from django.core.urlresolvers import reverse
from django.core.files import File
from django.core.files.temp import NamedTemporaryFile
from django.core.paginator import EmptyPage
from django.db import transaction
from django.http import Http404
from django.shortcuts import render, redirect
import requests

from boards import utils, settings
from boards.abstracts.paginator import get_paginator
from boards.abstracts.settingsmanager import get_settings_manager
from boards.forms import ThreadForm, PlainErrorList
from boards.models import Post, Thread, Ban, Tag, PostImage, Banner
from boards.views.banned import BannedView
from boards.views.base import BaseBoardView, CONTEXT_FORM
from boards.views.posting_mixin import PostMixin


FORM_TAGS = 'tags'
FORM_TEXT = 'text'
FORM_TITLE = 'title'
FORM_IMAGE = 'image'
FORM_THREADS = 'threads'

TAG_DELIMITER = ' '

PARAMETER_CURRENT_PAGE = 'current_page'
PARAMETER_PAGINATOR = 'paginator'
PARAMETER_THREADS = 'threads'
PARAMETER_BANNERS = 'banners'

PARAMETER_PREV_LINK = 'prev_page_link'
PARAMETER_NEXT_LINK = 'next_page_link'

TEMPLATE = 'boards/all_threads.html'
DEFAULT_PAGE = 1


class AllThreadsView(PostMixin, BaseBoardView):

    def __init__(self):
        self.settings_manager = None
        super(AllThreadsView, self).__init__()

    def get(self, request, form: ThreadForm=None):
        page = request.GET.get('page', DEFAULT_PAGE)

        params = self.get_context_data(request=request)

        if not form:
            form = ThreadForm(error_class=PlainErrorList)

        self.settings_manager = get_settings_manager(request)
        paginator = get_paginator(self.get_threads(),
                                  settings.get_int('View', 'ThreadsPerPage'))
        paginator.current_page = int(page)

        try:
            threads = paginator.page(page).object_list
        except EmptyPage:
            raise Http404()

        params[PARAMETER_THREADS] = threads
        params[CONTEXT_FORM] = form
        params[PARAMETER_BANNERS] = Banner.objects.order_by('-id').all()

        self.get_page_context(paginator, params, page)

        return render(request, TEMPLATE, params)

    def post(self, request):
        form = ThreadForm(request.POST, request.FILES,
                          error_class=PlainErrorList)
        form.session = request.session

        if form.is_valid():
            return self.create_thread(request, form)
        if form.need_to_ban:
            # Ban user because he is suspected to be a bot
            self._ban_current_user(request)

        return self.get(request, form)

    def get_page_context(self, paginator, params, page):
        """
        Get pagination context variables
        """

        params[PARAMETER_PAGINATOR] = paginator
        current_page = paginator.page(int(page))
        params[PARAMETER_CURRENT_PAGE] = current_page
        if current_page.has_previous():
            params[PARAMETER_PREV_LINK] = self.get_previous_page_link(
                    current_page)
        if current_page.has_next():
            params[PARAMETER_NEXT_LINK] = self.get_next_page_link(current_page)

    def get_previous_page_link(self, current_page):
        return reverse('index') + '?page=' \
                + str(current_page.previous_page_number())

    def get_next_page_link(self, current_page):
        return reverse('index') + '?page=' \
                + str(current_page.next_page_number())

    @staticmethod
    def parse_tags_string(tag_strings):
        """
        Parses tag list string and returns tag object list.
        """

        tags = []

        if tag_strings:
            tag_strings = tag_strings.split(TAG_DELIMITER)
            for tag_name in tag_strings:
                tag_name = tag_name.strip().lower()
                if len(tag_name) > 0:
                    tag, created = Tag.objects.get_or_create(name=tag_name)
                    tags.append(tag)

        return tags

    @transaction.atomic
    def create_thread(self, request, form: ThreadForm, html_response=True):
        """
        Creates a new thread with an opening post.
        """

        ip = utils.get_client_ip(request)
        is_banned = Ban.objects.filter(ip=ip).exists()

        if is_banned:
            if html_response:
                return redirect(BannedView().as_view())
            else:
                return

        data = form.cleaned_data

        title = data[FORM_TITLE]
        text = data[FORM_TEXT]
        image = form.get_image()
        threads = data[FORM_THREADS]

        text = self._remove_invalid_links(text)

        tag_strings = data[FORM_TAGS]

        tags = self.parse_tags_string(tag_strings)

        post = Post.objects.create_post(title=title, text=text, image=image,
                                        ip=ip, tags=tags, opening_posts=threads)

        # This is required to update the threads to which posts we have replied
        # when creating this one
        post.notify_clients()

        if html_response:
            return redirect(post.get_absolute_url())

    def get_threads(self):
        """
        Gets list of threads that will be shown on a page.
        """

        return Thread.objects.order_by('-bump_time')\
            .exclude(tags__in=self.settings_manager.get_hidden_tags())