# Copyright 2024 The HuggingFace Inc. 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.
"""
Processor class for UDOP.
"""

from transformers import logging

from ...image_processing_utils import BatchFeature
from ...image_utils import ImageInput
from ...processing_utils import ProcessingKwargs, ProcessorMixin, TextKwargs, Unpack
from ...tokenization_utils_base import PreTokenizedInput, TextInput
from ...utils import auto_docstring


logger = logging.get_logger(__name__)


class UdopTextKwargs(TextKwargs, total=False):
    word_labels: list[int] | list[list[int]] | None
    boxes: list[list[int]] | list[list[list[int]]] | None


class UdopProcessorKwargs(ProcessingKwargs, total=False):
    text_kwargs: UdopTextKwargs
    _defaults = {
        "text_kwargs": {
            "add_special_tokens": True,
            "padding": False,
            "truncation": False,
            "stride": 0,
            "return_overflowing_tokens": False,
            "return_special_tokens_mask": False,
            "return_offsets_mapping": False,
            "return_length": False,
            "verbose": True,
        },
    }


@auto_docstring
class UdopProcessor(ProcessorMixin):
    r"""
    Constructs a UDOP processor which combines a LayoutLMv3 image processor and a UDOP tokenizer into a single processor.

    [`UdopProcessor`] offers all the functionalities you need to prepare data for the model.

    It first uses [`LayoutLMv3ImageProcessor`] to resize, rescale and normalize document images, and optionally applies OCR
    to get words and normalized bounding boxes. These are then provided to [`UdopTokenizer`],
    which turns the words and bounding boxes into token-level `input_ids`, `attention_mask`, `token_type_ids`, `bbox`.
    Optionally, one can provide integer `word_labels`, which are turned into token-level `labels` for token
    classification tasks (such as FUNSD, CORD).

    Additionally, it also supports passing `text_target` and `text_pair_target` to the tokenizer, which can be used to
    prepare labels for language modeling tasks.
    """

    def __init__(self, image_processor, tokenizer):
        super().__init__(image_processor, tokenizer)

    @auto_docstring
    def __call__(
        self,
        images: ImageInput | None = None,
        text: TextInput | PreTokenizedInput | list[TextInput] | list[PreTokenizedInput] = None,
        **kwargs: Unpack[UdopProcessorKwargs],
    ) -> BatchFeature:
        # verify input
        output_kwargs = self._merge_kwargs(
            UdopProcessorKwargs,
            tokenizer_init_kwargs=self.tokenizer.init_kwargs,
            **kwargs,
        )

        boxes = output_kwargs["text_kwargs"].pop("boxes", None)
        word_labels = output_kwargs["text_kwargs"].pop("word_labels", None)
        text_pair = output_kwargs["text_kwargs"].pop("text_pair", None)
        return_overflowing_tokens = output_kwargs["text_kwargs"].get("return_overflowing_tokens", False)
        return_offsets_mapping = output_kwargs["text_kwargs"].get("return_offsets_mapping", False)
        text_target = output_kwargs["text_kwargs"].get("text_target", None)

        if self.image_processor.apply_ocr and (boxes is not None):
            raise ValueError(
                "You cannot provide bounding boxes if you initialized the image processor with apply_ocr set to True."
            )

        if self.image_processor.apply_ocr and (word_labels is not None):
            raise ValueError(
                "You cannot provide word labels if you initialized the image processor with apply_ocr set to True."
            )

        if return_overflowing_tokens and not return_offsets_mapping:
            raise ValueError("You cannot return overflowing tokens without returning the offsets mapping.")

        if text_target is not None:
            # use the processor to prepare the targets of UDOP
            return self.tokenizer(
                **output_kwargs["text_kwargs"],
            )

        else:
            # use the processor to prepare the inputs of UDOP
            # first, apply the image processor
            features = self.image_processor(images=images, **output_kwargs["images_kwargs"])
            features_words = features.pop("words", None)
            features_boxes = features.pop("boxes", None)

            output_kwargs["text_kwargs"].pop("text_target", None)
            output_kwargs["text_kwargs"].pop("text_pair_target", None)
            output_kwargs["text_kwargs"]["text_pair"] = text_pair
            output_kwargs["text_kwargs"]["boxes"] = boxes if boxes is not None else features_boxes
            output_kwargs["text_kwargs"]["word_labels"] = word_labels

            # second, apply the tokenizer
            if text is not None and self.image_processor.apply_ocr and text_pair is None:
                if isinstance(text, str):
                    text = [text]  # add batch dimension (as the image processor always adds a batch dimension)
                output_kwargs["text_kwargs"]["text_pair"] = features_words

            encoded_inputs = self.tokenizer(
                text=text if text is not None else features_words,
                **output_kwargs["text_kwargs"],
            )

            # add pixel values
            if return_overflowing_tokens is True:
                features["pixel_values"] = self.get_overflowing_images(
                    features["pixel_values"], encoded_inputs["overflow_to_sample_mapping"]
                )
            features.update(encoded_inputs)

            return features

    # Copied from transformers.models.layoutlmv3.processing_layoutlmv3.LayoutLMv3Processor.get_overflowing_images
    def get_overflowing_images(self, images, overflow_to_sample_mapping):
        # in case there's an overflow, ensure each `input_ids` sample is mapped to its corresponding image
        images_with_overflow = []
        for sample_idx in overflow_to_sample_mapping:
            images_with_overflow.append(images[sample_idx])

        if len(images_with_overflow) != len(overflow_to_sample_mapping):
            raise ValueError(
                "Expected length of images to be the same as the length of `overflow_to_sample_mapping`, but got"
                f" {len(images_with_overflow)} and {len(overflow_to_sample_mapping)}"
            )

        return images_with_overflow

    @property
    def model_input_names(self):
        tokenizer_input_names = self.tokenizer.model_input_names
        image_processor_input_names = self.image_processor.model_input_names

        return list(tokenizer_input_names + image_processor_input_names + ["bbox"])


__all__ = ["UdopProcessor"]