# Written by Bram Cohen, Arno Bakker
# see LICENSE.txt for license information
import sys, os
import signal
import re
import pickle
from threading import Event, Thread
from urllib import quote, unquote
from urlparse import urlparse
from os.path import exists
from cStringIO import StringIO
from traceback import print_exc
from time import time, gmtime, strftime, localtime
from random import shuffle, seed
from types import StringType, IntType, LongType, DictType
from binascii import b2a_hex

from Tribler.Core.simpledefs import *
from Tribler.Core.BitTornado.parseargs import parseargs, formatDefinitions
from Tribler.Core.BitTornado.RawServer import RawServer
from Tribler.Core.BitTornado.HTTPHandler import HTTPHandler, months
from Tribler.Core.BitTornado.parsedir import parsedir
from NatCheck import NatCheck
from T2T import T2TList
from Filter import Filter
from Tribler.Core.BitTornado.subnetparse import IP_List, ipv6_to_ipv4, to_ipv4, is_valid_ip, is_ipv4
from Tribler.Core.BitTornado.iprangeparse import IP_List as IP_Range_List
from Tribler.Core.BitTornado.torrentlistparse import parsetorrentlist
from Tribler.Core.BitTornado.bencode import bencode, bdecode, Bencached
from Tribler.Core.BitTornado.zurllib import urlopen
from Tribler.Core.Utilities.Crypto import sha
from Tribler.Core.BitTornado.clock import clock
from Tribler.Core.BitTornado.__init__ import version_short, createPeerID
from Tribler.Core.simpledefs import TRIBLER_TORRENT_EXT

try:
    True
except:
    True = 1
    False = 0

DEBUG=False

from Tribler.Core.defaults import trackerdefaults

defaults = []
for k,v in trackerdefaults.iteritems():
    defaults.append((k,v,"See triblerAPI"))


def statefiletemplate(x):
    if type(x) != DictType:
        raise ValueError
    for cname, cinfo in x.items():
        if cname == 'peers':
            for y in cinfo.values():      # The 'peers' key is a dictionary of SHA hashes (torrent ids)
                if type(y) != DictType:   # ... for the active torrents, and each is a dictionary
                    raise ValueError
                for id, info in y.items(): # ... of client ids interested in that torrent
                    if (len(id) != 20):
                        raise ValueError
                    if type(info) != DictType:  # ... each of which is also a dictionary
                        raise ValueError # ... which has an IP, a Port, and a Bytes Left count for that client for that torrent
                    if type(info.get('ip', '')) != StringType:
                        raise ValueError
                    port = info.get('port')
                    if type(port) not in (IntType,LongType) or port < 0:
                        raise ValueError
                    left = info.get('left')
                    if type(left) not in (IntType,LongType) or left < 0:
                        raise ValueError
        elif cname == 'completed':
            if (type(cinfo) != DictType): # The 'completed' key is a dictionary of SHA hashes (torrent ids)
                raise ValueError          # ... for keeping track of the total completions per torrent
            for y in cinfo.values():      # ... each torrent has an integer value
                if type(y) not in (IntType,LongType):
                    raise ValueError      # ... for the number of reported completions for that torrent
        elif cname == 'allowed':
            if (type(cinfo) != DictType): # a list of info_hashes and included data
                raise ValueError
            if x.has_key('allowed_dir_files'):
                adlist = [z[1] for z in x['allowed_dir_files'].values()]
                for y in cinfo.keys():        # and each should have a corresponding key here
                    if not y in adlist:
                        raise ValueError
        elif cname == 'allowed_dir_files':
            if (type(cinfo) != DictType): # a list of files, their attributes and info hashes
                raise ValueError
            dirkeys = {}
            for y in cinfo.values():      # each entry should have a corresponding info_hash
                if not y[1]:
                    continue
                if not x['allowed'].has_key(y[1]):
                    raise ValueError
                if dirkeys.has_key(y[1]): # and each should have a unique info_hash
                    raise ValueError
                dirkeys[y[1]] = 1
            

alas = 'your file may exist elsewhere in the universe\nbut alas, not here\n'

local_IPs = IP_List()
local_IPs.set_intranet_addresses()


def isotime(secs = None):
    if secs == None:
        secs = time()
    return strftime('%Y-%m-%d %H:%M UTC', gmtime(secs))

http_via_filter = re.compile(' for ([0-9.]+)\Z')

def _get_forwarded_ip(headers):
    if headers.has_key('http_x_forwarded_for'):
        header = headers['http_x_forwarded_for']
        try:
            x,y = header.split(',')
        except:
            return header
        if not local_IPs.includes(x):
            return x
        return y
    if headers.has_key('http_client_ip'):
        return headers['http_client_ip']
    if headers.has_key('http_via'):
        x = http_via_filter.search(headers['http_via'])
        try:
            return x.group(1)
        except:
            pass
    if headers.has_key('http_from'):
        return headers['http_from']
    return None

def get_forwarded_ip(headers):
    x = _get_forwarded_ip(headers)
    if not is_valid_ip(x) or local_IPs.includes(x):
        return None
    return x

def compact_peer_info(ip, port):
    try:
        s = ( ''.join([chr(int(i)) for i in ip.split('.')])
              + chr((port & 0xFF00) >> 8) + chr(port & 0xFF) )
        if len(s) != 6:
            raise ValueError
    except:
        s = ''  # not a valid IP, must be a domain name
    return s

def compact_ip(ip):
    return ''.join([chr(int(i)) for i in ip.split('.')])

