from django.conf import settings
from django.contrib.auth import authenticate, login
from django.contrib.auth.decorators import login_required
from django.core.urlresolvers import reverse
from django.http import HttpResponse, HttpResponseRedirect, HttpResponseBadRequest
from django.shortcuts import render_to_response
from django.template import RequestContext
from django.shortcuts import render
from django.utils.timezone import utc

from django.contrib.auth.models import User
from zephyr.models import Zephyr, UserProfile, ZephyrClass, Subscription, \
    Recipient, get_display_recipient, get_huddle, Realm, UserMessage, \
    create_user, do_send_zephyr
from zephyr.forms import RegistrationForm

from zephyr.decorator import asynchronous

import datetime
import simplejson
import socket
import re
import markdown
import hashlib

def require_post(view_func):
    def _wrapped_view_func(request, *args, **kwargs):
        if request.method != "POST":
            return HttpResponseBadRequest('This form can only be submitted by POST.')
        return view_func(request, *args, **kwargs)
    return _wrapped_view_func

def json_response(res_type="success", msg="", data={}, status=200):
    content = {"result":res_type, "msg":msg}
    content.update(data)
    return HttpResponse(content=simplejson.dumps(content),
                        mimetype='application/json', status=status)

def json_success(data={}):
    return json_response(data=data)

def json_error(msg, data={}):
    return json_response(res_type="error", msg=msg, data=data, status=400)

def sanitize_identifier(x):
    """Sanitize an email, class name, etc."""
    # We remove <> in order to avoid </script> within JSON embedded in HTML.
    #
    # FIXME: consider a whitelist
    return x.replace('<','').replace('>','')

def register(request):
    if request.method == 'POST':
        form = RegistrationForm(request.POST)
        if form.is_valid():
            email      = sanitize_identifier(request.POST['email'])
            password   = request.POST['password']
            full_name  = sanitize_identifier(request.POST['full_name'])
            short_name = sanitize_identifier(request.POST['short_name'])
            email      = sanitize_identifier(request.POST['email'])
            domain     = sanitize_identifier(request.POST['domain'])
            realm = Realm.objects.filter(domain=domain)
            if not realm:
                realm = Realm(domain=domain)
                realm.save()
            else:
                realm = Realm.objects.get(domain=domain)
            # FIXME: sanitize email addresses
            create_user(email, password, realm, full_name, short_name)
            login(request, authenticate(username=email, password=password))
            return HttpResponseRedirect(reverse('zephyr.views.home'))
    else:
        form = RegistrationForm()

    return render(request, 'zephyr/register.html', {
        'form': form,
    })

def accounts_home(request):
    return render_to_response('zephyr/accounts_home.html',
                              context_instance=RequestContext(request))

def home(request):
    if not request.user.is_authenticated():
        return HttpResponseRedirect('accounts/home/')
    user_profile = UserProfile.objects.get(user=request.user)

    zephyrs = [um.message for um in
               UserMessage.objects.filter(user_profile=user_profile)]

    if user_profile.pointer == -1 and zephyrs:
        user_profile.pointer = min([zephyr.id for zephyr in zephyrs])
        user_profile.save()

    zephyr_json = simplejson.dumps([zephyr.to_dict() for zephyr in zephyrs])

    # Populate personals autocomplete list based on everyone in your
    # realm.  Later we might want a 2-layer autocomplete, where we
    # consider specially some sort of "buddy list" who e.g. you've
    # talked to before, but for small organizations, the right list is
    # everyone in your realm.
    people = [profile.user.email for profile in
              UserProfile.objects.filter(realm=user_profile.realm) if
              profile != user_profile]

    subscriptions = Subscription.objects.filter(userprofile_id=user_profile, active=True)
    classes = [get_display_recipient(sub.recipient) for sub in subscriptions
               if sub.recipient.type == Recipient.CLASS]

    instances = list(set([zephyr.instance for zephyr in zephyrs
                          if zephyr.recipient.type == Recipient.CLASS]))

    return render_to_response('zephyr/index.html',
                              {'zephyr_array' : zephyr_json,
                               'user_profile': user_profile,
                               'email_hash'  : hashlib.md5(settings.HASH_SALT + user_profile.user.email).hexdigest(),
                               'people'      : simplejson.dumps(people),
                               'classes'     : simplejson.dumps(classes),
                               'instances'   : simplejson.dumps(instances),
                               'show_debug':
                                   settings.DEBUG and ('show_debug' in request.GET) },
                              context_instance=RequestContext(request))

