import copy
import json
import os

import datasets

_CITATION = """\@inproceedings{parikh2020totto,
title={{ToTTo}: A Controlled Table-To-Text Generation Dataset},
author={Parikh, Ankur P and Wang, Xuezhi and Gehrmann, Sebastian and Faruqui, Manaal and Dhingra, Bhuwan and Yang, Diyi and Das, Dipanjan},
booktitle={Proceedings of EMNLP},
year={2020}
}
"""

_DESCRIPTION = """\
ToTTo is an open-domain English table-to-text dataset with over 120,000 training examples that proposes a controlled generation task: given a Wikipedia table and a set of highlighted table cells, produce a one-sentence description.
"""

_URLs = {
    "totto": {
        "data": "https://storage.googleapis.com/totto-public/totto_data.zip",
        "challenge_set": "https://storage.googleapis.com/huggingface-nlp/datasets/gem/gem_challenge_sets/totto.zip",
    },
}


def _add_adjusted_col_offsets(table):
    """Add adjusted column offsets to take into account multi-column cells."""
    adjusted_table = []
    for row in table:
        real_col_index = 0
        adjusted_row = []
        for cell in row:
            adjusted_cell = copy.deepcopy(cell)
            adjusted_cell["adjusted_col_start"] = real_col_index
            adjusted_cell["adjusted_col_end"] = (
                adjusted_cell["adjusted_col_start"] + adjusted_cell["column_span"]
            )
            real_col_index += adjusted_cell["column_span"]
            adjusted_row.append(adjusted_cell)
        adjusted_table.append(adjusted_row)
    return adjusted_table


def _get_heuristic_row_headers(adjusted_table, row_index, col_index):
    """Heuristic to find row headers."""
    row_headers = []
    row = adjusted_table[row_index]
    for i in range(0, col_index):
        if row[i]["is_header"]:
            row_headers.append(row[i])
    return row_headers


def _get_heuristic_col_headers(adjusted_table, row_index, col_index):
    """Heuristic to find column headers."""
    adjusted_cell = adjusted_table[row_index][col_index]
    adjusted_col_start = adjusted_cell["adjusted_col_start"]
    adjusted_col_end = adjusted_cell["adjusted_col_end"]
    col_headers = []
    for r in range(0, row_index):
        row = adjusted_table[r]
        for cell in row:
            if (
                cell["adjusted_col_start"] < adjusted_col_end
                and cell["adjusted_col_end"] > adjusted_col_start
            ):
                if cell["is_header"]:
                    col_headers.append(cell)

    return col_headers


def get_highlighted_subtable(table, cell_indices, with_heuristic_headers=False):
    """Extract out the highlighted part of a table."""
    highlighted_table = []

    adjusted_table = _add_adjusted_col_offsets(table)

    for (row_index, col_index) in cell_indices:
        cell = table[row_index][col_index]
        if with_heuristic_headers:
            row_headers = _get_heuristic_row_headers(
                adjusted_table, row_index, col_index
            )
            col_headers = _get_heuristic_col_headers(
                adjusted_table, row_index, col_index
            )
        else:
            row_headers = []
            col_headers = []

        highlighted_cell = {
            "cell": cell,
            "row_headers": row_headers,
            "col_headers": col_headers,
        }
        highlighted_table.append(highlighted_cell)

    return highlighted_table


def linearize_subtable(subtable, table_page_title, table_section_title):
    """Linearize the highlighted subtable and return a string of its contents."""
    table_str = ""
    if table_page_title:
        table_str += "<page_title> " + table_page_title + " </page_title> "
    if table_section_title:
        table_str += "<section_title> " + table_section_title + " </section_title> "
    table_str += "<table> "

    for item in subtable:
        cell = item["cell"]
        row_headers = item["row_headers"]
        col_headers = item["col_headers"]

        # The value of the cell.
        item_str = "<cell> " + cell["value"] + " "

        # All the column headers associated with this cell.
        for col_header in col_headers:
            item_str += "<col_header> " + col_header["value"] + " </col_header> "

        # All the row headers associated with this cell.
        for row_header in row_headers:
            item_str += "<row_header> " + row_header["value"] + " </row_header> "

        item_str += "</cell> "
        table_str += item_str

    table_str += "</table>"
    return table_str


def linearize(example):
    table = example["table"]
    table_page_title = example["table_page_title"]
    table_section_title = example["table_section_title"]
    cell_indices = example["highlighted_cells"]
    subtable = get_highlighted_subtable(
        table=table, cell_indices=cell_indices, with_heuristic_headers=True
    )

    subtable_metadata_str = linearize_subtable(
        subtable=subtable,
        table_page_title=table_page_title,
        table_section_title=table_section_title,
    )
    return subtable_metadata_str


class Totto(datasets.GeneratorBasedBuilder):

