#!/usr/bin/env python3
#-*- mode: Python;-*-

import sys
import time
import traceback
import socket
import datetime
import http.client
import subprocess
import tempfile
import json
import gzip
import statistics

try:
    import requests
except:
    sys.stderr.write('ERROR: Could not import requests module.  Ensure it is installed.\n')
    sys.stderr.write('       Under Debian, the package name is "python3-requests"\n.')
    sys.exit(1)

from .stats import *


def getLocalIP(remote_host, remote_port):
    connection = socket.create_connection((remote_host, remote_port))
    ret_val = connection.getsockname()[0]
    connection.close()

    return ret_val


def getIfaceForIP(ip):
    try:
        import netifaces
    except:
        sys.stderr.write('ERROR: Could not import netifaces module.  Ensure it is installed.\n')
        sys.stderr.write('       Try: pip3 install netifaces\n.')
        sys.exit(1)
    
    for iface in netifaces.interfaces():
        addrs = netifaces.ifaddresses(iface).get(netifaces.AF_INET, None)
        if addrs:
            for a in addrs:
                if a.get('addr', None) == ip:
                    return iface


class snifferProcess(object):
    my_ip = None
    my_iface = None
    target_ip = None
    target_port = None
    _proc = None
    _spool = None
    
    def __init__(self, target_ip, target_port):
        self.target_ip = target_ip
        self.target_port = target_port
        self.my_ip = getLocalIP(target_ip, target_port)
        self.my_iface = getIfaceForIP(self.my_ip)
        print(self.my_ip, self.my_iface)

    def start(self):
        self._spool = tempfile.NamedTemporaryFile('w+t')
        self._proc = subprocess.Popen(['chrt', '-r', '99', 'nanown-listen',
                                       self.my_iface, self.my_ip,
                                       self.target_ip, "%d" % self.target_port,
                                       self._spool.name, '0'])
        time.sleep(0.25)

    def openPacketLog(self):
        return open(self._spool.name, 'rt')
        
    def stop(self):
        if self._proc:
            self._proc.terminate()
            self._proc.wait(2)
            if self._proc.poll() == None:
                self._proc.kill()
                self._proc.wait(1)
            self._proc = None
    
    def is_running(self):
        return (self._proc.poll() == None)
            
    def __del__(self):
        self.stop()

            
def startSniffer(target_ip, target_port, output_file):
    my_ip = getLocalIP(target_ip, target_port)
    my_iface = getIfaceForIP(my_ip)
    return subprocess.Popen(['chrt', '-r', '99', 'nanown-listen', my_iface, my_ip,
                             target_ip, "%d" % target_port, output_file, '0'])

def stopSniffer(sniffer):
    sniffer.terminate()
    sniffer.wait(2)
    if sniffer.poll() == None:
        sniffer.kill()
        sniffer.wait(1)


# Monkey patching that instruments the HTTPResponse to collect connection source port info
class MonitoredHTTPResponse(http.client.HTTPResponse):
    local_address = None

    def __init__(self, sock, *args, **kwargs):
        self.local_address = sock.getsockname()
        #print(self.local_address)
        super(MonitoredHTTPResponse, self).__init__(sock,*args,**kwargs)
            
requests.packages.urllib3.connection.HTTPConnection.response_class = MonitoredHTTPResponse


def removeDuplicatePackets(packets):
    #return packets
    suspect = ''
    seen = {}
    # XXX: Need to review this deduplication algorithm and make sure it is correct
    for p in packets:
        key = (p['sent'],p['tcpseq'],p['tcpack'],p['payload_len'])
        if (key not in seen):
            seen[key] = p
            continue
        if p['sent']==1 and (seen[key]['observed'] > p['observed']): #earliest sent
            seen[key] = p
            suspect += 's' # duplicated sent packets
            continue 
        if p['sent']==0 and (seen[key]['observed'] > p['observed']): #earliest rcvd
            seen[key] = p
            suspect += 'r' # duplicated received packets
            continue
    
