import os
import re
import heapq
import pickle
import struct
import contextlib
import numpy as np
from typing import Generator
from pathlib import Path
from dataclasses import dataclass, field
from fsspec.spec import AbstractBufferedFile
from datatrove.data import DocumentsPipeline
from datatrove.io import DataFolderLike, get_datafolder
from datatrove.pipeline.base import PipelineStep
from datatrove.pipeline.writers.disk_base import DiskWriter
from datatrove.utils.binaryio import read_tuples_from_file, seek_to_start
from datatrove.utils.hashing import HashConfig, create_hash_func
from datatrove.utils.logging import logger
from datatrove.utils.text import TextNormConfig, ngrams
from datatrove.utils.typeshelper import StatHints


# http://en.wikipedia.org/wiki/Mersenne_prime
_mersenne_prime = np.uint64((1 << 61) - 1)

SENTINEL = (1 << 32) - 1

dataset_map = {}
datasets = []
cnt = 0

def transform(dataset_idx: int, line_no: int) -> int:
    global cnt
    global dataset_map
    global datasets
    if dataset_idx not in dataset_map:
        dataset_map[dataset_idx] = cnt
        datasets.append(dataset_idx)
        cnt += 1
    return line_no * 10000 + dataset_map[dataset_idx]


@dataclass
class CustomMinhashConfig:
    """Configuration for Min-Hash deduplication

    Args:
        n_grams: n-grams size to use
        num_buckets: number of buckets to use
        seed: random seed used to generate the hash function parameters. Should be the same on all workers to ensure they all have the same parameters
    """

    n_grams: int = 13
    num_buckets: int = 9
    num_hashs: int = 128
    seed: int = 1

    norm_config: TextNormConfig = field(default_factory=TextNormConfig)
    hash_config: HashConfig = field(default_factory=HashConfig)

    def __str__(self):
        return f"{self.n_grams}ng_{self.num_buckets}bs_{self.hash_config}"


@dataclass(order=True)
class HashSig:
    """Hash signature for a given document in a given bucket

    Args:
        sig: tuple of hashes
        file_id: file id
        doc_id: document id
        reader_id: reader id. Used to know from where the next signature should be requested
    """

    sig: tuple[int]
    doc_id: int

    data_index: int
    reader_id: int

    def is_from_index(self):
        return False


def read_sigs(
    file: AbstractBufferedFile,
    config: CustomMinhashConfig,
    index_file: bool = False,
    min_hash: int = 0,
    max_hash: int = _mersenne_prime,
    ensure_order: bool = True,
    lines_to_buffer: int = 5,
    reader_id: int = 0,
) -> Generator:
    """Read signatures from a file

    Args:
        file: file to read from
        reader_id: reader id
        config: minhash configuration (a MinhashConfig object)
        index_file: is index file
    """
    line_format = f"{config.n_grams}{config.hash_config.struct_format}{'I' if not index_file else ''}"
    with file as f:
        if f.size == 0:
            return
        seek_to_start(f, min_hash, line_format, config.hash_config.struct_format)
        last = None
        # CC-MAIN-2013-20_00000.minhash.sig
        file_stem = Path(file.path).name.removesuffix(".minhash.sig")

        data_index = 0
        if len(file_stem) == 21:
            dataset_year = int(file_stem[8:12])
            dataset_num = int(file_stem[13:15])
            parquet_num = int(file_stem[16:21])
            # 13 20 00000
            data_index = ((dataset_year % 100) * 100 + dataset_num) * 100000 + parquet_num

        for data in read_tuples_from_file(f, line_format, lines_to_buffer=lines_to_buffer):
            sigdata = data if index_file else data[:-1]
            assert sigdata[0] >= min_hash and (
                ensure_order is False or last is None or sigdata >= last
            ), f"Hash order error. {f.tell()=}, {min_hash=}, {sigdata=}, {last=}"
            if sigdata[0] >= max_hash:
                break
            last = sigdata
            yield (
                HashSig(sig=sigdata, doc_id=-1, data_index=data_index, reader_id=reader_id)
                if index_file
                else HashSig(sig=sigdata, doc_id=data[-1], data_index=data_index, reader_id=reader_id)
            )


class CustomMinhashDedupSignature(PipelineStep):
    """Minhash Deduplication: First Pipeline Step

        Compute the minhash signature for each document and write it to disk.