def decompact_ip(cip):
    return '.'.join([str(ord(i)) for i in cip])


class Tracker:
    def __init__(self, config, rawserver):
        self.config = config
        self.response_size = config['tracker_response_size']
        self.dfile = config['tracker_dfile']
        self.natcheck = config['tracker_nat_check']
        favicon = config['tracker_favicon']
        self.parse_dir_interval = config['tracker_parse_dir_interval']
        self.favicon = None
        if favicon:
            try:
                h = open(favicon,'rb')
                self.favicon = h.read()
                h.close()
            except:
                print "**warning** specified favicon file -- %s -- does not exist." % favicon
        self.rawserver = rawserver
        self.cached = {}    # format: infohash: [[time1, l1, s1], [time2, l2, s2], [time3, l3, s3]]
        self.cached_t = {}  # format: infohash: [time, cache]
        self.times = {}
        self.state = {}
        self.seedcount = {}

        self.allowed_IPs = None
        self.banned_IPs = None
        if config['tracker_allowed_ips'] or config['tracker_banned_ips']:
            self.allowed_ip_mtime = 0
            self.banned_ip_mtime = 0
            self.read_ip_lists()
                
        self.only_local_override_ip = config['tracker_only_local_override_ip']
        if self.only_local_override_ip == 2:
            self.only_local_override_ip = not config['tracker_nat_check']

        if exists(self.dfile):
            try:
                h = open(self.dfile, 'rb')
                if self.config['tracker_dfile_format'] == ITRACKDBFORMAT_BENCODE:
                    ds = h.read()
                    tempstate = bdecode(ds)
                else:
                    tempstate = pickle.load(h)
                h.close()
                if not tempstate.has_key('peers'):
                    tempstate = {'peers': tempstate}
                statefiletemplate(tempstate)
                self.state = tempstate
            except:
                print '**warning** statefile '+self.dfile+' corrupt; resetting'
        self.downloads = self.state.setdefault('peers', {})
        self.completed = self.state.setdefault('completed', {})

        self.becache = {}   # format: infohash: [[l1, s1], [l2, s2], [l3, s3]]
        for infohash, ds in self.downloads.items():
            self.seedcount[infohash] = 0
            for x,y in ds.items():
                ip = y['ip']
                if ( (self.allowed_IPs and not self.allowed_IPs.includes(ip))
                     or (self.banned_IPs and self.banned_IPs.includes(ip)) ):
                    del ds[x]
                    continue
                if not y['left']:
                    self.seedcount[infohash] += 1
                if y.get('nat',-1):
                    continue
                gip = y.get('given_ip')
                if is_valid_ip(gip) and (
                    not self.only_local_override_ip or local_IPs.includes(ip) ):
                    ip = gip
                self.natcheckOK(infohash,x,ip,y['port'],y['left'])
            
        for x in self.downloads.keys():
            self.times[x] = {}
            for y in self.downloads[x].keys():
                self.times[x][y] = 0

        self.trackerid = createPeerID('-T-')
        seed(self.trackerid)
                
        self.reannounce_interval = config['tracker_reannounce_interval']
        self.save_dfile_interval = config['tracker_save_dfile_interval']
        self.show_names = config['tracker_show_names']
        rawserver.add_task(self.save_state, self.save_dfile_interval)
        self.prevtime = clock()
        self.timeout_downloaders_interval = config['tracker_timeout_downloaders_interval']
        rawserver.add_task(self.expire_downloaders, self.timeout_downloaders_interval)
        self.logfile = None
        self.log = None
        if (config['tracker_logfile']) and (config['tracker_logfile'] != '-'):
            try:
                self.logfile = config['tracker_logfile']
                self.log = open(self.logfile,'a')
                sys.stdout = self.log
                print "# Log Started: ", isotime()
            except:
                print "**warning** could not redirect stdout to log file: ", sys.exc_info()[0]

        if config['tracker_hupmonitor']:
            def huphandler(signum, frame, self = self):
                try:
                    self.log.close()
                    self.log = open(self.logfile,'a')
                    sys.stdout = self.log
                    print "# Log reopened: ", isotime()
                except:
                    print "**warning** could not reopen logfile"
             
            signal.signal(signal.SIGHUP, huphandler)            
                
        self.allow_get = config['tracker_allow_get']
        
        self.t2tlist = T2TList(config['tracker_multitracker_enabled'], self.trackerid,
                               config['tracker_multitracker_reannounce_interval'],
                               config['tracker_multitracker_maxpeers'], config['tracker_multitracker_http_timeout'],
                               self.rawserver)

        if config['tracker_allowed_list']:
            if config['tracker_allowed_dir']:
                print '**warning** allowed_dir and allowed_list options cannot be used together'
                print '**warning** disregarding allowed_dir'
                config['tracker_allowed_dir'] = ''
            self.allowed = self.state.setdefault('allowed_list',{})
            self.allowed_list_mtime = 0
            self.parse_allowed()
            self.remove_from_state('allowed','allowed_dir_files')
            if config['tracker_multitracker_allowed'] == ITRACKMULTI_ALLOW_AUTODETECT:
                config['tracker_multitracker_allowed'] = ITRACKMULTI_ALLOW_NONE
            config['tracker_allowed_controls'] = 0