    #if len(seen) < len(packets):
    #   sys.stderr.write("INFO: removed %d duplicate packets.\n" % (len(packets) - len(seen)))

    return suspect,seen.values()


def analyzePackets(packets, timestamp_precision, trim_sent=0, trim_rcvd=0):
    suspect,packets = removeDuplicatePackets(packets)

    sort_key = lambda d: (d['observed'],d['tcpseq'])
    alt_key = lambda d: (d['tcpseq'],d['observed'])
    sent = sorted((p for p in packets if p['sent']==1 and p['payload_len']>0), key=sort_key)
    rcvd = sorted((p for p in packets if p['sent']==0 and p['payload_len']>0), key=sort_key)
    rcvd_alt = sorted((p for p in packets if p['sent']==0 and p['payload_len']>0), key=alt_key)

    s_off = trim_sent
    if s_off >= len(sent):
        suspect += 'd' # dropped packet?
        s_off = -1
    last_sent = sent[s_off]

    r_off = len(rcvd) - trim_rcvd - 1
    if r_off < 0:
        suspect += 'd' # dropped packet?
        r_off = 0
    last_rcvd = rcvd[r_off]
    if last_rcvd != rcvd_alt[r_off]:
        suspect += 'R' # reordered received packets
    
    last_sent_ack = None
    try:
        last_sent_ack = min(((p['tcpack'],p['observed'],p) for p in packets
                             if p['sent']==0 and p['payload_len']+last_sent['tcpseq']>=p['tcpack']))[2]
        
    except Exception as e:
        sys.stderr.write("WARN: Could not find last_sent_ack.\n")

    packet_rtt = last_rcvd['observed'] - last_sent['observed']
    tsval_rtt = None
    if None not in (timestamp_precision, last_sent_ack):
        tsval_rtt = int(round((last_rcvd['tsval'] - last_sent_ack['tsval'])*timestamp_precision))

    if packet_rtt < 0 or (tsval_rtt != None and tsval_rtt < 0):
        #sys.stderr.write("WARN: Negative packet or tsval RTT. last_rcvd=%s,last_sent=%s\n" % (last_rcvd, last_sent))
        suspect += 'N'
        
    return {'packet_rtt':packet_rtt,
            'tsval_rtt':tsval_rtt,
            'suspect':suspect,
            'sent_trimmed':trim_sent,
            'rcvd_trimmed':trim_rcvd},len(sent),len(rcvd)


# septasummary and mad for each dist of differences
def evaluateTrim(db, unusual_case, strim, rtrim):
    cursor = db.conn.cursor()
    query="""
      SELECT packet_rtt-(SELECT avg(packet_rtt) FROM probes,trim_analysis 
                         WHERE sent_trimmed=:strim AND rcvd_trimmed=:rtrim AND trim_analysis.probe_id=probes.id AND probes.test_case!=:unusual_case AND sample=u.s AND probes.type in ('train','test'))
      FROM (SELECT probes.sample s,packet_rtt FROM probes,trim_analysis WHERE sent_trimmed=:strim AND rcvd_trimmed=:rtrim AND trim_analysis.probe_id=probes.id AND probes.test_case=:unusual_case AND probes.type in ('train','test') AND 1 NOT IN (select 1 from probes p,trim_analysis t WHERE p.sample=s AND t.probe_id=p.id AND t.suspect LIKE '%R%')) u
    """
    query="""
      SELECT packet_rtt-(SELECT avg(packet_rtt) FROM probes,trim_analysis 
                         WHERE sent_trimmed=:strim AND rcvd_trimmed=:rtrim AND trim_analysis.probe_id=probes.id AND probes.test_case!=:unusual_case AND sample=u.s AND probes.type in ('train','test'))
      FROM (SELECT probes.sample s,packet_rtt FROM probes,trim_analysis WHERE sent_trimmed=:strim AND rcvd_trimmed=:rtrim AND trim_analysis.probe_id=probes.id AND probes.test_case=:unusual_case AND probes.type in ('train','test')) u
    """
    #TODO: check for "N" in suspect field and return a flag
    
    params = {"strim":strim,"rtrim":rtrim,"unusual_case":unusual_case}
    cursor.execute(query, params)
    differences = [row[0] for row in cursor]

    return septasummary(differences),mad(differences)



def analyzeProbes(db, trim=None, recompute=False):
    db.conn.execute("CREATE INDEX IF NOT EXISTS packets_probe ON packets (probe_id)")
    db.conn.commit()

    pcursor = db.conn.cursor()
    pcursor.execute("SELECT tcpts_mean FROM meta")
    try:
        timestamp_precision = pcursor.fetchone()[0]
    except:
        timestamp_precision = None
    
    pcursor.execute("DELETE FROM trim_analysis")
    db.conn.commit()
    if recompute:
        pcursor.execute("DELETE FROM analysis")
        db.conn.commit()

    def loadPackets(db):
        cursor = db.conn.cursor()
        #cursor.execute("SELECT * FROM packets ORDER BY probe_id")
        cursor.execute("SELECT * FROM packets WHERE probe_id NOT IN (SELECT probe_id FROM analysis) ORDER BY probe_id")