    Args:
        output_folder: output folder
        config: minhash configuration (a MinhashConfig object)
    """

    type = "🫂 - DEDUP"
    name = "🎯 MinHash stage 1"

    def __init__(self, output_folder: DataFolderLike, config: CustomMinhashConfig = None, naming_prefix: str = ''):
        super().__init__()
        self.output_folder = get_datafolder(output_folder)
        self.config = config or CustomMinhashConfig()
        self.num_hashes = self.config.num_hashs
        self.naming_prefix = naming_prefix
        self._parameters = None
        self._hash_func = create_hash_func(self.config.hash_config)

    @property
    def parameters(self):
        """Minhash parameters

        Create parameters for a random bijective permutation function
        that maps a 32/64-bit hash value to another 32/64-bit hash value.
        http://en.wikipedia.org/wiki/Universal_hashing

        Note: For 64-bit hashes the upper-bound for codomain is not [0,2**64) but [0,2**61 - 1)
        """
        if self._parameters is None:
            gen = np.random.RandomState(self.config.seed)
            self._parameters = np.array(
                [
                    (
                        gen.randint(1, _mersenne_prime, dtype=np.uint64),
                        gen.randint(0, _mersenne_prime, dtype=np.uint64),
                    )
                    for _ in range(self.num_hashes)
                ],
                dtype=np.uint64,
            ).T
        return self._parameters

    def get_signature(self, shingles: np.ndarray) -> list[list[int]]:
        """Get the signature for a set of shingles (n-grams)

        Args:
            shingles: shingles (n-grams) numpy uint64 array of size (N, 1)

        Returns:
            list (num buckets) of lists of integers (hashes)
        """
        a, b = self.parameters
        phv = (shingles * a + b) % _mersenne_prime
        if self.config.hash_config.precision == 32:
            phv = np.bitwise_and(phv, self.config.hash_config.max)
        return [
            x.tolist()
            for x in np.split(np.min(phv, axis=0)[:self.config.num_buckets * self.config.n_grams], self.config.num_buckets)
        ]

    def get_shingles(self, text: str) -> np.ndarray:
        """Get shingles (hashed n-grams) from a string of text

        Shingles are created by hashing n-grams of simplified text (lower cases, whitespace normalized, no punctuation, etc).

        Args:
            text: input text

        Returns:
            numpy array of shingles: dtype = uint64, shape = (number of n_grams in string, 1)
        """
        return np.fromiter(
            [
                self._hash_func("".join(x))
                for x in ngrams(text, self.config.n_grams)
            ],
            dtype=np.uint64,
        ).reshape((-1, 1))

    # def write_buckets(self, batch_id, rank, band_hash_value_list):
    #     try:
    #         for bucket in range(self.config.num_buckets):
    #             with self.output_folder.open(f"{bucket:02d}/{batch_id:05d}_{rank:05d}.minhash.pkl", mode="wb") as fout:
    #                 pickle.dump(band_hash_value_list[bucket], fout)
    #     except Exception as e:
    #         logger.error(f"dump minhash fail, error: {e}")

    def run(self, data: DocumentsPipeline, rank: int = 0, world_size: int = 1) -> DocumentsPipeline:
        buckets = [
            self.output_folder.open(f"bucket_{bi:03d}/{self.naming_prefix}_{rank:05d}.minhash.sig", mode="wb")
            for bi in range(self.config.num_buckets)
        ]
        with self.track_time():
            # batch_id = 0
            for doc_idx, doc in enumerate(data):
                self.stat_update(StatHints.total)

                shingles = self.get_shingles(doc.text)
                if shingles.size != 0:
                    sig = self.get_signature(shingles)
                    for bi, (bucket, bucket_sig) in enumerate(zip(buckets, sig)):
                        # print(f"{self.n_grams=} {bucket_sig=}")
                        bucket.write(
                            struct.pack(
                                f"<{self.config.n_grams}{self.config.hash_config.struct_format}I",
                                *bucket_sig,
                                doc_idx,
                            )
                        )
            for file in buckets:
                file.close()

            logger.info("Sorting buckets...")
            for bi in range(len(buckets)):
                # read one by one, sort and write back
                sigs = sorted(
                    read_sigs(
                        self.output_folder.open(f"bucket_{bi:03d}/{self.naming_prefix}_{rank:05d}.minhash.sig", mode="rb"),
                        self.config,
                        ensure_order=False,
                        lines_to_buffer=-1,  # load everything in one go
                    )
                )
                with self.output_folder.open(f"bucket_{bi:03d}/{self.naming_prefix}_{rank:05d}.minhash.sig", mode="wb") as fo:
                    for sig in sigs:
                        fo.write(
                            struct.pack(
                                f"<{self.config.n_grams}{self.config.hash_config.struct_format}I",
                                *sig.sig,
                                sig.doc_id,
                            )
                        )


class CustomMinhashDedupBuckets(PipelineStep):
    """Minhash Deduplication: Second Pipeline Step

