from subprocess import Popen, PIPE
from getpass import getuser
from sys import exit

class AP:
    def __init__(self):
        self.mac = '00:00:00:00:00:00'
        self.essid = ''
        self.channel = -1
        self.frequency = .0
        self.signal_level = 0
        self.signal_quality = .0
        self.encryption_mode = None
        self.bit_rates = []
        self.last_beacon = 0

class Scan:
    def __init__(self):
        self.cells = []

    def read(self, data):
        d = [l.strip() for l in data.splitlines()]; i = 0
        mac = d[i].split('-')[1][-17:]; i+=1
        channel = int(d[i].split(':')[1]); i+=1
        frequency = float(d[i].split(':')[1][:5]); i+=1
        quality = float(eval(d[i].split()[0].split('=')[1]+'.'))
        level = int(d[i].split()[2].split('=')[1][:3]); i+=1
        enc = bool(d[i].split(':')[1]=='on'); i+=1
        essid = d[i].split(':')[1][1:-1]; i+=1
        bitrates = [int(v[:2].strip())
                    for v in d[i].split(':')[-1].split(';')]; i+=1
        bitrates.append([int(v[:2].strip())
                    for v in d[i].split(':')[-1].split(';')]); i+=1
        bitrates.append([int(v[:2].strip())
                    for v in d[i].split(':')[-1].split(';')]); i+=3
        lastbeacon = int(d[i].split(':')[-1][:-6]); i+= 1
        mode = 'WPE' if enc else ''
        while d[i]:
            if d[i].find('WPA2') != -1:
                mode = 'WPA2'
            elif d[i].find('WPA') != -1:
                mode = 'WPA'
            i+=1
        newcell = AP()
        newcell.mac = mac
        newcell.essid = essid
        newcell.channel = channel
        newcell.frequency = frequency
        newcell.signal_level = level
        newcell.signal_quality = quality
        newcell.encryption_mode = mode
        newcell.bit_rates = bitrates
        newcell.last_beacon = lastbeacon
        self.cells.append(newcell)

    def get(self, attr, value):
        result = []
        for cell in self.cells:
            v = getattr(cell, attr).lower()
            opts = [v.lower() for v in list(value)]
            if v in opts:
                result.append(cell)
        return result
    def get_sorted(self, attr, n=None, rev=False):
        return sorted(self.cells,
                      key=lambda c: getattr(c, attr),
                      reverse=rev)[:n]

def getscandata(dev):
    cmd = 'iwlist %s scan'%dev
    pipe = Popen(cmd.split(), 1024, stdout=PIPE, stderr=PIPE)
    if not pipe.stderr.read():
        return pipe.stdout.read().split('Cell')


if __name__ == '__main__':
    if getuser() != 'root':
        print 'Run with root'
        exit()

    scan = Scan()

    print 'scanning... '
    rawdata = getscandata('wlan3')
    if not rawdata:
        print 'error scanning network.'
        exit()
    print 'done'

    print 'parsing data...'
    for d in rawdata[1:]:
        scan.read(d)
    print 'done'

    for ap in scan.get_sorted('signal_quality', 5, rev=True):
        print '%s - %.2f%%'%(ap.essid, ap.signal_quality*100)