from datetime import timedelta
from itertools import groupby
import json
from operator import attrgetter, itemgetter

from django import forms
from django.forms.widgets import SelectMultiple, CheckboxSelectMultiple
from django.core.serializers.json import DjangoJSONEncoder
from django.db import connection
from django.db.models import Q
from django.http import Http404, HttpResponse
from django.shortcuts import get_object_or_404, redirect, render
from django.utils.timezone import now
from django.views.decorators.cache import cache_page
from django.views.decorators.csrf import csrf_exempt
from django.views.decorators.http import condition
from django_countries import countries
from django_countries.fields import Country

from .models import (Mirror, MirrorUrl, MirrorProtocol, MirrorLog,
        CheckLocation)
from .utils import get_mirror_statuses, get_mirror_errors, DEFAULT_CUTOFF


class MirrorlistForm(forms.Form):
    country = forms.MultipleChoiceField(required=False,
            widget=SelectMultiple(attrs={'size': '12'}))
    protocol = forms.MultipleChoiceField(required=False,
            widget=CheckboxSelectMultiple)
    ip_version = forms.MultipleChoiceField(required=False,
            label="IP version", choices=(('4','IPv4'), ('6','IPv6')),
            widget=CheckboxSelectMultiple)
    use_mirror_status = forms.BooleanField(required=False)

    def __init__(self, *args, **kwargs):
        super(MirrorlistForm, self).__init__(*args, **kwargs)
        fields = self.fields
        fields['country'].choices = [('all','All')] + self.get_countries()
        fields['country'].initial = ['all']
        protos = [(p.protocol, p.protocol) for p in
                MirrorProtocol.objects.filter(is_download=True)]
        initial = MirrorProtocol.objects.filter(is_download=True, default=True)
        fields['protocol'].choices = protos
        fields['protocol'].initial = [p.protocol for p in initial]
        fields['ip_version'].initial = ['4']

    def get_countries(self):
        country_codes = set()
        country_codes.update(MirrorUrl.objects.filter(active=True,
                mirror__active=True).exclude(country='').values_list(
                'country', flat=True).order_by().distinct())
        code_list = [(code, countries.name(code)) for code in country_codes]
        return sorted(code_list, key=itemgetter(1))

    def as_div(self):
        "Returns this form rendered as HTML <divs>s."
        return self._html_output(
            normal_row = u'<div%(html_class_attr)s>%(label)s %(field)s%(help_text)s</div>',
            error_row = u'%s',
            row_ender = '</div>',
            help_text_html = u' <span class="helptext">%s</span>',
            errors_on_separate_row = True)


@csrf_exempt
def generate_mirrorlist(request):
    if request.method == 'POST' or len(request.GET) > 0:
        form = MirrorlistForm(data=request.REQUEST)
        if form.is_valid():
            countries = form.cleaned_data['country']
            protocols = form.cleaned_data['protocol']
            use_status = form.cleaned_data['use_mirror_status']
            ipv4 = '4' in form.cleaned_data['ip_version']
            ipv6 = '6' in form.cleaned_data['ip_version']
            return find_mirrors(request, countries, protocols,
                    use_status, ipv4, ipv6)
    else:
        form = MirrorlistForm()

    return render(request, 'mirrors/mirrorlist_generate.html',
            {'mirrorlist_form': form})


def status_filter(original_urls):
    status_info = get_mirror_statuses()
    scores = {u.id: u.score for u in status_info['urls']}
    urls = []
    for u in original_urls:
        u.score = scores.get(u.id, None)
        # also include mirrors that don't have an up to date score
        # (as opposed to those that have been set with no score)
        if (u.id not in scores) or (u.score and u.score < 100.0):
            urls.append(u)
    # if a url doesn't have a score, treat it as the highest possible
    return sorted(urls, key=lambda x: x.score or 100.0)


def find_mirrors(request, countries=None, protocols=None, use_status=False,
        ipv4_supported=True, ipv6_supported=True):
    if not protocols:
        protocols = MirrorProtocol.objects.filter(is_download=True)
    elif hasattr(protocols, 'model') and protocols.model == MirrorProtocol:
        # we already have a queryset, no need to query again
        pass
    else:
        protocols = MirrorProtocol.objects.filter(protocol__in=protocols)
    qset = MirrorUrl.objects.select_related().filter(
            protocol__in=protocols, active=True,
            mirror__public=True, mirror__active=True)
    if countries and 'all' not in countries:
        qset = qset.filter(country__in=countries)

