from __future__ import unicode_literals

import requests
import time
from bs4 import BeautifulSoup
from datetime import datetime, timedelta
from decimal import Decimal

from .exceptions import (
  PageError, DisambiguationError, RedirectError, HTTPTimeoutError,
  WikiaException, ODD_ERROR_MESSAGE)
from .util import cache, stdout_encode, debug


API_URL = 'http://{lang}{sub_wikia}.wikia.com/api/v1/{action}'
STANDARD_URL = 'http://{lang}{sub_wikia}.wikia.com/wiki/{page}'
LANG = ""
RATE_LIMIT = False
RATE_LIMIT_MIN_WAIT = None
RATE_LIMIT_LAST_CALL = None
USER_AGENT = 'wikia (https://github.com/Timidger/Wikia/)'


def set_lang(language):
  '''
  Sets the global language variable, which is sent in the params
  '''
  global LANG
  LANG = language.lower() + '.' if language else ''

  for cached_func in (search, summary):
    cached_func.clear_cache()


def set_user_agent(user_agent_string):
  '''
  Set the User-Agent string to be used for all requests.

  Arguments:

  * user_agent_string - (string) a string specifying the User-Agent header
  '''
  global USER_AGENT
  USER_AGENT = user_agent_string


def set_rate_limiting(rate_limit, min_wait=timedelta(milliseconds=50)):
  '''
  Enable or disable rate limiting on requests to the wikia servers.
  If rate limiting is not enabled, under some circumstances (depending on
  load on Wikia, the number of requests you and other `wikia` users
  are making, and other factors), Wikia may return an HTTP timeout error.

  Enabling rate limiting generally prevents that issue, but please note that
  HTTPTimeoutError still might be raised.

  Arguments:

  * rate_limit - (Boolean) whether to enable rate limiting or not

  Keyword arguments:

  * min_wait - if rate limiting is enabled, `min_wait` is a timedelta describing the minimum time to wait before requests.
         Defaults to timedelta(milliseconds=50)
  '''
  global RATE_LIMIT
  global RATE_LIMIT_MIN_WAIT
  global RATE_LIMIT_LAST_CALL

  RATE_LIMIT = rate_limit
  if not rate_limit:
    RATE_LIMIT_MIN_WAIT = None
  else:
    RATE_LIMIT_MIN_WAIT = min_wait

  RATE_LIMIT_LAST_CALL = None


@cache
def search(query, sub_wikia, results=10):
  '''
  Do a Wikia search for `query`.

  Keyword arguments:

  * sub_wikia - the sub wikia to search in (i.e: "runescape", "elderscrolls")
  * results - the maxmimum number of results returned
  '''
  global LANG

  search_params = {
    'action': 'Search/List?/',
    'sub_wikia': sub_wikia,
    'lang': LANG,
    'limit': results,
    'query': query
  }

  raw_results = _wiki_request(search_params)

  if 'error' in raw_results:
    if raw_results['error']['info'] in ('HTTP request timed out.', 'Pool queue is full'):
      raise HTTPTimeoutError(query)
    else:
      raise WikiaException(raw_results['error']['info'])

  try:
      search_results = (d['title'] for d in raw_results['items'])
  except KeyError as e:
      raise WikiaError("Could not locate page \"{}\" in subwikia \"{}\"".format(query,
                                                                            sub_wikia))     
  return list(search_results)


def random(pages=1):
  '''
  Get a list of random Wikia article titles.

  .. note:: Random only gets articles from namespace 0, meaning no Category, U

  Keyword arguments:

  * pages - the number of random pages returned (max of 10)
  '''
  #http://en.wikia.org/w/api.php?action=query&list=random&rnlimit=5000&format=
  query_params = {
    'list': 'random',
    'rnnamespace': 0,
    'rnlimit': pages,
    'lang': LANG
  }

  request = _wiki_request(query_params)
  titles = [page['title'] for page in request['query']['random']]

  if len(titles) == 1:
    return titles[0]

  return titles


@cache
def summary(title, sub_wikia, chars=500, redirect=True):
  '''
  Plain text summary of the page from the sub-wikia.

