#!/usr/bin/env python3

# original wikiq headers are: title articleid revid date_time anon
# editor editor_id minor text_size text_entropy text_md5 reversion
# additions_size deletions_size

import argparse
import sys
import os.path
import re
from io import TextIOWrapper
from itertools import groupby

from subprocess import Popen, PIPE
from collections import deque
from hashlib import sha1
from typing import Any, IO, TextIO, Generator, Union

import mwxml
from mwxml import Dump

from deltas.tokenizers import wikitext_split
import mwpersistence
import mwreverts

import tables
from tables import RevisionTable

TO_ENCODE = ('title', 'editor')
PERSISTENCE_RADIUS = 7
from deltas import SequenceMatcher, SegmentMatcher

import pyarrow as pa
import pyarrow.parquet as pq
import pyarrow.csv as pacsv


class PersistMethod:
    none = 0
    sequence = 1
    segment = 2
    legacy = 3


def calculate_persistence(tokens_added):
    return (sum([(len(x.revisions) - 1) for x in tokens_added]),
            len(tokens_added))


def fix_hex_digests(revs: list[mwxml.Revision]) -> list[mwxml.Revision]:
    i = 0
    for rev in revs:
        if rev.text is None:
            rev.text = ""
        if not rev.sha1 and not rev.deleted.text:
            rev.sha1 = sha1(bytes(rev.text, "utf8")).hexdigest()
        revs[i] = rev
        i+=1
    return revs


class WikiqIterator:
    def __init__(self, fh, collapse_user=False):
        self.fh = fh
        self.collapse_user = collapse_user
        self.mwiterator = Dump.from_file(self.fh)
        self.namespace_map = {ns.id: ns.name for ns in
                              self.mwiterator.site_info.namespaces}
        self.__pages: Generator[WikiqPage] = self.load_pages()

    def load_pages(self):
        for page in self.mwiterator:
            yield WikiqPage(page,
                            namespace_map=self.namespace_map,
                            collapse_user=self.collapse_user)

    def __iter__(self):
        return self.__pages

    def __next__(self):
        return next(self.__pages)


class WikiqPage:
    __slots__ = ('id', 'redirect',
                 'restrictions', 'mwpage', '__revisions',
                 'collapse_user')

    def __init__(self, page, namespace_map, collapse_user=False):
        self.id = page.id
        # following mwxml, we assume namespace 0 in cases where
        # page.namespace is inconsistent with namespace_map
        if page.namespace not in namespace_map:
            page.namespace = 0
        if page.namespace != 0:
            page.title = ':'.join([namespace_map[page.namespace], page.title])
        self.restrictions = page.restrictions
        self.collapse_user = collapse_user
        self.mwpage = page
        self.__revisions: Generator[list[mwxml.Revision]] = self.rev_list()

    @staticmethod
    def user_text(rev) -> Union[str, None]:
        return None if rev.deleted.user else rev.user.text

    def rev_list(self):
        # Outline for how we want to handle collapse_user=True
        # iteration   rev.user   prev_rev.user   add prev_rev?
        #         0          A            None           Never
        #         1          A               A           False
        #         2          B               A            True
        #         3          A               B            True
        #         4          A               A           False
        # Post-loop                          A          Always

        if not self.collapse_user:
            for rev in self.mwpage:
                yield [rev]
            return

        for _, revs in groupby(self.mwpage, self.user_text):
            # All revisions are either from the same user, or this is a single
            # revision where the user is missing.
            yield list(revs)

    def __iter__(self):
        return self.__revisions

    def __next__(self):
        return next(self.__revisions)


"""
A RegexPair is defined by a regular expression (pattern) and a label.
The pattern can include capture groups.  If it does then each capture group will have a resulting column in the output.
If the pattern does not include a capture group, then only one output column will result.
"""


class RegexPair(object):
    def __init__(self, pattern, label):
        self.pattern = re.compile(pattern)
        self.label = label
        self.has_groups = bool(self.pattern.groupindex)
        if self.has_groups:
            self.capture_groups = list(self.pattern.groupindex.keys())

    def get_pyarrow_fields(self):
        if self.has_groups:
            fields = [pa.field(self._make_key(cap_group), pa.string())
                      for cap_group in self.capture_groups]
        else:
            fields = [pa.field(self.label, pa.string())]

        return fields

    def _make_key(self, cap_group):
        return "{}_{}".format(self.label, cap_group)

    def matchmake(self, content: str) -> dict:
        temp_dict = {}
        # if there are named capture groups in the regex
        if self.has_groups:

