"""Playlist model for managing content collections."""
from datetime import datetime
from typing import List, Optional

from app.extensions import db


# Association table for many-to-many relationship between playlists and content
playlist_content = db.Table('playlist_content',
    db.Column('playlist_id', db.Integer, db.ForeignKey('playlist.id', ondelete='CASCADE'), primary_key=True),
    db.Column('content_id', db.Integer, db.ForeignKey('content.id', ondelete='CASCADE'), primary_key=True),
    db.Column('position', db.Integer, default=0),
    db.Column('duration', db.Integer, default=10),
    db.Column('muted', db.Boolean, default=True),
    db.Column('edit_on_player_enabled', db.Boolean, default=False)
)


class Playlist(db.Model):
    """Playlist model representing a collection of content.
    
    Attributes:
        id: Primary key
        name: Unique playlist name
        description: Optional playlist description
        version: Version number for synchronization
        is_active: Whether playlist is active
        created_at: Playlist creation timestamp
        updated_at: Last modification timestamp
    """
    __tablename__ = 'playlist'
    
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(100), nullable=False, unique=True, index=True)
    description = db.Column(db.Text, nullable=True)
    orientation = db.Column(db.String(20), default='Landscape', nullable=False)
    version = db.Column(db.Integer, default=1, nullable=False)
    is_active = db.Column(db.Boolean, default=True, nullable=False)
    created_at = db.Column(db.DateTime, default=datetime.utcnow, nullable=False)
    updated_at = db.Column(db.DateTime, default=datetime.utcnow, 
                          onupdate=datetime.utcnow, nullable=False)
    
    # Relationships
    players = db.relationship('Player', back_populates='playlist', lazy='dynamic')
    contents = db.relationship('Content', secondary=playlist_content, 
                              back_populates='playlists', lazy='dynamic')
    
    def __repr__(self) -> str:
        """String representation of Playlist."""
        return f'<Playlist {self.name} (ID={self.id}, Version={self.version})>'
    
    @property
    def player_count(self) -> int:
        """Get number of players assigned to this playlist."""
        return self.players.count()
    
    @property
    def content_count(self) -> int:
        """Get number of content items in this playlist."""
        return self.contents.count()
    
    @property
    def total_duration(self) -> int:
        """Calculate total duration of all content in seconds."""
        total = 0
        for content in self.contents:
            total += content.duration or 10
        return total
    
    def increment_version(self) -> None:
        """Increment playlist version for sync detection."""
        self.version += 1
        self.updated_at = datetime.utcnow()
    
    def get_content_ordered(self) -> List:
        """Get content items ordered by position."""
        # Query through association table to get position
        from sqlalchemy import select
        stmt = select(playlist_content.c.content_id, 
                     playlist_content.c.position,
                     playlist_content.c.duration,
                     playlist_content.c.muted,
                     playlist_content.c.edit_on_player_enabled).where(
            playlist_content.c.playlist_id == self.id
        ).order_by(playlist_content.c.position)
        
        results = db.session.execute(stmt).fetchall()
        
        ordered_content = []
        for row in results:
            content = db.session.get(Content, row.content_id)
            if content:
                content._playlist_position = row.position
                content._playlist_duration = row.duration
                content._playlist_muted = row.muted if len(row) > 3 else True
                content._playlist_edit_on_player_enabled = row.edit_on_player_enabled if len(row) > 4 else False
                ordered_content.append(content)
        
        return ordered_content


# Import Content here to avoid circular import
from app.models.content import Content