  .. note:: This is a convenience wrapper - auto_suggest and redirect are enab

  Keyword arguments:

  * chars - if set, return only the first `chars` characters (actual text retu
  * auto_suggest - let Wikia find a valid page title for the query
  * redirect - allow redirection without raising RedirectError
  '''

  # use auto_suggest and redirect to get the correct article
  # also, use page's error checking to raise DisambiguationError if necessary
  page_info = page(sub_wikia, title, redirect=redirect)
  title = page_info.title
  pageid = page_info.pageid

  query_params = {
    'action': 'Articles/Details?/',
    'sub_wikia': sub_wikia,
    'titles': title,
    'query': title,
    'abstract': chars,
    'ids': pageid,
    'lang': LANG
  }

  request = _wiki_request(query_params)
  summary = request['items'][str(pageid)]['abstract']

  return summary


def page(sub_wikia, title=None, pageid=None, redirect=True, preload=False):
  '''
  Get a WikiaPage object for the page in the sub wikia with title `title` or the pageid
  `pageid` (mutually exclusive).

  Keyword arguments:

  * title - the title of the page to load
  * pageid - the numeric pageid of the page to load
  * redirect - allow redirection without raising RedirectError
  * preload - load content, summary, images, references, and links during initialization
  '''

  if title is not None:
    return WikiaPage(sub_wikia, title, redirect=redirect, preload=preload)
  elif pageid is not None:
    return WikiaPage(sub_wikia, pageid=pageid, preload=preload)
  else:
    raise ValueError("Either a title or a pageid must be specified")



class WikiaPage(object):
  '''
  Contains data from a Wikia page.
  Uses property methods to filter data from the raw HTML.
  '''

  def __init__(self, sub_wikia, title=None, pageid=None, redirect=True, preload=False, original_title=''):
    if title is not None:
      self.title = title
      self.original_title = original_title or title
    elif pageid is not None:
      self.pageid = pageid
    else:
      raise ValueError("Either a title or a pageid must be specified")

    self.sub_wikia = sub_wikia
    try:
        self.__load(redirect=redirect, preload=preload)
    except AttributeError as e:
        raise WikiaError("Could not locate page \"{}\" in subwikia \"{}\"".format(title or pageid,
                                                                           sub_wikia))
    if preload:
      for prop in ('content', 'summary', 'images', 'references', 'links', 'sections'):
        getattr(self, prop)

  def __repr__(self):
    return stdout_encode(u'<WikiaPage \'{}\'>'.format(self.title))

  def __eq__(self, other):
    try:
      return (
        self.pageid == other.pageid
        and self.title == other.title
        and self.url == other.url
      )
    except:
      return False

  def __load(self, redirect=True, preload=False):
    '''
    Load basic information from Wikia.
    Confirm that page exists and is not a disambiguation/redirect.

    Does not need to be called manually, should be called automatically during __init__.
    '''
    query_params = {
      'sub_wikia': self.sub_wikia,
      'action': 'Articles/Details?/',
      'prop': 'info|pageprops',
      'inprop': 'url',
      'ppprop': 'disambiguation',
      'redirects': '',
      'lang': LANG,
    }
    if not getattr(self, 'pageid', None):
      query_params['titles'] = self.title
    else:
      query_params['ids'] = self.pageid

    request = _wiki_request(query_params)
    query = list(request['items'].values())[0]
    pageid = query['id']
    page = query

    # missing is present if the page is missing
    if 'missing' in page:
      if hasattr(self, 'title'):
        raise PageError(self.title)
      else:
        raise PageError(pageid=self.pageid)

    # same thing for redirect, except it shows up in query instead of page for
    # whatever silly reason
    elif 'redirects' in query:
      if redirect:
        redirects = query['redirects'][0]

        if 'normalized' in query:
          normalized = query['normalized'][0]
          assert normalized['from'] == self.title, ODD_ERROR_MESSAGE

          from_title = normalized['to']

        else:
          from_title = self.title

        assert redirects['from'] == from_title, ODD_ERROR_MESSAGE

        # change the title and reload the whole object
        self.__init__(redirects['to'], redirect=redirect, preload=preload)

      else:
        raise RedirectError(getattr(self, 'title', page['title']))