            # if there are matches of some sort in this revision content, fill the lists for each cap_group
            if self.pattern.search(content) is not None:
                m = self.pattern.finditer(content)
                matchobjects = list(m)

                for cap_group in self.capture_groups:
                    key = self._make_key(cap_group)
                    temp_list = []
                    for match in matchobjects:
                        # we only want to add the match for the capture group if the match is not None
                        if match.group(cap_group) is not None:
                            temp_list.append(match.group(cap_group))

                    # if temp_list of matches is empty just make that column None
                    if len(temp_list) == 0:
                        temp_dict[key] = None
                    # else we put in the list we made in the for-loop above
                    else:
                        temp_dict[key] = ', '.join(temp_list)

            # there are no matches at all in this revision content, we default values to None
            else:
                for cap_group in self.capture_groups:
                    key = self._make_key(cap_group)
                    temp_dict[key] = None

        # there are no capture groups, we just search for all the matches of the regex
        else:
            # given that there are matches to be made
            if type(content) in (str, bytes):
                if self.pattern.search(content) is not None:
                    m = self.pattern.findall(content)
                    temp_dict[self.label] = ', '.join(m)
                else:
                    temp_dict[self.label] = None

        return temp_dict


class WikiqParser:
    def __init__(self,
                 input_file: Union[TextIOWrapper, IO[Any], IO[bytes]],
                 output_file: Union[TextIO, str],
                 regex_match_revision: list[str],
                 regex_match_comment: list[str],
                 regex_revision_label: list[str],
                 regex_comment_label: list[str],
                 collapse_user: bool = False,
                 persist: int = None,
                 namespaces: Union[list[int], None] = None,
                 revert_radius: int = 15,
                 output_parquet: bool = True,
                 parquet_buffer_size: int = 2000):
        """ 
        Parameters:
           persist : what persistence method to use. Takes a PersistMethod value
        """
        self.input_file = input_file

        self.collapse_user: bool = collapse_user
        self.persist: int = persist
        self.namespaces = []
        self.revert_radius = revert_radius

        if namespaces is not None:
            self.namespace_filter = set(namespaces)
        else:
            self.namespace_filter = None

        self.regex_schemas = []
        self.regex_revision_pairs: list[RegexPair] = self.make_matchmake_pairs(regex_match_revision,
                                                                               regex_revision_label)
        self.regex_comment_pairs: list[RegexPair] = self.make_matchmake_pairs(regex_match_comment, regex_comment_label)

        # here we initialize the variables we need for output.
        if output_parquet is True:
            self.output_parquet = True
            self.pq_writer = None
            self.output_file = output_file
            self.parquet_buffer = []
            self.parquet_buffer_size = parquet_buffer_size
        else:
            self.print_header = True
            if output_file == sys.stdout.buffer:

                self.output_file = output_file
            else:
                self.output_file = open(output_file, 'wb')
            self.output_parquet = False

    def make_matchmake_pairs(self, patterns, labels) -> list[RegexPair]:
        if (patterns is not None and labels is not None) and \
                (len(patterns) == len(labels)):
            result: list[RegexPair] = []
            for pattern, label in zip(patterns, labels):
                rp = RegexPair(pattern, label)
                result.append(rp)
                self.regex_schemas = self.regex_schemas + rp.get_pyarrow_fields()
            return result
        elif (patterns is None) and (labels is None):
            return []
        else:
            sys.exit('Each regular expression *must* come with a corresponding label and vice versa.')

    def matchmake_revision(self, rev: mwxml.Revision):
        result = self.matchmake_text(rev.text)
        for k, v in self.matchmake_comment(rev.comment).items():
            result[k] = v
        return result

    def matchmake_text(self, text: str):
        return self.matchmake_pairs(text, self.regex_revision_pairs)

    def matchmake_comment(self, comment: str):
        return self.matchmake_pairs(comment, self.regex_comment_pairs)

    @staticmethod
    def matchmake_pairs(text, pairs):
        result = {}
        for pair in pairs:
            for k, v in pair.matchmake(text).items():
                result[k] = v
        return result

    def __get_namespace_from_title(self, title):
        default_ns = None

        for ns in self.namespaces:
            # skip if the namespace is not defined
            if ns is None:
                default_ns = self.namespaces[ns]
                continue

            if title.startswith(ns + ":"):
                return self.namespaces[ns]

        # if we've made it this far with no matches, we return the default namespace
        return default_ns

    def process(self):