@login_required
@require_post
def update(request):
    user_profile = UserProfile.objects.get(user=request.user)
    pointer = request.POST.get('pointer')
    if not pointer:
        return json_error("Missing pointer")

    try:
        pointer = int(pointer)
    except ValueError:
        return json_error("Invalid pointer: must be an integer")

    if pointer < 0:
        return json_error("Invalid pointer value")

    user_profile.pointer = pointer
    user_profile.save()
    return json_success()

@login_required
@asynchronous
@require_post
def get_updates_longpoll(request, handler):
    last_received = request.POST.get('last_received')
    if not last_received:
        return json_error("Missing last_received argument")
    user_profile = UserProfile.objects.get(user=request.user)

    def on_receive(zephyrs):
        if handler.request.connection.stream.closed():
            return
        try:
            # Avoid message loop by not sending the MIT sync bot any
            # messages that we got from it in the first place.
            if request.POST.get('mit_sync_bot'):
                zephyrs = [zephyr for zephyr in zephyrs if not zephyr.synced_from_mit]
            handler.finish({'zephyrs': [zephyr.to_dict() for zephyr in zephyrs]})
        except socket.error:
            pass

    # We need to replace this abstraction with the message list
    user_profile.add_callback(handler.async_callback(on_receive), last_received)

@login_required
@require_post
def zephyr(request):
    if 'time' in request.POST:
        return json_error("Invalid field 'time'")
    return zephyr_backend(request, request.user)

@login_required
@require_post
def forge_zephyr(request):
    email = sanitize_identifier(request.POST['sender']).lower()
    user_profile = UserProfile.objects.get(user=request.user)

    if "time" not in request.POST:
        return json_error("Missing time")

    try:
        user = User.objects.get(email=email)
    except User.DoesNotExist:
        # forge a user for this person
        create_user(email, "test", user_profile.realm,
                    sanitize_identifier(request.POST['fullname']),
                    sanitize_identifier(request.POST['shortname']))
        user = User.objects.get(email=email)

    if (request.POST['type'] == 'personal' and ',' in request.POST['recipient']):
        # Huddle message, need to make sure we're not syncing it twice!
        if Zephyr.objects.filter(sender__user__email=email,
                                 content=md_engine.convert(request.POST['new_zephyr']),
                                 pub_date__gt=datetime.datetime.utcfromtimestamp(float(request.POST['time']) - 1).replace(tzinfo=utc),
                                 pub_date__lt=datetime.datetime.utcfromtimestamp(float(request.POST['time']) + 1).replace(tzinfo=utc)):
            # This is a duplicate huddle message, deduplicate!
            return json_success()

        # Now confirm all the other recipients exist in our system
        for user_email in request.POST["recipient"].split(","):
            try:
                User.objects.get(email=user_email)
            except User.DoesNotExist:
                # forge a user for this person
                create_user(user_email, "test", user_profile.realm,
                            user_email.split('@')[0],
                            user_email.split('@')[0])

    return zephyr_backend(request, user)

md_engine = markdown.Markdown(
    extensions    = ['fenced_code', 'codehilite'],
    safe_mode     = True,
    output_format = 'xhtml' )

