import logging
from datetime import datetime, timedelta
from dateutil.relativedelta import relativedelta
from sqlalchemy import Column, VARCHAR, CHAR, ForeignKey, DATETIME, update, and_, inspect, text, BLOB, INT, FLOAT
from sqlalchemy.engine import Engine
from sqlalchemy.orm import sessionmaker, declarative_base, Session, relationship

from app.util import parse_key

logging.basicConfig()
logger = logging.getLogger(__name__)
logger.setLevel(logging.INFO)

Base = declarative_base()


class Site(Base):
    __tablename__ = "site"

    INITIAL_SITE_KEY_XID = '00000000-0000-0000-0000-000000000000'
    INITIAL_SITE_NAME = 'default'

    site_key = Column(CHAR(length=36), primary_key=True, unique=True, index=True)  # uuid4, SITE_KEY_XID
    name = Column(VARCHAR(length=256), nullable=False)

    def __str__(self):
        return f'SITE_KEY_XID: {self.site_key}'

    @staticmethod
    def create_statement(engine: Engine):
        from sqlalchemy.schema import CreateTable
        return CreateTable(Site.__table__).compile(engine)

    @staticmethod
    def get_default_site(engine: Engine) -> "Site":
        session = sessionmaker(bind=engine)()
        entity = session.query(Site).filter(Site.site_key == Site.INITIAL_SITE_KEY_XID).first()
        session.close()
        return entity


class Instance(Base):
    __tablename__ = "instance"

    DEFAULT_INSTANCE_REF = '10000000-0000-0000-0000-000000000001'
    DEFAULT_TOKEN_EXPIRE_DELTA = 86_400  # 1 day
    DEFAULT_LEASE_EXPIRE_DELTA = 7_776_000  # 90 days
    DEFAULT_LEASE_RENEWAL_PERIOD = 0.15
    DEFAULT_CLIENT_TOKEN_EXPIRE_DELTA = 378_432_000  # 12 years
    # 1 day = 86400 (min. in production setup, max 90 days), 1 hour = 3600

    instance_ref = Column(CHAR(length=36), primary_key=True, unique=True, index=True)  # uuid4, INSTANCE_REF
    site_key = Column(CHAR(length=36), ForeignKey(Site.site_key, ondelete='CASCADE'), nullable=False, index=True)  # uuid4
    private_key = Column(BLOB(length=2048), nullable=False)
    public_key = Column(BLOB(length=512), nullable=False)
    token_expire_delta = Column(INT(), nullable=False, default=DEFAULT_TOKEN_EXPIRE_DELTA, comment='in seconds')
    lease_expire_delta = Column(INT(), nullable=False, default=DEFAULT_LEASE_EXPIRE_DELTA, comment='in seconds')
    lease_renewal_period = Column(FLOAT(precision=2), nullable=False, default=DEFAULT_LEASE_RENEWAL_PERIOD)
    client_token_expire_delta = Column(INT(), nullable=False, default=DEFAULT_CLIENT_TOKEN_EXPIRE_DELTA, comment='in seconds')

    __origin = relationship(Site, foreign_keys=[site_key])

    def __str__(self):
        return f'INSTANCE_REF: {self.instance_ref} (SITE_KEY_XID: {self.site_key})'

    @staticmethod
    def create_statement(engine: Engine):
        from sqlalchemy.schema import CreateTable
        return CreateTable(Instance.__table__).compile(engine)

    @staticmethod
    def create_or_update(engine: Engine, instance: "Instance"):
        session = sessionmaker(bind=engine)()
        entity = session.query(Instance).filter(Instance.instance_ref == instance.instance_ref).first()
        if entity is None:
            session.add(instance)
        else:
            x = dict(
                site_key=instance.site_key,
                private_key=instance.private_key,
                public_key=instance.public_key,
                token_expire_delta=instance.token_expire_delta,
                lease_expire_delta=instance.lease_expire_delta,
                lease_renewal_period=instance.lease_renewal_period,
                client_token_expire_delta=instance.client_token_expire_delta,
            )
            session.execute(update(Instance).where(Instance.instance_ref == instance.instance_ref).values(**x))
        session.commit()
        session.flush()
        session.close()

