#!/usr/bin/env python3

from collections import Counter, defaultdict
import csv
from dataclasses import dataclass
from datetime import datetime, timedelta
from enum import Enum
from logging import warning
from pathlib import Path
import re
from statistics import mean, median, stdev
from sys import argv
from urllib.parse import urlparse
from typing import Dict, List, Tuple

import user_agents


ACCESS_RE = re.compile(' '.join((
    r'(?P<address>\S+)',
    r'\S+',
    r'\S+',
    r'(?P<date>\[\S+ \S+\])',
    r'"GET (?P<resource>[^ ?]+)(\?\S+)? [^"]+"',
    r'200 [0-9]+',
    r'"(?P<referer>[^"]+)(\?\S+)?"',
    r'"(?P<useragent>[^"]+)"'
)))

DATE_FMT = '[%d/%b/%Y:%H:%M:%S %z]'

VISIT_MAX_DURATION = timedelta(hours=1)

DOMAINS = {
    'quatuorbellefeuille.com',
    'quatuorbellefeuille.fr',
    'klg.uber.space'
}


def normalize_path(p):
    if p == '/':
        return '/index.html'
    return p


@dataclass
class Access:
    address: str
    useragent: str
    referrer: str
    time: datetime
    resource: str

    @classmethod
    def from_log(cls, info):
        resource = normalize_path(info['resource'])

        referrer = urlparse(info['referer'])
        if referrer.netloc in DOMAINS:
            ref = normalize_path(referrer.path)
        else:
            ref = referrer.netloc

        return cls(
            info['address'], info['useragent'], ref,
            datetime.strptime(info['date'], DATE_FMT), resource
        )


def interesting(resource):
    return resource.endswith('.html') or resource == '/'


def parse(logs_paths):
    logs = []
    for lp in logs_paths:
        with open(lp) as logs_file:
            logs += logs_file.read().splitlines()

    matches = (ACCESS_RE.match(l) for l in logs)
    return tuple(
        Access.from_log(m) for m in matches
        if (m is not None and interesting(m['resource']))
    )


Visit = List[Access]


class UserAgentKind(Enum):
    PC = 'pc'
    MOBILE = 'mobile'
    TABLET = 'tablet'
    BOT = 'bot'
    NA = 'n/a'

    @classmethod
    def from_useragent(cls, ua_string):
        ua = user_agents.parse(ua_string)
        # is_bot is not mutually exclusive with other is_* predicates.
        if ua.is_bot:
            return cls.BOT
        if ua.is_pc:
            return cls.PC
        if ua.is_mobile:
            return cls.MOBILE
        if ua.is_tablet:
            return cls.TABLET
        warning(f'Unknown user agent kind: {ua_string}')
        return cls.NA

    def is_human(self):
        return self in {
            UserAgentKind.PC,
            UserAgentKind.MOBILE,
            UserAgentKind.TABLET
        }


@dataclass
class Visitor:
    address: str
    useragent: UserAgentKind
    referrers: List[str]
    visits: List[Visit]


def sort_visits(accesses):
    visitors: Dict[Tuple(str, str), Visitor] = {}

    for a in accesses:
        key = (a.address, a.useragent)

        visitor = visitors.get(key)
        if visitor is None:
            visitor = Visitor(
                a.address,
                UserAgentKind.from_useragent(a.useragent),
                a.referrer,
                [[a]]
            )
            visitors[key] = visitor
            continue

        last_visit = visitor.visits[-1]
        last_access = last_visit[-1].time
        if a.time - last_access < VISIT_MAX_DURATION:
            last_visit.append(a)
            continue

        visitor.visits.append([a])

    return visitors


def datetime_day(dt):
    return dt.replace(hour=0, minute=0, second=0)


def find_days(visits):
    return {
        datetime_day(v[0].time)
        for v in visits
    }


def daily_visitors(visitors, output_path):
    days: Dict[datetime, Counter] = defaultdict(Counter)
    columns = ('mobile', 'tablet', 'pc', 'bot', 'n/a')

    print('Visitors:')

    for v in visitors.values():
        for day in find_days(v.visits):
            days[day][v.useragent.value] += 1

    with open(output_path, 'w') as f:
        out = csv.writer(f)
        out.writerow(('day', 'total', *columns))
        print('day', 'total', *columns, sep='\t')

        for day in sorted(days):
            counter = days[day]
            counters = tuple(counter[c] for c in columns)
            values = (day.strftime('%F'), sum(counters), *counters)

            out.writerow(values)
            print(*values, sep='\t')


def daily_visits(visitors, output_path):
    days: Dict[datetime, Counter] = defaultdict(Counter)
    columns = ('mobile', 'tablet', 'pc', 'bot', 'n/a')

    print('Visits:')

    for v in visitors.values():
        for visit in v.visits:
            day = datetime_day(visit[0].time)
            days[day][v.useragent.value] += 1

    with open(output_path, 'w') as f:
        out = csv.writer(f)
        out.writerow(('day', 'total', *columns))
        print('day', 'total', *columns, sep='\t')

        for day in sorted(days):
            counter = days[day]
            counters = tuple(counter[c] for c in columns)
            values = (day.strftime('%F'), sum(counters), *counters)

            out.writerow(values)
            print(*values, sep='\t')


def daily_pages_per_visit(visitors, output_path):
    days: Dict[datetime, list] = defaultdict(list)
    columns = ('min', 'max', 'med', 'avg', 'dev')

    print('Pages/visit:')

    for v in visitors.values():
        if not v.useragent.is_human():
            continue

        for visit in v.visits:
            day = datetime_day(visit[0].time)
            days[day].append(len(visit))

    with open(output_path, 'w') as f:
        out = csv.writer(f)
        out.writerow(('day', *columns))
        print('day', *columns, sep='\t')

        for day in sorted(days):
            view_counts = days[day]
            values = (
                day.strftime('%F'),
                min(view_counts),
                max(view_counts),
                median(view_counts),
                mean(view_counts),
                stdev(view_counts)
            )

            out.writerow(values)
            print(*values[:4], *(f'{v:.2f}' for v in values[4:]), sep='\t')


def daily_stats(visitors, output_dir):
    output_dir = Path(output_dir)
    daily_visitors(visitors, output_dir.joinpath('dailyvisitors.csv'))
    daily_visits(visitors, output_dir.joinpath('dailyvisits.csv'))
    daily_pages_per_visit(visitors, output_dir.joinpath('dailypagespervisit.csv'))
    # daily_page_hits(visitors, output_dir.joinpath('dailypagehits.csv'))
    # daily_referrers(visitors, output_dir.joinpath('dailyreferrers.csv'))


def global_stats(visitors, output_dir):
    pass


def main(logs_paths, output_dir):
    accesses = parse(logs_paths)
    visitors = sort_visits(accesses)
    daily_stats(visitors, output_dir)
    global_stats(visitors, output_dir)


if __name__ == '__main__':
    main(argv[1:-1], argv[-1])