#!/usr/bin/python3

import os.path
import re

import sqlalchemy

from datetime import datetime
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import (
    Boolean,
    Column,
    DateTime,
    Float,
    ForeignKey,
    Integer,
    String,
    func
)
from sqlalchemy.exc import IntegrityError
from sqlalchemy.orm.exc import MultipleResultsFound, NoResultFound
from sqlalchemy.orm import relationship, sessionmaker, scoped_session

from app.config import Config
from app.log import DEBUG, ERROR

# Create session at the global level as per
# https://docs.sqlalchemy.org/en/13/orm/session_basics.html

Base = declarative_base()
Session = scoped_session(sessionmaker())


def db_init():
    # Set up database connection

    global Session

    engine = sqlalchemy.create_engine(
        f"{Config.MYSQL_CONNECT}?charset=utf8",
        encoding='utf-8',
        echo=Config.DISPLAY_SQL,
        pool_pre_ping=True)

    Session.configure(bind=engine)
    Base.metadata.create_all(engine)

    # Create a Session factory
    Session = sessionmaker(bind=engine)


# Database classes
class NoteColours(Base):
    __tablename__ = 'notecolours'

    id = Column(Integer, primary_key=True, autoincrement=True)
    substring = Column(String(256), index=False)
    colour = Column(String(21), index=False)
    enabled = Column(Boolean, default=True, index=True)
    is_regex = Column(Boolean, default=False, index=False)
    is_casesensitive = Column(Boolean, default=False, index=False)
    order = Column(Integer, index=True)

    def __repr__(self):
        return (
            f"<NoteColour(id={self.id}, substring={self.substring}, "
            f"colour={self.colour}>"
        )

    @classmethod
    def get_all(cls, session):
        """Return all records"""

        return session.query(cls).all()

    @classmethod
    def get_by_id(cls, session, note_id):
        """Return record identified by id, or None if not found"""

        return session.query(NoteColours).filter(
            NoteColours.id == note_id).first()

    @staticmethod
    def get_colour(session, text):
        """
        Parse text and return colour string if matched, else None
        """

        for rec in (
            session.query(NoteColours)
            .filter(NoteColours.enabled.is_(True))
            .order_by(NoteColours.order)
            .all()
        ):
            if rec.is_regex:
                flags = re.UNICODE
                if not rec.is_casesensitive:
                    flags |= re.IGNORECASE
                p = re.compile(rec.substring, flags)
                if p.match(text):
                    return rec.colour
            else:
                if rec.is_casesensitive:
                    if rec.substring in text:
                        return rec.colour
                else:
                    if rec.substring.lower() in text.lower():
                        return rec.colour

        return None


class Notes(Base):
    __tablename__ = 'notes'

    id = Column(Integer, primary_key=True, autoincrement=True)
    playlist_id = Column(Integer, ForeignKey('playlists.id'))
    playlist = relationship("Playlists", back_populates="notes")
    row = Column(Integer, nullable=False)
    note = Column(String(256), index=False)

    def __init__(self, session, playlist_id, row, text):
        """Create note"""

        DEBUG(f"Notes.__init__({playlist_id=}, {row=}, {text=})")
        self.playlist_id = playlist_id
        self.row = row
        self.note = text
        session.add(self)
        session.commit()

    def __repr__(self):
        return (
            f"<Note(id={self.id}, row={self.row}, note={self.note}>"
        )

    def delete_note(self, session):
        """Delete note"""

        DEBUG(f"delete_note({self.id=}")

        session.query(self).filter(id == self.id).delete()
        session.commit()

    def update_note(self, session, row, text=None):
        """
        Update note details. If text=None, don't change text.
        """

        DEBUG(f"Notes.update_note({self.id=}, {row=}, {text=})")

        note = session.query(self).filter(id == self.id).one()
        note.row = row
        if text:
            note.note = text
        session.commit()


class Playdates(Base):
    __tablename__ = 'playdates'

    id = Column(Integer, primary_key=True, autoincrement=True)
    lastplayed = Column(DateTime, index=True, default=None)
    track_id = Column(Integer, ForeignKey('tracks.id'))
    tracks = relationship("Tracks", back_populates="playdates")

    def __init__(self, session, track):
        """Record that track was played"""

        DEBUG(f"add_playdate(track={track})")

        self.lastplayed = datetime.now()
        self.track_id = track.id
        track.update_lastplayed(session)
        session.add(self)
        session.commit()

