"""
DuckDuckGo (definitions)

- `Instant Answer API`_
- `DuckDuckGo query`_

.. _Instant Answer API: https://duckduckgo.com/api
.. _DuckDuckGo query: https://api.duckduckgo.com/?q=DuckDuckGo&format=json&pretty=1

"""

import json
from urllib.parse import urlencode, urlparse, urljoin
from lxml import html

from searx import logger
from searx.data import WIKIDATA_UNITS
from searx.engines.duckduckgo import language_aliases
from searx.engines.duckduckgo import _fetch_supported_languages, supported_languages_url  # NOQA # pylint: disable=unused-import
from searx.utils import extract_text, html_to_text, match_language, get_string_replaces_function
from searx.external_urls import get_external_url, get_earth_coordinates_url, area_to_osm_zoom

logger = logger.getChild('duckduckgo_definitions')

URL = 'https://api.duckduckgo.com/'\
    + '?{query}&format=json&pretty=0&no_redirect=1&d=1'

WIKIDATA_PREFIX = [
    'http://www.wikidata.org/entity/',
    'https://www.wikidata.org/entity/'
]

replace_http_by_https = get_string_replaces_function({'http:': 'https:'})


def is_broken_text(text):
    """ duckduckgo may return something like "<a href="xxxx">http://somewhere Related website<a/>"

    The href URL is broken, the "Related website" may contains some HTML.

    The best solution seems to ignore these results.
    """
    return text.startswith('http') and ' ' in text


def result_to_text(text, htmlResult):
    # TODO : remove result ending with "Meaning" or "Category"
    result = None
    dom = html.fromstring(htmlResult)
    a = dom.xpath('//a')
    if len(a) >= 1:
        result = extract_text(a[0])
    else:
        result = text
    if not is_broken_text(result):
        return result
    return None


def request(query, params):
    params['url'] = URL.format(query=urlencode({'q': query}))
    language = match_language(params['language'], supported_languages, language_aliases)
    language = language.split('-')[0]
    params['headers']['Accept-Language'] = language
    return params


def response(resp):
    results = []

    search_res = json.loads(resp.text)

    # search_res.get('Entity') possible values (not exhaustive) :
    # * continent / country / department / location / waterfall
    # * actor / musician / artist
    # * book / performing art / film / television  / media franchise / concert tour / playwright
    # * prepared food
    # * website / software / os / programming language / file format / software engineer
    # * compagny

    content = ''
    heading = search_res.get('Heading', '')
    attributes = []
    urls = []
    infobox_id = None
    relatedTopics = []

    # add answer if there is one
    answer = search_res.get('Answer', '')
    if answer:
        logger.debug('AnswerType="%s" Answer="%s"', search_res.get('AnswerType'), answer)
        if search_res.get('AnswerType') not in ['calc', 'ip']:
            results.append({'answer': html_to_text(answer)})

    # add infobox
    if 'Definition' in search_res:
        content = content + search_res.get('Definition', '')

    if 'Abstract' in search_res:
        content = content + search_res.get('Abstract', '')

    # image
    image = search_res.get('Image')
    image = None if image == '' else image
    if image is not None and urlparse(image).netloc == '':
        image = urljoin('https://duckduckgo.com', image)

    # urls
    # Official website, Wikipedia page
    for ddg_result in search_res.get('Results', []):
        firstURL = ddg_result.get('FirstURL')
        text = ddg_result.get('Text')
        if firstURL is not None and text is not None:
            urls.append({'title': text, 'url': firstURL})
            results.append({'title': heading, 'url': firstURL})

    # related topics
    for ddg_result in search_res.get('RelatedTopics', []):
        if 'FirstURL' in ddg_result:
            firstURL = ddg_result.get('FirstURL')
            text = ddg_result.get('Text')
            if not is_broken_text(text):
                suggestion = result_to_text(text,
                                            ddg_result.get('Result'))
                if suggestion != heading and suggestion is not None:
                    results.append({'suggestion': suggestion})
        elif 'Topics' in ddg_result:
            suggestions = []
            relatedTopics.append({'name': ddg_result.get('Name', ''),
                                  'suggestions': suggestions})
            for topic_result in ddg_result.get('Topics', []):
                suggestion = result_to_text(topic_result.get('Text'),
                                            topic_result.get('Result'))
                if suggestion != heading and suggestion is not None:
                    suggestions.append(suggestion)

