#http://packages.python.org/CouchDB/client.html
import couchdb
import urllib2
from BeautifulSoup import BeautifulSoup
import re
import hashlib
from urlparse import urljoin
import time
import os
import sys
import mimetypes
import urllib
import urlparse
import socket

#couch = couchdb.Server('http://192.168.1.148:5984/')
#couch = couchdb.Server('http://192.168.1.113:5984/')
couch = couchdb.Server('http://127.0.0.1:5984/')


def mkhash(input):
    return hashlib.md5(input).hexdigest().encode("utf-8")


def canonurl(url):
    r"""Return the canonical, ASCII-encoded form of a UTF-8 encoded URL, or ''
    if the URL looks invalid.
    >>> canonurl('\xe2\x9e\xa1.ws')  # tinyarro.ws
    'http://xn--hgi.ws/'
    """
    # strip spaces at the ends and ensure it's prefixed with 'scheme://'
    url = url.strip()
    if not url:
        return ''
    if not urlparse.urlsplit(url).scheme:
        url = 'http://' + url

    # turn it into Unicode
    #try:
    #    url = unicode(url, 'utf-8')
    #except UnicodeDecodeError:
    #    return ''  # bad UTF-8 chars in URL

    # parse the URL into its components
    parsed = urlparse.urlsplit(url)
    scheme, netloc, path, query, fragment = parsed

    # ensure scheme is a letter followed by letters, digits, and '+-.' chars
    if not re.match(r'[a-z][-+.a-z0-9]*$', scheme, flags=re.I):
        return ''
    scheme = str(scheme)

    # ensure domain and port are valid, eg: sub.domain.<1-to-6-TLD-chars>[:port]
    match = re.match(r'(.+\.[a-z0-9]{1,6})(:\d{1,5})?$', netloc, flags=re.I)
    if not match:
        return ''
    domain, port = match.groups()
    netloc = domain + (port if port else '')
    netloc = netloc.encode('idna')

    # ensure path is valid and convert Unicode chars to %-encoded
    if not path:
        path = '/'  # eg: 'http://google.com' -> 'http://google.com/'
    path = urllib.quote(urllib.unquote(path.encode('utf-8')), safe='/;')

    # ensure query is valid
    query = urllib.quote(urllib.unquote(query.encode('utf-8')), safe='=&?/')

    # ensure fragment is valid
    fragment = urllib.quote(urllib.unquote(fragment.encode('utf-8')))

    # piece it all back together, truncating it to a maximum of 4KB
    url = urlparse.urlunsplit((scheme, netloc, path, query, fragment))
    return url[:4096]


def fullurl(url, href):
    href = href.replace(" ", "%20")
    href = re.sub('#.*$', '', href)
    return urljoin(url, href)

#http://diveintopython.org/http_web_services/etags.html
class NotModifiedHandler(urllib2.BaseHandler):
    def http_error_304(self, req, fp, code, message, headers):
        addinfourl = urllib2.addinfourl(fp, headers, req.get_full_url())
        addinfourl.code = code
        return addinfourl


def getLastAttachment(docsdb, url):
    hash = mkhash(url)
    doc = docsdb.get(hash)
    if doc != None and "_attachments" in doc.keys():
        last_attachment_fname = doc["_attachments"].keys()[-1]
        last_attachment = docsdb.get_attachment(doc, last_attachment_fname)
        return last_attachment
    else:
        return None


def fetchURL(docsdb, url, fieldName, agencyID, scrape_again=True):
    url = canonurl(url)
    hash = mkhash(url)
    req = urllib2.Request(url)
    print "Fetching %s (%s)" % (url, hash)
    if url.startswith("mailto") or url.startswith("javascript") or url.startswith("#") or url == None or url == "":
        print >> sys.stderr, "Not a valid HTTP url"
        return (None, None, None)
    doc = docsdb.get(hash)
    if doc == None:
        doc = {'_id': hash, 'agencyID': agencyID, 'url': url, 'fieldName': fieldName, 'type': 'website'}
    else:
        if (('page_scraped' in doc) and ((time.time() - doc['page_scraped']) < 60 * 24 * 14) or (scrape_again == False)):
            print "Uh oh, trying to scrape URL again too soon!" + hash
	    if (not doc.has_key('file_size') or doc["file_size"] != "0") and "_attachments" in doc.keys():
	            last_attachment_fname = doc["_attachments"].keys()[-1]
	            last_attachment = docsdb.get_attachment(doc, last_attachment_fname)
        	    content = last_attachment.read()
		    mime_type = doc['mime_type']
	    else:
		    content = None
		    mime_type = None
            return (doc['url'], mime_type, content)

    req.add_header("User-Agent", "Mozilla/4.0 (compatible; Prometheus webspider; owner maxious@lambdacomplex.org)")
    #if there is a previous version stored in couchdb, load caching helper tags
    if doc.has_key('etag'):
        req.add_header("If-None-Match", doc['etag'])
    if doc.has_key('last_modified'):
        req.add_header("If-Modified-Since", doc['last_modified'])