        # create a regex that creates the output filename
        # output_filename = re.sub(r'^.*/(enwiki\-\d+)\-.*p(\d+)p.*$',
        #                         r'output/wikiq-\1-\2.tsv',
        #                         input_filename)

        # Construct dump file iterator
        dump = WikiqIterator(self.input_file, collapse_user=self.collapse_user)

        reverts_column = tables.RevisionReverts()

        table = RevisionTable([
            tables.RevisionId(),
            tables.RevisionTimestamp(),
            tables.RevisionArticleId(),
            tables.RevisionEditorId(),
            tables.RevisionPageTitle(),
            tables.RevisionNamespace(),
            tables.RevisionDeleted(),
            tables.RevisionTextChars(),
            reverts_column,
            tables.RevisionSha1(),
            tables.RevisionIsMinor(),
            tables.RevisionEditorText(),
            tables.RevisionIsAnon(),
        ])

        if self.collapse_user:
            table.columns.append(tables.RevisionCollapsed())

        # extract list of namespaces
        self.namespaces = {ns.name: ns.id for ns in dump.mwiterator.site_info.namespaces}

        page_count = 0
        rev_count = 0

        writer: Union[pq.ParquetWriter, pacsv.CSVWriter]

        schema = table.schema()
        schema = schema.append(pa.field('revert', pa.bool_(), nullable=True))

        # Add regex fields to the schema.
        for pair in self.regex_revision_pairs:
            for field in pair.get_pyarrow_fields():
                schema = schema.append(field)

        for pair in self.regex_comment_pairs:
            for field in pair.get_pyarrow_fields():
                schema = schema.append(field)

        if self.persist != PersistMethod.none:
            table.columns.append(tables.RevisionText())
            schema = schema.append(pa.field('token_revs', pa.int64(), nullable=True))
            schema = schema.append(pa.field('tokens_added', pa.int64(), nullable=True))
            schema = schema.append(pa.field('tokens_removed', pa.int64(), nullable=True))
            schema = schema.append(pa.field('tokens_window', pa.int64(), nullable=True))

        if self.output_parquet:
            writer = pq.ParquetWriter(self.output_file, schema, flavor='spark')
        else:
            writer = pacsv.CSVWriter(self.output_file, schema, write_options=pacsv.WriteOptions(delimiter='\t'))

        regex_matches = {}

        # Iterate through pages
        for page in dump:

            # skip namespaces not in the filter
            if self.namespace_filter is not None:
                if page.mwpage.namespace not in self.namespace_filter:
                    continue

            # Disable detecting reverts if radius is 0.
            if self.revert_radius > 0:
                reverts_column.rev_detector = mwreverts.Detector(radius=self.revert_radius)
            else:
                reverts_column.rev_detector = None

            # Iterate through a page's revisions
            for revs in page:
                # Revisions may or may not be grouped into lists of contiguous revisions by the
                # same user. We call these "edit sessions". Otherwise revs is a list containing
                # exactly one revision.
                revs = list(revs)
                revs = fix_hex_digests(revs)

                table.add(page.mwpage, revs)

                # if re.match(r'^#redirect \[\[.*\]\]', rev.text, re.I):
                #    redirect = True
                # else:
                #    redirect = False

                # TODO missing: additions_size deletions_size

                rev_count += 1

                # Get the last revision in the edit session.
                rev = revs[-1]
                regex_dict = self.matchmake_revision(rev)
                for k, v in regex_dict.items():
                    if regex_matches.get(k) is None:
                        regex_matches[k] = []
                    regex_matches[k].append(v)

            # Collect the set of pages currently buffered in the table so we can run multi-page functions on them.
            row_buffer = table.pop()

            is_revert_column: list[Union[bool, None]] = []
            for r, d in zip(row_buffer['reverteds'], row_buffer['deleted']):
                if self.revert_radius == 0 or d:
                    is_revert_column.append(None)
                else:
                    is_revert_column.append(r is not None)

            row_buffer['revert'] = is_revert_column

            for k, v in regex_matches.items():
                row_buffer[k] = v
                regex_matches = {}

            if self.persist != PersistMethod.none:
                window = deque(maxlen=PERSISTENCE_RADIUS)

                row_buffer['token_revs'] = []
                row_buffer['tokens_added'] = []
                row_buffer['tokens_removed'] = []
                row_buffer['tokens_window'] = []