    # abstract
    abstractURL = search_res.get('AbstractURL', '')
    if abstractURL != '':
        # add as result ? problem always in english
        infobox_id = abstractURL
        urls.append({'title': search_res.get('AbstractSource'),
                     'url': abstractURL,
                     'official': True})
        results.append({'url': abstractURL,
                        'title': heading})

    # definition
    definitionURL = search_res.get('DefinitionURL', '')
    if definitionURL != '':
        # add as result ? as answer ? problem always in english
        infobox_id = definitionURL
        urls.append({'title': search_res.get('DefinitionSource'),
                     'url': definitionURL})

    # to merge with wikidata's infobox
    if infobox_id:
        infobox_id = replace_http_by_https(infobox_id)

    # attributes
    # some will be converted to urls
    if 'Infobox' in search_res:
        infobox = search_res.get('Infobox')
        if 'content' in infobox:
            osm_zoom = 17
            coordinates = None
            for info in infobox.get('content'):
                data_type = info.get('data_type')
                data_label = info.get('label')
                data_value = info.get('value')

                # Workaround: ddg may return a double quote
                if data_value == '""':
                    continue

                # Is it an external URL ?
                # * imdb_id / facebook_profile / youtube_channel / youtube_video / twitter_profile
                # * instagram_profile / rotten_tomatoes / spotify_artist_id / itunes_artist_id / soundcloud_id
                # * netflix_id
                external_url = get_external_url(data_type, data_value)
                if external_url is not None:
                    urls.append({'title': data_label,
                                 'url': external_url})
                elif data_type in ['instance', 'wiki_maps_trigger', 'google_play_artist_id']:
                    # ignore instance: Wikidata value from "Instance Of" (Qxxxx)
                    # ignore wiki_maps_trigger: reference to a javascript
                    # ignore google_play_artist_id: service shutdown
                    pass
                elif data_type == 'string' and data_label == 'Website':
                    # There is already an URL for the website
                    pass
                elif data_type == 'area':
                    attributes.append({'label': data_label,
                                       'value': area_to_str(data_value),
                                       'entity': 'P2046'})
                    osm_zoom = area_to_osm_zoom(data_value.get('amount'))
                elif data_type == 'coordinates':
                    if data_value.get('globe') == 'http://www.wikidata.org/entity/Q2':
                        # coordinate on Earth
                        # get the zoom information from the area
                        coordinates = info
                    else:
                        # coordinate NOT on Earth
                        attributes.append({'label': data_label,
                                           'value': data_value,
                                           'entity': 'P625'})
                elif data_type == 'string':
                    attributes.append({'label': data_label,
                                       'value': data_value})

            if coordinates:
                data_label = coordinates.get('label')
                data_value = coordinates.get('value')
                latitude = data_value.get('latitude')
                longitude = data_value.get('longitude')
                url = get_earth_coordinates_url(latitude, longitude, osm_zoom)
                urls.append({'title': 'OpenStreetMap',
                             'url': url,
                             'entity': 'P625'})

    if len(heading) > 0:
        # TODO get infobox.meta.value where .label='article_title'
        if image is None and len(attributes) == 0 and len(urls) == 1 and\
           len(relatedTopics) == 0 and len(content) == 0:
            results.append({'url': urls[0]['url'],
                            'title': heading,
                            'content': content})
        else:
            results.append({'infobox': heading,
                            'id': infobox_id,
                            'content': content,
                            'img_src': image,
                            'attributes': attributes,
                            'urls': urls,
                            'relatedTopics': relatedTopics})

    return results


def unit_to_str(unit):
    for prefix in WIKIDATA_PREFIX:
        if unit.startswith(prefix):
            wikidata_entity = unit[len(prefix):]
            return WIKIDATA_UNITS.get(wikidata_entity, unit)
    return unit


def area_to_str(area):
    """parse {'unit': 'http://www.wikidata.org/entity/Q712226', 'amount': '+20.99'}"""
    unit = unit_to_str(area.get('unit'))
    if unit is not None:
        try:
            amount = float(area.get('amount'))
            return '{} {}'.format(amount, unit)
        except ValueError:
            pass
    return '{} {}'.format(area.get('amount', ''), area.get('unit', ''))
