import datetime
 
from pylons import config
from sqlalchemy import Table, select, func, and_
 
import ckan.plugins as p
import ckan.model as model
 
cache_enabled = p.toolkit.asbool(config.get('ckanext.stats.cache_enabled', 'True'))
 
if cache_enabled:
    from pylons import cache
    our_cache = cache.get_cache('stats', type='dbm')
 
DATE_FORMAT = '%Y-%m-%d'
 
def table(name):
    return Table(name, model.meta.metadata, autoload=True)
 
def datetime2date(datetime_):
    return datetime.date(datetime_.year, datetime_.month, datetime_.day)
 
 
class Stats(object):
    @classmethod
    def top_rated_packages(cls, limit=10):
        # NB Not using sqlalchemy as sqla 0.4 doesn't work using both group_by
        # and apply_avg
        package = table('package')
        rating = table('rating')
        sql = select([package.c.id, func.avg(rating.c.rating), func.count(rating.c.rating)], from_obj=[package.join(rating)]).\
              where(package.c.private == 'f').\
              group_by(package.c.id).\
              order_by(func.avg(rating.c.rating).desc(), func.count(rating.c.rating).desc()).\
              limit(limit)
        res_ids = model.Session.execute(sql).fetchall()
        res_pkgs = [(model.Session.query(model.Package).get(unicode(pkg_id)), avg, num) for pkg_id, avg, num in res_ids]
        return res_pkgs
 
    @classmethod
    def most_edited_packages(cls, limit=10):
        package_revision = table('package_revision')
        package = table('package')
        s = select([package_revision.c.id, func.count(package_revision.c.revision_id)], from_obj=[package_revision.join(package)]).\
              where(package.c.private == 'f').\
            group_by(package_revision.c.id).\
            order_by(func.count(package_revision.c.revision_id).desc()).\
            limit(limit)
        res_ids = model.Session.execute(s).fetchall()
        res_pkgs = [(model.Session.query(model.Package).get(unicode(pkg_id)), val) for pkg_id, val in res_ids]
        return res_pkgs
 
    @classmethod
    def largest_groups(cls, limit=10):
        member = table('member')
        package = table('package')
        s = select([member.c.group_id, func.count(member.c.table_id)]).\
            group_by(member.c.group_id).\
            where(and_(member.c.group_id!=None, member.c.table_name=='package', package.c.private == 'f')).\
            order_by(func.count(member.c.table_id).desc()).\
            limit(limit)
 
        res_ids = model.Session.execute(s).fetchall()
        res_groups = [(model.Session.query(model.Group).get(unicode(group_id)), val) for group_id, val in res_ids]
        return res_groups
 
    @classmethod
    def top_tags(cls, limit=10, returned_tag_info='object'): # by package
        assert returned_tag_info in ('name', 'id', 'object')
        tag = table('tag')
        package_tag = table('package_tag')
        package = table('package')
        #TODO filter out tags with state=deleted
        if returned_tag_info == 'name':
            from_obj = [package_tag.join(tag)]
            tag_column = tag.c.name
        else:
            from_obj = None
            tag_column = package_tag.c.tag_id
        s = select([tag_column, func.count(package_tag.c.package_id)],
                    from_obj=from_obj)
        s = s.group_by(tag_column).\
              where(package.c.private == 'f').\
            order_by(func.count(package_tag.c.package_id).desc()).\
            limit(limit)
        res_col = model.Session.execute(s).fetchall()
        if returned_tag_info in ('id', 'name'):
            return res_col
        elif returned_tag_info == 'object':
            res_tags = [(model.Session.query(model.Tag).get(unicode(tag_id)), val) for tag_id, val in res_col]
            return res_tags
 
    @classmethod
    def top_package_owners(cls, limit=10):
        package_role = table('package_role')
        user_object_role = table('user_object_role')
        package = table('package')
#           join(package, package_role.c.package_id == package.c.id).\
#           where(package.c.private == 'f').\
        s = select([user_object_role.c.user_id, func.count(user_object_role.c.role)], from_obj=[user_object_role.join(package_role)]).\
            where(user_object_role.c.role==model.authz.Role.ADMIN).\
            where(user_object_role.c.user_id!=None).\
            group_by(user_object_role.c.user_id).\
            order_by(func.count(user_object_role.c.role).desc()).\
            limit(limit)
        res_ids = model.Session.execute(s).fetchall()
        res_users = [(model.Session.query(model.User).get(unicode(user_id)), val) for user_id, val in res_ids]
        return res_users
 
    @classmethod
    def summary_stats(cls):
       connection = model.Session.connection()
#                               select name,role from user_object_role inner join \"user\" on user_object_role.user_id = \"user\".id where name not in ('logged_in','visitor') group by name,role"
 
       res = connection.execute("SELECT 'Total Organisations', count(*) from \"group\" where type = 'organization' and state = 'active' union \
                                select 'Total Datasets', count(*) from package where state='active' or state='draft' or state='draft-complete' union \
                                select 'Total Data Files/Resources', count(*) from resource where state='active'").fetchall();
       return res
 