@login_required
@require_post
def zephyr_backend(request, sender):
    user_profile = UserProfile.objects.get(user=request.user)
    if "type" not in request.POST:
        return json_error("Missing type")
    if "new_zephyr" not in request.POST:
        return json_error("Missing message contents")

    zephyr_type_name = request.POST["type"]
    if zephyr_type_name == 'class':
        if "class" not in request.POST or not request.POST["class"]:
            return json_error("Missing class")
        if "instance" not in request.POST:
            return json_error("Missing instance")

        class_name = sanitize_identifier(request.POST['class']).strip()
        my_classes = ZephyrClass.objects.filter(name=class_name, realm=user_profile.realm)
        if my_classes:
            my_class = my_classes[0]
        else:
            my_class = ZephyrClass()
            my_class.name = class_name
            my_class.realm = user_profile.realm
            my_class.save()
            recipient = Recipient(type_id=my_class.id, type=Recipient.CLASS)
            recipient.save()
        try:
            recipient = Recipient.objects.get(type_id=my_class.id, type=Recipient.CLASS)
        except Recipient.DoesNotExist:
            return json_error("Invalid class")
    elif zephyr_type_name == 'personal':
        if "recipient" not in request.POST:
            return json_error("Missing recipient")

        recipient_data = sanitize_identifier(request.POST['recipient'])
        if ',' in recipient_data:
            # This is actually a huddle message, which shares the
            # "personal" zephyr sending form
            recipients = [r.strip() for r in recipient_data.split(',')]
            # Ignore any blank recipients
            recipients = [r for r in recipients if r]
            recipient_ids = []
            for recipient in recipients:
                try:
                    recipient_ids.append(
                        UserProfile.objects.get(user=User.objects.get(email=recipient)).id)
                except User.DoesNotExist:
                    return json_error("Invalid email '%s'" % (recipient))
            # Make sure the sender is included in the huddle
            recipient_ids.append(UserProfile.objects.get(user=request.user).id)
            huddle = get_huddle(recipient_ids)
            recipient = Recipient.objects.get(type_id=huddle.id, type=Recipient.HUDDLE)
        else:
            # This is actually a personal message
            if not User.objects.filter(email=recipient_data):
                return json_error("Invalid email")

            recipient_user = User.objects.get(email=recipient_data)
            recipient_user_profile = UserProfile.objects.get(user=recipient_user)
            recipient = Recipient.objects.get(type_id=recipient_user_profile.id,
                                              type=Recipient.PERSONAL)
    else:
        return json_error("Invalid zephyr type")

    new_zephyr = Zephyr()
    new_zephyr.sender = UserProfile.objects.get(user=sender)
    new_zephyr.content = md_engine.convert(request.POST['new_zephyr'])
    new_zephyr.recipient = recipient
    if zephyr_type_name == 'class':
        new_zephyr.instance = sanitize_identifier(request.POST['instance'])
    if 'time' in request.POST:
        # Forged zephyrs come with a timestamp
        new_zephyr.pub_date = datetime.datetime.utcfromtimestamp(float(request.POST['time'])).replace(tzinfo=utc)
    else:
        new_zephyr.pub_date = datetime.datetime.utcnow().replace(tzinfo=utc)

    # To avoid message loops, we must pass whether the message was
    # synced from MIT zephyr here.
    do_send_zephyr(new_zephyr, synced_from_mit = 'time' in request.POST)

    return json_success()

def gather_subscriptions(user_profile):
    subscriptions = Subscription.objects.filter(userprofile=user_profile, active=True)
    # For now, don't display the subscription for your ability to receive personals.
    return sorted([get_display_recipient(sub.recipient) for sub in subscriptions
            if sub.recipient.type == Recipient.CLASS])

@login_required
def subscriptions(request):
    user_profile = UserProfile.objects.get(user=request.user)

    return render_to_response('zephyr/subscriptions.html',
                              {'subscriptions': gather_subscriptions(user_profile),
                               'user_profile': user_profile},
                              context_instance=RequestContext(request))

@login_required
def json_list_subscriptions(request):
    subs = gather_subscriptions(UserProfile.objects.get(user=request.user))
    return HttpResponse(content=simplejson.dumps({"subscriptions": subs}),
                        mimetype='application/json', status=200)

@login_required
@require_post
def json_remove_subscription(request):
    user_profile = UserProfile.objects.get(user=request.user)
    if 'subscription' not in request.POST:
        return json_error("Missing subscriptions")

    sub_name = request.POST.get('subscription')
    zephyr_class = ZephyrClass.objects.get(name=sub_name, realm=user_profile.realm)
    recipient = Recipient.objects.get(type_id=zephyr_class.id,
                                      type=Recipient.CLASS)
    subscription = Subscription.objects.get(
        userprofile=user_profile, recipient=recipient)
    subscription.active = False
    subscription.save()

    return json_success({"data": sub_name})

@login_required
@require_post
def json_add_subscription(request):
    user_profile = UserProfile.objects.get(user=request.user)

    if "new_subscription" not in request.POST:
        return HttpResponseRedirect(reverse('zephyr.views.subscriptions'))

    sub_name = request.POST.get('new_subscription').strip()
    if not re.match('^[a-z A-z0-9_-]+$', sub_name):
        return json_error("Invalid characters in class names")

    zephyr_class = ZephyrClass.objects.filter(name=sub_name, realm=user_profile.realm)
    if zephyr_class:
        zephyr_class = zephyr_class[0]
        recipient = Recipient.objects.get(type_id=zephyr_class.id,
                                          type=Recipient.CLASS)
    else:
        (_, recipient) = ZephyrClass.create(sub_name, user_profile.realm)

    subscription = Subscription.objects.filter(userprofile=user_profile,
                                               recipient=recipient)
    if subscription:
        subscription = subscription[0]
        if not subscription.active:
            # Activating old subscription.
            subscription.active = True
            subscription.save()
            actually_new_sub = sub_name
        else:
            # Subscription already exists and is active
            return json_error("Subscription already exists")
    else:
        new_subscription = Subscription(userprofile=user_profile,
                                            recipient=recipient)
        new_subscription.save()
        actually_new_sub = sub_name
    return json_success({"data": actually_new_sub})


@login_required
def manage_settings(request):
    user_profile = UserProfile.objects.get(user=request.user)

    return render_to_response('zephyr/settings.html',
                              {'user_profile': user_profile,
                               'gravatar_hash': hashlib.md5(settings.MD5_SALT + user_profile.user.email).hexdigest(),
                               },
                              context_instance=RequestContext(request))

@login_required
@require_post
def change_settings(request):
    user_profile = UserProfile.objects.get(user=request.user)

    # First validate all the inputs
    if "full_name" not in request.POST:
        return json_error("Invalid settings request -- missing full_name.")
    if "short_name" not in request.POST:
        return json_error("Invalid settings request -- missing short_name.")
    if "timezone" not in request.POST:
        return json_error("Invalid settings request -- missing timezone.")
    if "new_password" not in request.POST:
        return json_error("Invalid settings request -- missing new_password.")
    if "old_password" not in request.POST:
        return json_error("Invalid settings request -- missing old_password.")
    if "confirm_password" not in request.POST:
        return json_error("Invalid settings request -- missing confirm_password.")

    old_password     = request.POST['old_password']
    new_password     = request.POST['new_password']
    confirm_password = request.POST['confirm_password']
    full_name        = sanitize_identifier(request.POST['full_name'])
    short_name       = sanitize_identifier(request.POST['short_name'])
    timezone         = sanitize_identifier(request.POST['timezone'])

    if new_password != "":
        if new_password != confirm_password:
            return json_error("New password must match confirmation password!")
        if not authenticate(username=user_profile.user.email, password=old_password):
            return json_error("Wrong password!")
        user_profile.user.set_password(new_password)

    result = {}
    if user_profile.full_name != full_name:
        user_profile.full_name = full_name
        result['full_name'] = full_name
    if user_profile.short_name != short_name:
        user_profile.short_name = short_name
        result['short_name'] = short_name
    # TODO: Change the timezone
    # user_profile.timezone = timezone
    user_profile.user.save()
    user_profile.save()

    return json_success(result)

@login_required
def class_exists(request, zephyr_class):
    return HttpResponse(bool(ZephyrClass.objects.filter(name=zephyr_class)))