import os
import platform
import shutil
import cPickle

orig_tracker_url = 'udp://xxx'
new_tracker_url = 'udp://xxx'

if platform.system() in ('Windows', 'Microsoft'):
    state_file_path = os.path.join(os.environ.get('APPDATA'), 'deluge', 'torrents.state')
else:
    state_file_path = os.path.expanduser('~/.config/deluge/state/torrents.state')

print "State file: %s" % state_file_path
print "Replace '%s' with '%s'" % (orig_tracker_url, new_tracker_url)
state_file = open(state_file_path, 'rb')
state = cPickle.load(state_file)
state_file.close()

state_modified = False
for torrent in state.torrents:
    for tracker in torrent.trackers:
        if tracker['url'] == orig_tracker_url:
            tracker['url'] = new_tracker_url
            state_modified = True


if state_modified:
    shutil.copyfile(state_file_path, state_file_path + '.old')
    state_file = open(state_file_path, 'wb')
    cPickle.dump(state, state_file)
    state_file.close()
    print "State Updated"
else:
    print "Nothing to do"