import json
import logging

from django.core import serializers
from django.db import transaction
from django.http import HttpResponse
from django.shortcuts import get_object_or_404
from django.views.decorators.csrf import csrf_protect

from boards.abstracts.settingsmanager import get_settings_manager
from boards.forms import PostForm, PlainErrorList
from boards.mdx_neboard import Parser
from boards.models import Post, Thread, Tag
from boards.models.thread import STATUS_ARCHIVE
from boards.models.user import Notification
from boards.utils import datetime_to_epoch
from boards.views.thread import ThreadView

__author__ = 'neko259'

PARAMETER_TRUNCATED = 'truncated'
PARAMETER_TAG = 'tag'
PARAMETER_OFFSET = 'offset'
PARAMETER_DIFF_TYPE = 'type'
PARAMETER_POST = 'post'
PARAMETER_UPDATED = 'updated'
PARAMETER_LAST_UPDATE = 'last_update'
PARAMETER_THREAD = 'thread'
PARAMETER_UIDS = 'uids'

DIFF_TYPE_HTML = 'html'
DIFF_TYPE_JSON = 'json'

STATUS_OK = 'ok'
STATUS_ERROR = 'error'

logger = logging.getLogger(__name__)


@transaction.atomic
def api_get_threaddiff(request):
    """
    Gets posts that were changed or added since time
    """

    thread_id = request.POST.get(PARAMETER_THREAD)
    uids_str = request.POST.get(PARAMETER_UIDS)

    if not thread_id or not uids_str:
        return HttpResponse(content='Invalid request.')

    uids = uids_str.strip().split(' ')

    opening_post = get_object_or_404(Post, id=thread_id)
    thread = opening_post.get_thread()

    json_data = {
        PARAMETER_UPDATED: [],
        PARAMETER_LAST_UPDATE: None,  # TODO Maybe this can be removed already?
    }
    posts = Post.objects.filter(threads__in=[thread]).exclude(uid__in=uids)

    diff_type = request.GET.get(PARAMETER_DIFF_TYPE, DIFF_TYPE_HTML)

    for post in posts:
        json_data[PARAMETER_UPDATED].append(post.get_post_data(
            format_type=diff_type, request=request))
    json_data[PARAMETER_LAST_UPDATE] = str(thread.last_edit_time)

    # If the tag is favorite, update the counter
    settings_manager = get_settings_manager(request)
    favorite = settings_manager.thread_is_fav(opening_post)
    if favorite:
        settings_manager.add_or_read_fav_thread(opening_post)

    return HttpResponse(content=json.dumps(json_data))


@csrf_protect
def api_add_post(request, opening_post_id):
    """
    Adds a post and return the JSON response for it
    """

    opening_post = get_object_or_404(Post, id=opening_post_id)

    logger.info('Adding post via api...')

    status = STATUS_OK
    errors = []

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

        if form.need_to_ban:
            # Ban user because he is suspected to be a bot
            # _ban_current_user(request)
            status = STATUS_ERROR
        if form.is_valid():
            post = ThreadView().new_post(request, form, opening_post,
                                         html_response=False)
            if not post:
                status = STATUS_ERROR
            else:
                logger.info('Added post #%d via api.' % post.id)
        else:
            status = STATUS_ERROR
            errors = form.as_json_errors()

    response = {
        'status': status,
        'errors': errors,
    }

    return HttpResponse(content=json.dumps(response))


def get_post(request, post_id):
    """
    Gets the html of a post. Used for popups. Post can be truncated if used
    in threads list with 'truncated' get parameter.
    """

    post = get_object_or_404(Post, id=post_id)
    truncated = PARAMETER_TRUNCATED in request.GET

    return HttpResponse(content=post.get_view(truncated=truncated, need_op_data=True))


def api_get_threads(request, count):
    """
    Gets the JSON thread opening posts list.
    Parameters that can be used for filtering:
    tag, offset (from which thread to get results)
    """

    if PARAMETER_TAG in request.GET:
        tag_name = request.GET[PARAMETER_TAG]
        if tag_name is not None:
            tag = get_object_or_404(Tag, name=tag_name)
            threads = tag.get_threads().exclude(status=STATUS_ARCHIVE)
    else: 
        threads = Thread.objects.exclude(status=STATUS_ARCHIVE)

    if PARAMETER_OFFSET in request.GET:
        offset = request.GET[PARAMETER_OFFSET]
        offset = int(offset) if offset is not None else 0
    else:
        offset = 0

    threads = threads.order_by('-bump_time')
    threads = threads[offset:offset + int(count)]

    opening_posts = []
    for thread in threads:
        opening_post = thread.get_opening_post()