        Find duplicate pairs from the signatures and possibly an index. Can also save an index with the new signatures.

    Args:
        input_folder: input folder containing the signature from step 1
        output_folder: output folder where results (document duplicate pairs) will be saved
        index_folder: index folder. If set, we will load all index files in this folder and use them as a reference for deduplicating the current dataset (remove any matches on our dataset with signatures from the index)
        config: minhash configuration (a MinhashConfig object)
        only_dedup_in_index: only deduplicate versus index (ignore any matches between 2 documents in our input dataset)
        create_index_name: create index name. If this parameter is set, index files will be created with this name that other datasets can use as a reference for dedup. Set to `None` to disable index file creation.
    """

    type = "🫂 - DEDUP"
    name = "🎯 MinHash stage 2"

    def __init__(
        self,
        input_folder: DataFolderLike,
        output_folder: DataFolderLike,
        config: CustomMinhashConfig = None,
        lines_to_buffer: int = 5,
    ):
        super().__init__()
        self.input_folder = get_datafolder(input_folder)
        self.output_folder = get_datafolder(output_folder)
        self.config = config or CustomMinhashConfig()
        self.lines_to_buffer = lines_to_buffer

    def get_worker_hash_range(self, sig_files, rank, world_size):
        workers_per_bucket = world_size // self.config.num_buckets
        bucket, bucket_worker = divmod(rank, workers_per_bucket)
        hash_min, hash_max = (
            0,
            _mersenne_prime if self.config.hash_config.precision == 64 else self.config.hash_config.max,
        )
        if workers_per_bucket > 1 and len(sig_files):
            # take the first file and find bucket_worker boundaries. all workers in a bucket process the same set of
            # files, so this should be consistent across workers (and span the entire range of hashes)
            with self.input_folder.open(sig_files[0], mode="rb") as f:
                line_size = struct.calcsize(f"{self.config.n_grams}{self.config.hash_config.struct_format}I")
                L, rem = divmod(f.size, line_size)
                assert rem == 0, "file size not divisible by line size"
                assert L >= workers_per_bucket, f"tried to use {workers_per_bucket=} but there are only {L} lines"
                if bucket_worker > 0:
                    # not first
                    f.seek(line_size * (L // workers_per_bucket) * bucket_worker, os.SEEK_SET)
                    hash_min = struct.unpack(
                        self.config.hash_config.struct_format,
                        f.read(struct.calcsize(self.config.hash_config.struct_format)),
                    )[0]
                if bucket_worker + 1 < workers_per_bucket:
                    # not last
                    f.seek(line_size * (L // workers_per_bucket) * (bucket_worker + 1), os.SEEK_SET)
                    hash_max = struct.unpack(
                        self.config.hash_config.struct_format,
                        f.read(struct.calcsize(self.config.hash_config.struct_format)),
                    )[0]
        return hash_min, hash_max

    def run(self, data: DocumentsPipeline = None, rank: int = 0, world_size: int = 1):
        assert data is None, "You should not use an input block before MinhashDedupBuckets"
        assert (world_size % self.config.num_buckets) == 0, "Number of tasks must be divisible by num_buckets"
        workers_per_bucket = world_size // self.config.num_buckets
        bucket, bucket_worker = divmod(rank, workers_per_bucket)

        with self.track_time():
            sig_files = self.input_folder.list_files(subdirectory=f"bucket_{bucket:03d}")
            hash_min, hash_max = self.get_worker_hash_range(sig_files, rank, world_size)

            logger.info(
                f"Running worker {bucket_worker + 1}/{workers_per_bucket} on bucket {bucket:03d}. "
                f"Hash range: {[hash_min, hash_max]}"
            )

            sig_readers = [
                read_sigs(
                    file,
                    self.config,
                    min_hash=hash_min,
                    max_hash=hash_max,
                    lines_to_buffer=self.lines_to_buffer,
                    reader_id=file_i,
                )
                for file_i, file in enumerate(self.input_folder.open_files(sig_files, mode="rb"))
            ]

            pq = [x for x in [next(sig_reader, None) for sig_reader in sig_readers] if x is not None]
            heapq.heapify(pq)
            logger.info("Finished initializing signatures priority queue.")