        elif config['tracker_allowed_dir']:
            self.allowed = self.state.setdefault('allowed',{})
            self.allowed_dir_files = self.state.setdefault('allowed_dir_files',{})
            self.allowed_dir_blocked = {}
            self.parse_allowed()
            self.remove_from_state('allowed_list')

        else:
            self.allowed = None
            self.remove_from_state('allowed','allowed_dir_files', 'allowed_list')
            if config['tracker_multitracker_allowed'] == ITRACKMULTI_ALLOW_AUTODETECT:
                config['tracker_multitracker_allowed'] = ITRACKMULTI_ALLOW_NONE
            config['tracker_allowed_controls'] = 0
                
        self.uq_broken = unquote('+') != ' '
        self.keep_dead = config['tracker_keep_dead']
        self.Filter = Filter(rawserver.add_task)
        
        aggregator = config['tracker_aggregator']
        if aggregator == 0:
            self.is_aggregator = False
            self.aggregator_key = None
        else:
            self.is_aggregator = True
            if aggregator == 1:
                self.aggregator_key = None
            else:
                self.aggregator_key = aggregator
            self.natcheck = False
                
        send = config['tracker_aggregate_forward']
        if not send:
            self.aggregate_forward = None
        else:
            try:
                self.aggregate_forward, self.aggregate_password = send
            except:
                self.aggregate_forward = send
                self.aggregate_password = None

        self.cachetime = 0
        self.track_cachetimeupdate()

    def track_cachetimeupdate(self):
        self.cachetime += 1     # raw clock, but more efficient for cache
        self.rawserver.add_task(self.track_cachetimeupdate,1)

    def aggregate_senddata(self, query):
        url = self.aggregate_forward+'?'+query
        if self.aggregate_password is not None:
            url += '&password='+self.aggregate_password
        rq = Thread(target = self._aggregate_senddata, args = [url])
        rq.setName( "AggregateSendData"+rq.getName() )
        rq.setDaemon(True)
        rq.start()

    def _aggregate_senddata(self, url):     # just send, don't attempt to error check,
        try:                                # discard any returned data
            h = urlopen(url)
            h.read()
            h.close()
        except:
            return


    def get_infopage(self):
        try:
            if not self.config['tracker_show_infopage']:
                return (404, 'Not Found', {'Content-Type': 'text/plain', 'Pragma': 'no-cache'}, alas)
            red = self.config['tracker_infopage_redirect']
            if red:
                return (302, 'Found', {'Content-Type': 'text/html', 'Location': red},
                        '<A HREF="'+red+'">Click Here</A>')
            
            s = StringIO()
            s.write('<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">\n' \
                '<html><head><title>Tribler Tracker Statistics</title>\n')
            if self.favicon is not None:
                s.write('<link rel="shortcut icon" href="/favicon.ico">\n')
            s.write('</head>\n<body>\n' \
                '<h3>Tribler Tracker Statistics</h3>\n')
            if self.config['tracker_allowed_dir']:
                if self.show_names:
                    names = [ (self.allowed[hash]['name'],hash)
                              for hash in self.allowed.keys() ]
                else:
                    names = [ (None,hash)
                              for hash in self.allowed.keys() ]
            else:
                names = [ (None,hash) for hash in self.downloads.keys() ]
            if not names:
                s.write('<p>Not tracking any files yet...</p>\n')
            else:
                names.sort()
                tn = 0
                tc = 0
                td = 0
                tt = 0  # Total transferred
                ts = 0  # Total size
                nf = 0  # Number of files displayed
                if self.config['tracker_allowed_dir'] and self.show_names:
                    s.write('<table summary="files" border="1">\n' \
                        '<tr><th>info hash</th><th>torrent name</th><th align="right">size</th><th align="right">complete</th><th align="right">downloading</th><th align="right">downloaded</th><th align="right">transferred</th></tr>\n')
                else:
                    s.write('<table summary="files">\n' \
                        '<tr><th>info hash</th><th align="right">complete</th><th align="right">downloading</th><th align="right">downloaded</th></tr>\n')
                for name,hash in names:
                    l = self.downloads[hash]
                    n = self.completed.get(hash, 0)
                    tn = tn + n
                    c = self.seedcount[hash]
                    tc = tc + c
                    d = len(l) - c
                    td = td + d
                    if self.config['tracker_allowed_dir'] and self.show_names:
                        if self.allowed.has_key(hash):
                            nf = nf + 1
                            sz = self.allowed[hash]['length']  # size
                            ts = ts + sz
                            szt = sz * n   # Transferred for this torrent
                            tt = tt + szt
                            if self.allow_get == 1:
                                # P2PURL
                                url = self.allowed[hash].get('url')
                                if url:
                                    linkname = '<a href="' + url + '">' + name + '</a>'
                                else:
                                    #linkname = '<a href="/file?info_hash=' + quote(hash) + '">' + name + '</a>'
                                    linkname = '<a href="/file?name=' + quote(name) + '">' + name + '</a>'
                            else:
                                linkname = name
                            s.write('<tr><td><code>%s</code></td><td>%s</td><td align="right">%s</td><td align="right">%i</td><td align="right">%i</td><td align="right">%i</td><td align="right">%s</td></tr>\n' \
                                % (b2a_hex(hash), linkname, size_format(sz), c, d, n, size_format(szt)))
                    else:
                        s.write('<tr><td><code>%s</code></td><td align="right"><code>%i</code></td><td align="right"><code>%i</code></td><td align="right"><code>%i</code></td></tr>\n' \
                            % (b2a_hex(hash), c, d, n))
                ttn = 0
                for i in self.completed.values():
                    ttn = ttn + i
                if self.config['tracker_allowed_dir'] and self.show_names:
                    s.write('<tr><td align="right" colspan="2">%i files</td><td align="right">%s</td><td align="right">%i</td><td align="right">%i</td><td align="right">%i/%i</td><td align="right">%s</td></tr>\n'
                            % (nf, size_format(ts), tc, td, tn, ttn, size_format(tt)))
                else:
                    s.write('<tr><td align="right">%i files</td><td align="right">%i</td><td align="right">%i</td><td align="right">%i/%i</td></tr>\n'
                            % (nf, tc, td, tn, ttn))
                s.write('</table>\n' \
                    '<ul>\n' \
                    '<li><em>info hash:</em> SHA1 hash of the "info" section of the metainfo (*.torrent)</li>\n' \
                    '<li><em>complete:</em> number of connected clients with the complete file</li>\n' \
                    '<li><em>downloading:</em> number of connected clients still downloading</li>\n' \
                    '<li><em>downloaded:</em> reported complete downloads (total: current/all)</li>\n' \
                    '<li><em>transferred:</em> torrent size * total downloaded (does not include partial transfers)</li>\n' \
                    '</ul>\n' \
                    '<hr>\n'
                    '<address>%s (%s)</address>\n' % (version_short, isotime()))


