    prompt_token_ids_with_image.extend([token] *
                                                       num_pad_tokens)
                else:
                    prompt_token_ids_with_image.append(token)
            prompt_token_ids = prompt_token_ids_with_image
        else:
            prompt_token_ids = _expand_pad_tokens(image_inputs,
                                                  hf_config.image_token_id,
                                                  make_batched_images, "image",
                                                  image_processor,
                                                  prompt_token_ids)

    if video_inputs is not None:
        prompt_token_ids = _expand_pad_tokens(video_inputs,
                                              hf_config.video_token_id,
                                              make_batched_videos, "video",
                                              image_processor,
                                              prompt_token_ids)

    return LLMInputs(
        prompt_token_ids=prompt_token_ids,
        prompt=llm_inputs["prompt"],
        multi_modal_data=multi_modal_data,
    )


@MULTIMODAL_REGISTRY.register_image_input_mapper(
    image_input_mapper_for_qwen2_vl)
@MULTIMODAL_REGISTRY.register_input_mapper("video",
                                           video_input_mapper_for_qwen2_vl)
@MULTIMODAL_REGISTRY.register_max_image_tokens(get_max_qwen2_vl_image_tokens)
@MULTIMODAL_REGISTRY.register_max_multimodal_tokens(
    "video", get_max_qwen2_vl_video_tokens)
@INPUT_REGISTRY.register_dummy_data(dummy_data_for_qwen2_vl)
@INPUT_REGISTRY.register_input_processor(input_processor_for_qwen2_vl)
class Qwen2VLForConditionalGeneration(nn.Module, SupportsMultiModal,
                                      SupportsPP):

    def __init__(self,
                 config: Qwen2VLConfig,
                 multimodal_config: MultiModalConfig,
                 cache_config: Optional[CacheConfig] = None,
                 quant_config: Optional[QuantizationConfig] = None) -> None:
        super().__init__()

        assert not cache_config.enable_prefix_caching, \
            "Qwen2-VL currently does not support prefix caching"

        self.config = config
        self.multimodal_config = multimodal_config

        self.visual = Qwen2VisionTransformer(
            config.vision_config,
            norm_eps=getattr(config, "rms_norm_eps", 1e-6),

            # NOTE: Qwen2-VL vision encoder does not support any
            # quantization method now.
            quant_config=None,
        )

        self.model = Qwen2Model(config, cache_config, quant_config)

        if get_pp_group().is_last_rank:
            if config.tie_word_embeddings:
                self.lm_head = self.model.embed_tokens
            else:
                self.lm_head = ParallelLMHead(config.vocab_size,
                                              config.hidden_size,
                                              quant_config=quant_config)
        else:
            self.lm_head = PPMissingLayer()

        self.logits_processor = LogitsProcessor(config.vocab_size)
        self.sampler = Sampler()
        self.make_empty_intermediate_tensors = (
            make_empty_intermediate_tensors_factory(
                ["hidden_states", "residual"], config.hidden_size))

    def _validate_and_reshape_mm_tensor(self,
                                        mm_input: Union[torch.Tensor,
                                                        List[torch.Tensor]],
                                        name: str) -> torch.Tensor:
        if not isinstance(mm_input, (torch.Tensor, list)):
            raise ValueError(f"Incorrect type of {name}. "
                             f"Got type: {type(mm_input)}")
        if isinstance(mm_input, torch.Tensor):
            if mm_input.ndim == 2:
                return mm_input
            if mm_input.ndim != 3:
                raise ValueError(f"{name} should be 2D or batched 3D tensor. "
                                 f"Got ndim: {mm_input.ndim}")
            return torch.concat(list(mm_input))
        else:
            return torch.concat(mm_input)

    def _parse_and_validate_image_input(
            self, **kwargs: object) -> Optional[Qwen2VLImageInputs]:
        pixel_values = kwargs.pop("pixel_values", None)
        image_embeds = kwargs.pop("image_embeds", None)
        image_grid_thw = kwargs.pop("image_grid_thw", None)