    # todo: validate on startup that "lease_expire_delta" is between 1 day and 90 days

    @staticmethod
    def get_default_instance(engine: Engine) -> "Instance":
        session = sessionmaker(bind=engine)()
        site = Site.get_default_site(engine)
        entity = session.query(Instance).filter(Instance.site_key == site.site_key).first()
        session.close()
        return entity

    def get_token_expire_delta(self) -> "dateutil.relativedelta.relativedelta":
        return relativedelta(seconds=self.token_expire_delta)

    def get_lease_expire_delta(self) -> "dateutil.relativedelta.relativedelta":
        return relativedelta(seconds=self.lease_expire_delta)

    def get_lease_renewal_delta(self) -> "datetime.timedelta":
        return timedelta(seconds=self.lease_expire_delta)

    def get_client_token_expire_delta(self) -> "dateutil.relativedelta.relativedelta":
        return relativedelta(seconds=self.client_token_expire_delta)

    def __get_private_key(self) -> "RsaKey":
        return parse_key(self.private_key)

    def get_public_key(self) -> "RsaKey":
        return parse_key(self.public_key)

    def get_jwt_encode_key(self) -> "jose.jkw":
        from jose import jwk
        from jose.constants import ALGORITHMS
        return jwk.construct(self.__get_private_key().export_key().decode('utf-8'), algorithm=ALGORITHMS.RS256)

    def get_jwt_decode_key(self) -> "jose.jwt":
        from jose import jwk
        from jose.constants import ALGORITHMS
        return jwk.construct(self.get_public_key().export_key().decode('utf-8'), algorithm=ALGORITHMS.RS256)

    def get_private_key_str(self, encoding: str = 'utf-8') -> str:
        return self.private_key.decode(encoding)

    def get_public_key_str(self, encoding: str = 'utf-8') -> str:
        return self.private_key.decode(encoding)


class Origin(Base):
    __tablename__ = "origin"

    origin_ref = Column(CHAR(length=36), primary_key=True, unique=True, index=True)  # uuid4
    # service_instance_xid = Column(CHAR(length=36), nullable=False, index=True)  # uuid4 # not necessary, we only support one service_instance_xid ('INSTANCE_REF')
    hostname = Column(VARCHAR(length=256), nullable=True)
    guest_driver_version = Column(VARCHAR(length=10), nullable=True)
    os_platform = Column(VARCHAR(length=256), nullable=True)
    os_version = Column(VARCHAR(length=256), nullable=True)

    def __repr__(self):
        return f'Origin(origin_ref={self.origin_ref}, hostname={self.hostname})'

    def serialize(self) -> dict:
        return {
            'origin_ref': self.origin_ref,
            # 'service_instance_xid': self.service_instance_xid,
            'hostname': self.hostname,
            'guest_driver_version': self.guest_driver_version,
            'os_platform': self.os_platform,
            'os_version': self.os_version,
        }

    @staticmethod
    def create_statement(engine: Engine):
        from sqlalchemy.schema import CreateTable
        return CreateTable(Origin.__table__).compile(engine)

    @staticmethod
    def create_or_update(engine: Engine, origin: "Origin"):
        session = sessionmaker(bind=engine)()
        entity = session.query(Origin).filter(Origin.origin_ref == origin.origin_ref).first()
        if entity is None:
            session.add(origin)
        else:
            x = dict(
                hostname=origin.hostname,
                guest_driver_version=origin.guest_driver_version,
                os_platform=origin.os_platform,
                os_version=origin.os_version
            )
            session.execute(update(Origin).where(Origin.origin_ref == origin.origin_ref).values(**x))
        session.commit()
        session.flush()
        session.close()

    @staticmethod
    def delete(engine: Engine, origin_refs: [str] = None) -> int:
        session = sessionmaker(bind=engine)()
        if origin_refs is None:
            deletions = session.query(Origin).delete()
        else:
            deletions = session.query(Origin).filter(Origin.origin_ref in origin_refs).delete()
        session.commit()
        session.close()
        return deletions


class Lease(Base):
    __tablename__ = "lease"

    instance_ref = Column(CHAR(length=36), ForeignKey(Instance.instance_ref, ondelete='CASCADE'), nullable=False, index=True)  # uuid4
    lease_ref = Column(CHAR(length=36), primary_key=True, nullable=False, index=True)  # uuid4
    origin_ref = Column(CHAR(length=36), ForeignKey(Origin.origin_ref, ondelete='CASCADE'), nullable=False, index=True)  # uuid4
    # scope_ref = Column(CHAR(length=36), nullable=False, index=True)  # uuid4 # not necessary, we only support one scope_ref ('ALLOTMENT_REF')
    lease_created = Column(DATETIME(), nullable=False)
    lease_expires = Column(DATETIME(), nullable=False)
    lease_updated = Column(DATETIME(), nullable=False)

