import re
import urllib.parse

import requests
from lxml import etree

from cloudbot import hook
from cloudbot.util import web, formatting

# security
parser = etree.XMLParser(resolve_entities=False, no_network=True)

api_url = 'http://api.wolframalpha.com/v2/query'
query_url = 'http://www.wolframalpha.com/input/?i={}'


@hook.command("wolframalpha", "wa", "calc", "ca", "math")
def wolframalpha(text, bot):
    """<query> -- Computes <query> using Wolfram Alpha."""
    api_key = bot.config.get("api_keys", {}).get("wolframalpha", None)
    if not api_key:
        return "error: missing api key"

    params = {
        'input': text,
        'appid': api_key
    }
    request = requests.get(api_url, params=params)

    if request.status_code != requests.codes.ok:
        return "Error getting query: {}".format(request.status_code)

    result = etree.fromstring(request.content, parser=parser)

    # get the URL for a user to view this query in a browser
    short_url = web.try_shorten(query_url.format(urllib.parse.quote_plus(text)))

    pod_texts = []
    for pod in result.xpath("//pod[@primary='true']"):
        title = pod.attrib['title']
        if pod.attrib['id'] == 'Input':
            continue

        results = []
        for subpod in pod.xpath('subpod/plaintext/text()'):
            subpod = subpod.strip().replace('\\n', '; ')
            subpod = re.sub(r'\s+', ' ', subpod)
            if subpod:
                results.append(subpod)
        if results:
            pod_texts.append(title + ': ' + ', '.join(results))

    ret = ' - '.join(pod_texts)

    if not pod_texts:
        return 'No results.'

    # I have no idea what this regex does.
    ret = re.sub(r'\\(.)', r'\1', ret)
    ret = formatting.truncate(ret, 250)

    if not ret:
        return 'No results.'

    return "{} - {}".format(ret, short_url)