        # TODO Add tags, replies and images count
        post_data = opening_post.get_post_data(include_last_update=True)
        post_data['status'] = thread.get_status()

        opening_posts.append(post_data)

    return HttpResponse(content=json.dumps(opening_posts))


# TODO Test this
def api_get_tags(request):
    """
    Gets all tags or user tags.
    """

    # TODO Get favorite tags for the given user ID

    tags = Tag.objects.get_not_empty_tags()

    term = request.GET.get('term')
    if term is not None:
        tags = tags.filter(name__contains=term)

    tag_names = [tag.name for tag in tags]

    return HttpResponse(content=json.dumps(tag_names))


# TODO The result can be cached by the thread last update time
# TODO Test this
def api_get_thread_posts(request, opening_post_id):
    """
    Gets the JSON array of thread posts
    """

    opening_post = get_object_or_404(Post, id=opening_post_id)
    thread = opening_post.get_thread()
    posts = thread.get_replies()

    json_data = {
        'posts': [],
        'last_update': None,
    }
    json_post_list = []

    for post in posts:
        json_post_list.append(post.get_post_data())
    json_data['last_update'] = datetime_to_epoch(thread.last_edit_time)
    json_data['posts'] = json_post_list

    return HttpResponse(content=json.dumps(json_data))


def api_get_notifications(request, username):
    last_notification_id_str = request.GET.get('last', None)
    last_id = int(last_notification_id_str) if last_notification_id_str is not None else None

    posts = Notification.objects.get_notification_posts(usernames=username,
                                                        last=last_id)

    json_post_list = []
    for post in posts:
        json_post_list.append(post.get_post_data())
    return HttpResponse(content=json.dumps(json_post_list))


def api_get_post(request, post_id):
    """
    Gets the JSON of a post. This can be
    used as and API for external clients.
    """

    post = get_object_or_404(Post, id=post_id)

    json = serializers.serialize("json", [post], fields=(
        "pub_time", "_text_rendered", "title", "text", "image",
        "image_width", "image_height", "replies", "tags"
    ))

    return HttpResponse(content=json)


def api_get_preview(request):
    raw_text = request.POST['raw_text']

    parser = Parser()
    return HttpResponse(content=parser.parse(parser.preparse(raw_text)))


def api_get_new_posts(request):
    """
    Gets favorite threads and unread posts count.
    """
    posts = list()

    include_posts = 'include_posts' in request.GET

    settings_manager = get_settings_manager(request)
    fav_threads = settings_manager.get_fav_threads()
    fav_thread_ops = Post.objects.filter(id__in=fav_threads.keys())\
        .order_by('-pub_time').prefetch_related('thread')

    ops = [{'op': op, 'last_id': fav_threads[str(op.id)]} for op in fav_thread_ops]
    if include_posts:
        new_post_threads = Thread.objects.get_new_posts(ops)
        if new_post_threads:
            thread_ids = {thread.id: thread for thread in new_post_threads}
        else:
            thread_ids = dict()

        for op in fav_thread_ops:
            fav_thread_dict = dict()

            op_thread = op.get_thread()
            if op_thread.id in thread_ids:
                thread = thread_ids[op_thread.id]
                new_post_count = thread.new_post_count
                fav_thread_dict['newest_post_link'] = thread.get_replies()\
                        .filter(id__gt=fav_threads[str(op.id)])\
                        .first().get_absolute_url(thread=thread)
            else:
                new_post_count = 0
            fav_thread_dict['new_post_count'] = new_post_count

            fav_thread_dict['id'] = op.id

            fav_thread_dict['post_url'] = op.get_link_view()
            fav_thread_dict['title'] = op.title

            posts.append(fav_thread_dict)
    else:
        fav_thread_dict = dict()
        fav_thread_dict['new_post_count'] = \
            Thread.objects.get_new_post_count(ops)
        posts.append(fav_thread_dict)

    return HttpResponse(content=json.dumps(posts))