            with self.output_folder.open(f"{bucket:05d}_{bucket_worker:02d}.dups", mode="wb") as out_f:
                last: HashSig | None = None
                while pq:
                    v: HashSig = heapq.heappop(pq)
                    assert last is None or v >= last, f"Sig queue sort error. {v=} < {last=}"
                    if last and last.sig == v.sig:
                        # write (file_id1, doc_id1, file_id2, doc_id2)
                        out_f.write(
                            struct.pack("<4I", last.data_index, last.doc_id, v.data_index, v.doc_id)
                        )
                        self.stat_update("total_matches")
                    last = v
                    next_sig = next(sig_readers[v.reader_id], None)
                    if next_sig:
                        assert next_sig >= v, f"Next sig sort error. {next_sig=} < {v=}"
                        heapq.heappush(pq, next_sig)


class CustomMinhashDedupCluster(PipelineStep):
    """Minhash Deduplication: Third Pipeline Step

    Cluster the documents using the previously found duplicate pairs. If A-B and B-C are duplicate pairs, then we will have the A-B-C cluster. Only one document per cluster will be kept after filtering
    """

    type = "🫂 - DEDUP"
    name = "🎯 MinHash stage 3"

    def __init__(
        self,
        input_folder: DataFolderLike,
        output_folder: DataFolderLike,
        config: CustomMinhashConfig = None,
        ignore_index_matches: bool = False,
        lines_to_buffer: int = 5,
    ):
        super().__init__()
        self.input_folder = get_datafolder(input_folder)
        self.output_folder = get_datafolder(output_folder)
        self.config = config or CustomMinhashConfig()
        self.ignore_index_matches = ignore_index_matches
        self.lines_to_buffer = lines_to_buffer

    def run(self, data: DocumentsPipeline = None, _: int = 0, world_size: int = 1):
        global datasets
        global dataset_map

        dup_files = self.input_folder.list_files(glob_pattern="*.dups")
        assert (
            len(dup_files) % self.config.num_buckets
        ) == 0, "Number of .dups files should be divisible by number of buckets"
        assert world_size == 1, "World size must be 1 for clustering"
        union_set = np.arange(0, 1_500_000 * 10_000, dtype=np.uint64)
        exists = np.zeros(1_500_000 * 10_000, dtype=bool)

        max_no = 0

        def parent(x):
            exists[x] = 1
            if union_set[x] == x:
                return x
            # Path Compression
            union_set[x] = parent(union_set[x])
            return union_set[x]

        with self.track_time():
            for dup_file in dup_files:
                with self.input_folder.open(dup_file, "rb") as dupf:
                    logger.info(f"Processing {dup_file}")
                    for f1, d1, f2, d2 in read_tuples_from_file(dupf, "4I", lines_to_buffer=self.lines_to_buffer):
                        a, b = transform(f1, d1), transform(f2, d2)
                        if a > max_no:
                            max_no = a
                        if b > max_no:
                            max_no = b
                        union_set[parent(b)] = parent(a)

            logger.info("Outputing")
            with self.output_folder.get_output_file_manager(mode="wb") as output_mg:
                for node in range(max_no + 1):
                    if exists[node]:
                        self.stat_update("duplicates")
                        p = parent(node)
                        if node != p:
                            dataset_idx = datasets[node % 10000]
                            dataset_year = dataset_idx // 10000000
                            dataset_num = (dataset_idx // 100000) % 100
                            parquet_num = dataset_idx % 100000
                            output_mg.write(f"CC-MAIN-20{dataset_year:02d}-{dataset_num:02d}_{parquet_num:05d}.remove", struct.pack("<I", node // 10000))
                            self.stat_update("to_remove")


class CustomMinhashDedupFilter(PipelineStep):
    """Minhash Deduplication: Fourth (and final) Pipeline Step