                if self.persist == PersistMethod.sequence:
                    state = mwpersistence.DiffState(SequenceMatcher(tokenizer=wikitext_split),
                                                    revert_radius=PERSISTENCE_RADIUS)
                elif self.persist == PersistMethod.segment:
                    state = mwpersistence.DiffState(SegmentMatcher(tokenizer=wikitext_split),
                                                    revert_radius=PERSISTENCE_RADIUS)
                else:
                    from mw.lib import persistence
                    state = persistence.State()

                for idx, text in enumerate(row_buffer['text']):
                    rev_id = row_buffer['revid'][idx]
                    if self.persist != PersistMethod.legacy:
                        _, tokens_added, tokens_removed = state.update(text, rev_id)
                    else:
                        _, tokens_added, tokens_removed = state.process(text, rev_id)

                    window.append((rev_id, tokens_added, tokens_removed))

                    if len(window) == PERSISTENCE_RADIUS:
                        old_rev_id, old_tokens_added, old_tokens_removed = window.popleft()
                        num_token_revs, num_tokens = calculate_persistence(old_tokens_added)

                        row_buffer['token_revs'].append(num_token_revs)
                        row_buffer['tokens_added'].append(num_tokens)
                        row_buffer['tokens_removed'].append(len(old_tokens_removed))
                        row_buffer['tokens_window'].append(PERSISTENCE_RADIUS - 1)

                del row_buffer['text']

                # print out metadata for the last RADIUS revisions
                for i, item in enumerate(window):
                    # if the window was full, we've already printed item 0
                    if len(window) == PERSISTENCE_RADIUS and i == 0:
                        continue

                    rev_id, tokens_added, tokens_removed = item
                    num_token_revs, num_tokens = calculate_persistence(tokens_added)

                    row_buffer['token_revs'].append(num_token_revs)
                    row_buffer['tokens_added'].append(num_tokens)
                    row_buffer['tokens_removed'].append(len(tokens_removed))
                    row_buffer['tokens_window'].append(len(window) - (i + 1))

            writer.write(pa.table(row_buffer, schema=schema))

            page_count += 1

        print("Done: %s revisions and %s pages." % (rev_count, page_count),
              file=sys.stderr)

        writer.close()


def match_archive_suffix(input_filename):
    if re.match(r'.*\.7z$', input_filename):
        cmd = ["7za", "x", "-so", input_filename]
    elif re.match(r'.*\.gz$', input_filename):
        cmd = ["zcat", input_filename]
    elif re.match(r'.*\.bz2$', input_filename):
        cmd = ["bzcat", "-dk", input_filename]
    else:
        raise ValueError("Unrecognized file type: %s" % input_filename)
    return cmd


def open_input_file(input_filename, fandom_2020=False):
    cmd = match_archive_suffix(input_filename)
    if fandom_2020:
        cmd.append("*.xml")
    try:
        return Popen(cmd, stdout=PIPE).stdout
    except NameError:
        return open(input_filename, 'r')


def get_output_filename(input_filename, parquet=False) -> str:
    output_filename = re.sub(r'\.(7z|gz|bz2)?$', '', input_filename)
    output_filename = re.sub(r'\.xml', '', output_filename)
    if parquet is False:
        output_filename = output_filename + ".tsv"
    else:
        output_filename = output_filename + ".parquet"
    return output_filename


def open_output_file(input_filename):
    # create a regex that creates the output filename
    output_filename = get_output_filename(input_filename, parquet=False)
    output_file = open(output_filename, "w")
    return output_file


def main():
    parser = argparse.ArgumentParser(description='Parse MediaWiki XML database dumps into tab delimited data.')

    # arguments for the input direction
    parser.add_argument('dumpfiles', metavar="DUMPFILE", nargs="*", type=str,
                        help="Filename of the compressed or uncompressed XML database dump. If absent, we'll look for content on stdin and output on stdout.")

    parser.add_argument('-o', '--output', metavar='OUTPUT', dest='output', type=str, nargs=1,
                        help="Directory for output files. If it ends with .parquet output will be in parquet format.")

    parser.add_argument('-s', '--stdout', dest="stdout", action="store_true",
                        help="Write output to standard out (do not create dump file)")

    parser.add_argument('--collapse-user', dest="collapse_user", action="store_true",
                        help="Operate only on the final revision made by user a user within all sequences of consecutive edits made by a user. This can be useful for addressing issues with text persistence measures.")