        probe_id = None
        entry = []
        ret_val = []
        for p in cursor:
            if probe_id == None:
                probe_id = p['probe_id']
            if p['probe_id'] != probe_id:
                ret_val.append((probe_id,entry))
                probe_id = p['probe_id']
                entry = []
            entry.append(dict(p))
        ret_val.append((probe_id,entry))
        return ret_val

    def processPackets(packet_cache, strim, rtrim):
        sent_tally = []
        rcvd_tally = []
        analyses = []
        for probe_id,packets in packet_cache:
            try:
                analysis,s,r = analyzePackets(packets, timestamp_precision,strim,rtrim)
                analysis['probe_id'] = probe_id
                analyses.append(analysis)
                sent_tally.append(s)
                rcvd_tally.append(r)
            except Exception as e:
                #traceback.print_exc()
                sys.stderr.write("WARN: couldn't find enough packets for probe_id=%s\n" % probe_id)

        start = time.time()    
        db.addTrimAnalyses(analyses)
        db.conn.commit()
        print("addTrimAnalyses: %f" % (time.time()-start))

        return statistics.mode(sent_tally),statistics.mode(rcvd_tally)
    
    #start = time.time()
    packet_cache = loadPackets(db)
    #print("packets loaded in: %f" % (time.time()-start))

    if trim != None:
        best_strim,best_rtrim = trim
        processPackets(packet_cache, best_strim, best_rtrim)
    else:
        num_sent,num_rcvd = processPackets(packet_cache, 0, 0)
        print("num_sent: %d, num_rcvd: %d" % (num_sent,num_rcvd))
        unusual_case,delta = findUnusualTestCase(db, (0,0))
        print("unusual_case: %s, delta: %f" % (unusual_case,delta))
        
        delta_margin = 0.15
        best_strim = 0
        best_rtrim = 0
        
        good_delta,good_mad = evaluateTrim(db, unusual_case, best_strim, best_rtrim)
        print("trim (%d,%d): delta=%f, mad=%f" % (best_strim,best_rtrim, good_delta, good_mad))
        
        for strim in range(1,num_sent):
            processPackets(packet_cache, strim, best_rtrim)
            delta,mad = evaluateTrim(db, unusual_case, strim, best_rtrim)
            print("trim (%d,%d): delta=%f, mad=%f" % (strim,best_rtrim, delta, mad))
            if delta*good_delta > 0.0 and (abs(good_delta) - abs(delta)) < abs(delta_margin*good_delta) and mad < good_mad:
                best_strim = strim
                good_delta,good_mad = delta,mad
            else:
                break

        for rtrim in range(1,num_rcvd):
            processPackets(packet_cache, best_strim, rtrim)
            delta,mad = evaluateTrim(db, unusual_case, best_strim, rtrim)
            print("trim (%d,%d): delta=%f, mad=%f" % (best_strim, rtrim, delta, mad))            
            if delta*good_delta > 0.0 and (abs(good_delta) - abs(delta)) < abs(delta_margin*good_delta) and mad < good_mad:
                best_rtrim = rtrim
            else:
                break

        print("selected trim parameters:",(best_strim,best_rtrim))
    
    pcursor.execute("""INSERT OR IGNORE INTO analysis 
                         SELECT id,probe_id,suspect,packet_rtt,tsval_rtt 
                           FROM trim_analysis 
                           WHERE sent_trimmed=? AND rcvd_trimmed=?""",
                    (best_strim,best_rtrim))
    db.conn.commit()
    
    return len(packet_cache)


        
def parseJSONLines(fp):
    for line in fp:
        yield json.loads(line)


def associatePackets(sniffer_fp, db):
    sniffer_fp.seek(0)