    @staticmethod
    def last_played(session, track_id):
        """Return datetime track last played or None"""

        last_played = session.query(Playdates.lastplayed).filter(
            (Playdates.track_id == track_id)
        ).order_by(Playdates.lastplayed.desc()).first()
        if last_played:
            return last_played[0]
        else:
            return None

    @staticmethod
    def remove_track(session, track_id):
        """
        Remove all records of track_id
        """

        session.query(Playdates).filter(
            Playdates.track_id == track_id,
        ).delete()
        session.commit()


class Playlists(Base):
    """
    Manage playlists
    """

    __tablename__ = "playlists"

    id = Column(Integer, primary_key=True, autoincrement=True)
    name = Column(String(32), nullable=False, unique=True)
    last_used = Column(DateTime, default=None, nullable=True)
    loaded = Column(Boolean, default=True, nullable=False)
    notes = relationship("Notes",
                         order_by="Notes.row",
                         back_populates="playlist")
    tracks = relationship("PlaylistTracks",
                          order_by="PlaylistTracks.row",
                          back_populates="playlists")

    def __init__(self, session, name):
        self.name = name
        session.add(self)
        session.commit()

    def __repr__(self):
        return f"<Playlists(id={self.id}, name={self.name}>"

    def add_note(self, session, row, text):
        """Add note to playlist at passed row"""

        return Notes(session, self.id, row, text)

    def add_track(self, session, track, row=None):
        """
        Add track to playlist at given row.
        If row=None, add to end of playlist
        """

        if not row:
            last_row = session.query(
                func.max(PlaylistTracks.row)
            ).filter_by(playlist_id=self.id).first()
            if last_row:
                row = last_row[0] + 1
            else:
                row = 0

        PlaylistTracks(session, self.id, track.id, row)

    def close(self, session):
        """Record playlist as no longer loaded"""

        self.loaded = False
        session.add(self)
        session.commit()

    @classmethod
    def get_all(cls, session):
        """Returns a list of all playlists ordered by last use"""

        return (
            session.query(cls)
            .order_by(cls.last_used.desc())
        ).all()

    @classmethod
    def get_by_id(cls, session, playlist_id):
        return (session.query(cls).filter(cls.id == playlist_id)).one()

    @classmethod
    def get_closed(cls, session):
        """Returns a list of all closed playlists ordered by last use"""

        return (
            session.query(cls)
            .filter(cls.loaded.is_(False))
            .order_by(cls.last_used.desc())
        ).all()

    @classmethod
    def get_open(cls, session):
        """
        Return a list of playlists marked "loaded", ordered by loaded date.
        """

        return (
            session.query(cls)
            .filter(cls.loaded.is_(True))
            .order_by(cls.last_used.desc())
        ).all()

    def mark_open(self, session):
        """Mark playlist as loaded and used now"""

        self.loaded = True
        self.last_used = datetime.now()
        session.add(self)
        session.commit()

    def remove_all_tracks(self, session):
        """
        Remove all tracks from this playlist
        """

        session.query(PlaylistTracks).filter(
            PlaylistTracks.playlist_id == self.id,
        ).delete()
        session.commit()

    def remove_track(self, session, row):

        DEBUG(f"Playlist.remove_track({self.id=}, {row=})")

        session.query(PlaylistTracks).filter(
            PlaylistTracks.playlist_id == self.id,
            PlaylistTracks.row == row
        ).delete()
        session.commit()


class PlaylistTracks(Base):
    __tablename__ = 'playlisttracks'

    id = Column(Integer, primary_key=True, autoincrement=True)
    playlist_id = Column(Integer, ForeignKey('playlists.id'), primary_key=True)
    track_id = Column(Integer, ForeignKey('tracks.id'), primary_key=True)
    row = Column(Integer, nullable=False)
    tracks = relationship("Tracks", back_populates="playlists")
    playlists = relationship("Playlists", back_populates="tracks")

    def __init__(self, session, playlist_id, track_id, row):
        DEBUG(f"PlaylistTracks.__init__({playlist_id=}, {track_id=}, {row=})")

        self.playlist_id = playlist_id,
        self.track_id = track_id,
        self.row = row
        session.add(self)
        session.commit()

    @staticmethod
    def get_track_playlists(session, track_id):
        """Return all PlaylistTracks objects with this track_id"""

        return session.query(PlaylistTracks).filter(
            PlaylistTracks.track_id == track_id).all()


class Settings(Base):
    __tablename__ = 'settings'

    id = Column(Integer, primary_key=True, autoincrement=True)
    name = Column(String(32), nullable=False, unique=True)
    f_datetime = Column(DateTime, default=None, nullable=True)
    f_int = Column(Integer, default=None, nullable=True)
    f_string = Column(String(128), default=None, nullable=True)

