# Copyright 2023 The Intel Labs Team Authors, The Microsoft Research Team Authors and HuggingFace Inc. team. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""PyTorch BridgeTower Model"""

from collections import OrderedDict
from collections.abc import Callable
from dataclasses import dataclass

import torch
from torch import nn
from torch.nn import CrossEntropyLoss

from ... import initialization as init
from ...activations import ACT2FN, QuickGELUActivation
from ...cache_utils import Cache, DynamicCache, EncoderDecoderCache
from ...masking_utils import create_bidirectional_mask, create_causal_mask
from ...modeling_layers import GradientCheckpointingLayer
from ...modeling_outputs import (
    BaseModelOutputWithPastAndCrossAttentions,
    BaseModelOutputWithPoolingAndCrossAttentions,
    MaskedLMOutput,
    ModelOutput,
    SequenceClassifierOutput,
)
from ...modeling_utils import ALL_ATTENTION_FUNCTIONS, PreTrainedModel
from ...processing_utils import Unpack
from ...pytorch_utils import apply_chunking_to_forward
from ...utils import TransformersKwargs, auto_docstring, logging, torch_int
from ...utils.generic import can_return_tuple, merge_with_config_defaults
from ...utils.output_capturing import capture_outputs
from .configuration_bridgetower import BridgeTowerConfig, BridgeTowerTextConfig, BridgeTowerVisionConfig


logger = logging.get_logger(__name__)

_TOKENIZER_FOR_DOC = "RobertaTokenizer"


@auto_docstring(
    custom_intro="""
    Output type of [`BridgeTowerModel`].
    """
)
@dataclass
class BridgeTowerModelOutput(ModelOutput):
    r"""
    text_features (`torch.FloatTensor` of shape `(batch_size, text_sequence_length, hidden_size)`):
        Sequence of hidden-states at the text output of the last layer of the model.
    image_features (`torch.FloatTensor` of shape `(batch_size, image_sequence_length, hidden_size)`):
        Sequence of hidden-states at the image output of the last layer of the model.
    pooler_output (`torch.FloatTensor` of shape `(batch_size, hidden_size x 2)`):
        Concatenation of last layer hidden-state of the first token of the text and image sequence (classification
        token), respectively, after further processing through layers used for auxiliary pretraining tasks.
    """

    text_features: torch.FloatTensor | None = None
    image_features: torch.FloatTensor | None = None
    pooler_output: torch.FloatTensor | None = None
    hidden_states: tuple[torch.FloatTensor] | None = None
    attentions: tuple[torch.FloatTensor] | None = None


@auto_docstring(
    custom_intro="""
    Output type of ['BridgeTowerForContrastiveLearning']
    """
)
@dataclass
class BridgeTowerContrastiveOutput(ModelOutput):
    r"""
    loss (`torch.FloatTensor` of shape `(1,)`, *optional*, returned when `return_loss` is `True`):
        Image-text contrastive loss.
    logits (`torch.FloatTensor` of shape `(batch_size, sequence_length, config.vocab_size)`):
        Prediction scores of the language modeling head (scores for each vocabulary token before SoftMax).
    text_embeds (`torch.FloatTensor)`, *optional*, returned when model is initialized with `with_projection=True`):
        The text embeddings obtained by applying the projection layer to the pooler_output.
    image_embeds (`torch.FloatTensor)`, *optional*, returned when model is initialized with `with_projection=True`):
        The image embeddings obtained by applying the projection layer to the pooler_output.
    cross_embeds (`torch.FloatTensor)`, *optional*, returned when model is initialized with `with_projection=True`):
        The text-image cross-modal embeddings obtained by applying the projection layer to the pooler_output.
    attentions (`tuple(torch.FloatTensor)`, *optional*, returned when `output_attentions=True` is passed or when `config.output_attentions=True`):
        Tuple of `torch.FloatTensor` (one for each layer) of shape `(batch_size, num_heads, sequence_length,
        sequence_length)`.
    """

    loss: torch.FloatTensor | None = None
    logits: torch.FloatTensor | None = None
    text_embeds: tuple[torch.FloatTensor] | None = None
    image_embeds: tuple[torch.FloatTensor] | None = None
    cross_embeds: tuple[torch.FloatTensor] | None = None
    hidden_states: tuple[torch.FloatTensor] | None = None
    attentions: tuple[torch.FloatTensor] | None = None


class BridgeTowerResidualAttention(nn.Module):
    def __init__(self, config):
        super().__init__()

        self.attn = nn.MultiheadAttention(config.hidden_size, config.hidden_size // 64)
        self.ln_1 = nn.LayerNorm(config.hidden_size, eps=config.layer_norm_eps)
        self.mlp = nn.ModuleDict(
            OrderedDict(
                [
                    ("c_fc", nn.Linear(config.hidden_size, config.hidden_size * 4)),
                    ("gelu", QuickGELUActivation()),
                    ("c_proj", nn.Linear(config.hidden_size * 4, config.hidden_size)),
                ]
            )
        )
        self.ln_2 = nn.LayerNorm(config.hidden_size, eps=config.layer_norm_eps)
        self.attn_mask = None

    def attention(self, hidden_state: torch.Tensor, attention_mask: torch.Tensor):
        if attention_mask is not None:
            attention_mask = attention_mask.to(dtype=torch.bool, device=hidden_state.device)
        self.attn_mask = (
            self.attn_mask.to(dtype=hidden_state.dtype, device=hidden_state.device)
            if self.attn_mask is not None
            else None
        )
        return self.attn(
            hidden_state,
            hidden_state,
            hidden_state,
            need_weights=False,
            attn_mask=self.attn_mask,
            key_padding_mask=attention_mask,
        )[0]

    def forward(self, hidden_state: torch.Tensor, attention_mask: torch.Tensor | None = None):
        residual_state = hidden_state + self.attention(self.ln_1(hidden_state), attention_mask)
        hidden_state = self.ln_2(residual_state)
        for layer in self.mlp.values():
            hidden_state = layer(hidden_state)
        hidden_state = residual_state + hidden_state
        return hidden_state


class BridgeTowerTransformer(nn.Module):
    def __init__(self, config):
        super().__init__()
        self.hidden_size = config.hidden_size
        self.num_hidden_layers = config.num_hidden_layers
        if config.remove_last_layer:
            self.resblocks = nn.ModuleList(
                [BridgeTowerResidualAttention(config) for _ in range(self.num_hidden_layers - 1)]
            )
        else:
            self.resblocks = nn.ModuleList(
                [BridgeTowerResidualAttention(config) for _ in range(self.num_hidden_layers)]
            )
        self.stop_gradient = config.stop_gradient

    def forward(self, hidden_state: torch.Tensor, attention_mask: torch.Tensor | None = None):
        hidden_states = []
        for block in self.resblocks:
            hidden_state = block(hidden_state, attention_mask)
            if self.stop_gradient:
                hidden_states.append(hidden_state.detach())
            else:
                hidden_states.append(hidden_state)
        return hidden_states


# Copied from transformers.models.clip.modeling_clip.CLIPVisionEmbeddings with CLIP->BridgeTower
class BridgeTowerVisionEmbeddings(nn.Module):
    def __init__(self, config: BridgeTowerVisionConfig):
        super().__init__()
        self.config = config
        self.embed_dim = config.hidden_size
        self.image_size = config.image_size
        self.patch_size = config.patch_size

        self.class_embedding = nn.Parameter(torch.randn(self.embed_dim))

        self.patch_embedding = nn.Conv2d(
            in_channels=config.num_channels,
            out_channels=self.embed_dim,
            kernel_size=self.patch_size,
            stride=self.patch_size,
            bias=False,
        )

        self.num_patches = (self.image_size // self.patch_size) ** 2
        self.num_positions = self.num_patches + 1
        self.position_embedding = nn.Embedding(self.num_positions, self.embed_dim)
        self.register_buffer("position_ids", torch.arange(self.num_positions).expand((1, -1)), persistent=False)

    def interpolate_pos_encoding(self, embeddings: torch.Tensor, height: int, width: int) -> torch.Tensor:
        """
        This method allows to interpolate the pre-trained position encodings, to be able to use the model on higher resolution
        images. This method is also adapted to support torch.jit tracing.

