from django.http import HttpResponse, HttpResponseForbidden
from django.shortcuts import get_object_or_404
from django.conf import settings
import ipaddress

from .views import cache
from .models import Message, List

import json


def is_host_allowed(request):
    for ip_range in settings.API_CLIENTS:
        if ipaddress.ip_address(request.META['REMOTE_ADDR']) in ipaddress.ip_network(ip_range):
            return True
    return False


@cache(hours=4)
def listinfo(request):
    if not settings.PUBLIC_ARCHIVES:
        return HttpResponseForbidden('No API access on private archives for now')

    if not is_host_allowed(request):
        return HttpResponseForbidden('Invalid host')

    resp = HttpResponse(content_type='application/json')
    json.dump([{
        'name': l.listname,
        'shortdesc': l.shortdesc,
        'description': l.description,
        'active': l.active,
        'group': l.group.groupname,
    } for l in List.objects.select_related('group').all()], resp)

    return resp


@cache(hours=4)
def latest(request, listname):
    if not settings.PUBLIC_ARCHIVES:
        return HttpResponseForbidden('No API access on private archives for now')

    if not is_host_allowed(request):
        return HttpResponseForbidden('Invalid host')

    # Return the latest <n> messages on this list.
    # If <n> is not specified, return 50. Max value for <n> is 100.
    if 'n' in request.GET:
        try:
            limit = int(request.GET['n'])
        except Exception:
            limit = 0
    else:
        limit = 50
    if limit <= 0 or limit > 100:
        limit = 50

    extrawhere = []
    extraparams = []

    # Return only messages that have attachments?
    if 'a' in request.GET:
        if request.GET['a'] == '1':
            extrawhere.append("has_attachment")

    # Restrict by full text search
    if 's' in request.GET and request.GET['s']:
        extrawhere.append("fti @@ plainto_tsquery('public.pg', %s)")
        extraparams.append(request.GET['s'])

    if listname != '*':
        list = get_object_or_404(List, listname=listname)
        extrawhere.append("threadid IN (SELECT threadid FROM list_threads WHERE listid=%s)" % list.listid)
    else:
        list = None
        extrawhere = ''

    mlist = Message.objects.defer('bodytxt', 'cc', 'to').select_related().extra(where=extrawhere, params=extraparams).order_by('-date')[:limit]
    allyearmonths = set([(m.date.year, m.date.month) for m in mlist])

    resp = HttpResponse(content_type='application/json')
    json.dump([
        {
            'msgid': m.messageid,
            'date': m.date.isoformat(),
            'from': m.mailfrom,
            'subj': m.subject,
        }
        for m in mlist], resp)

    # Make sure this expires from the varnish cache when new entries show
    # up in this month.
    # XXX: need to deal with the global view, but for now API callers come in directly
    if list and settings.PUBLIC_ARCHIVES:
        resp['xkey'] = ' '.join(['pgam_{0}/{1}/{2}'.format(list.listid, year, month) for year, month in allyearmonths])
    return resp


@cache(hours=4)
def thread(request, msgid):
    if not settings.PUBLIC_ARCHIVES:
        return HttpResponseForbidden('No API access on private archives for now')

    if not is_host_allowed(request):
        return HttpResponseForbidden('Invalid host')

    # Return metadata about a single thread. A list of all the emails
    # that are in the thread with their basic attributes are included.
    msg = get_object_or_404(Message, messageid=msgid)
    mlist = Message.objects.defer('bodytxt', 'cc', 'to').filter(threadid=msg.threadid)

    resp = HttpResponse(content_type='application/json')
    json.dump([
        {
            'msgid': m.messageid,
            'date': m.date.isoformat(),
            'from': m.mailfrom,
            'subj': m.subject,
            'atts': [{'id': a.id, 'name': a.filename} for a in m.attachment_set.all()],
        }
        for m in mlist], resp)
    if settings.PUBLIC_ARCHIVES:
        resp['xkey'] = 'pgat_{0}'.format(msg.threadid)
    return resp