    Filter the documents based on the minhash clusters to keep only one per cluster
    """

    type = "🫂 - DEDUP"
    name = "🎯 MinHash stage 4"

    def __init__(
        self,
        remove_id_input_folder: DataFolderLike,
        sig_input_folder: DataFolderLike,
        exclusion_writer: DiskWriter = None,
        lines_to_buffer: int = 5,
        naming_prefix: str = '',
        config: CustomMinhashConfig = None,
    ):
        super().__init__()
        self.remove_id_folder = get_datafolder(remove_id_input_folder)
        self.sig_folder = get_datafolder(sig_input_folder)
        self.exclusion_writer = exclusion_writer
        self.lines_to_buffer = lines_to_buffer
        self.naming_prefix = naming_prefix
        self.config = config or CustomMinhashConfig()

    def run(self, data: DocumentsPipeline, rank: int = 0, world_size: int = 1):
        files = self.remove_id_folder.list_files(glob_pattern=f"{self.naming_prefix}*{rank:05d}.remove")
        if not files or len(files) == 0:
            logger.info(f"Found 0 files by pattern {self.naming_prefix}*{rank:05d}.remove, maybe no dups")
            for bucket in range(self.config.num_buckets):
                for sig_file_name in self.sig_folder.list_files(glob_pattern=f"bucket_{bucket:03d}/{self.naming_prefix}*{rank:05d}.minhash.sig"):
                    file_name = Path(sig_file_name).name.removesuffix(".minhash.sig")
                    save_docs = []
                    for sig in read_sigs(
                        self.sig_folder.open(f"bucket_{bucket:03d}/{file_name}.minhash.sig", "rb"),
                        self.config,
                        ensure_order=False,
                    ):
                        self.stat_update(StatHints.total)
                        save_doc = {}
                        save_doc['doc_id'] = file_name + ':' + str(sig.doc_id)
                        save_doc['hash'] = bytes(np.array(sig.sig).astype(np.uint64).byteswap().data)
                        save_docs.append(save_doc)
                        self.stat_update(StatHints.forwarded)
                    with self.sig_folder.open(f"bucket_{bucket:03d}/{file_name}.pkl", "wb") as out_file:
                        pickle.dump(save_docs, out_file)

            return

        single_int = struct.Struct("<I")
        for file in files:
            logger.info(f"Processing {file}")

            remove_id_file = self.remove_id_folder.open(file, "rb")
            logger.info(remove_id_file)
            remove_ids = set()
            while True:
                chunk = remove_id_file.read(single_int.size)
                if not chunk:
                    break
                remove_ids.add(single_int.unpack(chunk))
            remove_id_file.close()

            file_name = Path(file).name.removesuffix(".remove")
            for bucket in range(self.config.num_buckets):
                save_docs = []
                for sig in read_sigs(
                    self.sig_folder.open(f"bucket_{bucket:03d}/{file_name}.minhash.sig", "rb"),
                    self.config,
                    ensure_order=False,
                ):
                    self.stat_update(StatHints.total)
                    if sig.doc_id in remove_ids:
                        continue
                    save_doc = {}
                    save_doc['doc_id'] = file_name + ':' + str(sig.doc_id)
                    save_doc['hash'] = bytes(np.array(sig.sig).astype(np.uint64).byteswap().data)
                    save_docs.append(save_doc)
                    self.stat_update(StatHints.forwarded)
                with self.sig_folder.open(f"bucket_{bucket:03d}/{file_name}.pkl", "wb") as out_file:
                    pickle.dump(save_docs, out_file)
            #     for bucket_id in range(self.config.num_buckets):
            #         save_doc = {}
            #         save_doc[self.config.doc_id_field_name] = doc.metadata['dump'] + ':' + doc.id
            #         save_doc[self.config.hash_field_name] = hash_value_list[bucket_id]
            #         bucket_id = int.from_bytes(hash_value_list[bucket_id], 'big') % self.config.num_buckets
            #         band_hash_value_list[bucket_id].append(save_doc)
            #     if doc_idx % self.config.write_line_num == 0 and doc_idx != 0:
            #         self.write_bands(rank, batch_id, band_hash_value_list)
            #         batch_id += 1
            #         band_hash_value_list = [[[] for _ in range(self.config.num_buckets)] for _ in range(self.config.num_buckets)]
            # if len(band_hash_value_list[0]) > 0:
            #     self.write_bands(rank, batch_id, band_hash_value_list)