import itertools

import matplotlib.pyplot as plt

from django.core.management.base import BaseCommand, CommandError
from django.db.models import Q
from django.utils.dateparse import parse_date
from django.utils.timezone import make_aware, make_naive

from eodb.events.models import Commit, Email, Redmine, Formdata

class GraphCommand(BaseCommand):
    def add_arguments(self, parser):
        parser.add_argument('--username', metavar='USERNAME')
        parser.add_argument('--module', metavar='MODULE')
        parser.add_argument('--datemin', metavar='DATEMIN')
        parser.add_argument('--datemax', metavar='DATEMAX')
        parser.add_argument('--committime', action='store_true',
                            help='use commit datetime instead of author datetime')
        parser.add_argument('--events', default='git',
                help='use event of this type (git (default), emails, redmine)')
        parser.add_argument('--notitle', action='store_true')
        parser.add_argument('--entrouvert', action='store_true',
                help='limit to @entrouvert persons')
        parser.add_argument('--filename', metavar='FILENAME')

    def get_series(self, options):
        usernames = options['username'].split(',') if options.get('username') else []
        modules = options['module'].split(',') if options.get('module') else []

        if len(usernames) > 1 and len(modules) > 1:
            raise CommandError('only one dimension is allowed')

        if len(usernames) > 1:
            for username in usernames:
                options['username'] = username
                yield (username, self.get_events(options))
        elif len(modules) > 1:
            for module in modules:
                options['module'] = module
                yield (module, self.get_events(options))
        else:
            yield (None, self.get_events(options))

    def get_event_datetime(self, event, options):
        datetime_var = 'author_datetime'
        if options.get('committime'):
            datetime_var = 'commit_datetime'
        try:
            return make_aware(make_naive(getattr(event, datetime_var)))
        except:  # maybe pytz.exceptions.AmbiguousTimeError
            return getattr(event, datetime_var)

    def get_events(self, options):
        if options.get('entrouvert'):
            domain_filter = Q(author_email__endswith='@entrouvert.com') | \
                            Q(author_email__endswith='@entrouvert.org')
        elif options['events'] in ('formdata',):
            domain_filter = Q(author_datetime__isnull=False)
        else:
            domain_filter = Q()

        filters = {}
        if options.get('username'):
            filters['author_email__startswith'] = options['username'] + '@'

        if options.get('module'):
            filters['module'] = options['module']

        datetime_var = 'author_datetime'
        if options.get('committime'):
            datetime_var = 'commit_datetime'
        if options.get('datemin'):
            filters[datetime_var + '__gte'] = parse_date(options['datemin'])
        if options.get('datemax'):
            filters[datetime_var + '__lt'] = parse_date(options['datemax'])

        if options['events'] == 'all':
            return itertools.chain(
                    Email.objects.filter(domain_filter).filter(**filters),
                    Redmine.objects.filter(domain_filter).filter(**filters),
                    Commit.objects.filter(domain_filter).filter(**filters),
            )

        return {'emails': Email, 'redmine': Redmine, 'git': Commit,
                'formdata': Formdata}[
                options['events']].objects.filter(domain_filter).filter(**filters)

    def get_title(self, options):
        title = {
            'emails': 'Email activity',
            'git': 'Git activity',
            'redmine': 'Redmine activity',
            'formdata': 'Formdata activity',
            'all': 'Global activity',
        }[options['events']]
        if options.get('username'):
            title += ' for %s' % options['username']
        if options.get('module'):
            title += ' in module %s' % options['module']
        if options.get('datemin'):
            title += ' from %s' % options['datemin']
        if options.get('datemax'):
            title += ' until %s' % options['datemax']
        return title

    def plot(self, options):
        if not options.get('notitle'):
            plt.title(self.get_title(options))
        if options.get('filename'):
            plt.savefig(options['filename'])
        else:
            plt.show()