import json
import os
import re
import time
import urllib2
import urlparse

from sqlalchemy import inspect

from rcal.db import Session
from rcal.model import Calendar, Category

BASEPATH = os.path.join(
    os.environ['PYTHONPATH'],
    '..',
    '..')

CONFIG = json.load(open(
    os.path.join(
        BASEPATH,
        'config',
        'reddit-import.json'),
    'r'))


def get_cal_list():
    cache_path = os.path.join(
        BASEPATH,
        CONFIG['cache'])
    if not os.path.exists(cache_path) or \
       int(time.time()) - int(os.path.getmtime(cache_path)) > \
       CONFIG['cache_time']:
        opener = urllib2.build_opener()
        opener.addheaders = [('User-Agent', CONFIG['user_agent'])]
        cal_list = json.loads(opener.open(CONFIG['reddit_url']).read())
        cal_list = cal_list['data']['content_md']
        with open(cache_path, 'w') as cache_file:
            cache_file.write(cal_list)
            cache_file.close()
    else:
        cal_list = open(cache_path, 'r').read()
    return cal_list


def update_calendar(cal, session):
    db_cal = Calendar.fetch(cal['uid'], session)

    if inspect(db_cal).pending:
        print 'Adding calendar %s (%s)' % (cal['name'], cal['uid'])
        db_cal.name = cal['name']
        db_cal.url = cal['url']
        db_cal.website = cal['website']
        db_cal.category = Category.fetch(cal['category'], session)

    if db_cal.name != cal['name']:
        print 'Updating calendar name: %s -> %s (%s)' % (
            db_cal.name, cal['name'], db_cal.uid)
        db_cal.name = cal['name']
    if db_cal.url != cal['url']:
        print 'Updating calendar url: %s -> %s (%s)' % (
            db_cal.url, cal['url'], db_cal.uid)
        db_cal.url = cal['url']
    if db_cal.website != cal['website']:
        print 'Updating calendar website: %s -> %s (%s)' % (
            db_cal.website, cal['website'], db_cal.uid)
        db_cal.website = cal['website']

    # informational only
    if db_cal.category.name != cal['category']:
        print 'Calendar category changed: %s -> %s (%s)' % (
            db_cal.category.name, cal['category'], db_cal.uid)


def get_imported_calendars(cells, ical_markdown):
    imported_calendars = []
    for row in cells:
        row = [r for r in row if r.strip()]
        if len(row) == 5:
            markdown_match = re.match(ical_markdown, row[2])
            if markdown_match:
                ical_url = urlparse.urlparse(markdown_match.group(1))
                if ical_url.netloc == 'calendar.google.com':
                    ical_path = re.sub(
                        '^/?calendar/ical/', '', ical_url.path).split('/')
                    if len(ical_path) == 3:
                        imported_calendars.append({
                            'uid': ical_path[0],
                            'url': ical_url.geturl(),
                            'name': row[0],
                            'website': row[4].split()[0],
                            'category': row[1]
                        })
                    else:
                        print 'Unknown iCal URL format: %s' % (
                            ical_url.geturl())
                else:
                    print 'Unknown iCal URL format: %s' % (
                        ical_url.geturl())
    return imported_calendars


def main():
    session = Session.create()

    cal_list = get_cal_list()

    ical_markdown = re.compile(r'^\[iCal\]\((.*)\)$')
    cells = [row.split('|') for row in cal_list.split('\n')]

    imported_calendars = get_imported_calendars(cells, ical_markdown)
    imported_calendar_uids = [c['uid'] for c in imported_calendars]

    db_only_calendars = session.query(Calendar).filter(
        ~Calendar.uid.in_(imported_calendar_uids)).all()

    if len(db_only_calendars):
        print 'Local calendars not in remote source:'
        for cal in db_only_calendars:
            print '%s (%s)' % (cal.name, cal.uid)
        print

    for cal in imported_calendars:
        update_calendar(cal, session)

    session.commit()

if __name__ == '__main__':
    main()