    @classmethod
    def get_int(cls, session, name):
        try:
            int_setting = session.query(cls).filter(
                cls.name == name).one()
        except NoResultFound:
            int_setting = Settings()
            int_setting.name = name
            int_setting.f_int = None
            session.add(int_setting)
            session.commit()
        return int_setting

    def update(self, session, data):
        for key, value in data.items():
            assert hasattr(self, key)
            setattr(self, key, value)
        session.commit()


class Tracks(Base):
    __tablename__ = 'tracks'

    id = Column(Integer, primary_key=True, autoincrement=True)
    title = Column(String(256), index=True)
    artist = Column(String(256), index=True)
    duration = Column(Integer, index=True)
    start_gap = Column(Integer, index=False)
    fade_at = Column(Integer, index=False)
    silence_at = Column(Integer, index=False)
    path = Column(String(2048), index=False, nullable=False)
    mtime = Column(Float, index=True)
    lastplayed = Column(DateTime, index=True, default=None)
    playlists = relationship("PlaylistTracks", back_populates="tracks")
    playdates = relationship("Playdates", back_populates="tracks")

    def __init__(self, session, path):
        self.path = path
        session.add(self)
        session.commit()

    def __repr__(self):
        return (
            f"<Track(id={self.id}, title={self.title}, "
            f"artist={self.artist}, path={self.path}>"
        )

    @staticmethod
    def get_all_paths(session):
        """Return a list of paths of all tracks"""

        return [a[0] for a in session.query(Tracks.path).all()]

    @classmethod
    def get_all_tracks(cls, session):
        """Return a list of all tracks"""

        return session.query(cls).all()

    @classmethod
    def get_or_create(cls, session, path):
        """
        If a track with path exists, return it;
        else created new track and return it
        """

        DEBUG(f"Tracks.get_or_create({path=})")

        try:
            track = session.query(cls).filter(cls.path == path).one()
        except NoResultFound:
            track = Tracks(session, path)

        return track

    @classmethod
    def get_from_filename(cls, session, filename):
        """
        Return track if one and only one track in database has passed
        filename (ie, basename of path). Return None if zero or more
        than one track matches.
        """

        DEBUG(f"Tracks.get_track_from_filename({filename=})")
        try:
            track = session.query(Tracks).filter(Tracks.path.ilike(
                f'%{os.path.sep}{filename}')).one()
            return track
        except (NoResultFound, MultipleResultsFound):
            return None

    @classmethod
    def get_from_id(cls, session, id):
        return session.query(Tracks).filter(
            Tracks.id == id).one()

    @classmethod
    def get_from_path(cls, session, path):
        """
        Return track with passee path, or None.
        """

        DEBUG(f"Tracks.get_track_from_path({path=})")

        return session.query(Tracks).filter(Tracks.path == path).first()

    @classmethod
    def get_by_id(cls, session, track_id):
        """Return track or None"""

        try:
            DEBUG(f"Tracks.get_track(track_id={track_id})")
            track = session.query(Tracks).filter(Tracks.id == track_id).one()
            return track
        except NoResultFound:
            ERROR(f"get_track({track_id}): not found")
            return None

    @staticmethod
    def remove_by_path(session, path):
        "Remove track with passed path from database"

        DEBUG(f"Tracks.remove_path({path=})")

        try:
            session.query(Tracks).filter(Tracks.path == path).delete()
            session.commit()
        except IntegrityError as exception:
            ERROR(f"Can't remove track with {path=} ({exception=})")

    @classmethod
    def search_artists(cls, session, text):

        return (
            session.query(Tracks)
            .filter(Tracks.artist.ilike(f"%{text}%"))
            .order_by(Tracks.title)
        ).all()

    @classmethod
    def search_titles(cls, session, text):
        return (
            session.query(Tracks)
            .filter(Tracks.title.ilike(f"%{text}%"))
            .order_by(Tracks.title)
        ).all()

    def update_lastplayed(self, session):
        self.lastplayed = datetime.now()
        session.add(self)
        session.commit()

    def update_artist(self, session, artist):
        self.artist = artist
        session.add(self)
        session.commit()

    def update_title(self, session, title):
        self.title = title
        session.add(self)
        session.commit()

    def update_path(self, newpath):
        self.path = newpath