import requests
import re
import urlparse
import traceback
import feedparser
import time
import urllib2
import httplib
from requests.models import ConnectionError
from django.conf import settings
from utils import log as logging
from apps.rss_feeds.models import MFeedPage
from utils.feed_functions import timelimit, mail_feed_error_to_admin

BROKEN_PAGES = [
    'tag:', 
    'info:', 
    'uuid:', 
    'urn:', 
    '[]',
]

class PageImporter(object):
    
    def __init__(self, feed):
        self.feed = feed
        
    @property
    def headers(self):
        s = requests.session()
        s.config['keep_alive'] = False
        return {
            'User-Agent': 'NewsBlur Page Fetcher (%s subscriber%s) - %s '
                          '(Mozilla/5.0 (Macintosh; Intel Mac OS X 10_7_1) '
                          'AppleWebKit/534.48.3 (KHTML, like Gecko) Version/5.1 '
                          'Safari/534.48.3)' % (
                self.feed.num_subscribers,
                's' if self.feed.num_subscribers != 1 else '',
                settings.NEWSBLUR_URL
            ),
            'Connection': 'close',
        }
    
    @timelimit(15)
    def fetch_page(self, urllib_fallback=False):
        feed_link = self.feed.feed_link
        if not feed_link:
            self.save_no_page()
            return
        
        try:
            if feed_link.startswith('www'):
                self.feed.feed_link = 'http://' + feed_link
            if feed_link.startswith('http'):
                if urllib_fallback:
                    request = urllib2.Request(feed_link, headers=self.headers)
                    response = urllib2.urlopen(request)
                    time.sleep(0.01) # Grrr, GIL.
                    data = response.read()
                else:
                    response = requests.get(feed_link, headers=self.headers)
                    data = response.content
            elif any(feed_link.startswith(s) for s in BROKEN_PAGES):
                self.save_no_page()
                return
            else:
                data = open(feed_link, 'r').read()
            html = self.rewrite_page(data)
            self.save_page(html)
        except (ValueError, urllib2.URLError, httplib.BadStatusLine, httplib.InvalidURL), e:
            self.feed.save_page_history(401, "Bad URL", e)
            fp = feedparser.parse(self.feed.feed_address)
            feed_link = fp.feed.get('link', "")
            self.feed.save()
        except (urllib2.HTTPError), e:
            self.feed.save_page_history(e.code, e.msg, e.fp.read())
        except (httplib.IncompleteRead), e:
            self.feed.save_page_history(500, "IncompleteRead", e)
        except Exception, e:
            logging.debug('[%d] ! -------------------------' % (self.feed.id,))
            tb = traceback.format_exc()
            logging.debug(tb)
            logging.debug('[%d] ! -------------------------' % (self.feed.id,))
            self.feed.save_page_history(500, "Error", tb)
            mail_feed_error_to_admin(self.feed, e, locals())
            if not urllib_fallback:
                self.fetch_page(urllib_fallback=True)
        else:
            self.feed.save_page_history(200, "OK")

    def save_no_page(self):
        self.feed.has_page = False
        self.feed.save()
        self.feed.save_page_history(404, "Feed has no original page.")

    def rewrite_page(self, response):
        BASE_RE = re.compile(r'<head(.*?\>)', re.I)
        base_code = u'<base href="%s" />' % (self.feed.feed_link,)
        try:
            html = BASE_RE.sub(r'<head\1 '+base_code, response)
        except:
            response = response.decode('latin1').encode('utf-8')
            html = BASE_RE.sub(r'<head\1 '+base_code, response)
        
        if '<base href' not in html:
            html = "%s %s" % (base_code, html)
        
        # html = self.fix_urls(html)
        
        return html.strip()

    def fix_urls(self, document):
        # BEWARE: This will rewrite URLs inside of <script> tags. You know, like
        # Google Analytics. Ugh.
        
        FIND_RE = re.compile(r'\b(href|src)\s*=\s*("[^"]*"|\'[^\']*\'|[^"\'<>=\s]+)')
        ret = []
        last_end = 0
        
        for match in FIND_RE.finditer(document):
            url = match.group(2)
            if url[0] in "\"'":
                url = url.strip(url[0])
            parsed = urlparse.urlparse(url)
            if parsed.scheme == parsed.netloc == '': #relative to domain
                url = urlparse.urljoin(self.feed.feed_link, url)
                ret.append(document[last_end:match.start(2)])
                ret.append('"%s"' % (url,))
                last_end = match.end(2)
        ret.append(document[last_end:])
        
        return ''.join(ret)
        
    def save_page(self, html):
        if html and len(html) > 100:
            feed_page, _ = MFeedPage.objects.get_or_create(feed_id=self.feed.pk)
            feed_page.page_data = html
            feed_page.save()