            s.write('</body>\n' \
                '</html>\n')
            return (200, 'OK', {'Content-Type': 'text/html; charset=iso-8859-1'}, s.getvalue())
        except:
            print_exc()
            return (500, 'Internal Server Error', {'Content-Type': 'text/html; charset=iso-8859-1'}, 'Server Error')


    def scrapedata(self, hash, return_name = True):
        l = self.downloads[hash]
        n = self.completed.get(hash, 0)
        c = self.seedcount[hash]
        d = len(l) - c
        f = {'complete': c, 'incomplete': d, 'downloaded': n}
        if return_name and self.show_names and self.config['tracker_allowed_dir']:
            f['name'] = self.allowed[hash]['name']
        return (f)

    def get_scrape(self, paramslist):
        fs = {}
        if paramslist.has_key('info_hash'):
            if self.config['tracker_scrape_allowed'] not in [ITRACKSCRAPE_ALLOW_SPECIFIC,ITRACKSCRAPE_ALLOW_FULL]:
                return (400, 'Not Authorized', {'Content-Type': 'text/plain', 'Pragma': 'no-cache'},
                    bencode({'failure reason':
                    'specific scrape function is not available with this tracker.'}))
            for hash in paramslist['info_hash']:
                if self.allowed is not None:
                    if self.allowed.has_key(hash):
                        fs[hash] = self.scrapedata(hash)
                else:
                    if self.downloads.has_key(hash):
                        fs[hash] = self.scrapedata(hash)
        else:
            if self.config['tracker_scrape_allowed'] != ITRACKSCRAPE_ALLOW_FULL:
                return (400, 'Not Authorized', {'Content-Type': 'text/plain', 'Pragma': 'no-cache'},
                    bencode({'failure reason':
                    'full scrape function is not available with this tracker.'}))
            if self.allowed is not None:
                keys = self.allowed.keys()
            else:
                keys = self.downloads.keys()
            for hash in keys:
                fs[hash] = self.scrapedata(hash)

        return (200, 'OK', {'Content-Type': 'text/plain'}, bencode({'files': fs}))


    def get_file_by_name(self,name):
        # Assumption: name is in UTF-8, as is the names in self.allowed
        for hash,rec in self.allowed.iteritems():
            if 'name' in rec and rec['name'] == name:
                return self.get_file(hash)
        return (404, 'Not Found', {'Content-Type': 'text/plain', 'Pragma': 'no-cache'}, alas)

    def get_file(self, hash):
        if not self.allow_get:
            return (400, 'Not Authorized', {'Content-Type': 'text/plain', 'Pragma': 'no-cache'},
                'get function is not available with this tracker.')
        if not self.allowed.has_key(hash):
            return (404, 'Not Found', {'Content-Type': 'text/plain', 'Pragma': 'no-cache'}, alas)
        fname = self.allowed[hash]['file']
        fpath = self.allowed[hash]['path']
        return (200, 'OK', {'Content-Type': 'application/x-bittorrent',
            'Content-Disposition': 'attachment; filename=' + fname},
            open(fpath, 'rb').read())


    def get_tstream_from_httpseed(self, httpseedurl):
        if not self.allow_get:
            return (400, 'Not Authorized', {'Content-Type': 'text/plain', 'Pragma': 'no-cache'},
                'get function is not available with this tracker.')
            