        if pixel_values is None and image_embeds is None:
            return None

        if pixel_values is not None:
            pixel_values = self._validate_and_reshape_mm_tensor(
                pixel_values, "image pixel values")
            image_grid_thw = self._validate_and_reshape_mm_tensor(
                image_grid_thw, "image grid_thw")

            if not isinstance(pixel_values, (torch.Tensor, list)):
                raise ValueError("Incorrect type of image pixel values. "
                                 f"Got type: {type(pixel_values)}")

            return Qwen2VLImagePixelInputs(type="pixel_values",
                                           data=pixel_values,
                                           image_grid_thw=image_grid_thw)

        if image_embeds is not None:
            image_embeds = self._validate_and_reshape_mm_tensor(
                image_embeds, "image embeds")

            if not isinstance(image_embeds, torch.Tensor):
                raise ValueError("Incorrect type of image embeddings. "
                                 f"Got type: {type(image_embeds)}")
            return Qwen2VLImageEmbeddingInputs(type="image_embeds",
                                               data=image_embeds)

    def _parse_and_validate_video_input(
            self, **kwargs: object) -> Optional[Qwen2VLVideoInputs]:
        pixel_values_videos = kwargs.pop("pixel_values_videos", None)
        video_grid_thw = kwargs.pop("video_grid_thw", None)

        if pixel_values_videos is None:
            return None

        pixel_values_videos = self._validate_and_reshape_mm_tensor(
            pixel_values_videos, "video pixel values")
        video_grid_thw = self._validate_and_reshape_mm_tensor(
            video_grid_thw, "video grid_thw")

        return Qwen2VLVideoInputs(
            pixel_values_videos=pixel_values_videos,
            video_grid_thw=video_grid_thw,
        )

    def _process_image_input(self,
                             image_input: Qwen2VLImageInputs) -> torch.Tensor:
        if image_input["type"] == "image_embeds":
            return image_input["data"].type(self.visual.dtype)

        pixel_values = image_input["data"].type(self.visual.dtype)
        image_embeds = self.visual(pixel_values,
                                   grid_thw=image_input["image_grid_thw"])
        return image_embeds

    def _process_video_input(self,
                             video_input: Qwen2VLVideoInputs) -> torch.Tensor:
        pixel_values_videos = video_input["pixel_values_videos"].type(
            self.visual.dtype)
        video_embeds = self.visual(pixel_values_videos,
                                   grid_thw=video_input["video_grid_thw"])
        return video_embeds

    def _merge_multimodal_embeddings(
        self,
        input_ids: torch.Tensor,
        inputs_embeds: torch.Tensor,
        multimodal_embeddings: torch.Tensor,
        placeholder_token_id: int,
    ) -> torch.Tensor:
        mask = (input_ids == placeholder_token_id)
        inputs_embeds[mask, :] = multimodal_embeddings
        return inputs_embeds

    def forward(
        self,
        input_ids: torch.Tensor,
        positions: torch.Tensor,
        kv_caches: List[torch.Tensor],
        attn_metadata: AttentionMetadata,
        intermediate_tensors: Optional[IntermediateTensors] = None,
        **kwargs: object,
    ) -> Union[torch.Tensor, IntermediateTensors]:
        """Run forward pass for Qwen2-VL.

        Args:
            input_ids: Flattened (concatenated) input_ids corresponding to a
                batch.
            positions: Flattened (concatenated) position ids corresponding to a
                batch.
                **NOTE**: If mrope is enabled (default setting for Qwen2-VL
                opensource models), the shape will be `(3, seq_len)`,
                otherwise it will be `(seq_len,).
            pixel_values: Pixel values to be fed to a model.
                `None` if no images are passed.
            image_grid_thw: Tensor `(n_images, 3)` of image 3D grid in LLM.
                `None` if no images are passed.
            pixel_values_videos: Pixel values of videos to be fed to a model.
                `None` if no videos are passed.
            video_grid_thw: Tensor `(n_videos, 3)` of video 3D grid in LLM.
                `None` if no videos are passed.
        """
        if intermediate_tensors is not None:
            input_ids = None
            inputs_embeds = None
        else:
            image_input = self._parse_and_validate_image_input(**kwargs)
            video_input = self._parse_and_validate_video_input(**kwargs)