    # since we only asked for disambiguation in ppprop,
    # if a pageprop is returned,
    # then the page must be a disambiguation page
    elif 'pageprops' in page:
      query_params = {
        'prop': 'revisions',
        'rvprop': 'content',
        'rvparse': '',
        'rvlimit': 1,
        'lang': LANG,
      }
      if hasattr(self, 'pageid'):
        query_params['pageids'] = self.pageid
      else:
        query_params['titles'] = self.title
      request = _wiki_request(query_params)
      html = request['query']['pages'][pageid]['revisions'][0]['*']

      lis = BeautifulSoup(html).find_all('li')
      filtered_lis = [li for li in lis if not 'tocsection' in ''.join(li.get('class', []))]
      may_refer_to = [li.a.get_text() for li in filtered_lis if li.a]

      raise DisambiguationError(getattr(self, 'title', page['title']), may_refer_to)

    else:
      self.pageid = pageid
      self.title = page['title'].lower()
      lang = query_params['lang']
      self.url = STANDARD_URL.format(lang=lang, sub_wikia=self.sub_wikia, page=self.title)

  def __continued_query(self, query_params):
    '''
    Based on https://www.mediawiki.org/wiki/API:Query#Continuing_queries
    '''
    query_params.update(self.__title_query_param)

    last_continue = {}
    prop = query_params.get('prop', None)

    while True:
      params = query_params.copy()
      params.update(last_continue)

      request = _wiki_request(params)

      if 'query' not in request:
        break

      pages = request['query']['pages']
      if 'generator' in query_params:
        for datum in pages.values():  # in python 3.3+: "yield from pages.values()"
          yield datum
      else:
        for datum in pages[self.pageid][prop]:
          yield datum

      if 'continue' not in request:
        break

      last_continue = request['continue']

  @property
  def __title_query_param(self):
    if getattr(self, 'title', None) is not None:
      return {'titles': self.title}
    else:
      return {'pageids': self.pageid}

  def html(self):
    '''
    Get full page HTML.

    .. warning:: This can get pretty slow on long pages.
    '''

    if not getattr(self, '_html', False):
      query_params = {
        'prop': 'revisions',
        'rvprop': 'content',
        'rvlimit': 1,
        'rvparse': '',
        'titles': self.title,
        'lang': LANG,
      }

      request = _wiki_request(query_params)
      self._html = request['query']['pages'][self.pageid]['revisions'][0]['*']

    return self._html

  @property
  def content(self):
    '''
    Plain text content of the page, excluding images, tables, and other data.
    '''

    if not getattr(self, '_content', False):
      query_params = {
        'prop': 'extracts|revisions',
        'explaintext': '',
        'rvprop': 'ids',
        'lang': LANG
      }
      if not getattr(self, 'title', None) is None:
         query_params['titles'] = self.title
      else:
         query_params['pageids'] = self.pageid
      request = _wiki_request(query_params)
      self._content     = request['query']['pages'][self.pageid]['extract']
      self._revision_id = request['query']['pages'][self.pageid]['revisions'][0]['revid']
      self._parent_id   = request['query']['pages'][self.pageid]['revisions'][0]['parentid']

    return self._content

  @property
  def revision_id(self):
    '''
    Revision ID of the page.

    The revision ID is a number that uniquely identifies the current
    version of the page. It can be used to create the permalink or for
    other direct API calls. See `Help:Page history
    <http://en.wikia.org/wiki/Wikia:Revision>`_ for more
    information.
    '''

    if not getattr(self, '_revid', False):
      # fetch the content (side effect is loading the revid)
      self.content

    return self._revision_id

  @property
  def parent_id(self):
    '''
    Revision ID of the parent version of the current revision of this
    page. See ``revision_id`` for more information.
    '''

    if not getattr(self, '_parentid', False):
      # fetch the content (side effect is loading the revid)
      self.content

    return self._parent_id

  @property
  def summary(self):
    '''
    Plain text summary of the page.
    '''

    if not getattr(self, '_summary', False):
      query_params = {
        'query': self.title,
        'action': 'Articles/Details?/',
        'prop': 'extracts',
        'explaintext': '',
        'exintro': '',
        'lang': LANG,
        'sub_wikia': self.sub_wikia,
      }
      if not getattr(self, 'title', None) is None:
         query_params['titles'] = self.title
      else:
         query_params['pageids'] = self.pageid

      request = _wiki_request(query_params)
      self._summary = request['query']['pages'][self.pageid]['extract']

    return self._summary

  @property
  def images(self):
    '''
    List of URLs of images on the page.
    '''

    if not getattr(self, '_images', False):
      self._images = [
        page['imageinfo'][0]['url']
        for page in self.__continued_query({
          'generator': 'images',
          'gimlimit': 'max',
          'prop': 'imageinfo',
          'iiprop': 'url',
        })
        if 'imageinfo' in page
      ]