        Adapted from:
        - https://github.com/facebookresearch/dino/blob/de9ee3df6cf39fac952ab558447af1fa1365362a/vision_transformer.py#L174-L194, and
        - https://github.com/facebookresearch/dinov2/blob/e1277af2ba9496fbadf7aec6eba56e8d882d1e35/dinov2/models/vision_transformer.py#L179-L211
        """

        num_patches = embeddings.shape[1] - 1
        position_embedding = self.position_embedding.weight.unsqueeze(0)
        num_positions = position_embedding.shape[1] - 1

        # always interpolate when tracing to ensure the exported model works for dynamic input shapes
        if not torch.jit.is_tracing() and num_patches == num_positions and height == width:
            return self.position_embedding(self.position_ids)

        class_pos_embed = position_embedding[:, :1]
        patch_pos_embed = position_embedding[:, 1:]

        dim = embeddings.shape[-1]

        new_height = height // self.patch_size
        new_width = width // self.patch_size

        sqrt_num_positions = torch_int(num_positions**0.5)
        patch_pos_embed = patch_pos_embed.reshape(1, sqrt_num_positions, sqrt_num_positions, dim)
        patch_pos_embed = patch_pos_embed.permute(0, 3, 1, 2)

        patch_pos_embed = nn.functional.interpolate(
            patch_pos_embed,
            size=(new_height, new_width),
            mode="bicubic",
            align_corners=False,
        )

        patch_pos_embed = patch_pos_embed.permute(0, 2, 3, 1).view(1, -1, dim)

        return torch.cat((class_pos_embed, patch_pos_embed), dim=1)

    def forward(self, pixel_values: torch.FloatTensor, interpolate_pos_encoding=False) -> torch.Tensor:
        batch_size, _, height, width = pixel_values.shape
        if not interpolate_pos_encoding and (height != self.image_size or width != self.image_size):
            raise ValueError(
                f"Input image size ({height}*{width}) doesn't match model ({self.image_size}*{self.image_size})."
            )
        target_dtype = self.patch_embedding.weight.dtype
        patch_embeds = self.patch_embedding(pixel_values.to(dtype=target_dtype))  # shape = [*, width, grid, grid]
        patch_embeds = patch_embeds.flatten(2).transpose(1, 2)

        class_embeds = self.class_embedding.expand(batch_size, 1, -1)
        embeddings = torch.cat([class_embeds, patch_embeds], dim=1)
        if interpolate_pos_encoding:
            embeddings = embeddings + self.interpolate_pos_encoding(embeddings, height, width)
        else:
            embeddings = embeddings + self.position_embedding(self.position_ids)
        return embeddings


class BridgeTowerVisionTransformer(nn.Module):
    def __init__(self, config):
        super().__init__()

        self.embeddings = BridgeTowerVisionEmbeddings(config)
        self.ln_pre = nn.LayerNorm(config.hidden_size, eps=config.layer_norm_eps)
        self.transformer = BridgeTowerTransformer(config)
        self.ln_post = nn.LayerNorm(config.hidden_size, eps=config.layer_norm_eps)
        self.share_layernorm = config.share_layernorm
        if not config.share_layernorm:
            self.ln_separate = nn.ModuleList(
                [nn.LayerNorm(config.hidden_size, eps=config.layer_norm_eps) for _ in range(config.num_hidden_layers)]
            )

    def forward(
        self,
        pixel_values: torch.Tensor,
        attention_mask,
        interpolate_pos_encoding: bool = False,
    ):
        hidden_states = self.embeddings(pixel_values, interpolate_pos_encoding)
        hidden_states = self.ln_pre(hidden_states)
        # NLD -> LND
        hidden_states = hidden_states.permute(1, 0, 2)

        hidden_states = self.transformer(hidden_states, attention_mask)
        # shape = [num_hidden_layers, hidden_size, *, grid ** 2]
        hidden_states = torch.stack(hidden_states, dim=0)
        # shape = [num_hidden_layers, *, hidden_size, grid ** 2]
        hidden_states = hidden_states.permute(0, 2, 1, 3)
        if self.share_layernorm:
            hidden_states = self.ln_post(hidden_states)
        else:
            hidden_states_stack = []
            for hidden_states, ln in zip(hidden_states, self.ln_separate):
                hidden_states = ln(hidden_states)
                hidden_states_stack.append(hidden_states)
            # shape = [num_hidden_layers, *, hidden_size, grid ** 2]
            hidden_states = torch.stack(hidden_states_stack, dim=0)
        return hidden_states

    def forward_pre(
        self,
        pixel_values: torch.Tensor,
        interpolate_pos_encoding: bool = False,
    ):
        hidden_states = self.embeddings(pixel_values, interpolate_pos_encoding=interpolate_pos_encoding)
        hidden_states = self.ln_pre(hidden_states)
        # NLD -> LND
        hidden_states = hidden_states.permute(1, 0, 2)
        return hidden_states

    def forward_post(self, hidden_state: torch.Tensor):
        visual_output_post = hidden_state.permute(1, 0, 2)
        visual_output_post = self.ln_post(visual_output_post)
        return visual_output_post


class BridgeTowerLinkTower(nn.Module):
    def __init__(self, config):
        super().__init__()
        self.link_tower_type = config.link_tower_type
        self.hidden_size = config.hidden_size
        if config.link_tower_type in ["add", "scaled_add", "interpolate"]:
            if config.link_tower_type == "scaled_add":
                self.scaled_factor = nn.Parameter(torch.tensor(1.0))
            elif config.link_tower_type == "interpolate":
                self.beta = nn.Parameter(torch.tensor(0.5))
            self.LayerNorm = nn.LayerNorm(self.hidden_size, eps=config.layer_norm_eps)
        else:
            raise NotImplementedError(f"link_tower_type {config.link_tower_type} is not implemented")

    def forward(self, hidden_states, cross_modal_hidden_states, attention_mask):
        if self.link_tower_type == "add":
            return self.LayerNorm(hidden_states + cross_modal_hidden_states)
        elif self.link_tower_type == "scaled_add":
            return self.LayerNorm(hidden_states * self.scaled_factor + cross_modal_hidden_states)
        elif self.link_tower_type == "interpolate":
            return self.LayerNorm(hidden_states * (1 - self.beta) + cross_modal_hidden_states * self.beta)
        else:
            raise NotImplementedError(f"link_tower_type {self.link_tower_type} is not implemented")


# Copied from transformers.models.bert.modeling_bert.BertSelfOutput with Bert->BridgeTower
class BridgeTowerSelfOutput(nn.Module):
    def __init__(self, config):
        super().__init__()
        self.dense = nn.Linear(config.hidden_size, config.hidden_size)
        self.LayerNorm = nn.LayerNorm(config.hidden_size, eps=config.layer_norm_eps)
        self.dropout = nn.Dropout(config.hidden_dropout_prob)

    def forward(self, hidden_states: torch.Tensor, input_tensor: torch.Tensor) -> torch.Tensor:
        hidden_states = self.dense(hidden_states)
        hidden_states = self.dropout(hidden_states)
        hidden_states = self.LayerNorm(hidden_states + input_tensor)
        return hidden_states


# Copied from transformers.models.bert.modeling_bert.BertIntermediate with Bert->BridgeTower
class BridgeTowerIntermediate(nn.Module):
    def __init__(self, config):
        super().__init__()
        self.dense = nn.Linear(config.hidden_size, config.intermediate_size)
        if isinstance(config.hidden_act, str):
            self.intermediate_act_fn = ACT2FN[config.hidden_act]
        else:
            self.intermediate_act_fn = config.hidden_act

    def forward(self, hidden_states: torch.Tensor) -> torch.Tensor:
        hidden_states = self.dense(hidden_states)
        hidden_states = self.intermediate_act_fn(hidden_states)
        return hidden_states


# Copied from transformers.models.bert.modeling_bert.BertOutput with Bert->BridgeTower
class BridgeTowerOutput(nn.Module):
    def __init__(self, config):
        super().__init__()
        self.dense = nn.Linear(config.intermediate_size, config.hidden_size)
        self.LayerNorm = nn.LayerNorm(config.hidden_size, eps=config.layer_norm_eps)
        self.dropout = nn.Dropout(config.hidden_dropout_prob)

    def forward(self, hidden_states: torch.Tensor, input_tensor: torch.Tensor) -> torch.Tensor:
        hidden_states = self.dense(hidden_states)
        hidden_states = self.dropout(hidden_states)
        hidden_states = self.LayerNorm(hidden_states + input_tensor)
        return hidden_states


# Copied from transformers.models.bert.modeling_bert.BertPooler with Bert->BridgeTower
class BridgeTowerPooler(nn.Module):
    def __init__(self, config):
        super().__init__()
        self.dense = nn.Linear(config.hidden_size, config.hidden_size)
        self.activation = nn.Tanh()

    def forward(self, hidden_states: torch.Tensor) -> torch.Tensor:
        # We "pool" the model by simply taking the hidden state corresponding
        # to the first token.
        first_token_tensor = hidden_states[:, 0]
        pooled_output = self.dense(first_token_tensor)
        pooled_output = self.activation(pooled_output)
        return pooled_output


# Copied from transformers.models.bert.modeling_bert.eager_attention_forward
def eager_attention_forward(
    module: nn.Module,
    query: torch.Tensor,
    key: torch.Tensor,
    value: torch.Tensor,
    attention_mask: torch.Tensor | None,
    scaling: float | None = None,
    dropout: float = 0.0,
    **kwargs: Unpack[TransformersKwargs],
):
    if scaling is None:
        scaling = query.size(-1) ** -0.5

