#!/usr/bin/env python
#
# indexer.py
#
# Copyright 2018 Alan Orth.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
# ---
#
# Connects to a DSpace Solr statistics core and ingests item views and downloads
# into a SQLite database for use with other applications (an API, for example).
#
# This script is written for Python 3 and requires several modules that you can
# install with pip (I recommend setting up a Python virtual environment first):
#
#   $ pip install SolrClient
#
# See: https://solrclient.readthedocs.io/en/latest/SolrClient.html
# See: https://wiki.duraspace.org/display/DSPACE/Solr
#
# Tested with Python 3.5 and 3.6.

from database import database_connection_rw
from solr import solr_connection

def index_views():
    print("Populating database with item views.")

    # determine the total number of items with views (aka Solr's numFound)
    res = solr.query('statistics', {
        'q':'type:2',
        'fq':'isBot:false AND statistics_type:view',
        'facet':True,
        'facet.field':'id',
    }, rows=0)

    # divide results into "pages" (numFound / 100)
    results_numFound = res.get_num_found()
    results_per_page = 100
    results_num_pages = round(results_numFound / results_per_page)
    results_current_page = 0

    while results_current_page <= results_num_pages:
        print('Page {0} of {1}.'.format(results_current_page, results_num_pages))

        res = solr.query('statistics', {
            'q':'type:2',
            'fq':'isBot:false AND statistics_type:view',
            'facet':True,
            'facet.field':'id',
            'facet.limit':results_per_page,
            'facet.offset':results_current_page * results_per_page
        })

        # make sure total number of results > 0
        if res.get_num_found() > 0:
            # SolrClient's get_facets() returns a dict of dicts
            views = res.get_facets()
            # in this case iterate over the 'id' dict and get the item ids and views
            for item_id, item_views in views['id'].items():
                db.execute('''REPLACE INTO itemviews VALUES (?, ?)''', (item_id, item_views))

        db.commit()

        results_current_page += 1

def index_downloads():
    print("Populating database with item downloads.")

    # determine the total number of items with downloads (aka Solr's numFound)
    res = solr.query('statistics', {
        'q':'type:0',
        'fq':'isBot:false AND statistics_type:view AND bundleName:ORIGINAL',
        'facet':True,
        'facet.field':'owningItem',
    }, rows=0)

    # divide results into "pages" (numFound / 100)
    results_numFound = res.get_num_found()
    results_per_page = 100
    results_num_pages = round(results_numFound / results_per_page)
    results_current_page = 0

    while results_current_page <= results_num_pages:
        print('Page {0} of {1}.'.format(results_current_page, results_num_pages))

        res = solr.query('statistics', {
            'q':'type:0',
            'fq':'isBot:false AND statistics_type:view AND bundleName:ORIGINAL',
            'facet':True,
            'facet.field':'owningItem',
            'facet.limit':results_per_page,
            'facet.offset':results_current_page * results_per_page
        })

        # make sure total number of results > 0
        if res.get_num_found() > 0:
            # SolrClient's get_facets() returns a dict of dicts
            downloads = res.get_facets()
            # in this case iterate over the 'owningItem' dict and get the item ids and downloads
            for item_id, item_downloads in downloads['owningItem'].items():
                db.execute('''REPLACE INTO itemdownloads VALUES (?, ?)''', (item_id, item_downloads))

        db.commit()

        results_current_page += 1

db = database_connection_rw()
solr = solr_connection()

# use separate views and downloads tables so we can REPLACE INTO carelessly (ie, item may have views but no downloads)
db.execute('''CREATE TABLE IF NOT EXISTS itemviews
                  (id integer primary key, views integer)''')
db.execute('''CREATE TABLE IF NOT EXISTS itemdownloads
                  (id integer primary key, downloads integer)''')
index_views()
index_downloads()

db.close()

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