#!/usr/bin/python3

import sqlalchemy

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

from config import Config
from log import DEBUG, ERROR

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

# Set up database connection
engine = sqlalchemy.create_engine(f"{Config.MYSQL_CONNECT}?charset=utf8",
                                  encoding='utf-8',
                                  echo=Config.DISPLAY_SQL,
                                  pool_pre_ping=True)
Base = declarative_base()
Base.metadata.create_all(engine)

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


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

    @staticmethod
    def add_note(playlist_id, row, text):
        DEBUG(f"add_note(playlist_id={playlist_id}, row={row}, text={text})")
        note = Notes()
        note.playlist_id = playlist_id
        note.row = row
        note.note = text
        session.add(note)
        session.commit()
        return note.id

    @classmethod
    def update_note(cls, id, row, text):
        DEBUG(f"update_note(id={id}, row={row}, text={text})")

        note = session.query(cls).filter(cls.id == id).one()
        note.row = row
        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")

    @staticmethod
    def add_playdate(track):
        DEBUG(f"add_playdate(track={track})")
        pd = Playdates()
        pd.lastplayed = datetime.now()
        pd.track_id = track.id
        session.add(pd)
        track.update_lastplayed()
        session.commit()


class Playlists(Base):
    """
    Usage:

    pl = session.query(Playlists).filter(Playlists.id == 1).one()

    pl
    <Playlist(id=1, name=Default>

    pl.tracks
    [<__main__.PlaylistTracks at 0x7fcd20181c18>,
     <__main__.PlaylistTracks at 0x7fcd20181c88>,
     <__main__.PlaylistTracks at 0x7fcd20181be0>,
     <__main__.PlaylistTracks at 0x7fcd20181c50>]

    [a.tracks for a in pl.tracks]
    [<Track(id=3992, title=Yesterday Man, artist=Various, path=/h[...]
     <Track(id=2238, title=These Boots Are Made For Walkin', arti[...]
     <Track(id=3837, title=Babe, artist=Various, path=/home/kae/m[...]
     <Track(id=2332, title=Such Great Heights - Remastered, artis[...]]

    glue = PlaylistTracks(row=5)

    tr = session.query(Tracks).filter(Tracks.id == 676).one()

    tr
    <Track(id=676, title=Seven Nation Army, artist=White Stripes,
    path=/home/kae/music/White Stripes/Elephant/01. Seven Nation Army.flac>

    glue.track_id = tr.id

    pl.tracks.append(glue)

    session.commit()

    [a.tracks for a in pl.tracks]
    [<Track(id=3992, title=Yesterday Man, artist=Various, path=/h[...]
     <Track(id=2238, title=These Boots Are Made For Walkin', arti[...]
     <Track(id=3837, title=Babe, artist=Various, path=/home/kae/m[...]
     <Track(id=2332, title=Such Great Heights - Remastered, artis[...]
     <Track(id=676, title=Seven Nation Army, artist=White Stripes[...]]
    """

    __tablename__ = "playlists"

    id = Column(Integer, primary_key=True, autoincrement=True)
    name = Column(String(32), nullable=False, unique=True)
    notes = relationship("Notes",
                         order_by="Notes.row",
                         back_populates="playlist")
    tracks = relationship("PlaylistTracks",
                          order_by="PlaylistTracks.row",
                          back_populates="playlists")

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

    @staticmethod
    def new(name):
        DEBUG(f"Playlists.new(name={name})")
        pl = Playlists()
        pl.name = name
        session.add(pl)
        session.commit()
        return pl.id

    @staticmethod
    def get_all_playlists():
        "Returns a list of (id, name) of all playlists"

        return session.query(Playlists).all()

    @classmethod
    def get_playlist_by_id(cls, plid):
        "Returns a playlist object for playlist id"

        return session.query(Playlists).filter(Playlists.id == plid).one()

    def add_track(self, track, row):
        glue = PlaylistTracks(row=row)
        glue.track_id = track.id
        self.tracks.append(glue)

    def get_notes(self):
        return [a.note for a in self.notes]

    def get_tracks(self):
        return [a.tracks for a in self.tracks]


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")

    @staticmethod
    def new_row(playlist_id):
        "Return row number > largest existing row number"

        last_row = session.query(func.max(PlaylistTracks.row)).one()[0]
        return last_row + 1

    @staticmethod
    def remove_track(playlist_id, track_id):
        DEBUG(f"remove_track(playlist_id={playlist_id}, track_id={track_id})")
        session.query(PlaylistTracks).filter(
            PlaylistTracks.playlist_id == playlist_id,
            PlaylistTracks.track_id == track_id
        ).delete()

    @staticmethod
    def update_track_row(playlist_id, track_id, old_row, new_row):
        DEBUG(
            f"update_track_row(playlist_id={playlist_id}, "
            f"track_id={track_id}, old_row={old_row}, new_row={new_row})"
        )

        plt = session.query(PlaylistTracks).filter(
            PlaylistTracks.playlist_id == playlist_id,
            PlaylistTracks.track_id == track_id,
            PlaylistTracks.row == old_row
        ).one()
        plt.row = new_row
        session.commit()

    @staticmethod
    def remove_track(playlist_id, track_id):
        DEBUG(f"remove_track({playlist_id}, {track_id})")
        session.query(PlaylistTracks).filter(
            PlaylistTracks.playlist_id == playlist_id,
            PlaylistTracks.track_id == track_id
        ).delete()


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

    @classmethod
    def get_or_create(cls, path):
        DEBUG(f"Tracks.get_or_create(path={path})")
        try:
            track = session.query(cls).filter(cls.path == path).one()
        except NoResultFound:
            track = Tracks()
            track.path = path
            session.add(track)
        return track

    @staticmethod
    def get_duration(id):
        try:
            return session.query(
                Tracks.duration).filter(Tracks.id == id).one()[0]
        except NoResultFound:
            ERROR(f"Can't find track id {id}")
            return None

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

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

    @staticmethod
    def get_path(id):
        try:
            return session.query(Tracks.path).filter(Tracks.id == id).one()[0]
        except NoResultFound:
            ERROR(f"Can't find track id {id}")
            return None

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

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

    @staticmethod
    def track_from_id(id):
        return session.query(Tracks).filter(
            Tracks.id == id).one()

    def update_lastplayed(self):
        self.lastplayed = datetime.now()