        # TODO: normalize?
        wanturlhash = sha(httpseedurl).digest()
        # TODO: reverse table?
        found = False
        for infohash,a in self.allowed.iteritems():
            for goturlhash in a['url-hash-list']:
                if goturlhash == wanturlhash:
                    found = True
                    break
            if found:
                break
                 
        if not found or not self.allowed.has_key(infohash):
            return (404, 'Not Found', {'Content-Type': 'text/plain', 'Pragma': 'no-cache'}, alas)
            
        fname = self.allowed[infohash]['file']
        fpath = self.allowed[infohash]['path']
        print >>sys.stderr,"tracker: get_stream: Sending",fname
        return (200, 'OK', {'Content-Type': 'application/x-bittorrent',
            'Content-Disposition': 'attachment; filename=' + fname},
            open(fpath, 'rb').read())


    def check_allowed(self, infohash, paramslist):
        if ( self.aggregator_key is not None
                and not ( paramslist.has_key('password')
                        and paramslist['password'][0] == self.aggregator_key ) ):
            return (200, 'Not Authorized', {'Content-Type': 'text/plain', 'Pragma': 'no-cache'},
                bencode({'failure reason':
                'Requested download is not authorized for use with this tracker.'}))

        if self.allowed is not None:
            if not self.allowed.has_key(infohash):
                return (200, 'Not Authorized', {'Content-Type': 'text/plain', 'Pragma': 'no-cache'},
                    bencode({'failure reason':
                    'Requested download is not authorized for use with this tracker.'}))
            if self.config['tracker_allowed_controls']:
                if self.allowed[infohash].has_key('failure reason'):
                    return (200, 'Not Authorized', {'Content-Type': 'text/plain', 'Pragma': 'no-cache'},
                        bencode({'failure reason': self.allowed[infohash]['failure reason']}))

        if paramslist.has_key('tracker'):
            if ( self.config['tracker_multitracker_allowed'] == ITRACKMULTI_ALLOW_NONE or       # turned off
                          paramslist['peer_id'][0] == self.trackerid ): # oops! contacted myself
                return (200, 'Not Authorized', {'Content-Type': 'text/plain', 'Pragma': 'no-cache'},
                    bencode({'failure reason': 'disallowed'}))
            
            if ( self.config['tracker_multitracker_allowed'] == ITRACKMULTI_ALLOW_AUTODETECT
                        and not self.allowed[infohash].has_key('announce-list') ):
                return (200, 'Not Authorized', {'Content-Type': 'text/plain', 'Pragma': 'no-cache'},
                    bencode({'failure reason':
                    'Requested download is not authorized for multitracker use.'}))

        return None


    def add_data(self, infohash, event, ip, paramslist):
        peers = self.downloads.setdefault(infohash, {})
        ts = self.times.setdefault(infohash, {})
        self.completed.setdefault(infohash, 0)
        self.seedcount.setdefault(infohash, 0)

        def params(key, default = None, l = paramslist):
            if l.has_key(key):
                return l[key][0]
            return default
        
        myid = params('peer_id','')
        if len(myid) != 20:
            raise ValueError, 'id not of length 20'
        if event not in ['started', 'completed', 'stopped', 'snooped', None]:
            raise ValueError, 'invalid event'
        port = long(params('port',''))
        if port < 0 or port > 65535:
            raise ValueError, 'invalid port'
        left = long(params('left',''))
        if left < 0:
            raise ValueError, 'invalid amount left'
        uploaded = long(params('uploaded',''))
        downloaded = long(params('downloaded',''))

        peer = peers.get(myid)
        islocal = local_IPs.includes(ip)
        mykey = params('key')
        if peer:
            auth = peer.get('key',-1) == mykey or peer.get('ip') == ip

        gip = params('ip')
        if is_valid_ip(gip) and (islocal or not self.only_local_override_ip):
            ip1 = gip
        else:
            ip1 = ip

        if params('numwant') is not None:
            rsize = min(int(params('numwant')),self.response_size)
        else:
            rsize = self.response_size

        if event == 'stopped':
            if peer:
                if auth:
                    self.delete_peer(infohash,myid)
        
        elif not peer:
            ts[myid] = clock()
            peer = {'ip': ip, 'port': port, 'left': left}
            if mykey:
                peer['key'] = mykey
            if gip:
                peer['given ip'] = gip
            if port:
                if not self.natcheck or islocal:
                    peer['nat'] = 0
                    self.natcheckOK(infohash,myid,ip1,port,left)
                else:
                    NatCheck(self.connectback_result,infohash,myid,ip1,port,self.rawserver)
            else:
                peer['nat'] = 2**30
            if event == 'completed':
                self.completed[infohash] += 1
            if not left:
                self.seedcount[infohash] += 1

            peers[myid] = peer

        else:
            if not auth:
                return rsize    # return w/o changing stats

            ts[myid] = clock()
            if not left and peer['left']:
                self.completed[infohash] += 1
                self.seedcount[infohash] += 1
                if not peer.get('nat', -1):
                    for bc in self.becache[infohash]:
                        bc[1][myid] = bc[0][myid]
                        del bc[0][myid]
            if peer['left']:
                peer['left'] = left