    parser.add_argument('-p', '--persistence', dest="persist", default=None, const='', type=str,
                        choices=['', 'segment', 'sequence', 'legacy'], nargs='?',
                        help="Compute and report measures of content persistent: (1) persistent token revisions, (2) tokens added, and (3) number of revision used in computing the first measure. This may by slow.  The default is -p=sequence, which uses the same algorithm as in the past, but with improvements to wikitext parsing. Use -p=legacy for old behavior used in older research projects. Use -p=segment for advanced persistence calculation method that is robust to content moves, but prone to bugs, and slower.")

    parser.add_argument('-n', '--namespace-include', dest="namespace_filter", type=int, action='append',
                        help="Id number of namespace to include. Can be specified more than once.")

    parser.add_argument('-rr',
                        '--revert-radius',
                        dest="revert_radius",
                        type=int,
                        action='store',
                        default=15,
                        help="Number of edits to check when looking for reverts (default: 15)")

    parser.add_argument('-RP', '--revision-pattern', dest="regex_match_revision", default=None, type=str,
                        action='append',
                        help="The regular expression to search for in revision text. The regex must be surrounded by quotes.")

    parser.add_argument('-RPl', '--revision-pattern-label', dest="regex_revision_label", default=None, type=str,
                        action='append',
                        help="The label for the outputted column based on matching the regex in revision text.")

    parser.add_argument('-CP', '--comment-pattern', dest="regex_match_comment", default=None, type=str, action='append',
                        help="The regular expression to search for in comments of revisions.")

    parser.add_argument('-CPl', '--comment-pattern-label', dest="regex_comment_label", default=None, type=str,
                        action='append',
                        help="The label for the outputted column based on matching the regex in comments.")

    parser.add_argument('--fandom-2020', dest="fandom_2020",
                        action='store_true',
                        help="Whether the archive is from the fandom 2020 dumps by Wikiteam. These dumps can have multiple .xml files in their archives.")

    args = parser.parse_args()

    # set persistence method

    if args.persist is None:
        persist = PersistMethod.none
    elif args.persist == "segment":
        persist = PersistMethod.segment
    elif args.persist == "legacy":
        persist = PersistMethod.legacy
    else:
        persist = PersistMethod.sequence

    if args.namespace_filter is not None:
        namespaces = args.namespace_filter
    else:
        namespaces = None

    if len(args.dumpfiles) > 0:
        for filename in args.dumpfiles:
            input_file = open_input_file(filename, args.fandom_2020)

            # open directory for output
            if args.output:
                output = args.output[0]
            else:
                output = "."

            output_parquet = output.endswith(".parquet")

            print("Processing file: %s" % filename, file=sys.stderr)

            if args.stdout:
                # Parquet libraries need a binary output, so just sys.stdout doesn't work.
                output_file = sys.stdout.buffer
            elif os.path.isdir(output) or output_parquet:
                filename = os.path.join(output, os.path.basename(filename))
                output_file = get_output_filename(filename, parquet=output_parquet)
            else:
                output_file = output

            wikiq = WikiqParser(input_file,
                                output_file,
                                collapse_user=args.collapse_user,
                                persist=persist,
                                namespaces=namespaces,
                                revert_radius=args.revert_radius,
                                regex_match_revision=args.regex_match_revision,
                                regex_revision_label=args.regex_revision_label,
                                regex_match_comment=args.regex_match_comment,
                                regex_comment_label=args.regex_comment_label,
                                output_parquet=output_parquet)

            wikiq.process()

            # close things
            input_file.close()

    else:
        wikiq = WikiqParser(sys.stdin,
                            sys.stdout,
                            collapse_user=args.collapse_user,
                            persist=persist,
                            # persist_legacy=args.persist_legacy,
                            namespaces=namespaces,
                            revert_radius=args.revert_radius,
                            regex_match_revision=args.regex_match_revision,
                            regex_revision_label=args.regex_revision_label,
                            regex_match_comment=args.regex_match_comment,
                            regex_comment_label=args.regex_comment_label)

        wikiq.process()

    # stop_words = "a,able,about,across,after,all,almost,also,am,among,an,and,any,are,as,at,be,because,been,but,by,can,cannot,could,dear,did,do,does,either,else,ever,every,for,from,get,got,had,has,have,he,her,hers,him,his,how,however,i,if,in,into,is,it,its,just,least,let,like,likely,may,me,might,most,must,my,neither,no,nor,not,of,off,often,on,only,or,other,our,own,rather,said,say,says,she,should,since,so,some,than,that,the,their,them,then,there,these,they,this,tis,to,too,twas,us,wants,was,we,were,what,when,where,which,while,who,whom,why,will,with,would,yet,you,your"
    # stop_words = stop_words.split(",")


if __name__ == "__main__":
    main()
