# Natural Language Toolkit:
#
# Copyright (C) 2001-2017 NLTK Project
# Author: Piotr Kasprzyk <p.j.kasprzyk@gmail.com>
# URL: <http://nltk.org/>
# For license information, see LICENSE.TXT

from six import string_types

from nltk.corpus.reader.api import *
from nltk.corpus.reader.xmldocs import XMLCorpusReader


PARA = re.compile(r'<p(?: [^>]*){0,1}>(.*?)</p>')
SENT = re.compile(r'<s(?: [^>]*){0,1}>(.*?)</s>')

TAGGEDWORD = re.compile(r'<([wc](?: [^>]*){0,1}>)(.*?)</[wc]>')
WORD = re.compile(r'<[wc](?: [^>]*){0,1}>(.*?)</[wc]>')

TYPE = re.compile(r'type="(.*?)"')
ANA = re.compile(r'ana="(.*?)"')

TEXTID = re.compile(r'text id="(.*?)"')


class TEICorpusView(StreamBackedCorpusView):
    def __init__(self, corpus_file,
                 tagged, group_by_sent, group_by_para,
                 tagset=None, head_len=0, textids=None):

        self._tagged = tagged
        self._textids = textids

        self._group_by_sent = group_by_sent
        self._group_by_para = group_by_para
        # WARNING -- skip header
        StreamBackedCorpusView.__init__(self, corpus_file, startpos=head_len)

    _pagesize = 4096

    def read_block(self, stream):
        block = stream.readlines(self._pagesize)
        block = concat(block)
        while (block.count('<text id') > block.count('</text>')) \
                or block.count('<text id') == 0:
            tmp = stream.readline()
            if len(tmp) <= 0:
                break
            block += tmp

        block = block.replace('\n', '')

        textids = TEXTID.findall(block)
        if self._textids:
            for tid in textids:
                if tid not in self._textids:
                    beg = block.find(tid) - 1
                    end = block[beg:].find('</text>') + len('</text>')
                    block = block[:beg] + block[beg + end:]

        output = []
        for para_str in PARA.findall(block):
            para = []
            for sent_str in SENT.findall(para_str):
                if not self._tagged:
                    sent = WORD.findall(sent_str)
                else:
                    sent = list(
                        map(self._parse_tag, TAGGEDWORD.findall(sent_str)))
                if self._group_by_sent:
                    para.append(sent)
                else:
                    para.extend(sent)
            if self._group_by_para:
                output.append(para)
            else:
                output.extend(para)
        return output

    def _parse_tag(self, tag_word_tuple):
        (tag, word) = tag_word_tuple
        if tag.startswith('w'):
            tag = ANA.search(tag).group(1)
        else:  # tag.startswith('c')
            tag = TYPE.search(tag).group(1)
        return word, tag


class Pl196xCorpusReader(CategorizedCorpusReader, XMLCorpusReader):
    head_len = 2770

    def __init__(self, *args, **kwargs):
        if 'textid_file' in kwargs:
            self._textids = kwargs['textid_file']
        else:
            self._textids = None

        XMLCorpusReader.__init__(self, *args)
        CategorizedCorpusReader.__init__(self, kwargs)

        self._init_textids()

    def _init_textids(self):
        self._f2t = defaultdict(list)
        self._t2f = defaultdict(list)
        if self._textids is not None:
            with open(self._textids) as fp:
                for line in fp:
                    line = line.strip()
                    file_id, text_ids = line.split(' ', 1)
                    if file_id not in self.fileids():
                        raise ValueError(
                            'In text_id mapping file %s: %s not found'
                            % (self._textids, file_id)
                        )
                    for text_id in text_ids.split(self._delimiter):
                        self._add_textids(file_id, text_id)

    def _add_textids(self, file_id, text_id):
        self._f2t[file_id].append(text_id)
        self._t2f[text_id].append(file_id)

    def _resolve(self, fileids, categories, textids=None):
        tmp = None
        if len(filter(lambda accessor: accessor is None,
                      (fileids, categories, textids))) != 1:

            raise ValueError('Specify exactly one of: fileids, '
                             'categories or textids')

        if fileids is not None:
            return fileids, None

        if categories is not None:
            return self.fileids(categories), None

        if textids is not None:
            if isinstance(textids, string_types):
                textids = [textids]
            files = sum((self._t2f[t] for t in textids), [])
            tdict = dict()
            for f in files:
                tdict[f] = (set(self._f2t[f]) & set(textids))
            return files, tdict