    # Take the dot product between "query" and "key" to get the raw attention scores.
    attn_weights = torch.matmul(query, key.transpose(2, 3)) * scaling

    if attention_mask is not None:
        attn_weights = attn_weights + attention_mask

    attn_weights = nn.functional.softmax(attn_weights, dim=-1)
    attn_weights = nn.functional.dropout(attn_weights, p=dropout, training=module.training)

    attn_output = torch.matmul(attn_weights, value)
    attn_output = attn_output.transpose(1, 2).contiguous()

    return attn_output, attn_weights


# Copied from transformers.models.roberta.modeling_roberta.RobertaSelfAttention with Roberta->BridgeTower
class BridgeTowerSelfAttention(nn.Module):
    def __init__(self, config, is_causal=False, layer_idx=None):
        super().__init__()
        if config.hidden_size % config.num_attention_heads != 0 and not hasattr(config, "embedding_size"):
            raise ValueError(
                f"The hidden size ({config.hidden_size}) is not a multiple of the number of attention "
                f"heads ({config.num_attention_heads})"
            )
        self.config = config

        self.num_attention_heads = config.num_attention_heads
        self.attention_head_size = int(config.hidden_size / config.num_attention_heads)
        self.all_head_size = self.num_attention_heads * self.attention_head_size
        self.scaling = self.attention_head_size**-0.5

        self.query = nn.Linear(config.hidden_size, self.all_head_size)
        self.key = nn.Linear(config.hidden_size, self.all_head_size)
        self.value = nn.Linear(config.hidden_size, self.all_head_size)

        self.dropout = nn.Dropout(config.attention_probs_dropout_prob)

        self.is_decoder = config.is_decoder
        self.is_causal = is_causal
        self.layer_idx = layer_idx

    def forward(
        self,
        hidden_states: torch.Tensor,
        attention_mask: torch.FloatTensor | None = None,
        past_key_values: Cache | None = None,
        **kwargs: Unpack[TransformersKwargs],
    ) -> tuple[torch.Tensor]:
        input_shape = hidden_states.shape[:-1]
        hidden_shape = (*input_shape, -1, self.attention_head_size)

        # get all proj
        query_layer = self.query(hidden_states).view(*hidden_shape).transpose(1, 2)
        key_layer = self.key(hidden_states).view(*hidden_shape).transpose(1, 2)
        value_layer = self.value(hidden_states).view(*hidden_shape).transpose(1, 2)

        if past_key_values is not None:
            # decoder-only roberta can have a simple dynamic cache for example
            current_past_key_values = past_key_values
            if isinstance(past_key_values, EncoderDecoderCache):
                current_past_key_values = past_key_values.self_attention_cache

            # save all key/value_layer to cache to be re-used for fast auto-regressive generation
            key_layer, value_layer = current_past_key_values.update(key_layer, value_layer, self.layer_idx)

        attention_interface: Callable = ALL_ATTENTION_FUNCTIONS.get_interface(
            self.config._attn_implementation, eager_attention_forward
        )

        attn_output, attn_weights = attention_interface(
            self,
            query_layer,
            key_layer,
            value_layer,
            attention_mask,
            dropout=0.0 if not self.training else self.dropout.p,
            scaling=self.scaling,
            **kwargs,
        )
        attn_output = attn_output.reshape(*input_shape, -1).contiguous()
        return attn_output, attn_weights


# Copied from transformers.models.roberta.modeling_roberta.RobertaCrossAttention with Roberta->BridgeTower
class BridgeTowerCrossAttention(nn.Module):
    def __init__(self, config, is_causal=False, layer_idx=None):
        super().__init__()
        if config.hidden_size % config.num_attention_heads != 0 and not hasattr(config, "embedding_size"):
            raise ValueError(
                f"The hidden size ({config.hidden_size}) is not a multiple of the number of attention "
                f"heads ({config.num_attention_heads})"
            )
        self.config = config

        self.num_attention_heads = config.num_attention_heads
        self.attention_head_size = int(config.hidden_size / config.num_attention_heads)
        self.all_head_size = self.num_attention_heads * self.attention_head_size
        self.scaling = self.attention_head_size**-0.5

        self.query = nn.Linear(config.hidden_size, self.all_head_size)
        self.key = nn.Linear(config.hidden_size, self.all_head_size)
        self.value = nn.Linear(config.hidden_size, self.all_head_size)

        self.dropout = nn.Dropout(config.attention_probs_dropout_prob)

        self.is_causal = is_causal
        self.layer_idx = layer_idx

    def forward(
        self,
        hidden_states: torch.Tensor,
        encoder_hidden_states: torch.FloatTensor | None = None,
        attention_mask: torch.FloatTensor | None = None,
        past_key_values: EncoderDecoderCache | None = None,
        **kwargs: Unpack[TransformersKwargs],
    ) -> tuple[torch.Tensor]:
        # determine input shapes
        input_shape = hidden_states.shape[:-1]

        hidden_shape = (*input_shape, -1, self.attention_head_size)

        # get query proj
        query_layer = self.query(hidden_states).view(hidden_shape).transpose(1, 2)

        is_updated = past_key_values.is_updated.get(self.layer_idx) if past_key_values is not None else False
        if past_key_values is not None and is_updated:
            # reuse k,v, cross_attentions
            key_layer = past_key_values.cross_attention_cache.layers[self.layer_idx].keys
            value_layer = past_key_values.cross_attention_cache.layers[self.layer_idx].values
        else:
            kv_shape = (*encoder_hidden_states.shape[:-1], -1, self.attention_head_size)
            key_layer = self.key(encoder_hidden_states).view(kv_shape).transpose(1, 2)
            value_layer = self.value(encoder_hidden_states).view(kv_shape).transpose(1, 2)

            if past_key_values is not None:
                # save all states to the cache
                key_layer, value_layer = past_key_values.cross_attention_cache.update(
                    key_layer, value_layer, self.layer_idx
                )
                # set flag that curr layer for cross-attn is already updated so we can re-use in subsequent calls
                past_key_values.is_updated[self.layer_idx] = True

        attention_interface: Callable = ALL_ATTENTION_FUNCTIONS.get_interface(
            self.config._attn_implementation, eager_attention_forward
        )

        attn_output, attn_weights = attention_interface(
            self,
            query_layer,
            key_layer,
            value_layer,
            attention_mask,
            dropout=0.0 if not self.training else self.dropout.p,
            scaling=self.scaling,
            **kwargs,
        )
        attn_output = attn_output.reshape(*input_shape, -1).contiguous()
        return attn_output, attn_weights


# Copied from transformers.models.bert.modeling_bert.BertAttention with Bert->BridgeTower,BERT->BRIDGE_TOWER
class BridgeTowerAttention(nn.Module):
    def __init__(self, config, is_causal=False, layer_idx=None, is_cross_attention=False):
        super().__init__()
        self.is_cross_attention = is_cross_attention
        attention_class = BridgeTowerCrossAttention if is_cross_attention else BridgeTowerSelfAttention
        self.self = attention_class(config, is_causal=is_causal, layer_idx=layer_idx)
        self.output = BridgeTowerSelfOutput(config)

    def forward(
        self,
        hidden_states: torch.Tensor,
        attention_mask: torch.FloatTensor | None = None,
        encoder_hidden_states: torch.FloatTensor | None = None,
        encoder_attention_mask: torch.FloatTensor | None = None,
        past_key_values: Cache | None = None,
        **kwargs: Unpack[TransformersKwargs],
    ) -> tuple[torch.Tensor]:
        attention_mask = attention_mask if not self.is_cross_attention else encoder_attention_mask
        attention_output, attn_weights = self.self(
            hidden_states,
            encoder_hidden_states=encoder_hidden_states,
            attention_mask=attention_mask,
            past_key_values=past_key_values,
            **kwargs,
        )
        attention_output = self.output(attention_output, hidden_states)
        return attention_output, attn_weights


class BridgeTowerBertCrossLayer(nn.Module):
    def __init__(self, config, layer_idx=None):
        super().__init__()
        self.chunk_size_feed_forward = config.chunk_size_feed_forward
        self.seq_len_dim = 1
        self.attention = BridgeTowerAttention(config, is_causal=True, layer_idx=layer_idx)
        self.is_decoder = config.is_decoder
        self.add_cross_attention = config.add_cross_attention
        self.crossattention = BridgeTowerAttention(
            config,
            is_causal=False,
            layer_idx=layer_idx,
            is_cross_attention=True,
        )
        self.intermediate = BridgeTowerIntermediate(config)
        self.output = BridgeTowerOutput(config)

    def forward(
        self,
        hidden_states,
        encoder_hidden_states,
        attention_mask=None,
        encoder_attention_mask=None,
        past_key_values=None,
        **kwargs: Unpack[TransformersKwargs],
    ):
        self_attention_output, self_attn_weights = self.attention(
            hidden_states,
            attention_mask=attention_mask,
            past_key_values=None,
            **kwargs,
        )
        attention_output = self_attention_output

        cross_attention_output, cross_attn_weights = self.crossattention(
            attention_output,
            attention_mask=attention_mask,
            encoder_hidden_states=encoder_hidden_states,
            encoder_attention_mask=encoder_attention_mask,
            past_key_values=past_key_values,
            **kwargs,
        )
        attention_output = cross_attention_output

        layer_output = apply_chunking_to_forward(
            self.feed_forward_chunk, self.chunk_size_feed_forward, self.seq_len_dim, attention_output
        )
        return (
            layer_output,
            self_attn_weights,
            cross_attn_weights,
        )

    def feed_forward_chunk(self, attention_output):
        intermediate_output = self.intermediate(attention_output)
        layer_output = self.output(intermediate_output, attention_output)
        return layer_output


class BridgeTowerTextLayer(GradientCheckpointingLayer):
    def __init__(self, config, layer_idx=None):
        super().__init__()
        self.chunk_size_feed_forward = config.chunk_size_feed_forward
        self.seq_len_dim = 1
        self.attention = BridgeTowerAttention(config, is_causal=config.is_decoder, layer_idx=layer_idx)
        self.is_decoder = config.is_decoder
        self.add_cross_attention = config.add_cross_attention
        if self.add_cross_attention:
            if not self.is_decoder:
                raise ValueError(f"{self} should be used as a decoder model if cross attention is added")
            self.crossattention = BridgeTowerAttention(
                config,
                is_causal=False,
                layer_idx=layer_idx,
                is_cross_attention=True,
            )
        self.intermediate = BridgeTowerIntermediate(config)
        self.output = BridgeTowerOutput(config)

    # copied from transformers.models.bert.modeling_bert.BertLayer.forward
    def forward(
        self,
        hidden_states: torch.Tensor,
        attention_mask: torch.FloatTensor | None = None,
        encoder_hidden_states: torch.FloatTensor | None = None,
        encoder_attention_mask: torch.FloatTensor | None = None,
        past_key_values: Cache | None = None,
        **kwargs: Unpack[TransformersKwargs],
    ) -> torch.Tensor:
        self_attention_output, _ = self.attention(
            hidden_states,
            attention_mask,
            past_key_values=past_key_values,
            **kwargs,
        )
        attention_output = self_attention_output

        if self.is_decoder and encoder_hidden_states is not None:
            if not hasattr(self, "crossattention"):
                raise ValueError(
                    f"If `encoder_hidden_states` are passed, {self} has to be instantiated with cross-attention layers"
                    " by setting `config.add_cross_attention=True`"
                )

            cross_attention_output, _ = self.crossattention(
                self_attention_output,
                None,  # attention_mask
                encoder_hidden_states,
                encoder_attention_mask,
                past_key_values=past_key_values,
                **kwargs,
            )
            attention_output = cross_attention_output

        layer_output = apply_chunking_to_forward(
            self.feed_forward_chunk, self.chunk_size_feed_forward, self.seq_len_dim, attention_output
        )
        return layer_output

    def feed_forward_chunk(self, attention_output):
        intermediate_output = self.intermediate(attention_output)
        layer_output = self.output(intermediate_output, attention_output)
        return layer_output


# copied from transformers.models.roberta.modeling_roberta.RobertaEncoder with Roberta->BridgeTowerText
class BridgeTowerTextEncoder(nn.Module):
    def __init__(self, config):
        super().__init__()
        self.config = config
        self.layer = nn.ModuleList(
            [BridgeTowerTextLayer(config, layer_idx=i) for i in range(config.num_hidden_layers)]
        )

    def forward(
        self,
        hidden_states: torch.Tensor,
        attention_mask: torch.FloatTensor | None = None,
        encoder_hidden_states: torch.FloatTensor | None = None,
        encoder_attention_mask: torch.FloatTensor | None = None,
        past_key_values: Cache | None = None,
        use_cache: bool | None = None,
        **kwargs: Unpack[TransformersKwargs],
    ) -> BaseModelOutputWithPastAndCrossAttentions:
        for layer_module in self.layer:
            hidden_states = layer_module(
                hidden_states,
                attention_mask,
                encoder_hidden_states,  # as a positional argument for gradient checkpointing
                encoder_attention_mask=encoder_attention_mask,
                past_key_values=past_key_values,
                **kwargs,
            )

        return BaseModelOutputWithPastAndCrossAttentions(
            last_hidden_state=hidden_states,
            past_key_values=past_key_values if use_cache else None,
        )


# Copied from transformers.models.roberta.modeling_roberta.RobertaEmbeddings with Roberta->BridgeTowerText
class BridgeTowerTextEmbeddings(nn.Module):
    """Construct the embeddings from word, position and token_type embeddings."""

    def __init__(self, config):
        super().__init__()
        self.word_embeddings = nn.Embedding(config.vocab_size, config.hidden_size, padding_idx=config.pad_token_id)
        self.token_type_embeddings = nn.Embedding(config.type_vocab_size, config.hidden_size)

        self.LayerNorm = nn.LayerNorm(config.hidden_size, eps=config.layer_norm_eps)
        self.dropout = nn.Dropout(config.hidden_dropout_prob)
        # position_ids (1, len position emb) is contiguous in memory and exported when serialized
        self.register_buffer(
            "position_ids", torch.arange(config.max_position_embeddings).expand((1, -1)), persistent=False
        )
        self.register_buffer(
            "token_type_ids", torch.zeros(self.position_ids.size(), dtype=torch.long), persistent=False
        )

        self.padding_idx = config.pad_token_id
        self.position_embeddings = nn.Embedding(
            config.max_position_embeddings, config.hidden_size, padding_idx=self.padding_idx
        )

    def forward(
        self,
        input_ids: torch.LongTensor | None = None,
        token_type_ids: torch.LongTensor | None = None,
        position_ids: torch.LongTensor | None = None,
        inputs_embeds: torch.FloatTensor | None = None,
        past_key_values_length: int = 0,
    ) -> torch.Tensor:
        if position_ids is None:
            if input_ids is not None:
                # Create the position ids from the input token ids. Any padded tokens remain padded.
                position_ids = self.create_position_ids_from_input_ids(
                    input_ids, self.padding_idx, past_key_values_length
                )
            else:
                position_ids = self.create_position_ids_from_inputs_embeds(inputs_embeds, self.padding_idx)

        if input_ids is not None:
            input_shape = input_ids.size()
        else:
            input_shape = inputs_embeds.size()[:-1]

        batch_size, seq_length = input_shape

        # Setting the token_type_ids to the registered buffer in constructor where it is all zeros, which usually occurs
        # when its auto-generated, registered buffer helps users when tracing the model without passing token_type_ids, solves
        # issue #5664
        if token_type_ids is None:
            if hasattr(self, "token_type_ids"):
                # NOTE: We assume either pos ids to have bsz == 1 (broadcastable) or bsz == effective bsz (input_shape[0])
                buffered_token_type_ids = self.token_type_ids.to(position_ids.device).expand(position_ids.shape[0], -1)
                buffered_token_type_ids = torch.gather(buffered_token_type_ids, dim=1, index=position_ids)
                token_type_ids = buffered_token_type_ids.expand(batch_size, seq_length)
            else:
                token_type_ids = torch.zeros(input_shape, dtype=torch.long, device=self.position_ids.device)

        if inputs_embeds is None:
            inputs_embeds = self.word_embeddings(input_ids)
        token_type_embeddings = self.token_type_embeddings(token_type_ids)
        embeddings = inputs_embeds + token_type_embeddings

        position_embeddings = self.position_embeddings(position_ids)
        embeddings = embeddings + position_embeddings

        embeddings = self.LayerNorm(embeddings)
        embeddings = self.dropout(embeddings)
        return embeddings

    @staticmethod
    def create_position_ids_from_inputs_embeds(inputs_embeds, padding_idx):
        """
        We are provided embeddings directly. We cannot infer which are padded so just generate sequential position ids.

        Args:
            inputs_embeds: torch.Tensor

        Returns: torch.Tensor
        """
        input_shape = inputs_embeds.size()[:-1]
        sequence_length = input_shape[1]

        position_ids = torch.arange(
            padding_idx + 1, sequence_length + padding_idx + 1, dtype=torch.long, device=inputs_embeds.device
        )
        return position_ids.unsqueeze(0).expand(input_shape)

    @staticmethod
    def create_position_ids_from_input_ids(input_ids, padding_idx, past_key_values_length=0):
        """
        Replace non-padding symbols with their position numbers. Position numbers begin at padding_idx+1. Padding symbols
        are ignored. This is modified from fairseq's `utils.make_positions`.

        Args:
            x: torch.Tensor x:

        Returns: torch.Tensor
        """
        # The series of casts and type-conversions here are carefully balanced to both work with ONNX export and XLA.
        mask = input_ids.ne(padding_idx).int()
        incremental_indices = (torch.cumsum(mask, dim=1).type_as(mask) + past_key_values_length) * mask
        return incremental_indices.long() + padding_idx


@auto_docstring
class BridgeTowerPreTrainedModel(PreTrainedModel):
    config: BridgeTowerConfig
    base_model_prefix = "bridgetower"
    input_modalities = ("image", "text")
    supports_gradient_checkpointing = False
    _no_split_modules = ["BridgeTowerSelfAttention", "BridgeTowerResidualAttention"]
    _skip_keys_device_placement = ["past_key_values"]
    _can_record_outputs = {
        "hidden_states": BridgeTowerTextLayer,
        "attentions": BridgeTowerSelfAttention,
        "cross_attentions": BridgeTowerCrossAttention,
    }

    @torch.no_grad()
    def _init_weights(self, module: nn.Module):
        std = self.config.initializer_factor
        if isinstance(module, BridgeTowerVisionTransformer):
            proj_std = (self.config.hidden_size**-0.5) * ((2 * self.config.num_hidden_layers) ** -0.5)
            attn_std = self.config.hidden_size**-0.5
            fc_std = (2 * self.config.hidden_size) ** -0.5
            for block in module.transformer.resblocks:
                init.normal_(block.attn.in_proj_weight, std=attn_std * std)
                init.zeros_(block.attn.in_proj_bias)
                init.normal_(block.attn.out_proj.weight, std=proj_std * std)
                init.normal_(block.mlp.c_fc.weight, std=fc_std * std)
                init.normal_(block.mlp.c_proj.weight, std=proj_std * std)

            init.normal_(module.embeddings.class_embedding, std=attn_std * std)
            init.normal_(module.embeddings.position_embedding.weight, std=attn_std * std)
        elif isinstance(module, (nn.Linear, nn.Conv2d, nn.Embedding)):
            init.normal_(module.weight, mean=0.0, std=0.05 * std)
        elif isinstance(module, nn.LayerNorm):
            init.zeros_(module.bias)
            init.ones_(module.weight)
        elif isinstance(module, BridgeTowerForContrastiveLearning):
            init.constant_(module.logit_scale, self.config.logit_scale_init_value)
        elif isinstance(module, BridgeTowerVisionEmbeddings):
            init.copy_(module.position_ids, torch.arange(module.num_positions).expand((1, -1)))
        elif isinstance(module, BridgeTowerTextEmbeddings):
            init.copy_(module.position_ids, torch.arange(module.position_ids.shape[-1]).expand((1, -1)))
            init.zeros_(module.token_type_ids)

        if isinstance(module, (nn.Linear, BridgeTowerMLMHead)) and module.bias is not None:
            init.zeros_(module.bias)


class BridgeTowerVisionModel(BridgeTowerPreTrainedModel):
    config: BridgeTowerVisionConfig
    input_modalities = ("image",)

    def __init__(self, config):
        super().__init__(config)
        self.visual = BridgeTowerVisionTransformer(config)
        self.post_init()

    @property
    def dtype(self):
        return self.visual.embeddings.patch_embedding.weight.dtype

    def forward(self, image, image_mask=None, interpolate_pos_encoding=False, **kwargs):
        return self.visual(image.type(self.dtype), image_mask, interpolate_pos_encoding)


@auto_docstring(
    custom_intro="""
    The model can behave as an encoder (with only self-attention) as well as a decoder, in which case a layer of
    cross-attention is added between the self-attention layers, following the architecture described in *Attention is
    all you need*_ by Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N. Gomez, Lukasz
    Kaiser and Illia Polosukhin.

    To behave as an decoder the model needs to be initialized with the `is_decoder` argument of the configuration set
    to `True`. To be used in a Seq2Seq model, the model needs to initialized with both `is_decoder` argument and
    `add_cross_attention` set to `True`; an `encoder_hidden_states` is then expected as an input to the forward pass.

    .. _*Attention is all you need*: https://huggingface.co/papers/1706.03762
    """
)
class BridgeTowerTextModel(BridgeTowerPreTrainedModel):
    config: BridgeTowerTextConfig
    input_modalities = ("text",)

    def __init__(self, config, add_pooling_layer=True):
        r"""
        add_pooling_layer (bool, *optional*, defaults to `True`):
            Whether to add a pooling layer
        """
        super().__init__(config)
        self.config = config
        self.gradient_checkpointing = False

        self.embeddings = BridgeTowerTextEmbeddings(config)
        self.encoder = BridgeTowerTextEncoder(config)

        self.pooler = BridgeTowerPooler(config) if add_pooling_layer else None

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

    def get_input_embeddings(self):
        return self.embeddings.word_embeddings

    def set_input_embeddings(self, value):
        self.embeddings.word_embeddings = value

    @merge_with_config_defaults
    @capture_outputs
    @auto_docstring
    # NOTE: bridgetower with its multimodality has a more complicated scheme making records harder
    # for now we skip the copies from bert but stay close to the original
    # copied from transformers.models.bert.modeling_bert.BertModel.forward
    def forward(
        self,
        input_ids: torch.Tensor | None = None,
        attention_mask: torch.Tensor | None = None,
        token_type_ids: torch.Tensor | None = None,
        position_ids: torch.Tensor | None = None,
        inputs_embeds: torch.Tensor | None = None,
        encoder_hidden_states: torch.Tensor | None = None,
        encoder_attention_mask: torch.Tensor | None = None,
        past_key_values: Cache | None = None,
        use_cache: bool | None = None,
        **kwargs: Unpack[TransformersKwargs],
    ) -> BaseModelOutputWithPoolingAndCrossAttentions:
        if (input_ids is None) ^ (inputs_embeds is not None):
            raise ValueError("You must specify exactly one of input_ids or inputs_embeds")

        if not self.config.is_decoder:
            use_cache = False

        if use_cache and past_key_values is None:
            past_key_values = EncoderDecoderCache(DynamicCache(config=self.config), DynamicCache(config=self.config))

        past_key_values_length = past_key_values.get_seq_length() if past_key_values is not None else 0

        embedding_output = self.embeddings(
            input_ids=input_ids,
            position_ids=position_ids,
            token_type_ids=token_type_ids,
            inputs_embeds=inputs_embeds,
            past_key_values_length=past_key_values_length,
        )

        attention_mask, encoder_attention_mask = self._create_attention_masks(
            attention_mask=attention_mask,
            encoder_attention_mask=encoder_attention_mask,
            embedding_output=embedding_output,
            encoder_hidden_states=encoder_hidden_states,
            past_key_values=past_key_values,
        )

        encoder_outputs = self.encoder(
            embedding_output,
            attention_mask=attention_mask,
            encoder_hidden_states=encoder_hidden_states,
            encoder_attention_mask=encoder_attention_mask,
            past_key_values=past_key_values,
            use_cache=use_cache,
            position_ids=position_ids,
            **kwargs,
        )
        sequence_output = encoder_outputs[0]
        pooled_output = self.pooler(sequence_output) if self.pooler is not None else None

        return BaseModelOutputWithPoolingAndCrossAttentions(
            last_hidden_state=sequence_output,
            pooler_output=pooled_output,
            past_key_values=encoder_outputs.past_key_values,
        )

    # Copied from transformers.models.bert.modeling_bert.BertModel._create_attention_masks
    def _create_attention_masks(
        self,
        attention_mask,
        encoder_attention_mask,
        embedding_output,
        encoder_hidden_states,
        past_key_values,
    ):
        if self.config.is_decoder:
            attention_mask = create_causal_mask(
                config=self.config,
                inputs_embeds=embedding_output,
                attention_mask=attention_mask,
                past_key_values=past_key_values,
            )
        else:
            attention_mask = create_bidirectional_mask(
                config=self.config,
                inputs_embeds=embedding_output,
                attention_mask=attention_mask,
            )

        if encoder_attention_mask is not None:
            encoder_attention_mask = create_bidirectional_mask(
                config=self.config,
                inputs_embeds=embedding_output,
                attention_mask=encoder_attention_mask,
                encoder_hidden_states=encoder_hidden_states,
            )

        return attention_mask, encoder_attention_mask


@auto_docstring(
    custom_intro="""
    The bare BridgeTower Model transformer outputting BridgeTowerModelOutput object without any specific head on
    """
)
class BridgeTowerModel(BridgeTowerPreTrainedModel):
    def __init__(self, config):
        super().__init__(config)
        self.config = config
        vision_config = config.vision_config
        text_config = config.text_config

        if config.share_cross_modal_transformer_layers:
            self.cross_modal_text_transform = nn.Linear(text_config.hidden_size, config.hidden_size)
            self.cross_modal_image_transform = nn.Linear(vision_config.hidden_size, config.hidden_size)
        else:
            self.cross_modal_text_transform = nn.ModuleList(
                [nn.Linear(text_config.hidden_size, config.hidden_size) for _ in range(config.num_hidden_layers)]
            )
            self.cross_modal_image_transform = nn.ModuleList(
                [nn.Linear(vision_config.hidden_size, config.hidden_size) for _ in range(config.num_hidden_layers)]
            )

        self.token_type_embeddings = nn.Embedding(2, config.hidden_size)

        self.vision_model = BridgeTowerVisionModel(vision_config)

        self.text_model = BridgeTowerTextModel(text_config)

        if not vision_config.share_layernorm and config.init_layernorm_from_vision_encoder:
            for ln in self.vision_model.visual.cross_modal_ln_separate:
                ln.weight.data = self.vision_model.visual.ln_post.weight.data
                ln.bias.data = self.vision_model.visual.ln_post.bias.data

        self.cross_modal_image_layers = nn.ModuleList(
            [BridgeTowerBertCrossLayer(text_config) for _ in range(config.num_hidden_layers)]
        )
        self.cross_modal_text_layers = nn.ModuleList(
            [BridgeTowerBertCrossLayer(text_config) for _ in range(config.num_hidden_layers)]
        )

