import hashlib
from django.core.urlresolvers import reverse
from django.http import HttpResponseRedirect
from django.template import RequestContext
from django.shortcuts import render, redirect, get_object_or_404
from django.utils import timezone

from boards import forms
import boards
from boards import utils
from boards.forms import ThreadForm, PostForm, SettingsForm, PlainErrorList, \
    ThreadCaptchaForm, PostCaptchaForm, LoginForm

from boards.models import Post, Tag, Ban, User, RANK_USER, NO_PARENT
from boards import authors
import neboard


def index(request, page=0):
    context = _init_default_context(request)

    if utils.need_include_captcha(request):
        threadFormClass = ThreadCaptchaForm
        kwargs = {'request': request}
    else:
        threadFormClass = ThreadForm
        kwargs = {}

    if request.method == 'POST':
        form = threadFormClass(request.POST, request.FILES,
                               error_class=PlainErrorList, **kwargs)
        form.session = request.session

        if form.is_valid():
            return _new_post(request, form)
    else:
        form = threadFormClass(error_class=PlainErrorList, **kwargs)

    threads = []
    for thread in Post.objects.get_threads(page=int(page)):
        threads.append({'thread': thread,
                        'bumpable': thread.can_bump()})

    context['threads'] = None if len(threads) == 0 else threads
    context['form'] = form
    context['pages'] = range(Post.objects.get_thread_page_count())

    return render(request, 'boards/posting_general.html',
                  context)


def _new_post(request, form, thread_id=boards.models.NO_PARENT):
    """Add a new post (in thread or as a reply)."""

    ip = _get_client_ip(request)
    is_banned = Ban.objects.filter(ip=ip).count() > 0

    if is_banned:
        return redirect(you_are_banned)

    data = form.cleaned_data

    title = data['title']
    text = data['text']

    if 'image' in data.keys():
        image = data['image']
    else:
        image = None

    tags = []

    new_thread = thread_id == boards.models.NO_PARENT
    if new_thread:
        tag_strings = data['tags']

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

    # TODO Add a possibility to define a link image instead of an image file.
    # If a link is given, download the image automatically.

    op = None if thread_id == boards.models.NO_PARENT else \
        get_object_or_404(Post, id=thread_id)
    post = Post.objects.create_post(title=title, text=text, ip=ip,
                                    thread=op, image=image,
                                    tags=tags)

    thread_to_show = (post.id if new_thread else thread_id)

    if new_thread:
        return redirect(thread, post_id=thread_to_show)
    else:
        return redirect(reverse(thread, kwargs={'post_id': thread_to_show}) +
                        '#' + str(post.id))


def tag(request, tag_name, page=0):
    """Get all tag threads (posts without a parent)."""

    tag = get_object_or_404(Tag, name=tag_name)
    threads = []
    for thread in Post.objects.get_threads(tag=tag, page=int(page)):
        threads.append({'thread': thread,
                        'bumpable': thread.can_bump()})

    if request.method == 'POST':
        form = ThreadForm(request.POST, request.FILES,
                          error_class=PlainErrorList)
        if form.is_valid():
            return _new_post(request, form)
    else:
        form = forms.ThreadForm(initial={'tags': tag_name},
                                error_class=PlainErrorList)

    context = _init_default_context(request)
    context['threads'] = None if len(threads) == 0 else threads
    context['tag'] = tag
    context['pages'] = range(Post.objects.get_thread_page_count(tag=tag))

    context['form'] = form

    return render(request, 'boards/posting_general.html',
                  context)


def thread(request, post_id):
    """Get all thread posts"""

    if utils.need_include_captcha(request):
        postFormClass = PostCaptchaForm
        kwargs = {'request': request}
    else:
        postFormClass = PostForm
        kwargs = {}

    if request.method == 'POST':
        form = postFormClass(request.POST, request.FILES,
                             error_class=PlainErrorList, **kwargs)
        form.session = request.session

        if form.is_valid():
            return _new_post(request, form, post_id)
    else:
        form = postFormClass(error_class=PlainErrorList, **kwargs)

    posts = Post.objects.get_thread(post_id)

    context = _init_default_context(request)

    context['posts'] = posts
    context['form'] = form
    context['bumpable'] = posts[0].can_bump()

    return render(request, 'boards/thread.html', context)


def login(request):
    """Log in with user id"""

    context = _init_default_context(request)