    def decode_tag(self, tag):
        # to be implemented
        return tag

    def textids(self, fileids=None, categories=None):
        """
        In the pl196x corpus each category is stored in single
        file and thus both methods provide identical functionality. In order
        to accommodate finer granularity, a non-standard textids() method was
        implemented. All the main functions can be supplied with a list
        of required chunks---giving much more control to the user.
        """
        fileids, _ = self._resolve(fileids, categories)
        if fileids is None: return sorted(self._t2f)

        if isinstance(fileids, string_types):
            fileids = [fileids]
        return sorted(sum((self._f2t[d] for d in fileids), []))

    def words(self, fileids=None, categories=None, textids=None):
        fileids, textids = self._resolve(fileids, categories, textids)
        if fileids is None:
            fileids = self._fileids
        elif isinstance(fileids, string_types):
            fileids = [fileids]

        if textids:
            return concat([TEICorpusView(self.abspath(fileid),
                                         False, False, False,
                                         head_len=self.head_len,
                                         textids=textids[fileid])
                           for fileid in fileids])
        else:
            return concat([TEICorpusView(self.abspath(fileid),
                                         False, False, False,
                                         head_len=self.head_len)
                           for fileid in fileids])

    def sents(self, fileids=None, categories=None, textids=None):
        fileids, textids = self._resolve(fileids, categories, textids)
        if fileids is None:
            fileids = self._fileids
        elif isinstance(fileids, string_types):
            fileids = [fileids]

        if textids:
            return concat([TEICorpusView(self.abspath(fileid),
                                         False, True, False,
                                         head_len=self.head_len,
                                         textids=textids[fileid])
                           for fileid in fileids])
        else:
            return concat([TEICorpusView(self.abspath(fileid),
                                         False, True, False,
                                         head_len=self.head_len)
                           for fileid in fileids])

    def paras(self, fileids=None, categories=None, textids=None):
        fileids, textids = self._resolve(fileids, categories, textids)
        if fileids is None:
            fileids = self._fileids
        elif isinstance(fileids, string_types):
            fileids = [fileids]

        if textids:
            return concat([TEICorpusView(self.abspath(fileid),
                                         False, True, True,
                                         head_len=self.head_len,
                                         textids=textids[fileid])
                           for fileid in fileids])
        else:
            return concat([TEICorpusView(self.abspath(fileid),
                                         False, True, True,
                                         head_len=self.head_len)
                           for fileid in fileids])

    def tagged_words(self, fileids=None, categories=None, textids=None):
        fileids, textids = self._resolve(fileids, categories, textids)
        if fileids is None:
            fileids = self._fileids
        elif isinstance(fileids, string_types):
            fileids = [fileids]

        if textids:
            return concat([TEICorpusView(self.abspath(fileid),
                                         True, False, False,
                                         head_len=self.head_len,
                                         textids=textids[fileid])
                           for fileid in fileids])
        else:
            return concat([TEICorpusView(self.abspath(fileid),
                                         True, False, False,
                                         head_len=self.head_len)
                           for fileid in fileids])

    def tagged_sents(self, fileids=None, categories=None, textids=None):
        fileids, textids = self._resolve(fileids, categories, textids)
        if fileids is None:
            fileids = self._fileids
        elif isinstance(fileids, string_types):
            fileids = [fileids]

        if textids:
            return concat([TEICorpusView(self.abspath(fileid),
                                         True, True, False,
                                         head_len=self.head_len,
                                         textids=textids[fileid])
                           for fileid in fileids])
        else:
            return concat([TEICorpusView(self.abspath(fileid),
                                         True, True, False,
                                         head_len=self.head_len)
                           for fileid in fileids])

    def tagged_paras(self, fileids=None, categories=None, textids=None):
        fileids, textids = self._resolve(fileids, categories, textids)
        if fileids is None:
            fileids = self._fileids
        elif isinstance(fileids, string_types):
            fileids = [fileids]

        if textids:
            return concat([TEICorpusView(self.abspath(fileid),
                                         True, True, True,
                                         head_len=self.head_len,
                                         textids=textids[fileid])
                           for fileid in fileids])
        else:
            return concat([TEICorpusView(self.abspath(fileid),
                                         True, True, True,
                                         head_len=self.head_len)
                           for fileid in fileids])

    def xml(self, fileids=None, categories=None):
        fileids, _ = self._resolve(fileids, categories)
        if len(fileids) == 1:
            return XMLCorpusReader.xml(self, fileids[0])
        else:
            raise TypeError('Expected a single file')

    def raw(self, fileids=None, categories=None):
        fileids, _ = self._resolve(fileids, categories)
        if fileids is None:
            fileids = self._fileids
        elif isinstance(fileids, string_types):
            fileids = [fileids]
        return concat([self.open(f).read() for f in fileids])