    __instance = relationship(Instance, foreign_keys=[instance_ref])
    __origin = relationship(Origin, foreign_keys=[origin_ref])

    def __repr__(self):
        return f'Lease(origin_ref={self.origin_ref}, lease_ref={self.lease_ref}, expires={self.lease_expires})'

    def serialize(self) -> dict:
        renewal_period = self.__instance.lease_renewal_period
        renewal_delta = self.__instance.get_lease_renewal_delta

        lease_renewal = int(Lease.calculate_renewal(renewal_period, renewal_delta).total_seconds())
        lease_renewal = self.lease_updated + relativedelta(seconds=lease_renewal)

        return {
            'lease_ref': self.lease_ref,
            'origin_ref': self.origin_ref,
            # 'scope_ref': self.scope_ref,
            'lease_created': self.lease_created.isoformat(),
            'lease_expires': self.lease_expires.isoformat(),
            'lease_updated': self.lease_updated.isoformat(),
            'lease_renewal': lease_renewal.isoformat(),
        }

    @staticmethod
    def create_statement(engine: Engine):
        from sqlalchemy.schema import CreateTable
        return CreateTable(Lease.__table__).compile(engine)

    @staticmethod
    def create_or_update(engine: Engine, lease: "Lease"):
        session = sessionmaker(bind=engine)()
        entity = session.query(Lease).filter(Lease.lease_ref == lease.lease_ref).first()
        if entity is None:
            if lease.lease_updated is None:
                lease.lease_updated = lease.lease_created
            session.add(lease)
        else:
            x = dict(origin_ref=lease.origin_ref, lease_expires=lease.lease_expires, lease_updated=lease.lease_updated)
            session.execute(update(Lease).where(Lease.lease_ref == lease.lease_ref).values(**x))
        session.commit()
        session.flush()
        session.close()

    @staticmethod
    def find_by_origin_ref(engine: Engine, origin_ref: str) -> ["Lease"]:
        session = sessionmaker(bind=engine)()
        entities = session.query(Lease).filter(Lease.origin_ref == origin_ref).all()
        session.close()
        return entities

    @staticmethod
    def find_by_lease_ref(engine: Engine, lease_ref: str) -> "Lease":
        session = sessionmaker(bind=engine)()
        entity = session.query(Lease).filter(Lease.lease_ref == lease_ref).first()
        session.close()
        return entity

    @staticmethod
    def find_by_origin_ref_and_lease_ref(engine: Engine, origin_ref: str, lease_ref: str) -> "Lease":
        session = sessionmaker(bind=engine)()
        entity = session.query(Lease).filter(and_(Lease.origin_ref == origin_ref, Lease.lease_ref == lease_ref)).first()
        session.close()
        return entity

    @staticmethod
    def renew(engine: Engine, lease: "Lease", lease_expires: datetime, lease_updated: datetime):
        session = sessionmaker(bind=engine)()
        x = dict(lease_expires=lease_expires, lease_updated=lease_updated)
        session.execute(update(Lease).where(and_(Lease.origin_ref == lease.origin_ref, Lease.lease_ref == lease.lease_ref)).values(**x))
        session.commit()
        session.close()

    @staticmethod
    def cleanup(engine: Engine, origin_ref: str) -> int:
        session = sessionmaker(bind=engine)()
        deletions = session.query(Lease).filter(Lease.origin_ref == origin_ref).delete()
        session.commit()
        session.close()
        return deletions

    @staticmethod
    def delete(engine: Engine, lease_ref: str) -> int:
        session = sessionmaker(bind=engine)()
        deletions = session.query(Lease).filter(Lease.lease_ref == lease_ref).delete()
        session.commit()
        session.close()
        return deletions

    @staticmethod
    def delete_expired(engine: Engine) -> int:
        session = sessionmaker(bind=engine)()
        deletions = session.query(Lease).filter(Lease.lease_expires <= datetime.utcnow()).delete()
        session.commit()
        session.close()
        return deletions