    ip_version = Q()
    if ipv4_supported:
        ip_version |= Q(has_ipv4=True)
    if ipv6_supported:
        ip_version |= Q(has_ipv6=True)
    qset = qset.filter(ip_version)

    if not use_status:
        sort_key = attrgetter('country.name', 'mirror.name', 'url')
        urls = sorted(qset, key=sort_key)
        template = 'mirrors/mirrorlist.txt'
    else:
        urls = status_filter(qset)
        template = 'mirrors/mirrorlist_status.txt'

    context = {
        'mirror_urls': urls,
    }
    return render(request, template, context, content_type='text/plain')


def find_mirrors_simple(request, protocol):
    if protocol == 'smart':
        return redirect('mirrorlist_simple', 'http', permanent=True)
    proto = get_object_or_404(MirrorProtocol, protocol=protocol)
    return find_mirrors(request, protocols=[proto])


def mirrors(request):
    mirror_list = Mirror.objects.select_related().order_by('tier', 'name')
    protos = MirrorUrl.objects.values_list(
            'mirror_id', 'protocol__protocol').order_by(
            'mirror_id', 'protocol__protocol').distinct()
    countries = MirrorUrl.objects.values_list(
            'mirror_id', 'country').order_by(
            'mirror_id', 'country').distinct()

    if not request.user.is_authenticated():
        mirror_list = mirror_list.filter(public=True, active=True)
        protos = protos.filter(
                mirror__public=True, mirror__active=True, active=True)
        countries = countries.filter(
                mirror__public=True, mirror__active=True, active=True)

    protos = {k: list(v) for k, v in groupby(protos, key=itemgetter(0))}
    countries = {k: list(v) for k, v in groupby(countries, key=itemgetter(0))}

    for mirror in mirror_list:
        item_protos = protos.get(mirror.id, [])
        mirror.protocols = [item[1] for item in item_protos]
        mirror.country = None
        item_countries = countries.get(mirror.id, [])
        if len(item_countries) == 1:
            mirror.country = Country(item_countries[0][1])

    return render(request, 'mirrors/mirrors.html',
            {'mirror_list': mirror_list})


def mirror_details(request, name):
    mirror = get_object_or_404(Mirror, name=name)
    authorized = request.user.is_authenticated()
    if not authorized and \
            (not mirror.public or not mirror.active):
        raise Http404
    error_cutoff = timedelta(days=7)

    status_info = get_mirror_statuses(mirror_id=mirror.id,
            show_all=authorized)
    checked_urls = {url for url in status_info['urls'] \
            if url.mirror_id == mirror.id}
    all_urls = mirror.urls.select_related('protocol')
    if not authorized:
        all_urls = all_urls.filter(active=True)
    all_urls = set(all_urls)
    # Add dummy data for URLs that we haven't checked recently
    other_urls = all_urls.difference(checked_urls)
    for url in other_urls:
        for attr in ('last_sync', 'completion_pct', 'delay', 'duration_avg',
                'duration_stddev', 'score'):
            setattr(url, attr, None)
    all_urls = sorted(checked_urls.union(other_urls), key=attrgetter('url'))

    error_logs = get_mirror_errors(mirror_id=mirror.id, cutoff=error_cutoff,
            show_all=True)

    context = {
        'mirror': mirror,
        'urls': all_urls,
        'cutoff': error_cutoff,
        'error_logs': error_logs,
    }
    return render(request, 'mirrors/mirror_details.html', context)


def mirror_details_json(request, name):
    authorized = request.user.is_authenticated()
    mirror = get_object_or_404(Mirror, name=name)
    if not authorized and (not mirror.public or not mirror.active):
        raise Http404
    status_info = get_mirror_statuses(mirror_id=mirror.id,
            show_all=authorized)
    data = status_info.copy()
    data['version'] = 3
    to_json = json.dumps(data, ensure_ascii=False,
            cls=ExtendedMirrorStatusJSONEncoder)
    response = HttpResponse(to_json, content_type='application/json')
    return response


def url_details(request, name, url_id):
    url = get_object_or_404(MirrorUrl.objects.select_related(),
            id=url_id, mirror__name=name)
    mirror = url.mirror
    authorized = request.user.is_authenticated()
    if not authorized and \
            (not mirror.public or not mirror.active or not url.active):
        raise Http404
    error_cutoff = timedelta(days=7)
    cutoff_time = now() - error_cutoff
    logs = MirrorLog.objects.select_related('location').filter(
            url=url, check_time__gte=cutoff_time).order_by('-check_time')

    context = {
        'url': url,
        'logs': logs,
    }
    return render(request, 'mirrors/url_details.html', context)


def status_last_modified(request, *args, **kwargs):
    cursor = connection.cursor()
    cursor.execute("SELECT MAX(check_time) FROM mirrors_mirrorlog")
    return cursor.fetchone()[0]