    return self._images

  @property
  def coordinates(self):
    '''
    Tuple of Decimals in the form of (lat, lon) or None
    '''
    if not getattr(self, '_coordinates', False):
      query_params = {
        'prop': 'coordinates',
        'colimit': 'max',
        'titles': self.title,
      }

      request = _wiki_request(query_params)

      if 'query' in request:
        coordinates = request['query']['pages'][self.pageid]['coordinates']
        self._coordinates = (Decimal(coordinates[0]['lat']), Decimal(coordinates[0]['lon']))
      else:
        self._coordinates = None

    return self._coordinates

  @property
  def references(self):
    '''
    List of URLs of external links on a page.
    May include external links within page that aren't technically cited anywhere.
    '''

    if not getattr(self, '_references', False):
      def add_protocol(url):
        return url if url.startswith('http') else 'http:' + url

      self._references = [
        add_protocol(link['*'])
        for link in self.__continued_query({
          'prop': 'extlinks',
          'ellimit': 'max'
        })
      ]

    return self._references

  @property
  def links(self):
    '''
    List of titles of Wikia page links on a page.

    .. note:: Only includes articles from namespace 0, meaning no Category, User talk, or other meta-Wikia pages.
    '''

    if not getattr(self, '_links', False):
      self._links = [
        link['title']
        for link in self.__continued_query({
          'prop': 'links',
          'plnamespace': 0,
          'pllimit': 'max'
        })
      ]

    return self._links

  @property
  def sections(self):
    '''
    List of section titles from the table of contents on the page.
    '''

    if not getattr(self, '_sections', False):
      query_params = {
        'action': 'Search/List?/',
        'prop': 'sections',
      }
      query_params.update(self.__title_query_param)

      request = _wiki_request(query_params)
      self._sections = [section['line'] for section in request['parse']['sections']]

    return self._sections

  def section(self, section_title):
    '''
    Get the plain text content of a section from `self.sections`.
    Returns None if `section_title` isn't found, otherwise returns a whitespace stripped string.

    This is a convenience method that wraps self.content.

    .. warning:: Calling `section` on a section that has subheadings will NOT return
           the full text of all of the subsections. It only gets the text between
           `section_title` and the next subheading, which is often empty.
    '''

    section = u"== {} ==".format(section_title)
    try:
      index = self.content.index(section) + len(section)
    except ValueError:
      return None

    try:
      next_index = self.content.index("==", index)
    except ValueError:
      next_index = len(self.content)

    return self.content[index:next_index].lstrip("=").strip()


@cache
def languages():
  '''
  List all the currently supported language prefixes (usually ISO language code).

  Can be inputted to `set_lang` to change the Wikia that `wikia` requests
  results from.

  Returns: dict of <prefix>: <local_lang_name> pairs. To get just a list of prefixes,
  use `wikia.languages().keys()`.
  '''
  response = _wiki_request({
    'meta': 'siteinfo',
    'siprop': 'languages'
  })

  languages = response['query']['languages']

  return {
    lang['code']: lang['*']
    for lang in languages
  }


def donate():
  '''
  Open up the Wikimedia donate page in your favorite browser.
  '''
  import webbrowser

  webbrowser.open('https://donate.wikimedia.org/w/index.php?title=Special:FundraiserLandingPage', new=2)


def _wiki_request(params):
  '''
  Make a request to the Wikia API using the given search parameters.
  Returns a parsed dict of the JSON response.
  '''
  global RATE_LIMIT_LAST_CALL
  global USER_AGENT
  #params.update({"lang": LANG})
  # Such as .../Search
  api_url = API_URL.format(**params)
  params['format'] = 'json'
  headers = {
    'User-Agent': USER_AGENT
  }

  if RATE_LIMIT and RATE_LIMIT_LAST_CALL and \
    RATE_LIMIT_LAST_CALL + RATE_LIMIT_MIN_WAIT > datetime.now():

    # it hasn't been long enough since the last API call
    # so wait until we're in the clear to make the request

    wait_time = (RATE_LIMIT_LAST_CALL + RATE_LIMIT_MIN_WAIT) - datetime.now()
    time.sleep(int(wait_time.total_seconds()))

  r = requests.get(api_url, params=params, headers=headers)

  if RATE_LIMIT:
    RATE_LIMIT_LAST_CALL = datetime.now()

  return r.json()


class WikiaError(Exception):
    pass
