import json
import logging

from django.db import transaction
from django.http import HttpResponse
from django.shortcuts import get_object_or_404
from django.core import serializers

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


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

    thread = get_object_or_404(Post, id=thread_id).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(get_post_data(post.id, diff_type,
            request))
    json_data[PARAMETER_LAST_UPDATE] = str(thread.last_edit_time)

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


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))


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().filter(archived=False)
    else: 
        threads = Thread.objects.filter(archived=False)

    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 = get_post_data(opening_post.id, include_last_update=True)
        post_data['bumpable'] = thread.can_bump()
        post_data['archived'] = thread.archived

        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(get_post_data(post.id))
    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(username=username,
                                                        last=last_id)

    json_post_list = []
    for post in posts:
        json_post_list.append(get_post_data(post.id))
    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)


# TODO Remove this method and use post method directly
def get_post_data(post_id, format_type=DIFF_TYPE_JSON, request=None,
                  include_last_update=False):
    post = get_object_or_404(Post, id=post_id)
    return post.get_post_data(format_type=format_type, request=request,
                              include_last_update=include_last_update)


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

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