    if request.method == 'POST':
        form = LoginForm(request.POST, request.FILES,
                         error_class=PlainErrorList)
        if form.is_valid():
            user = User.objects.get(user_id=form.cleaned_data['user_id'])
            request.session['user_id'] = user.id
            return redirect(index)

    else:
        form = LoginForm()

    context['form'] = form

    return render(request, 'boards/login.html', context)


def settings(request):
    """User's settings"""

    context = _init_default_context(request)

    if request.method == 'POST':
        form = SettingsForm(request.POST)
        if form.is_valid():
            selected_theme = form.cleaned_data['theme']

            user = _get_user(request)
            user.save_setting('theme', selected_theme)

        return redirect(settings)
    else:
        selected_theme = _get_theme(request)
        form = SettingsForm(initial={'theme': selected_theme})
        context['form'] = form

        return render(request, 'boards/settings.html', context)


def all_tags(request):
    """All tags list"""

    context = _init_default_context(request)
    context['all_tags'] = Tag.objects.get_not_empty_tags()

    return render(request, 'boards/tags.html', context)


def jump_to_post(request, post_id):
    """Determine thread in which the requested post is and open it's page"""

    post = get_object_or_404(Post, id=post_id)

    if not post.thread:
        return redirect(thread, post_id=post.id)
    else:
        return redirect(reverse(thread, kwargs={'post_id': post.thread.id})
                        + '#' + str(post.id))


def authors(request):
    context = _init_default_context(request)
    context['authors'] = boards.authors.authors

    return render(request, 'boards/authors.html', context)


def delete(request, post_id):
    user = _get_user(request)
    post = get_object_or_404(Post, id=post_id)

    if user.is_moderator():
        # TODO Show confirmation page before deletion
        Post.objects.delete_post(post)
    
    if not post.thread:
        return _redirect_to_next(request)
    else:
        return redirect(thread, post_id=post.thread.id)


def ban(request, post_id):
    user = _get_user(request)
    post = get_object_or_404(Post, id=post_id)

    if user.is_moderator():
        # TODO Show confirmation page before ban
        Ban.objects.get_or_create(ip=post.poster_ip)

    return _redirect_to_next(request)


def you_are_banned(request):
    context = _init_default_context(request)
    return render(request, 'boards/staticpages/banned.html', context)


def page_404(request):
    context = _init_default_context(request)
    return render(request, 'boards/404.html', context)


def tag_subscribe(request, tag_name):
    user = _get_user(request)
    tag = get_object_or_404(Tag, name=tag_name)

    if not tag in user.fav_tags.all():
        user.fav_tags.add(tag)

    return _redirect_to_next(request)


def tag_unsubscribe(request, tag_name):
    user = _get_user(request)
    tag = get_object_or_404(Tag, name=tag_name)

    if tag in user.fav_tags.all():
        user.fav_tags.remove(tag)

    return _redirect_to_next(request)


def static_page(request, name):
    context = _init_default_context(request)
    return render(request, 'boards/staticpages/' + name + '.html', context)


def _get_theme(request, user=None):
    """Get user's CSS theme"""

    if not user:
        user = _get_user(request)
    theme = user.get_setting('theme')
    if not theme:
        theme = neboard.settings.DEFAULT_THEME

    return theme


def _get_client_ip(request):
    x_forwarded_for = request.META.get('HTTP_X_FORWARDED_FOR')
    if x_forwarded_for:
        ip = x_forwarded_for.split(',')[-1].strip()
    else:
        ip = request.META.get('REMOTE_ADDR')
    return ip


def _init_default_context(request):
    """Create context with default values that are used in most views"""

    context = RequestContext(request)

    user = _get_user(request)
    context['user'] = user
    context['tags'] = user.get_sorted_fav_tags()
    context['theme'] = _get_theme(request, user)

    return context


def _get_user(request):
    """Get current user from the session"""

    session = request.session
    if not 'user_id' in session:
        request.session.save()

        md5 = hashlib.md5()
        md5.update(session.session_key)
        new_id = md5.hexdigest()

        time_now = timezone.now()
        user = User.objects.create(user_id=new_id, rank=RANK_USER,
                                   registration_time=time_now,
                                   last_access_time=time_now)

        session['user_id'] = user.id
    else:
        user = User.objects.get(id=session['user_id'])
        user.last_access_time = timezone.now()
        user.save()

    return user


def _redirect_to_next(request):
    if 'next' in request.GET:
        next_page = request.GET['next']
        return HttpResponseRedirect(next_page)
    else:
        return redirect(index)