            if image_input is None and video_input is None:
                inputs_embeds = None
            else:
                rope_scaling = getattr(self.config, "rope_scaling", {})
                if rope_scaling.get("type", None) == "mrope":
                    assert positions.ndim == 2 and positions.size(0) == 3, (
                        "multimodal section rotary embedding requires "
                        f"(3, seq_len) positions, but got {positions.size()}")

                inputs_embeds = self.model.embed_tokens(input_ids)

                if image_input is not None:
                    image_embeds = self._process_image_input(image_input)
                    inputs_embeds = self._merge_multimodal_embeddings(
                        input_ids,
                        inputs_embeds,
                        image_embeds,
                        placeholder_token_id=self.config.image_token_id,
                    )

                if video_input is not None:
                    video_embeds = self._process_video_input(video_input)
                    inputs_embeds = self._merge_multimodal_embeddings(
                        input_ids,
                        inputs_embeds,
                        video_embeds,
                        placeholder_token_id=self.config.video_token_id,
                    )

                input_ids = None

        hidden_states = self.model(
            input_ids=input_ids,
            positions=positions,
            kv_caches=kv_caches,
            attn_metadata=attn_metadata,
            intermediate_tensors=intermediate_tensors,
            inputs_embeds=inputs_embeds,
        )
        return hidden_states

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

    def sample(
        self,
        logits: torch.Tensor,
        sampling_metadata: SamplingMetadata,
    ) -> Optional[SamplerOutput]:
        next_tokens = self.sampler(logits, sampling_metadata)
        return next_tokens

    def load_weights(self, weights: Iterable[Tuple[str, torch.Tensor]]):
        stacked_params_mapping = [
            # (param_name, shard_name, shard_id)
            ("qkv_proj", "q_proj", "q"),
            ("qkv_proj", "k_proj", "k"),
            ("qkv_proj", "v_proj", "v"),
            ("gate_up_proj", "up_proj", 1),
            ("gate_up_proj", "gate_proj", 0),
        ]
        params_dict = dict(self.named_parameters(remove_duplicate=False))
        for name, loaded_weight in weights:
            if "rotary_emb.inv_freq" in name:
                continue
            if self.config.tie_word_embeddings and "lm_head.weight" in 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)
                # Skip loading extra bias for GPTQ models.
                if name.endswith(".bias") and name not in params_dict:
                    continue
                if is_pp_missing_parameter(name, self):
                    continue
                param = params_dict[name]
                weight_loader = param.weight_loader
                weight_loader(param, loaded_weight, shard_id)
                break
            else:
                if "visual" in name and "qkv.weight" in name:
                    visual_num_heads = self.config.vision_config.num_heads
                    visual_embed_dim = self.config.vision_config.embed_dim
                    head_size = visual_embed_dim // visual_num_heads
                    loaded_weight = loaded_weight.view(3, visual_num_heads,
                                                       head_size,
                                                       visual_embed_dim)
                    loaded_weight = loaded_weight.transpose(0, 1)
                    loaded_weight = loaded_weight.reshape(-1, visual_embed_dim)
                elif "visual" in name and "qkv.bias" in name:
                    visual_num_heads = self.config.vision_config.num_heads
                    visual_embed_dim = self.config.vision_config.embed_dim
                    head_size = visual_embed_dim // visual_num_heads
                    loaded_weight = loaded_weight.view(3, visual_num_heads,
                                                       head_size)
                    loaded_weight = loaded_weight.transpose(0, 1)
                    loaded_weight = loaded_weight.reshape(-1)
                try:
                    # Skip loading extra bias for GPTQ models.
                    if name.endswith(".bias") and name not in params_dict:
                        continue
                    if is_pp_missing_parameter(name, self):
                        continue
                    param = params_dict[name]
                except KeyError:
                    print(params_dict.keys())
                    raise

                weight_loader = getattr(param, "weight_loader",
                                        default_weight_loader)
                weight_loader(param, loaded_weight)