@condition(last_modified_func=status_last_modified)
def status(request, tier=None):
    if tier is not None:
        tier = int(tier)
        if tier not in [t[0] for t in Mirror.TIER_CHOICES]:
            raise Http404
    bad_timedelta = timedelta(days=3)
    status_info = get_mirror_statuses()

    urls = status_info['urls']
    good_urls = []
    bad_urls = []
    for url in urls:
        # screen by tier if we were asked to
        if tier is not None and url.mirror.tier != tier:
            continue
        # split them into good and bad lists based on delay
        if url.completion_pct is None:
            # skip URLs that have never been checked
            continue
        elif not url.delay or url.delay > bad_timedelta:
            bad_urls.append(url)
        else:
            good_urls.append(url)

    error_logs = get_mirror_errors()
    if tier is not None:
        error_logs = [log for log in error_logs
                if log['url__mirror__tier'] == tier]

    context = status_info.copy()
    context.update({
        'good_urls': sorted(good_urls, key=attrgetter('score')),
        'bad_urls': sorted(bad_urls, key=lambda u: u.delay or timedelta.max),
        'error_logs': error_logs,
        'tier': tier,
    })
    return render(request, 'mirrors/status.html', context)


class MirrorStatusJSONEncoder(DjangoJSONEncoder):
    '''Base JSONEncoder extended to handle datetime.timedelta and MirrorUrl
    serialization. The base class takes care of datetime.datetime types.'''
    url_attributes = ('url', 'protocol', 'last_sync', 'completion_pct',
            'delay', 'duration_avg', 'duration_stddev', 'score')

    def default(self, obj):
        if isinstance(obj, timedelta):
            # always returned as integer seconds
            return obj.days * 24 * 3600 + obj.seconds
        if isinstance(obj, MirrorUrl):
            data = {attr: getattr(obj, attr) for attr in self.url_attributes}
            country = obj.country
            data['country'] = unicode(country.name)
            data['country_code'] = country.code
            return data
        if isinstance(obj, MirrorProtocol):
            return unicode(obj)
        return super(MirrorStatusJSONEncoder, self).default(obj)


class ExtendedMirrorStatusJSONEncoder(MirrorStatusJSONEncoder):
    '''Adds URL check history information.'''
    log_attributes = ('check_time', 'last_sync', 'duration', 'is_success',
            'location_id')

    def default(self, obj):
        if isinstance(obj, MirrorUrl):
            data = super(ExtendedMirrorStatusJSONEncoder, self).default(obj)
            cutoff = now() - DEFAULT_CUTOFF
            data['logs'] = list(obj.logs.filter(
                    check_time__gte=cutoff).order_by('check_time'))
            return data
        if isinstance(obj, MirrorLog):
            return {attr: getattr(obj, attr) for attr in self.log_attributes}
        return super(ExtendedMirrorStatusJSONEncoder, self).default(obj)


@cache_page(67)
@condition(last_modified_func=status_last_modified)
def status_json(request, tier=None):
    if tier is not None:
        tier = int(tier)
        if tier not in [t[0] for t in Mirror.TIER_CHOICES]:
            raise Http404
    status_info = get_mirror_statuses()
    data = status_info.copy()
    if tier is not None:
        data['urls'] = [url for url in data['urls'] if url.mirror.tier == tier]
    data['version'] = 3
    to_json = json.dumps(data, ensure_ascii=False, cls=MirrorStatusJSONEncoder)
    response = HttpResponse(to_json, content_type='application/json')
    return response


class LocationJSONEncoder(DjangoJSONEncoder):
    '''Base JSONEncoder extended to handle CheckLocation objects.'''

    def default(self, obj):
        if isinstance(obj, CheckLocation):
            return {
                'id': obj.pk,
                'hostname': obj.hostname,
                'source_ip': obj.source_ip,
                'country': unicode(obj.country.name),
                'country_code': obj.country.code,
                'ip_version': obj.ip_version,
            }
        return super(LocationJSONEncoder, self).default(obj)


def locations_json(request):
    data = {}
    data['version'] = 1
    data['locations'] = list(CheckLocation.objects.all().order_by('pk'))
    to_json = json.dumps(data, ensure_ascii=False, cls=LocationJSONEncoder)
    response = HttpResponse(to_json, content_type='application/json')
    return response

# vim: set ts=4 sw=4 et: