# Copyright 2010, DPR authors, The Hugging Face Team.
#
# 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.
"""DPR model configuration"""

from ...configuration_utils import PreTrainedConfig
from ...utils import logging


logger = logging.get_logger(__name__)


class DPRConfig(PreTrainedConfig):
    r"""
    [`DPRConfig`] is the configuration class to store the configuration of a *DPRModel*.

    This is the configuration class to store the configuration of a [`DPRContextEncoder`], [`DPRQuestionEncoder`], or a
    [`DPRReader`]. It is used to instantiate the components of the DPR model according to the specified arguments,
    defining the model component architectures. Instantiating a configuration with the defaults will yield a similar
    configuration to that of the DPRContextEncoder
    [facebook/dpr-ctx_encoder-single-nq-base](https://huggingface.co/facebook/dpr-ctx_encoder-single-nq-base)
    architecture.

    This class is a subclass of [`BertConfig`]. Please check the superclass for the documentation of all kwargs.

    Args:
        vocab_size (`int`, *optional*, defaults to 30522):
            Vocabulary size of the DPR model. Defines the different tokens that can be represented by the *inputs_ids*
            passed to the forward method of [`BertModel`].
        hidden_size (`int`, *optional*, defaults to 768):
            Dimensionality of the encoder layers and the pooler layer.
        num_hidden_layers (`int`, *optional*, defaults to 12):
            Number of hidden layers in the Transformer encoder.
        num_attention_heads (`int`, *optional*, defaults to 12):
            Number of attention heads for each attention layer in the Transformer encoder.
        intermediate_size (`int`, *optional*, defaults to 3072):
            Dimensionality of the "intermediate" (i.e., feed-forward) layer in the Transformer encoder.
        hidden_act (`str` or `function`, *optional*, defaults to `"gelu"`):
            The non-linear activation function (function or string) in the encoder and pooler. If string, `"gelu"`,
            `"relu"`, `"silu"` and `"gelu_new"` are supported.
        hidden_dropout_prob (`float`, *optional*, defaults to 0.1):
            The dropout probability for all fully connected layers in the embeddings, encoder, and pooler.
        attention_probs_dropout_prob (`float`, *optional*, defaults to 0.1):
            The dropout ratio for the attention probabilities.
        max_position_embeddings (`int`, *optional*, defaults to 512):
            The maximum sequence length that this model might ever be used with. Typically set this to something large
            just in case (e.g., 512 or 1024 or 2048).
        type_vocab_size (`int`, *optional*, defaults to 2):
            The vocabulary size of the *token_type_ids* passed into [`BertModel`].
        initializer_range (`float`, *optional*, defaults to 0.02):
            The standard deviation of the truncated_normal_initializer for initializing all weight matrices.
        layer_norm_eps (`float`, *optional*, defaults to 1e-12):
            The epsilon used by the layer normalization layers.
        pad_token_id (`int`, *optional*, defaults to 0):
            Padding token id.
        bos_token_id (`int`, *optional*):
            Beginning of stream token id.
        eos_token_id (`int`, *optional*):
            End of stream token id.
        projection_dim (`int`, *optional*, defaults to 0):
            Dimension of the projection for the context and question encoders. If it is set to zero (default), then no
            projection is done.
        is_decoder (`bool`, *optional*, defaults to `False`):
            Whether to only use the decoder in an encoder-decoder architecture, otherwise it has no effect on
            decoder-only or encoder-only architectures.
        add_cross_attention (`bool`, *optional*, defaults to `False`):
            Whether cross-attention layers should be added to the model.

    Example:

    ```python
    >>> from transformers import DPRConfig, DPRContextEncoder

    >>> # Initializing a DPR facebook/dpr-ctx_encoder-single-nq-base style configuration
    >>> configuration = DPRConfig()

    >>> # Initializing a model (with random weights) from the facebook/dpr-ctx_encoder-single-nq-base style configuration
    >>> model = DPRContextEncoder(configuration)

    >>> # Accessing the model configuration
    >>> configuration = model.config
    ```"""

    model_type = "dpr"

    def __init__(
        self,
        vocab_size=30522,
        hidden_size=768,
        num_hidden_layers=12,
        num_attention_heads=12,
        intermediate_size=3072,
        hidden_act="gelu",
        hidden_dropout_prob=0.1,
        attention_probs_dropout_prob=0.1,
        max_position_embeddings=512,
        type_vocab_size=2,
        initializer_range=0.02,
        layer_norm_eps=1e-12,
        pad_token_id=0,
        bos_token_id=None,
        eos_token_id=None,
        projection_dim: int = 0,
        is_decoder=False,
        add_cross_attention=False,
        **kwargs,
    ):
        super().__init__(**kwargs)
        self.pad_token_id = pad_token_id
        self.bos_token_id = bos_token_id
        self.eos_token_id = eos_token_id
        self.is_decoder = is_decoder
        self.add_cross_attention = add_cross_attention

        self.vocab_size = vocab_size
        self.hidden_size = hidden_size
        self.num_hidden_layers = num_hidden_layers
        self.num_attention_heads = num_attention_heads
        self.hidden_act = hidden_act
        self.intermediate_size = intermediate_size
        self.hidden_dropout_prob = hidden_dropout_prob
        self.attention_probs_dropout_prob = attention_probs_dropout_prob
        self.max_position_embeddings = max_position_embeddings
        self.type_vocab_size = type_vocab_size
        self.initializer_range = initializer_range
        self.layer_norm_eps = layer_norm_eps
        self.projection_dim = projection_dim


__all__ = ["DPRConfig"]