models.py

"""
models.py — BookClub

SQLAlchemy models for all database entities.
"""

import uuid
from datetime import datetime, timezone
from extensions import db


def generate_uuid():
    return str(uuid.uuid4())


class User(db.Model):
    """A BookClub member."""

    id = db.Column(db.String(36), primary_key=True, default=generate_uuid)
    username = db.Column(db.String(64), unique=True, nullable=False)
    email = db.Column(db.String(120), unique=True, nullable=False)
    reading_streak = db.Column(db.Integer, default=0)
    last_finished_at = db.Column(db.DateTime, nullable=True)
    joined_at = db.Column(db.DateTime, default=lambda: datetime.now(timezone.utc))

    # Relationships
    reading_events = db.relationship("ReadingEvent", backref="reader", lazy=True)
    added_books = db.relationship("Book", backref="added_by_user", lazy=True)

    def to_dict(self):
        return {
            "id": self.id,
            "username": self.username,
            "reading_streak": self.reading_streak,
            "last_finished_at": (
                self.last_finished_at.isoformat() if self.last_finished_at else None
            ),
        }


class Book(db.Model):
    """A book in the shared reading list."""

    id = db.Column(db.String(36), primary_key=True, default=generate_uuid)
    title = db.Column(db.String(200), nullable=False)
    author = db.Column(db.String(200), nullable=False)
    pages = db.Column(db.Integer, nullable=False)
    genre = db.Column(db.String(100), nullable=True)
    added_by = db.Column(db.String(36), db.ForeignKey("user.id"), nullable=False)
    added_at = db.Column(db.DateTime, default=lambda: datetime.now(timezone.utc))

    reading_events = db.relationship("ReadingEvent", backref="book", lazy=True)

    def to_dict(self):
        return {
            "id": self.id,
            "title": self.title,
            "author": self.author,
            "pages": self.pages,
            "genre": self.genre,
            "added_by": self.added_by,
            "added_at": self.added_at.isoformat(),
        }


class ReadingEvent(db.Model):
    """
    Records a user's interaction with a book.

    started_at  — when the user began reading (always set)
    finished_at — when the user marked the book as finished (None if still reading)
    """

    id = db.Column(db.String(36), primary_key=True, default=generate_uuid)
    user_id = db.Column(db.String(36), db.ForeignKey("user.id"), nullable=False)
    book_id = db.Column(db.String(36), db.ForeignKey("book.id"), nullable=False)
    started_at = db.Column(
        db.DateTime, nullable=False, default=lambda: datetime.now(timezone.utc)
    )
    finished_at = db.Column(db.DateTime, nullable=True)

    __table_args__ = (
        db.UniqueConstraint("user_id", "book_id", name="unique_user_book"),
    )

    def to_dict(self):
        return {
            "id": self.id,
            "user_id": self.user_id,
            "book_id": self.book_id,
            "started_at": self.started_at.isoformat(),
            "finished_at": self.finished_at.isoformat() if self.finished_at else None,
        }