    @staticmethod
    def calculate_renewal(renewal_period: float, delta: timedelta) -> timedelta:
        """
        import datetime
        LEASE_RENEWAL_PERIOD=0.2  # 20%
        delta = datetime.timedelta(days=1)
        renew = delta.total_seconds() * LEASE_RENEWAL_PERIOD
        renew = datetime.timedelta(seconds=renew)
        expires = delta - renew  # 19.2

        import datetime
        LEASE_RENEWAL_PERIOD=0.15  # 15%
        delta = datetime.timedelta(days=90)
        renew = delta.total_seconds() * LEASE_RENEWAL_PERIOD
        renew = datetime.timedelta(seconds=renew)
        expires = delta - renew  # 76 days, 12:00:00 hours

        """
        renew = delta.total_seconds() * renewal_period
        renew = timedelta(seconds=renew)
        return renew


def init_default_site(session: Session):
    from uuid import uuid4
    from app.util import generate_key

    private_key = generate_key()
    public_key = private_key.public_key()

    site = Site(
        site_key=Site.INITIAL_SITE_KEY_XID,
        name=Site.INITIAL_SITE_NAME
    )
    session.add(site)
    session.commit()

    instance = Instance(
        instance_ref=Instance.DEFAULT_INSTANCE_REF,
        site_key=site.site_key,
        private_key=private_key.export_key(),
        public_key=public_key.export_key(),
    )
    session.add(instance)
    session.commit()


def init(engine: Engine):
    tables = [Site, Instance, Origin, Lease]
    db = inspect(engine)
    session = sessionmaker(bind=engine)()
    for table in tables:
        exists = db.dialect.has_table(engine.connect(), table.__tablename__)
        logger.info(f'> Table "{table.__tablename__:<16}" exists: {exists}')
        if not exists:
            session.execute(text(str(table.create_statement(engine))))
            session.commit()

    # create default site
    cnt = session.query(Site).count()
    if cnt == 0:
        init_default_site(session)

    session.flush()
    session.close()


def migrate(engine: Engine):
    from os import getenv as env
    from os.path import join, dirname, isfile
    from util import load_key

    db = inspect(engine)

    # todo: add update guide to use 1.LATEST to 2.0
    def upgrade_1_x_to_2_0():
        site = Site.get_default_site(engine)
        logger.info(site)
        instance = Instance.get_default_instance(engine)
        logger.info(instance)

        # SITE_KEY_XID
        if site_key := env('SITE_KEY_XID', None) is not None:
            site.site_key = str(site_key)

        # INSTANCE_REF
        if instance_ref := env('INSTANCE_REF', None) is not None:
            instance.instance_ref = str(instance_ref)

        # ALLOTMENT_REF
        if allotment_ref := env('ALLOTMENT_REF', None) is not None:
            pass  # todo

        # INSTANCE_KEY_RSA, INSTANCE_KEY_PUB
        default_instance_private_key_path = str(join(dirname(__file__), 'cert/instance.private.pem'))
        if instance_private_key := env('INSTANCE_KEY_RSA', None) is not None:
            instance.private_key = load_key(str(instance_private_key))
        elif isfile(default_instance_private_key_path):
            instance.private_key = load_key(default_instance_private_key_path)
        default_instance_public_key_path = str(join(dirname(__file__), 'cert/instance.public.pem'))
        if instance_public_key := env('INSTANCE_KEY_PUB', None) is not None:
            instance.public_key = load_key(str(instance_public_key))
        elif isfile(default_instance_public_key_path):
            instance.public_key = load_key(default_instance_public_key_path)

        # TOKEN_EXPIRE_DELTA
        if token_expire_delta := env('TOKEN_EXPIRE_DAYS', None) not in (None, 0):
            instance.token_expire_delta = token_expire_delta * 86_400
        if token_expire_delta := env('TOKEN_EXPIRE_HOURS', None) not in (None, 0):
            instance.token_expire_delta = token_expire_delta * 3_600

        # LEASE_EXPIRE_DELTA, LEASE_RENEWAL_DELTA
        if lease_expire_delta := env('LEASE_EXPIRE_DAYS', None) not in (None, 0):
            instance.lease_expire_delta = lease_expire_delta * 86_400
        if lease_expire_delta := env('LEASE_EXPIRE_HOURS', None) not in (None, 0):
            instance.lease_expire_delta = lease_expire_delta * 3_600

        # LEASE_RENEWAL_PERIOD
        if lease_renewal_period := env('LEASE_RENEWAL_PERIOD', None) is not None:
            instance.lease_renewal_period = lease_renewal_period

        # todo: update site, instance

    upgrade_1_x_to_2_0()