# pylint: disable=too-few-public-methods, invalid-name
from sqlalchemy import Column, ForeignKey, Table
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import relationship
from sqlalchemy.types import (TIMESTAMP, Boolean, DateTime, Integer, String,
                              TypeDecorator)

from dateutil.tz import tzutc


# pylint: disable=abstract-method, unused-argument
class UTCDateTime(TypeDecorator):
    impl = DateTime

    def process_bind_param(self, value, engine):
        if value is not None:
            return value.astimezone(tzutc())

    def process_result_value(self, value, engine):
        if value is not None:
            return value.replace(tzinfo=tzutc())


BASE = declarative_base()


class Calendar(BASE):
    __tablename__ = 'calendars'

    uid = Column(String(255), primary_key=True)
    url = Column(String(255))
    name = Column(String(255), index=True)
    website = Column(String(255))
    visible = Column(Boolean, index=True)
    last_updated = Column(TIMESTAMP)

    _category = Column(
        Integer,
        ForeignKey(
            'categories.id',
            onupdate='CASCADE',
            ondelete='SET NULL'))
    category = relationship(
        'Category',
        back_populates='calendars',
        order_by='Calendar.name')

    entries = relationship(
        'Entry',
        back_populates='calendar',
        cascade="all",
        passive_deletes=True,
        order_by='Entry.begin_date')

    @staticmethod
    def fetch(uid, session, name=None, url=None):
        calendar = session.query(Calendar).filter(Calendar.uid == uid).first()
        if not calendar:
            calendar = Calendar()
            calendar.uid = uid
            session.add(calendar)
        if name:
            calendar.name = name
        if url:
            calendar.url = url
        return calendar


class Entry(BASE):
    __tablename__ = 'entries'

    id = Column(Integer, primary_key=True)
    uid = Column(String(255), index=True, unique=True, nullable=False)
    begin_date = Column(UTCDateTime, index=True)
    end_date = Column(UTCDateTime)
    all_day = Column(Boolean)
    name = Column(String(255))
    location = Column(String(255))

    _calendar = Column(
        String(255),
        ForeignKey(
            'calendars.uid',
            onupdate='CASCADE',
            ondelete='CASCADE'))
    calendar = relationship(
        'Calendar',
        back_populates='entries',
        order_by='Entry.begin_date')

    @staticmethod
    def fetch(uid, session):
        entry = session.query(Entry).filter(Entry.uid == uid).first()
        if not entry:
            entry = Entry()
            session.add(entry)
        return entry


class Category(BASE):
    __tablename__ = 'categories'

    id = Column(Integer, primary_key=True)
    name = Column(String(255), index=True)

    calendars = relationship(
        'Calendar',
        back_populates='category',
        cascade="all",
        passive_deletes=True,
        order_by='Calendar.name')

    @staticmethod
    def fetch(name, session):
        category = session.query(Category).filter(
            Category.name == name).first()
        if not category:
            category = Category()
            category.name = name
            session.add(category)
        return category


user_selections = Table(
    'user_selections', BASE.metadata,
    Column('_user', Integer,
           ForeignKey('users.id', onupdate='CASCADE', ondelete='CASCADE')),
    Column('_calendar', String(255),
           ForeignKey('calendars.uid', onupdate='CASCADE', ondelete='CASCADE'))
)


class User(BASE):
    __tablename__ = 'users'

    id = Column(Integer, primary_key=True)
    login = Column(String(255), unique=True, index=True)
    password = Column(String(255))
    is_admin = Column(Boolean)
    last_login = Column(UTCDateTime)

    calendars = relationship('Calendar',
                             secondary=user_selections)

__all__ = ('Calendar', 'Entry', 'Category', 'User')