 
    @classmethod
    def activity_counts(cls):
       connection = model.Session.connection()
       res = connection.execute("select to_char(timestamp, 'YYYY-MM') as month,activity_type, count(*) from activity group by month, activity_type order by month;").fetchall();
       return res
 
 
class RevisionStats(object):
    @classmethod
    def package_addition_rate(cls, weeks_ago=0):
        week_commenced = cls.get_date_weeks_ago(weeks_ago)
        return cls.get_objects_in_a_week(week_commenced,
                                          type_='package_addition_rate')
 
    @classmethod
    def package_revision_rate(cls, weeks_ago=0):
        week_commenced = cls.get_date_weeks_ago(weeks_ago)
        return cls.get_objects_in_a_week(week_commenced,
                                          type_='package_revision_rate')
 
    @classmethod
    def get_date_weeks_ago(cls, weeks_ago):
        '''
        @param weeks_ago: specify how many weeks ago to give count for
                          (0 = this week so far)
        '''
        date_ = datetime.date.today()
        return date_ - datetime.timedelta(days=
                             datetime.date.weekday(date_) + 7 * weeks_ago)
 
    @classmethod
    def get_week_dates(cls, weeks_ago):
        '''
        @param weeks_ago: specify how many weeks ago to give count for
                          (0 = this week so far)
        '''
        package_revision = table('package_revision')
        revision = table('revision')
        today = datetime.date.today()
        date_from = datetime.datetime(today.year, today.month, today.day) -\
                    datetime.timedelta(days=datetime.date.weekday(today) + \
                                       7 * weeks_ago)
        date_to = date_from + datetime.timedelta(days=7)
        return (date_from, date_to)
 
    @classmethod
    def get_date_week_started(cls, date_):
        assert isinstance(date_, datetime.date)
        if isinstance(date_, datetime.datetime):
            date_ = datetime2date(date_)
        return date_ - datetime.timedelta(days=datetime.date.weekday(date_))
 
    @classmethod
    def get_package_revisions(cls):
        '''
        @return: Returns list of revisions and date of them, in
                 format: [(id, date), ...]
        '''
        package_revision = table('package_revision')
        revision = table('revision')
        s = select([package_revision.c.id, revision.c.timestamp], from_obj=[package_revision.join(revision)]).order_by(revision.c.timestamp)
        res = model.Session.execute(s).fetchall() # [(id, datetime), ...]
        return res
 
    @classmethod
    def get_new_packages(cls):
        '''
        @return: Returns list of new pkgs and date when they were created, in
                 format: [(id, date_ordinal), ...]
        '''
        def new_packages():
            # Can't filter by time in select because 'min' function has to
            # be 'for all time' else you get first revision in the time period.
            package_revision = table('package_revision')
            revision = table('revision')
            s = select([package_revision.c.id, func.min(revision.c.timestamp)], from_obj=[package_revision.join(revision)]).\
              where(package.c.private == 'f').\
              group_by(package_revision.c.id).order_by(func.min(revision.c.timestamp))
            res = model.Session.execute(s).fetchall() # [(id, datetime), ...]
            res_pickleable = []
            for pkg_id, created_datetime in res:
                res_pickleable.append((pkg_id, created_datetime.toordinal()))
            return res_pickleable
        if cache_enabled:
            week_commences = cls.get_date_week_started(datetime.date.today())
            key = 'all_new_packages_%s' + week_commences.strftime(DATE_FORMAT)
            new_packages = our_cache.get_value(key=key,
                                               createfunc=new_packages)
        else:
            new_packages = new_packages()
        return new_packages
 
    @classmethod
    def get_deleted_packages(cls):
        '''
        @return: Returns list of deleted pkgs and date when they were deleted, in
                 format: [(id, date_ordinal), ...]
        '''
        def deleted_packages():
            # Can't filter by time in select because 'min' function has to
            # be 'for all time' else you get first revision in the time period.
            package_revision = table('package_revision')
            revision = table('revision')
            s = select([package_revision.c.id, func.min(revision.c.timestamp)], from_obj=[package_revision.join(revision)]).\
                where(package_revision.c.state==model.State.DELETED).\
                group_by(package_revision.c.id).\
                order_by(func.min(revision.c.timestamp))
            res = model.Session.execute(s).fetchall() # [(id, datetime), ...]
            res_pickleable = []
            for pkg_id, deleted_datetime in res:
                res_pickleable.append((pkg_id, deleted_datetime.toordinal()))
            return res_pickleable
        if cache_enabled:
            week_commences = cls.get_date_week_started(datetime.date.today())
            key = 'all_deleted_packages_%s' + week_commences.strftime(DATE_FORMAT)
            deleted_packages = our_cache.get_value(key=key,
                                                   createfunc=deleted_packages)
        else:
            deleted_packages = deleted_packages()
        return deleted_packages
 
    @classmethod
    def get_num_packages_by_week(cls):
        def num_packages():
            new_packages_by_week = cls.get_by_week('new_packages')
            deleted_packages_by_week = cls.get_by_week('deleted_packages')
            first_date = (min(