        # Class token => Linear => Tanh
        self.cross_modal_image_pooler = BridgeTowerPooler(config)
        self.cross_modal_text_pooler = BridgeTowerPooler(config)

        # Initialize BridgeTower Components
        self.cross_modal_text_layernorm = nn.LayerNorm(config.hidden_size, eps=config.layer_norm_eps)
        self.cross_modal_image_layernorm = nn.LayerNorm(config.hidden_size, eps=config.layer_norm_eps)

        if config.share_link_tower_layers:
            self.cross_modal_text_link_tower = BridgeTowerLinkTower(config)
            self.cross_modal_image_link_tower = BridgeTowerLinkTower(config)
        else:
            self.cross_modal_text_link_tower = nn.ModuleList(
                [BridgeTowerLinkTower(config) for _ in range(config.num_hidden_layers - 1)]
            )
            self.cross_modal_image_link_tower = nn.ModuleList(
                [BridgeTowerLinkTower(config) for _ in range(config.num_hidden_layers - 1)]
            )

        self.post_init()

    def get_input_embeddings(self):
        return self.text_model.get_input_embeddings()

    def set_input_embeddings(self, value):
        self.text_model.set_input_embeddings(value)

    def _apply_text_transform(self, hidden_states: torch.Tensor, layer_idx: int) -> torch.Tensor:
        if self.config.share_cross_modal_transformer_layers:
            return self.cross_modal_text_transform(hidden_states)
        return self.cross_modal_text_transform[layer_idx](hidden_states)

    def _apply_image_transform(self, hidden_states: torch.Tensor, layer_idx: int) -> torch.Tensor:
        if self.config.share_cross_modal_transformer_layers:
            return self.cross_modal_image_transform(hidden_states)
        return self.cross_modal_image_transform[layer_idx](hidden_states)

    @can_return_tuple
    @auto_docstring
    def forward(
        self,
        input_ids: torch.LongTensor | None = None,
        attention_mask: torch.FloatTensor | None = None,
        token_type_ids: torch.LongTensor | None = None,
        pixel_values: torch.FloatTensor | None = None,
        pixel_mask: torch.LongTensor | None = None,
        inputs_embeds: torch.FloatTensor | None = None,
        image_embeds: torch.FloatTensor | None = None,
        image_token_type_idx: int | None = None,
        labels: torch.LongTensor | None = None,
        interpolate_pos_encoding: bool = False,
        **kwargs: Unpack[TransformersKwargs],
    ) -> tuple[torch.Tensor] | BridgeTowerModelOutput:
        r"""
        image_embeds (`torch.FloatTensor` of shape `(batch_size, num_patches, hidden_size)`, *optional*):
            Optionally, instead of passing `pixel_values`, you can choose to directly pass an embedded representation.
            This is useful if you want more control over how to convert `pixel_values` into patch embeddings.
        image_token_type_idx (`int`, *optional*):
            - The token type ids for images.
        labels (`torch.LongTensor` of shape `(batch_size,)`, *optional*):
            Labels are currently not supported.

        Examples:

        ```python
        >>> from transformers import BridgeTowerProcessor, BridgeTowerModel
        >>> from PIL import Image
        >>> import httpx
        >>> from io import BytesIO

        >>> # prepare image and text
        >>> url = "http://images.cocodataset.org/val2017/000000039769.jpg"
        >>> with httpx.stream("GET", url) as response:
        ...     image = Image.open(BytesIO(response.read()))
        >>> text = "hello world"
        >>> processor = BridgeTowerProcessor.from_pretrained("BridgeTower/bridgetower-base")
        >>> model = BridgeTowerModel.from_pretrained("BridgeTower/bridgetower-base")

        >>> inputs = processor(image, text, return_tensors="pt")
        >>> outputs = model(**inputs)
        >>> outputs.keys()
        odict_keys(['text_features', 'image_features', 'pooler_output'])
        ```"""
        all_hidden_states_text = []
        all_hidden_states_image = []
        all_hidden_states_cross = []
        all_self_attentions = []

        if inputs_embeds is not None and input_ids is None:
            raise NotImplementedError(
                "BridgeTowerModel does not use `inputs_embeds`.  Make sure to pass in `input_ids` instead."
            )

        image_token_type_idx = image_token_type_idx or 1
        input_shape = input_ids.size()
        text_embeds = self.text_model.embeddings(input_ids=input_ids)
        all_hidden_states_text.append(text_embeds)

        if attention_mask is None:
            attention_mask = torch.ones(input_shape, dtype=torch.long, device=input_ids.device)

        extend_text_masks = create_bidirectional_mask(
            config=self.config,
            inputs_embeds=text_embeds[:, 0:1, :],  # weird case where the mask always wants q_len == 1
            attention_mask=attention_mask,
        )

        # The split_index determines how many layers of the uni-modal encoder are applied before the cross-modal encoder
        split_index = len(self.text_model.encoder.layer) - self.config.num_hidden_layers + 1

        # Run the first 'split_index' layers of the textual encoder
        for layer in self.text_model.encoder.layer[:split_index]:
            text_embeds = layer(text_embeds, extend_text_masks)
            all_hidden_states_text.append(text_embeds)

        if image_embeds is None:
            image_embeds = self.vision_model.visual.forward_pre(
                pixel_values.type(self.vision_model.dtype), interpolate_pos_encoding=interpolate_pos_encoding
            )
        else:
            # Permute as BridgeTowerResidualAttention has batch_first=True
            image_embeds = image_embeds.permute(1, 0, 2)

        all_hidden_states_image.append(image_embeds)

        # Run the first 'split_index' layers of the visual encoder
        for block in self.vision_model.visual.transformer.resblocks[:split_index]:
            image_embeds = block(image_embeds)
            all_hidden_states_image.append(image_embeds)

        image_embeds_with_ln = self.vision_model.visual.forward_post(image_embeds.type(self.vision_model.dtype))

        # first layer is a special case because we don't have the output from the cross-encoder yet
        cross_modal_text = self._apply_text_transform(text_embeds, layer_idx=0)

        text_token_type_embeddings = self.token_type_embeddings(
            torch.zeros(1, dtype=torch.long, device=input_ids.device)
        ).expand_as(cross_modal_text)

        cross_modal_text = self.cross_modal_text_layernorm(cross_modal_text + text_token_type_embeddings)

        image_embeds_with_ln = self._apply_image_transform(image_embeds_with_ln, layer_idx=0)
        image_token_type_embeddings = self.token_type_embeddings(
            torch.full((1,), image_token_type_idx, dtype=torch.long, device=input_ids.device)
        ).expand_as(image_embeds_with_ln)

        image_embeds_with_ln = image_embeds_with_ln + image_token_type_embeddings
        cross_modal_image = self.cross_modal_image_layernorm(image_embeds_with_ln)

        pixel_mask = torch.ones(
            (cross_modal_image.size(0), cross_modal_image.size(1)),
            dtype=torch.long,
            device=input_ids.device,
        )
        extend_image_masks = create_bidirectional_mask(
            config=self.config,
            inputs_embeds=cross_modal_image,
            attention_mask=pixel_mask,
        )

        layer_outputs_text = self.cross_modal_text_layers[0](
            cross_modal_text,
            cross_modal_image,
            attention_mask=extend_text_masks,
            encoder_attention_mask=extend_image_masks,
        )
        cross_text_features = layer_outputs_text[0]

        layer_outputs_image = self.cross_modal_image_layers[0](
            cross_modal_image,
            cross_modal_text,
            attention_mask=extend_image_masks,
            encoder_attention_mask=extend_text_masks,
        )
        cross_image_features = layer_outputs_image[0]

        all_hidden_states_cross.append((cross_text_features, cross_image_features))

        all_self_attentions.append((layer_outputs_text[1], layer_outputs_image[1]))

        link_layer_index = 0

        #  Each of the top 6 layers of the visual and textual encoders ([split_index:]) is connected to each layer of
        #  the cross-modal encoder via bridge layers, which brings bottom-up alignment and fusion to the cross-modal encoder.
        for i in range(split_index, len(self.text_model.encoder.layer)):
            text_embeds = self.text_model.encoder.layer[i](text_embeds, extend_text_masks)
            image_embeds = self.vision_model.visual.transformer.resblocks[i](image_embeds).type(
                self.vision_model.dtype
            )
            image_embeds_with_ln = (
                self._apply_image_transform(self.vision_model.visual.forward_post(image_embeds), link_layer_index + 1)
                + image_token_type_embeddings
            )

            text_link_tower = self.cross_modal_text_link_tower[link_layer_index]
            image_link_tower = self.cross_modal_image_link_tower[link_layer_index]