    BUILDER_CONFIGS = [
        datasets.BuilderConfig(
            name="totto",
            version=datasets.Version("1.0.0"),
            description=f"GEM benchmark: struct2text task",
        )
    ]

    def _info(self):
        return datasets.DatasetInfo(
            description=_DESCRIPTION,
            features=datasets.Features(
                {
                    "gem_id": datasets.Value("string"),
                    "gem_parent_id": datasets.Value("string"),
                    "totto_id": datasets.Value("int32"),
                    "table_page_title": datasets.Value("string"),
                    "table_webpage_url": datasets.Value("string"),
                    "table_section_title": datasets.Value("string"),
                    "table_section_text": datasets.Value("string"),
                    "table": [
                        [
                            {
                                "column_span": datasets.Value("int32"),
                                "is_header": datasets.Value("bool"),
                                "row_span": datasets.Value("int32"),
                                "value": datasets.Value("string"),
                            }
                        ]
                    ],
                    "highlighted_cells": [[datasets.Value("int32")]],
                    "example_id": datasets.Value("string"),
                    "sentence_annotations": [
                        {
                            "original_sentence": datasets.Value("string"),
                            "sentence_after_deletion": datasets.Value("string"),
                            "sentence_after_ambiguity": datasets.Value("string"),
                            "final_sentence": datasets.Value("string"),
                        }
                    ],
                    "overlap_subset": datasets.Value("string"),
                    "target": datasets.Value("string"),  # single target for train
                    "references": [datasets.Value("string")],
                    "linearized_input": datasets.Value("string"),
                },
            ),
            supervised_keys=None,
            homepage="",
            citation=_CITATION,
        )

    def _split_generators(self, dl_manager):
        """Returns SplitGenerators."""
        dl_dir = dl_manager.download_and_extract(_URLs[self.config.name])
        challenge_sets = [
            ("challenge_train_sample", "train_totto_RandomSample500.json"),
            ("challenge_validation_sample", "validation_totto_RandomSample500.json"),
            # ("challenge_test_scramble", "test_totto_ScrambleInputStructure500.json"),
        ]

        return [
            datasets.SplitGenerator(
                name=datasets.Split.TRAIN,
                gen_kwargs={
                    "filepath": os.path.join(
                        dl_dir["data"], "totto_data/totto_train_data.jsonl"
                    ),
                    "split": "train",
                },
            ),
            datasets.SplitGenerator(
                name=datasets.Split.VALIDATION,
                gen_kwargs={
                    "filepath": os.path.join(
                        dl_dir["data"], "totto_data/totto_dev_data.jsonl"
                    ),
                    "split": "validation",
                },
            ),
            datasets.SplitGenerator(
                name=datasets.Split.TEST,
                gen_kwargs={
                    "filepath": os.path.join(
                        dl_dir["data"], "totto_data/unlabeled_totto_test_data.jsonl"
                    ),
                    "split": "test",
                },
            ),
        ] + [
            datasets.SplitGenerator(
                name=challenge_split,
                gen_kwargs={
                    "filepath": os.path.join(
                        dl_dir["challenge_set"], self.config.name, filename
                    ),
                    "split": challenge_split,
                },
            )
            for challenge_split, filename in challenge_sets
        ]

    def _generate_examples(self, filepath, split, filepaths=None, lang=None):
        """Yields examples."""
        if "challenge" in split:
            exples = json.load(open(filepath, encoding="utf-8"))
            if isinstance(exples, dict):
                assert len(exples) == 1, "multiple entries found"
                exples = list(exples.values())[0]
            for id_, exple in enumerate(exples):
                if len(exple) == 0:
                    continue
                exple["gem_parent_id"] = exple["gem_id"]
                exple["gem_id"] = f"{self.config.name}-{split}-{id_}"
                exple["linearized_input"] = linearize(exple)
                yield id_, exple
        else:
            with open(filepath, "r", encoding="utf-8") as json_file:
                json_list = list(json_file)
                id_ = -1
                i = -1
                for json_str in json_list:
                    result = json.loads(json_str)
                    linearized_input = linearize(result)
                    if split == "train":
                        i += 1
                        for sentence in result["sentence_annotations"]:
                            id_ += 1
                            response = {
                                "gem_id": f"{self.config.name}-{split}-{id_}",
                                "gem_parent_id": f"{self.config.name}-{split}-{id_}",
                                "totto_id": i,
                                "table_page_title": result["table_page_title"],
                                "table_webpage_url": result["table_webpage_url"],
                                "table_section_title": result["table_section_title"],
                                "table_section_text": result["table_section_text"],
                                "table": result["table"],
                                "highlighted_cells": result["highlighted_cells"],
                                "example_id": str(result["example_id"]),
                                "overlap_subset": "none",
                                "sentence_annotations": [sentence],
                                "references": [sentence["final_sentence"]],
                                "target": sentence["final_sentence"],
                                "linearized_input": linearized_input,
                            }
                            yield id_, response
                    else:
                        id_ += 1
                        response = {
                            "gem_id": f"{self.config.name}-{split}-{id_}",
                            "gem_parent_id": f"{self.config.name}-{split}-{id_}",
                            "totto_id": id_,
                            "table_page_title": result["table_page_title"],
                            "table_webpage_url": result["table_webpage_url"],
                            "table_section_title": result["table_section_title"],
                            "table_section_text": result["table_section_text"],
                            "table": result["table"],
                            "highlighted_cells": result["highlighted_cells"],
                            "example_id": str(result["example_id"]),
                            "overlap_subset": str(result["overlap_subset"]),
                            "linearized_input": linearized_input,
                        }
                        response["sentence_annotations"] = (
                            [] if split == "test" else result["sentence_annotations"]
                        )
                        response["references"] = [
                            sentence["final_sentence"]
                            for sentence in response["sentence_annotations"]
                        ]
                        response["target"] = (
                            response["references"][0]
                            if len(response["references"]) > 0
                            else ""
                        )
                        yield id_, response