import uuid
from datetime import datetime

from flask_login import UserMixin
from werkzeug.security import check_password_hash, generate_password_hash

from .extensions import db


class Company(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(120), unique=True, nullable=False)
    created_at = db.Column(db.DateTime, default=datetime.utcnow, nullable=False)

    users = db.relationship("User", back_populates="company", cascade="all, delete-orphan")
    displays = db.relationship("Display", back_populates="company", cascade="all, delete-orphan")
    playlists = db.relationship("Playlist", back_populates="company", cascade="all, delete-orphan")


class User(UserMixin, db.Model):
    id = db.Column(db.Integer, primary_key=True)
    username = db.Column(db.String(80), unique=True, nullable=False)
    email = db.Column(db.String(255), unique=True, nullable=True)
    password_hash = db.Column(db.String(255), nullable=True)
    is_admin = db.Column(db.Boolean, default=False, nullable=False)

    company_id = db.Column(db.Integer, db.ForeignKey("company.id"), nullable=True)
    company = db.relationship("Company", back_populates="users")

    created_at = db.Column(db.DateTime, default=datetime.utcnow, nullable=False)

    def set_password(self, password: str):
        self.password_hash = generate_password_hash(password)

    def check_password(self, password: str) -> bool:
        if not self.password_hash:
            return False
        return check_password_hash(self.password_hash, password)


class Playlist(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    company_id = db.Column(db.Integer, db.ForeignKey("company.id"), nullable=False)
    name = db.Column(db.String(120), nullable=False)
    created_at = db.Column(db.DateTime, default=datetime.utcnow, nullable=False)

    company = db.relationship("Company", back_populates="playlists")
    items = db.relationship(
        "PlaylistItem",
        back_populates="playlist",
        cascade="all, delete-orphan",
        order_by="PlaylistItem.position.asc()",
    )


class PlaylistItem(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    playlist_id = db.Column(db.Integer, db.ForeignKey("playlist.id"), nullable=False)

    # image|video|webpage
    item_type = db.Column(db.String(20), nullable=False)
    title = db.Column(db.String(200), nullable=True)

    # For image/video: stored under /static/uploads
    file_path = db.Column(db.String(400), nullable=True)
    # For webpage
    url = db.Column(db.String(1000), nullable=True)

    # For image/webpage duration (seconds). For video we play until ended.
    duration_seconds = db.Column(db.Integer, default=10, nullable=False)
    position = db.Column(db.Integer, default=0, nullable=False)

    created_at = db.Column(db.DateTime, default=datetime.utcnow, nullable=False)

    playlist = db.relationship("Playlist", back_populates="items")


class Display(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    company_id = db.Column(db.Integer, db.ForeignKey("company.id"), nullable=False)
    name = db.Column(db.String(120), nullable=False)
    token = db.Column(db.String(64), unique=True, nullable=False, default=lambda: uuid.uuid4().hex)

    assigned_playlist_id = db.Column(db.Integer, db.ForeignKey("playlist.id"), nullable=True)
    assigned_playlist = db.relationship("Playlist")

    created_at = db.Column(db.DateTime, default=datetime.utcnow, nullable=False)

    company = db.relationship("Company", back_populates="displays")


class DisplaySession(db.Model):
    """Tracks active viewers of a display token so we can limit concurrent usage."""

    id = db.Column(db.Integer, primary_key=True)
    display_id = db.Column(db.Integer, db.ForeignKey("display.id"), nullable=False, index=True)
    sid = db.Column(db.String(64), nullable=False)

    created_at = db.Column(db.DateTime, default=datetime.utcnow, nullable=False)
    last_seen_at = db.Column(db.DateTime, default=datetime.utcnow, nullable=False, index=True)

    # Optional diagnostics
    ip = db.Column(db.String(64), nullable=True)
    user_agent = db.Column(db.String(300), nullable=True)

    display = db.relationship("Display")

    __table_args__ = (db.UniqueConstraint("display_id", "sid", name="uq_display_session_display_sid"),)