            # Bridge layers for textual and visual encoders
            transformed_text_embeds = self._apply_text_transform(text_embeds, link_layer_index + 1)
            cross_text_features_ = text_link_tower(
                transformed_text_embeds + text_token_type_embeddings,
                cross_text_features,
                extend_text_masks,
            )
            cross_image_features_ = image_link_tower(image_embeds_with_ln, cross_image_features, extend_image_masks)

            # Cross-modal encoder via bridge layers of textual and visual encoders
            layer_outputs_text = self.cross_modal_text_layers[link_layer_index + 1](
                cross_text_features_,
                cross_image_features_,
                attention_mask=extend_text_masks,
                encoder_attention_mask=extend_image_masks,
            )
            cross_text_features = layer_outputs_text[0]

            layer_outputs_image = self.cross_modal_image_layers[link_layer_index + 1](
                cross_image_features_,
                cross_text_features_,
                attention_mask=extend_image_masks,
                encoder_attention_mask=extend_text_masks,
            )
            cross_image_features = layer_outputs_image[0]

            link_layer_index += 1

            all_hidden_states_text.append(text_embeds)
            all_hidden_states_image.append(image_embeds)
            all_hidden_states_cross.append((cross_text_features, cross_image_features))

            all_self_attentions.append((layer_outputs_text[1], layer_outputs_image[1]))

        #  Concatenate the cls token of the text and image features to get the final represtation
        text_features, image_features = cross_text_features, cross_image_features
        cls_features = self.get_cls_features(text_features, image_features)

        return BridgeTowerModelOutput(
            text_features=text_features,
            image_features=image_features,
            pooler_output=cls_features,
            hidden_states=(
                tuple(all_hidden_states_text),
                tuple(all_hidden_states_image),
                tuple(all_hidden_states_cross),
            ),
            attentions=tuple(all_self_attentions),
        )

    def get_cls_features(self, text_features, image_features):
        cls_features_text = self.cross_modal_text_pooler(text_features)
        cls_features_image = self.cross_modal_image_pooler(image_features)
        return torch.cat([cls_features_text, cls_features_image], dim=-1)


# Copied from transformers.models.vilt.modeling_vilt.ViltPredictionHeadTransform with Vilt->BridgeTower
class BridgeTowerPredictionHeadTransform(nn.Module):
    def __init__(self, config):
        super().__init__()
        self.dense = nn.Linear(config.hidden_size, config.hidden_size)
        if isinstance(config.hidden_act, str):
            self.transform_act_fn = ACT2FN[config.hidden_act]
        else:
            self.transform_act_fn = config.hidden_act
        self.LayerNorm = nn.LayerNorm(config.hidden_size, eps=config.layer_norm_eps)

    def forward(self, hidden_states):
        hidden_states = self.dense(hidden_states)
        hidden_states = self.transform_act_fn(hidden_states)
        hidden_states = self.LayerNorm(hidden_states)
        return hidden_states


class BridgeTowerMLMHead(nn.Module):
    def __init__(self, config, weight=None):
        super().__init__()
        self.config = config
        self.transform = BridgeTowerPredictionHeadTransform(config)
        self.decoder = nn.Linear(config.hidden_size, config.text_config.vocab_size, bias=False)
        self.bias = nn.Parameter(torch.zeros(config.text_config.vocab_size))
        if weight is not None:
            self.decoder.weight = weight

    def forward(self, x):
        mlm_score = self.transform(x)
        mlm_score = self.decoder(mlm_score) + self.bias
        return mlm_score


class BridgeTowerITMHead(nn.Module):
    def __init__(self, hidden_size):
        super().__init__()
        self.fc = nn.Linear(hidden_size, 2)

    def forward(self, x):
        itm_score = self.fc(x)
        return itm_score


@auto_docstring(
    custom_intro="""
    BridgeTower Model with a language modeling head on top as done during pretraining.
    """
)
class BridgeTowerForMaskedLM(BridgeTowerPreTrainedModel):
    _tied_weights_keys = {"mlm_score.decoder.weight": "bridgetower.text_model.embeddings.word_embeddings.weight"}

    def __init__(self, config):
        super().__init__(config)

        self.bridgetower = BridgeTowerModel(config)
        self.mlm_score = BridgeTowerMLMHead(config)

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

    def get_output_embeddings(self):
        return self.mlm_score.decoder

    def set_output_embeddings(self, new_embeddings):
        self.mlm_score.decoder = new_embeddings

    @can_return_tuple
    @auto_docstring
    def forward(
        self,
        input_ids: torch.LongTensor | None = None,
        attention_mask: torch.FloatTensor | None = None,
        token_type_ids: torch.LongTensor | None = None,
        pixel_values: torch.FloatTensor | None = None,
        pixel_mask: torch.LongTensor | None = None,
        inputs_embeds: torch.FloatTensor | None = None,
        image_embeds: torch.FloatTensor | None = None,
        labels: torch.LongTensor | None = None,
        **kwargs: Unpack[TransformersKwargs],
    ) -> MaskedLMOutput:
        r"""
        image_embeds (`torch.FloatTensor` of shape `(batch_size, num_patches, hidden_size)`, *optional*):
            Optionally, instead of passing `pixel_values`, you can choose to directly pass an embedded representation.
            This is useful if you want more control over how to convert `pixel_values` into patch embeddings.
        labels (`torch.LongTensor` of shape `(batch_size, sequence_length)`, *optional*):
            Labels for computing the masked language modeling loss. Indices should be in `[-100, 0, ...,
            config.vocab_size]` (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]`

        Examples:

        ```python
        >>> from transformers import BridgeTowerProcessor, BridgeTowerForMaskedLM
        >>> from PIL import Image
        >>> import httpx
        >>> from io import BytesIO

        >>> url = "http://images.cocodataset.org/val2017/000000360943.jpg"
        >>> with httpx.stream("GET", url) as response:
        ...     image = Image.open(BytesIO(response.read())).convert("RGB")
        >>> text = "a <mask> looking out of the window"

        >>> processor = BridgeTowerProcessor.from_pretrained("BridgeTower/bridgetower-base-itm-mlm")
        >>> model = BridgeTowerForMaskedLM.from_pretrained("BridgeTower/bridgetower-base-itm-mlm")

        >>> # prepare inputs
        >>> encoding = processor(image, text, return_tensors="pt")

        >>> # forward pass
        >>> outputs = model(**encoding)

        >>> results = processor.decode(outputs.logits.argmax(dim=-1).squeeze(0).tolist())

        >>> print(results)
        .a cat looking out of the window.
        ```"""
        outputs = self.bridgetower(
            input_ids=input_ids,
            attention_mask=attention_mask,
            token_type_ids=token_type_ids,
            pixel_values=pixel_values,
            pixel_mask=pixel_mask,
            inputs_embeds=inputs_embeds,
            image_embeds=image_embeds,
            **kwargs,
        )

        mlm_logits = self.mlm_score(outputs.text_features)
        masked_lm_loss = None
        if labels is not None:
            loss_fct = CrossEntropyLoss()  # -100 index = padding token

            labels = labels.to(mlm_logits.device)
            masked_lm_loss = loss_fct(mlm_logits.view(-1, self.config.text_config.vocab_size), labels.view(-1))

        return MaskedLMOutput(
            loss=masked_lm_loss,
            logits=mlm_logits,
            hidden_states=outputs.hidden_states,
            attentions=outputs.attentions,
        )


@auto_docstring(
    custom_intro="""
    BridgeTower Model transformer with a classifier head on top (a linear layer on top of the final hidden state of the
    [CLS] token) for image-to-text matching.
    """
)
class BridgeTowerForImageAndTextRetrieval(BridgeTowerPreTrainedModel):
    def __init__(self, config):
        super().__init__(config)

        self.bridgetower = BridgeTowerModel(config)

        self.itm_score = BridgeTowerITMHead(config.hidden_size * 2)

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

    @can_return_tuple
    @auto_docstring
    def forward(
        self,
        input_ids: torch.LongTensor | None = None,
        attention_mask: torch.FloatTensor | None = None,
        token_type_ids: torch.LongTensor | None = None,
        pixel_values: torch.FloatTensor | None = None,
        pixel_mask: torch.LongTensor | None = None,
        inputs_embeds: torch.FloatTensor | None = None,
        image_embeds: torch.FloatTensor | None = None,
        labels: torch.LongTensor | None = None,
        **kwargs: Unpack[TransformersKwargs],
    ) -> SequenceClassifierOutput:
        r"""
        image_embeds (`torch.FloatTensor` of shape `(batch_size, num_patches, hidden_size)`, *optional*):
            Optionally, instead of passing `pixel_values`, you can choose to directly pass an embedded representation.
            This is useful if you want more control over how to convert `pixel_values` into patch embeddings.
        labels (`torch.LongTensor` of shape `(batch_size, 1)`, *optional*):
            Labels for computing the image-text matching loss. 0 means the pairs don't match and 1 means they match.
            The pairs with 0 will be skipped for calculation.

