#! /usr/bin/env python
#-*- coding: utf-8 -*-

# pyAggr3g470r - A Web based news aggregator.
# Copyright (C) 2010-2015  Cédric Bonhomme - https://www.cedricbonhomme.org
#
# For more information : https://bitbucket.org/cedricbonhomme/pyaggr3g470r/
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

__author__ = "Cedric Bonhomme"
__version__ = "$Revision: 0.3 $"
__date__ = "$Date: 2013/06/24 $"
__revision__ = "$Date: 2013/11/10 $"
__copyright__ = "Copyright (c) Cedric Bonhomme"
__license__ = "AGPLv3"

import os
import logging

from whoosh.index import create_in, open_dir
from whoosh.index import EmptyIndexError
from whoosh.fields import *
from whoosh.query import *
from whoosh.qparser import QueryParser
from whoosh.writing import AsyncWriter
from collections import defaultdict

from pyaggr3g470r.models import User
from pyaggr3g470r.decorators import async
from pyaggr3g470r import utils

logger = logging.getLogger(__name__)

indexdir = "./pyaggr3g470r/var/indexdir"

schema = Schema(title=TEXT,
                content=TEXT,
                article_id=NUMERIC(int, stored=True),
                feed_id=NUMERIC(int, stored=True),
                user_id=NUMERIC(int, stored=True))

@async
def create_index(user_id):
    """
    Creates the index.
    """
    user = User.query.filter(User.id == user_id).first()
    logger.info("Starting indexation of the database.")
    if not os.path.exists(indexdir):
        os.makedirs(indexdir)
    ix = create_in(indexdir, schema)
    writer = ix.writer()
    for feed in user.feeds:
        logger.info("Indexing " + feed.title)
        for article in feed.articles:
            writer.add_document(title=article.title,
                                content=utils.clear_string(article.content),
                                article_id=article.id,
                                feed_id=feed.id,
                                user_id=user.id)
    writer.commit()
    logger.info("Indexation done.")

def add_to_index(user_id, articles, feed):
    """
    Add a list of articles to the index.
    Here an AsyncWriter is used because the function will
    be called in multiple threads by the feedgetter module.
    """
    try:
        ix = open_dir(indexdir)
    except (EmptyIndexError, OSError):
        if not os.path.exists(indexdir):
            os.makedirs(indexdir)
        ix = create_in(indexdir, schema)
    writer = AsyncWriter(ix)
    for article in articles:
        writer.add_document(title=article.title,
                            content=utils.clear_string(article.content),
                            article_id=article.id,
                            feed_id=feed.id,
                            user_id=user_id)
    writer.commit()


def delete_article(user_id, feed_id, article_id):
    """
    Delete an article from the index.
    """
    try:
        ix = open_dir(indexdir)
    except (EmptyIndexError, OSError):
        return
    writer = ix.writer()
    document = And([Term("user_id", user_id), Term("feed_id", feed_id),
                    Term("article_id", article_id)])
    writer.delete_by_query(document)
    writer.commit()


def search(user_id, term):
    """
    Search for `term` in the index.
    Returns a list of articles.
    """
    result_dict = defaultdict(list)
    try:
        ix = open_dir(indexdir)
    except (EmptyIndexError, OSError):
        raise EmptyIndexError
    with ix.searcher() as searcher:
        query = QueryParser("content", ix.schema).parse(term)
        user_doc = Term("user_id", user_id)
        results = searcher.search(query, filter=user_doc, limit=None)
        for article in results:
            result_dict[article["feed_id"]].append(article["article_id"])
        return result_dict, len(results)


def nb_documents():
    """
    Return the number of undeleted documents.
    """
    try:
        ix = open_dir(indexdir)
    except (EmptyIndexError, OSError):
        raise EmptyIndexError
    return ix.doc_count()

if __name__ == "__main__":
    # Point of entry in execution mode.
    #create_index()
    print(nb_documents())
    results = search("Nothomb")
    for article in results:
        print(article)