    # now combine sampler data with packet data
    buffered = []

    cursor = db.conn.cursor()
    cursor.execute("SELECT count(*) count,min(time_of_day) start,max(time_of_day+userspace_rtt) end from probes")
    ptimes = cursor.fetchone()
    window_size = 100*int((ptimes['end']-ptimes['start'])/ptimes['count'])
    #print("associate window_size:", window_size)

    db.addPackets(parseJSONLines(sniffer_fp), window_size)

    cursor.execute("SELECT count(*) count FROM packets WHERE probe_id is NULL")
    unmatched = cursor.fetchone()['count']
    if unmatched > 0:
        sys.stderr.write("WARNING: %d observed packets didn't find a home...\n" % unmatched)
 
    return None


def enumStoredTestCases(db):
    cursor = db.conn.cursor()
    cursor.execute("SELECT test_case FROM probes GROUP BY test_case")
    return [tc[0] for tc in cursor]


def findUnusualTestCase(db, trim=None):
    test_cases = enumStoredTestCases(db)
    if trim != None:
        params = {'strim':trim[0], 'rtrim':trim[1]}
        qsuffix = " AND sent_trimmed=:strim AND rcvd_trimmed=:rtrim"
        table = "trim_analysis"
    else:
        params = {}
        qsuffix = ""
        table = "analysis"
    
    cursor = db.conn.cursor()
    cursor.execute("SELECT packet_rtt FROM probes,"+table+" a WHERE probes.id=a.probe_id AND probes.type in ('train','test')"+qsuffix, params)
    global_tm = quadsummary([row['packet_rtt'] for row in cursor])

    tm_abs = []
    tm_map = {}

    # XXX: if more speed needed, percentile extension to sqlite might be handy...
    for tc in test_cases:
        params['test_case']=tc
        query = """SELECT packet_rtt FROM probes,"""+table+""" a
                   WHERE probes.id=a.probe_id AND probes.type in ('train','test') 
                   AND probes.test_case=:test_case""" + qsuffix
        cursor.execute(query, params)
        tm_map[tc] = quadsummary([row['packet_rtt'] for row in cursor])
        tm_abs.append((abs(tm_map[tc]-global_tm), tc))

    magnitude,tc = max(tm_abs)
    params['test_case']=tc
    query = """SELECT packet_rtt FROM probes,"""+table+""" a
               WHERE probes.id=a.probe_id AND probes.type in ('train','test') 
               AND probes.test_case<>:test_case""" + qsuffix
    cursor.execute(query,params)
    remaining_tm = quadsummary([row['packet_rtt'] for row in cursor])

    delta = tm_map[tc]-remaining_tm
    # Hack to make the chosen unusual_case more intuitive to the user
    if len(test_cases) == 2 and delta < 0.0:
        tc = [t for t in test_cases if t != tc][0]
        delta = abs(delta)

    return tc,delta


def reportProgress(db, sample_types, start_time):
    cursor = db.conn.cursor()
    output = ''
    total_completed = 0
    total_requested = 0
    for st in sample_types:
        cursor.execute("SELECT count(id) c FROM (SELECT id FROM probes WHERE type=? AND time_of_day>? GROUP BY sample)", (st[0],int(start_time*1000000000)))
        count = cursor.fetchone()[0]
        output += " | %s remaining: %6d" % (st[0], st[1]-count)
        total_completed += count
        total_requested += st[1]

    rate = total_completed / (time.time() - start_time)
    total_time = total_requested / rate
    eta = datetime.datetime.fromtimestamp(start_time+total_time)
    print("STATUS:",output[3:],"| est. total_time: %s | ETA: %s" % (str(datetime.timedelta(seconds=total_time)), eta.strftime("%Y-%m-%d %X")))



def evaluateTestResults(db):
    cursor = db.conn.cursor()
    query = """
      SELECT classifier FROM classifier_results GROUP BY classifier ORDER BY classifier;
    """
    cursor.execute(query)
    classifiers = []
    for c in cursor:
        classifiers.append(c[0])

    best_obs = []
    best_error = []
    max_obs = 0
    for classifier in classifiers:
        query="""
        SELECT classifier,params,num_observations,(false_positives+false_negatives)/2 error 
        FROM classifier_results 
        WHERE trial_type='test'
         AND classifier=:classifier
         AND (false_positives+false_negatives)/2.0 < 5.0 
        ORDER BY num_observations,(false_positives+false_negatives) 
        LIMIT 1
        """
        cursor.execute(query, {'classifier':classifier})
        row = cursor.fetchone()
        if row == None:
            query="""
            SELECT classifier,params,num_observations,(false_positives+false_negatives)/2 error 
            FROM classifier_results 
            WHERE trial_type='test' and classifier=:classifier
            ORDER BY (false_positives+false_negatives),num_observations
            LIMIT 1
            """
            cursor.execute(query, {'classifier':classifier})
            row = cursor.fetchone()
            if row == None:
                sys.stderr.write("WARN: couldn't find test results for classifier '%s'.\n" % classifier)
                continue
            row = dict(row)

            best_error.append(dict(row))
        else:
            best_obs.append(dict(row))


    return best_obs,best_error