    opener = urllib2.build_opener(NotModifiedHandler())
    try:
        url_handle = opener.open(req, None, 20)
        doc['url'] = url_handle.geturl() # may have followed a redirect to a new url
        headers = url_handle.info() # the addinfourls have the .info() too
        doc['etag'] = headers.getheader("ETag")
        doc['last_modified'] = headers.getheader("Last-Modified")
        doc['date'] = headers.getheader("Date")
        doc['page_scraped'] = time.time()
        doc['web_server'] = headers.getheader("Server")
        doc['via'] = headers.getheader("Via")
        doc['powered_by'] = headers.getheader("X-Powered-By")
        doc['file_size'] = headers.getheader("Content-Length")
        content_type = headers.getheader("Content-Type")
        if content_type != None:
            doc['mime_type'] = content_type.split(";")[0]
        else:
            (type, encoding) = mimetypes.guess_type(url)
            doc['mime_type'] = type
        if hasattr(url_handle, 'code'):
            if url_handle.code == 304:
                print "the web page has not been modified" + hash
                last_attachment_fname = doc["_attachments"].keys()[-1]
                last_attachment = docsdb.get_attachment(doc, last_attachment_fname)
                content = last_attachment
                return (doc['url'], doc['mime_type'], content.read())
            else:
                print "new webpage loaded"
                content = url_handle.read()
                docsdb.save(doc)
                doc = docsdb.get(hash) # need to get a _rev
                docsdb.put_attachment(doc, content, str(time.time()) + "-" + os.path.basename(url), doc['mime_type'])
                return (doc['url'], doc['mime_type'], content)
                #store as attachment epoch-filename

    except (urllib2.URLError, socket.timeout) as e:
        print >> sys.stderr,"error!"
        error = ""
        if hasattr(e, 'reason'):
            error = "error %s in downloading %s" % (str(e.reason), url)
        elif hasattr(e, 'code'):
            error = "error %s in downloading %s" % (e.code, url)
        print >> sys.stderr, error
        doc['error'] = error
        docsdb.save(doc)
        return (None, None, None)


def scrapeAndStore(docsdb, url, depth, fieldName, agencyID):
    (url, mime_type, content) = fetchURL(docsdb, url, fieldName, agencyID)
    badURLs = ["http://www.ausport.gov.au/supporting/funding/grants_and_scholarships/grant_funding_report"]
    if content != None and depth > 0 and url != "http://www.ausport.gov.au/supporting/funding/grants_and_scholarships/grant_funding_report":
        if mime_type == "text/html" or mime_type == "application/xhtml+xml" or mime_type == "application/xml":
            # http://www.crummy.com/software/BeautifulSoup/documentation.html
            soup = BeautifulSoup(content)
            navIDs = soup.findAll(
                id=re.compile('nav|Nav|menu|bar|left|right|sidebar|more-links|breadcrumb|footer|header'))
            for nav in navIDs:
                print "Removing element", nav['id']
                nav.extract()
                navClasses = soup.findAll(
                    attrs={'class': re.compile('nav|menu|bar|left|right|sidebar|more-links|breadcrumb|footer|header')})
                for nav in navClasses:
                    print "Removing element", nav['class']
                    nav.extract()
                links = soup.findAll('a') # soup.findAll('a', id=re.compile("^p-"))
                linkurls = set([])
                for link in links:
                    if link.has_key("href"):
                        if link['href'].startswith("http"):
                            # lets not do external links for now
                            # linkurls.add(link['href'])
                            None
                        if link['href'].startswith("mailto"):
                            # not http
                            None
                        if link['href'].startswith("javascript"):
                            # not http
                            None
                        else:
                            # remove anchors and spaces in urls
                            linkurls.add(fullurl(url, link['href']))
                for linkurl in linkurls:
                    #print linkurl
                    scrapeAndStore(docsdb, linkurl, depth - 1, fieldName, agencyID)

# select database
agencydb = couch['disclosr-agencies']
docsdb = couch['disclosr-documents']

if __name__ == "__main__":
    for row in agencydb.view('app/all'): #not recently scraped agencies view?
        agency = agencydb.get(row.id)
        print agency['name']
        for key in agency.keys():
            if key == "FOIDocumentsURL" and "status" not in agency.keys() and False:
                scrapeAndStore(docsdb, agency[key], 0, key, agency['_id'])
            if key == 'website' and True:
                scrapeAndStore(docsdb, agency[key], 0, key, agency['_id'])
                if "metadata" not in agency.keys():
                    agency['metadata'] = {}
                agency['metadata']['lastScraped'] = time.time()
            if key.endswith('URL') and False:
                print key
                depth = 1
                if 'scrapeDepth' in agency.keys():
                    depth = agency['scrapeDepth']
                scrapeAndStore(docsdb, agency[key], depth, key, agency['_id'])
        agencydb.save(agency)