        Examples:

        ```python
        >>> from transformers import BridgeTowerProcessor, BridgeTowerForImageAndTextRetrieval
        >>> import httpx
        >>> from io import BytesIO
        >>> from PIL import Image

        >>> url = "http://images.cocodataset.org/val2017/000000039769.jpg"
        >>> with httpx.stream("GET", url) as response:
        ...     image = Image.open(BytesIO(response.read()))
        >>> texts = ["An image of two cats chilling on a couch", "A football player scoring a goal"]

        >>> processor = BridgeTowerProcessor.from_pretrained("BridgeTower/bridgetower-base-itm-mlm")
        >>> model = BridgeTowerForImageAndTextRetrieval.from_pretrained("BridgeTower/bridgetower-base-itm-mlm")

        >>> # forward pass
        >>> scores = dict()
        >>> for text in texts:
        ...     # prepare inputs
        ...     encoding = processor(image, text, return_tensors="pt")
        ...     outputs = model(**encoding)
        ...     scores[text] = outputs.logits[0, 1].item()
        ```"""
        outputs = self.bridgetower(
            input_ids=input_ids,
            attention_mask=attention_mask,
            token_type_ids=token_type_ids,
            pixel_values=pixel_values,
            pixel_mask=pixel_mask,
            inputs_embeds=inputs_embeds,
            image_embeds=image_embeds,
            **kwargs,
        )

        pooler_output = outputs.pooler_output

        logits = self.itm_score(pooler_output)

        itm_loss = None
        if labels is not None:
            loss_fct = CrossEntropyLoss()

            labels = labels.to(logits.device)
            itm_loss = loss_fct(logits, labels)

        return SequenceClassifierOutput(
            loss=itm_loss,
            logits=logits,
            hidden_states=outputs.hidden_states,
            attentions=outputs.attentions,
        )


class BridgeTowerContrastiveHead(nn.Module):
    def __init__(self, hidden_size, embed_size):
        super().__init__()
        self.fc = nn.Linear(hidden_size, embed_size)

    def forward(self, x):
        x = self.fc(x)
        return x


@auto_docstring(
    custom_intro="""
    BridgeTower Model with a image-text contrastive head on top computing image-text contrastive loss.
    """
)
class BridgeTowerForContrastiveLearning(BridgeTowerPreTrainedModel):
    def __init__(self, config):
        super().__init__(config)

        self.bridgetower = BridgeTowerModel(config)

        self.itc_text_head = BridgeTowerContrastiveHead(config.hidden_size, config.contrastive_hidden_size)
        self.itc_image_head = BridgeTowerContrastiveHead(config.hidden_size, config.contrastive_hidden_size)
        self.itc_cross_modal_head = BridgeTowerContrastiveHead(config.hidden_size * 2, config.contrastive_hidden_size)

        self.logit_scale = nn.Parameter(torch.tensor(self.config.logit_scale_init_value))
        # Initialize weights and apply final processing
        self.post_init()

    @can_return_tuple
    @auto_docstring
    def forward(
        self,
        input_ids: torch.LongTensor | None = None,
        attention_mask: torch.FloatTensor | None = None,
        token_type_ids: torch.LongTensor | None = None,
        pixel_values: torch.FloatTensor | None = None,
        pixel_mask: torch.LongTensor | None = None,
        inputs_embeds: torch.FloatTensor | None = None,
        image_embeds: torch.FloatTensor | None = None,
        return_loss: bool | None = None,
        **kwargs: Unpack[TransformersKwargs],
    ) -> BridgeTowerContrastiveOutput:
        r"""
        image_embeds (`torch.FloatTensor` of shape `(batch_size, num_patches, hidden_size)`, *optional*):
            Optionally, instead of passing `pixel_values`, you can choose to directly pass an embedded representation.
            This is useful if you want more control over how to convert `pixel_values` into patch embeddings.
        return_loss (`bool`, *optional*):
            Whether or not to return the contrastive loss.

        Examples:

        ```python
        >>> from transformers import BridgeTowerProcessor, BridgeTowerForContrastiveLearning
        >>> import httpx
        >>> from io import BytesIO
        >>> from PIL import Image
        >>> import torch

        >>> image_urls = [
        ...     "https://farm4.staticflickr.com/3395/3428278415_81c3e27f15_z.jpg",
        ...     "http://images.cocodataset.org/val2017/000000039769.jpg",
        ... ]
        >>> texts = ["two dogs in a car", "two cats sleeping on a couch"]

        >>> with httpx.stream("GET", urls[0]) as response:
        ...     image1 = Image.open(BytesIO(response.read()))

        >>> with httpx.stream("GET", urls[1]) as response:
        ...     image2 = Image.open(BytesIO(response.read()))

        >>> images = [image1, image2]

        >>> processor = BridgeTowerProcessor.from_pretrained("BridgeTower/bridgetower-large-itm-mlm-itc")
        >>> model = BridgeTowerForContrastiveLearning.from_pretrained("BridgeTower/bridgetower-large-itm-mlm-itc")

        >>> inputs = processor(images, texts, padding=True, return_tensors="pt")
        >>> loss = model(**inputs, return_loss=True).loss

        >>> inputs = processor(images, texts[::-1], padding=True, return_tensors="pt")
        >>> loss_swapped = model(**inputs, return_loss=True).loss

        >>> print("Loss", round(loss.item(), 4))
        Loss 0.0019

        >>> print("Loss with swapped images", round(loss_swapped.item(), 4))
        Loss with swapped images 2.126
        ```"""
        kwargs.setdefault("output_hidden_states", True)
        outputs = self.bridgetower(
            input_ids=input_ids,
            attention_mask=attention_mask,
            token_type_ids=token_type_ids,
            pixel_values=pixel_values,
            pixel_mask=pixel_mask,
            inputs_embeds=inputs_embeds,
            image_embeds=image_embeds,
            **kwargs,
        )

        pooler_output = outputs.pooler_output
        hidden_states_txt, hidden_states_img, hidden_states_cross_modal = outputs.hidden_states

        text_embeds = hidden_states_txt[-1]
        image_embeds = hidden_states_img[-1]

        image_embeds_with_ln = self.bridgetower.vision_model.visual.forward_post(image_embeds)
        image_token_type_embeddings = self.bridgetower.token_type_embeddings(
            torch.full((1,), 1, dtype=torch.long, device=self.bridgetower.token_type_embeddings.weight.device)
        ).expand_as(image_embeds_with_ln)

        image_embeds = self.bridgetower.cross_modal_image_transform(image_embeds_with_ln) + image_token_type_embeddings

        # normalized features
        text_embeds = nn.functional.normalize(self.itc_text_head(text_embeds[:, 0, :]), dim=-1, p=2)
        image_embeds = nn.functional.normalize(self.itc_image_head(image_embeds[:, 0, :]), dim=-1, p=2).to(
            device=text_embeds.device
        )
        cross_embeds = nn.functional.normalize(self.itc_cross_modal_head(pooler_output), dim=-1, p=2).to(
            device=text_embeds.device
        )

        logits = torch.stack([text_embeds, image_embeds, cross_embeds], dim=-2)

        logit_scale = self.logit_scale.exp().to(device=text_embeds.device)
        logits_text_to_image = torch.matmul(text_embeds, image_embeds.t()) * logit_scale
        logits_text_to_cross = torch.matmul(text_embeds, cross_embeds.t()) * logit_scale
        logits_image_to_cross = torch.matmul(image_embeds, cross_embeds.t()) * logit_scale

        itc_loss = None

        if return_loss:
            labels = torch.arange(len(logits), device=logits.device)
            text_to_image_loss = nn.functional.cross_entropy(logits_text_to_image, labels)
            text_to_cross_loss = nn.functional.cross_entropy(logits_text_to_cross, labels)
            image_to_cross_loss = nn.functional.cross_entropy(logits_image_to_cross, labels)
            itc_loss = (text_to_image_loss + text_to_cross_loss + image_to_cross_loss) / 3.0

        return BridgeTowerContrastiveOutput(
            loss=itc_loss,
            logits=logits,
            text_embeds=text_embeds,
            image_embeds=image_embeds,
            cross_embeds=cross_embeds,
            hidden_states=outputs.hidden_states,
            attentions=outputs.attentions,
        )


__all__ = [
    "BridgeTowerForContrastiveLearning",
    "BridgeTowerForImageAndTextRetrieval",
    "BridgeTowerForMaskedLM",
    "BridgeTowerModel",
    "BridgeTowerPreTrainedModel",
]
