# SPDX-License-Identifier: GPL-2.0-only
#
# This file is part of Nominatim. (https://nominatim.org)
#
# Copyright (C) 2022 by the Nominatim developer community.
# For a full list of authors see the git log.
"""
    Module containing the SPWikiLoader class.
"""
import re
import logging
from collections.abc import Iterator
from nominatim.tools.special_phrases.special_phrase import SpecialPhrase
from nominatim.tools.exec_utils import get_url

LOG = logging.getLogger()
class SPWikiLoader(Iterator):
    """
        Handles loading of special phrases from the wiki.
    """
    def __init__(self, config):
        super().__init__()
        self.config = config
        # Compile the regex here to increase performances.
        self.occurence_pattern = re.compile(
            r'\| *([^\|]+) *\|\| *([^\|]+) *\|\| *([^\|]+) *\|\| *([^\|]+) *\|\| *([\-YN])'
        )
        self._load_languages()

    def __next__(self):
        if not self.languages:
            raise StopIteration

        lang = self.languages.pop(0)
        loaded_xml = self._get_wiki_content(lang)
        LOG.warning('Importing phrases for lang: %s...', lang)
        return self.parse_xml(loaded_xml)

    def parse_xml(self, xml):
        """
            Parses XML content and extracts special phrases from it.
            Return a list of SpecialPhrase.
        """
        # One match will be of format [label, class, type, operator, plural]
        matches = self.occurence_pattern.findall(xml)
        returned_phrases = set()
        for match in matches:
            returned_phrases.add(
                SpecialPhrase(match[0], match[1], match[2], match[3])
            )
        return returned_phrases

    def _load_languages(self):
        """
            Get list of all languages from env config file
            or default if there is no languages configured.
            The system will extract special phrases only from all specified languages.
        """
        if self.config.LANGUAGES:
            self.languages = self.config.get_str_list('LANGUAGES')
        else:
            self.languages = [
            'af', 'ar', 'br', 'ca', 'cs', 'de', 'en', 'es',
            'et', 'eu', 'fa', 'fi', 'fr', 'gl', 'hr', 'hu',
            'ia', 'is', 'it', 'ja', 'mk', 'nl', 'no', 'pl',
            'ps', 'pt', 'ru', 'sk', 'sl', 'sv', 'uk', 'vi']

    @staticmethod
    def _get_wiki_content(lang):
        """
            Request and return the wiki page's content
            corresponding to special phrases for a given lang.
            Requested URL Example :
                https://wiki.openstreetmap.org/wiki/Special:Export/Nominatim/Special_Phrases/EN
        """
        url = 'https://wiki.openstreetmap.org/wiki/Special:Export/Nominatim/Special_Phrases/' \
              + lang.upper()
        return get_url(url)