#!/usr/bin/python3

import os.path

from dbconfig import Session, scoped_session

from typing import List, Optional

from sqlalchemy import (
    Boolean,
    Column,
    DateTime,
    ForeignKey,
    func,
    Integer,
    select,
    String,
)

from sqlalchemy.ext.associationproxy import association_proxy

from sqlalchemy.orm import (
    declarative_base,
    relationship,
)
from sqlalchemy.orm.exc import (
    NoResultFound
)
from config import Config
from log import log

Base = declarative_base()


# Database classes
class Accounts(Base):
    __tablename__ = 'accounts'

    id = Column(Integer, primary_key=True, autoincrement=True)
    account_id = Column(String(32), index=True, nullable=False)
    username = Column(String(256), index=True, default=None)
    acct = Column(String(256), index=False, default=None)
    display_name = Column(String(256), index=False, default=None)
    bot = Column(Boolean, index=False, nullable=False, default=False)
    url = Column(String(256), index=False)
    followed = Column(Boolean, index=False, nullable=False, default=False)

    def __repr__(self) -> str:
        return (
            f"<Accounts(id={self.id}, username={self.username}, "
            f"acct={self.acct}, followed={self.followed}>"
        )

    def __init__(self, session: Session, account_id: str) -> None:

        self.account_id = account_id

        session.add(self)
        session.flush()

    @classmethod
    def get_followed(cls, session: Session) -> List["Accounts"]:
        """
        Return a list of account objects that we follow
        """

        records = (
            session.execute(
                select(cls)
                .where(cls.followed.is_(True))
            ).scalars().all()
        )

        return records

    @classmethod
    def get_or_create(cls, session: Session, account_id: str) -> "Accounts":
        """
        Return any existing account with this id or create a new one
        """

        try:
            rec = (
                session.execute(
                    select(cls)
                    .where(cls.account_id == account_id)
                ).scalar_one()
            )
        except NoResultFound:
            rec = Accounts(session, account_id)

        return rec


class Hashtags(Base):
    __tablename__ = 'hashtags'

    id = Column(Integer, primary_key=True, autoincrement=True)
    name = Column(String(256), index=True, nullable=False)
    url = Column(String(256), index=False)

    tags_to_posts = relationship("PostTags", back_populates="hashtag")
    posts = association_proxy("tags_to_posts", "post")

    followed = Column(Boolean, index=False, nullable=False, default=False)

    def __repr__(self) -> str:
        return (
            f"<Hashtags(id={self.id}, name={self.name}, "
            f"url={self.url}, followed={self.followed}>"
        )

    def __init__(self, session: Session, name: str, url: str) -> None:
        self.name = name
        self.url = url

        session.add(self)
        session.flush()

    @classmethod
    def get_all(cls, session: Session) -> List["Hashtags"]:
        """
        Return a list of all hashtags
        """

        records = (
            session.execute(
                select(cls)
            ).scalars().all()
        )

        return records

    @classmethod
    def get_followed(cls, session: Session) -> List["Hashtags"]:
        """
        Return a list of hashtags objects that we follow
        """

        records = (
            session.execute(
                select(cls)
                .where(cls.followed.is_(True))
            ).scalars().all()
        )

        return records

    @classmethod
    def get_or_create(cls, session: Session,
                      name: str, url: str) -> "Hashtags":
        """
        Return any existing hashtag with this name or create a new one
        """

        try:
            rec = (
                session.execute(
                    select(cls)
                    .where(cls.name == name)
                ).scalar_one()
            )
        except NoResultFound:
            rec = Hashtags(session, name, url)

        return rec


class Posts(Base):
    __tablename__ = 'posts'

    id = Column(Integer, primary_key=True, autoincrement=True)
    post_id = Column(String(32), index=True, nullable=False)

    account_id = Column(Integer, ForeignKey('accounts.id'), nullable=True)
    account = relationship("Accounts", foreign_keys=[account_id])

    created_at = Column(DateTime, index=True, default=None)
    uri = Column(String(256), index=False)

    posts_to_tags = relationship("PostTags", back_populates="post")
    hashtags = association_proxy("posts_to_tags", "hashtag")

    favourited = Column(Boolean, index=True, nullable=False, default=False)
    bookmarked = Column(Boolean, index=True, nullable=False, default=False)

    def __repr__(self) -> str:
        return f"<Posts(id={self.id}>"

    def __init__(self, session: Session, post_id) -> None:

        self.post_id = post_id

        session.add(self)
        session.flush()

    @classmethod
    def get_by_post_id(cls, session: Session, post_id: str) -> "Posts":
        """
        Return post identified by post_id or None
        """

        return (
            session.scalars(
                select(cls)
                .where(cls.post_id == post_id)
                .limit(1)
            ).first()
        )

    @classmethod
    def get_or_create(cls, session: Session, post_id: str) -> "Posts":
        """
        Return any existing post with this id or create a new one
        """

        try:
            rec = (
                session.execute(
                    select(cls)
                    .where(cls.post_id == post_id)
                ).scalar_one()
            )
        except NoResultFound:
            rec = Posts(session, post_id)

        return rec

    @staticmethod
    def max_post_id(session):
        """
        Return the maximum post_id
        """

        return session.scalars(select(func.max(Posts.post_id))).first()


class PostTags(Base):
    __tablename__ = 'post_tags'

    id = Column(Integer, primary_key=True, autoincrement=True)
    post_id = Column(Integer, ForeignKey('posts.id'), nullable=False,
                     index=True)
    hashtag_id = Column(Integer, ForeignKey('hashtags.id'), nullable=False,
                        index=True)

    post = relationship(Posts, back_populates="posts_to_tags")
    hashtag = relationship("Hashtags")

    def __init__(self, hashtag=None, post=None):
        self.post = post
        self.hashtag = hashtag