            if port:
                recheck = False
                if ip != peer['ip']:
                    peer['ip'] = ip
                    recheck = True
                if gip != peer.get('given ip'):
                    if gip:
                        peer['given ip'] = gip
                    elif peer.has_key('given ip'):
                        del peer['given ip']
                    recheck = True

                natted = peer.get('nat', -1)
                if recheck:
                    if natted == 0:
                        l = self.becache[infohash]
                        y = not peer['left']
                        for x in l:
                            del x[y][myid]
                        if not self.natcheck or islocal:
                            del peer['nat'] # restart NAT testing
                if natted and natted < self.natcheck:
                    recheck = True

                if recheck:
                    if not self.natcheck or islocal:
                        peer['nat'] = 0
                        self.natcheckOK(infohash,myid,ip1,port,left)
                    else:
                        NatCheck(self.connectback_result,infohash,myid,ip1,port,self.rawserver)

        return rsize


    def peerlist(self, infohash, stopped, tracker, is_seed, return_type, rsize):
        data = {}    # return data
        seeds = self.seedcount[infohash]
        data['complete'] = seeds
        data['incomplete'] = len(self.downloads[infohash]) - seeds
        
        if ( self.config['tracker_allowed_controls']
                and self.allowed[infohash].has_key('warning message') ):
            data['warning message'] = self.allowed[infohash]['warning message']

        if tracker:
            data['interval'] = self.config['tracker_multitracker_reannounce_interval']
            if not rsize:
                return data
            cache = self.cached_t.setdefault(infohash, None)
            if ( not cache or len(cache[1]) < rsize
                 or cache[0] + self.config['tracker_min_time_between_cache_refreshes'] < clock() ):
                bc = self.becache.setdefault(infohash,[[{}, {}], [{}, {}], [{}, {}]])
                cache = [ clock(), bc[0][0].values() + bc[0][1].values() ]
                self.cached_t[infohash] = cache
                shuffle(cache[1])
                cache = cache[1]

            data['peers'] = cache[-rsize:]
            del cache[-rsize:]
            return data

        data['interval'] = self.reannounce_interval
        if stopped or not rsize:     # save some bandwidth
            data['peers'] = []
            return data

        bc = self.becache.setdefault(infohash,[[{}, {}], [{}, {}], [{}, {}]])
        len_l = len(bc[0][0])
        len_s = len(bc[0][1])
        if not (len_l+len_s):   # caches are empty!
            data['peers'] = []
            return data
        l_get_size = int(float(rsize)*(len_l)/(len_l+len_s))
        cache = self.cached.setdefault(infohash,[None,None,None])[return_type]
        if cache and ( not cache[1]
                       or (is_seed and len(cache[1]) < rsize)
                       or len(cache[1]) < l_get_size
                       or cache[0]+self.config['tracker_min_time_between_cache_refreshes'] < self.cachetime ):
            cache = None
        if not cache:
            peers = self.downloads[infohash]
            vv = [[],[],[]]
            for key, ip, port in self.t2tlist.harvest(infohash):   # empty if disabled
                if not peers.has_key(key):
                    vv[0].append({'ip': ip, 'port': port, 'peer id': key})
                    vv[1].append({'ip': ip, 'port': port})
                    vv[2].append(compact_peer_info(ip, port))
            cache = [ self.cachetime,
                      bc[return_type][0].values()+vv[return_type],
                      bc[return_type][1].values() ]
            shuffle(cache[1])
            shuffle(cache[2])
            self.cached[infohash][return_type] = cache
            for rr in xrange(len(self.cached[infohash])):
                if rr != return_type:
                    try:
                        self.cached[infohash][rr][1].extend(vv[rr])
                    except:
                        pass
        if len(cache[1]) < l_get_size:
            peerdata = cache[1]
            if not is_seed:
                peerdata.extend(cache[2])
            cache[1] = []
            cache[2] = []
        else:
            if not is_seed:
                peerdata = cache[2][l_get_size-rsize:]
                del cache[2][l_get_size-rsize:]
                rsize -= len(peerdata)
            else:
                peerdata = []
            if rsize:
                peerdata.extend(cache[1][-rsize:])
                del cache[1][-rsize:]
        if return_type == 2:
            peerdata = ''.join(peerdata)
        data['peers'] = peerdata
        return data


    def get(self, connection, path, headers):
        real_ip = connection.get_ip()
        ip = real_ip
        if is_ipv4(ip):
            ipv4 = True
        else:
            try:
                ip = ipv6_to_ipv4(ip)
                ipv4 = True
            except ValueError:
                ipv4 = False

        # Arno: log received GET
        if self.config['tracker_logfile']:
            self.getlog(ip, path, headers)

        if ( (self.allowed_IPs and not self.allowed_IPs.includes(ip))
             or (self.banned_IPs and self.banned_IPs.includes(ip)) ):
            return (400, 'Not Authorized', {'Content-Type': 'text/plain', 'Pragma': 'no-cache'},
                bencode({'failure reason':
                'your IP is not allowed on this tracker'}))

        nip = get_forwarded_ip(headers)
        if nip and not self.only_local_override_ip:
            ip = nip
            try:
                ip = to_ipv4(ip)
                ipv4 = True
            except ValueError:
                ipv4 = False

        paramslist = {}
        def params(key, default = None, l = paramslist):
            if l.has_key(key):
                return l[key][0]
            return default

        try:
            (scheme, netloc, path, pars, query, fragment) = urlparse(path)
            if self.uq_broken == 1:
                path = path.replace('+',' ')
                query = query.replace('+',' ')
            path = unquote(path)[1:]
            for s in query.split('&'):
                if s:
                    i = s.find('=')
                    if i == -1:
                        break
                    kw = unquote(s[:i])
                    paramslist.setdefault(kw, [])
                    paramslist[kw] += [unquote(s[i+1:])]
                    
            if DEBUG:
                print >>sys.stderr,"tracker: Got request /"+path+'?'+query
                    
            if path == '' or path == 'index.html':
                return self.get_infopage()
            if (path == 'file'):
                # Arno: 2010-02-26: name based retrieval
                if paramslist.has_key('name'):
                    return self.get_file_by_name(params('name'))
                else:
                    return self.get_file(params('info_hash'))
            
            if path == 'tlookup':
                return self.get_tstream_from_httpseed(unquote(query))
            if path == 'favicon.ico' and self.favicon is not None:
                return (200, 'OK', {'Content-Type' : 'image/x-icon'}, self.favicon)

            # automated access from here on

            if path == 'scrape':
                return self.get_scrape(paramslist)
            
            if path != 'announce':
                return (404, 'Not Found', {'Content-Type': 'text/plain', 'Pragma': 'no-cache'}, alas)

            # main tracker function

            filtered = self.Filter.check(real_ip, paramslist, headers)
            if filtered:
                return (400, 'Not Authorized', {'Content-Type': 'text/plain', 'Pragma': 'no-cache'},
                    bencode({'failure reason': filtered}))
            
            infohash = params('info_hash')
            if not infohash:
                raise ValueError, 'no info hash'

            notallowed = self.check_allowed(infohash, paramslist)
            if notallowed:
                return notallowed

            event = params('event')

            rsize = self.add_data(infohash, event, ip, paramslist)

        except ValueError, e:
            print_exc()
            return (400, 'Bad Request', {'Content-Type': 'text/plain'}, 
                'you sent me garbage - ' + str(e))

        if self.aggregate_forward and not paramslist.has_key('tracker'):
            self.aggregate_senddata(query)

        if self.is_aggregator:      # don't return peer data here
            return (200, 'OK', {'Content-Type': 'text/plain', 'Pragma': 'no-cache'},
                    bencode({'response': 'OK'}))

        if params('compact') and ipv4:
            return_type = 2
        elif params('no_peer_id'):
            return_type = 1
        else:
            return_type = 0
            
        data = self.peerlist(infohash, event=='stopped',
                             params('tracker'), not params('left'),
                             return_type, rsize)

        if paramslist.has_key('scrape'):
            data['scrape'] = self.scrapedata(infohash, False)
            
        return (200, 'OK', {'Content-Type': 'text/plain', 'Pragma': 'no-cache'}, bencode(data))


    def natcheckOK(self, infohash, peerid, ip, port, not_seed):
        if DEBUG:
            print >>sys.stderr,"tracker: natcheck: Recorded succes"
        bc = self.becache.setdefault(infohash,[[{}, {}], [{}, {}], [{}, {}]])
        bc[0][not not_seed][peerid] = Bencached(bencode({'ip': ip, 'port': port,
                                              'peer id': peerid}))
        bc[1][not not_seed][peerid] = Bencached(bencode({'ip': ip, 'port': port}))
        bc[2][not not_seed][peerid] = compact_peer_info(ip, port)


    def natchecklog(self, peerid, ip, port, result):
        year, month, day, hour, minute, second, a, b, c = localtime(time())
        print '%s - %s [%02d/%3s/%04d:%02d:%02d:%02d] "!natcheck-%s:%i" %i 0 - -' % (
            ip, quote(peerid), day, months[month], year, hour, minute, second,
            ip, port, result)

    def getlog(self, ip, path, headers):
        year, month, day, hour, minute, second, a, b, c = localtime(time())
        print '%s - %s [%02d/%3s/%04d:%02d:%02d:%02d] "GET %s HTTP/1.1" 100 0 - -' % (
            ip, ip, day, months[month], year, hour, minute, second, path)

    def connectback_result(self, result, downloadid, peerid, ip, port):
        record = self.downloads.get(downloadid, {}).get(peerid)
        if ( record is None 
                 or (record['ip'] != ip and record.get('given ip') != ip)
                 or record['port'] != port ):
            if self.config['tracker_log_nat_checks']:
                self.natchecklog(peerid, ip, port, 404)
            if DEBUG:
                print >>sys.stderr,"tracker: natcheck: No record found for tested peer"
            return
        if self.config['tracker_log_nat_checks']:
            if result:
                x = 200
            else:
                x = 503
            self.natchecklog(peerid, ip, port, x)
        if not record.has_key('nat'):
            record['nat'] = int(not result)
            if result:
                self.natcheckOK(downloadid,peerid,ip,port,record['left'])
        elif result and record['nat']:
            record['nat'] = 0
            self.natcheckOK(downloadid,peerid,ip,port,record['left'])
        elif not result:
            record['nat'] += 1
            if DEBUG:
                print >>sys.stderr,"tracker: natcheck: Recorded failed attempt"


    def remove_from_state(self, *l):
        for s in l:
            try:
                del self.state[s]
            except:
                pass

    def save_state(self):
        self.rawserver.add_task(self.save_state, self.save_dfile_interval)
        h = open(self.dfile, 'wb')
        if self.config['tracker_dfile_format'] == ITRACKDBFORMAT_BENCODE:
            h.write(bencode(self.state))
        else:
            pickle.dump(self.state,h,-1)
        h.close()


    def parse_allowed(self,source=None):
        if DEBUG:
            print >>sys.stderr,"tracker: parse_allowed: Source is",source,"alloweddir",self.config['tracker_allowed_dir']
        
        if source is None:
            self.rawserver.add_task(self.parse_allowed, self.parse_dir_interval)

        if self.config['tracker_allowed_dir']:
            r = parsedir( self.config['tracker_allowed_dir'], self.allowed,
                          self.allowed_dir_files, self.allowed_dir_blocked,
                          [".torrent",TRIBLER_TORRENT_EXT] )
            ( self.allowed, self.allowed_dir_files, self.allowed_dir_blocked,
                added, garbage2 ) = r
            
            if DEBUG:
                print >>sys.stderr,"tracker: parse_allowed: Found new",`added`
            
            self.state['allowed'] = self.allowed
            self.state['allowed_dir_files'] = self.allowed_dir_files

            self.t2tlist.parse(self.allowed)
            
        else:
            f = self.config['tracker_allowed_list']
            if self.allowed_list_mtime == os.path.getmtime(f):
                return
            try:
                r = parsetorrentlist(f, self.allowed)
                (self.allowed, added, garbage2) = r
                self.state['allowed_list'] = self.allowed
            except (IOError, OSError):
                print '**warning** unable to read allowed torrent list'
                return
            self.allowed_list_mtime = os.path.getmtime(f)

        for infohash in added.keys():
            self.downloads.setdefault(infohash, {})
            self.completed.setdefault(infohash, 0)
            self.seedcount.setdefault(infohash, 0)


    def read_ip_lists(self):
        self.rawserver.add_task(self.read_ip_lists,self.parse_dir_interval)
            
        f = self.config['tracker_allowed_ips']
        if f and self.allowed_ip_mtime != os.path.getmtime(f):
            self.allowed_IPs = IP_List()
            try:
                self.allowed_IPs.read_fieldlist(f)
                self.allowed_ip_mtime = os.path.getmtime(f)
            except (IOError, OSError):
                print '**warning** unable to read allowed_IP list'
                
        f = self.config['tracker_banned_ips']
        if f and self.banned_ip_mtime != os.path.getmtime(f):
            self.banned_IPs = IP_Range_List()
            try:
                self.banned_IPs.read_rangelist(f)
                self.banned_ip_mtime = os.path.getmtime(f)
            except (IOError, OSError):
                print '**warning** unable to read banned_IP list'
                

    def delete_peer(self, infohash, peerid):
        dls = self.downloads[infohash]
        peer = dls[peerid]
        if not peer['left']:
            self.seedcount[infohash] -= 1
        if not peer.get('nat',-1):
            l = self.becache[infohash]
            y = not peer['left']
            for x in l:
                del x[y][peerid]
        del self.times[infohash][peerid]
        del dls[peerid]

    def expire_downloaders(self):
        for x in self.times.keys():
            for myid, t in self.times[x].items():
                if t < self.prevtime:
                    self.delete_peer(x,myid)
        self.prevtime = clock()
        if (self.keep_dead != 1):
            for key, value in self.downloads.items():
                if len(value) == 0 and (
                        self.allowed is None or not self.allowed.has_key(key) ):
                    del self.times[key]
                    del self.downloads[key]
                    del self.seedcount[key]
        self.rawserver.add_task(self.expire_downloaders, self.timeout_downloaders_interval)


def track(args):
    if not args:
        print formatDefinitions(defaults, 80)
        return
    try:
        config, files = parseargs(args, defaults, 0, 0)
    except ValueError, e:
        print 'error: ' + str(e)
        print 'run with no arguments for parameter explanations'
        return
    r = RawServer(Event(), config['tracker_timeout_check_interval'],
                  config['tracker_socket_timeout'], ipv6_enable = config['ipv6_enabled'])
    t = Tracker(config, r)
    r.bind(config['minport'], config['bind'],
           reuse = True, ipv6_socket_style = config['ipv6_binds_v4'])
    r.listen_forever(HTTPHandler(t.get, config['min_time_between_log_flushes']))
    t.save_state()
    print '# Shutting down: ' + isotime()

def size_format(s):
    if (s < 1024):
        r = str(s) + 'B'
    elif (s < 1048576):
        r = str(int(s/1024)) + 'KiB'
    elif (s < 1073741824L):
        r = str(int(s/1048576)) + 'MiB'
    elif (s < 1099511627776L):
        r = str(int((s/1073741824.0)*100.0)/100.0) + 'GiB'
    else:
        r = str(int((s/1099511627776.0)*100.0)/100.0) + 'TiB'
    return(r)

