app/models/course.py

"""Course and Module models for content organization."""

from datetime import datetime
from enum import Enum as PyEnum
from sqlalchemy import Column, String, Boolean, DateTime, Enum, Text, Integer, ForeignKey
from sqlalchemy.orm import relationship
from uuid import uuid4
from app.database import Base


class ContentType(str, PyEnum):
    PDF = "pdf"
    VIDEO = "video"
    MARKDOWN = "markdown"
    QUIZ = "quiz"
    EXTERNAL_LINK = "external_link"


class DifficultyLevel(str, PyEnum):
    BEGINNER = "beginner"
    INTERMEDIATE = "intermediate"
    ADVANCED = "advanced"


class Course(Base):
    __tablename__ = "courses"

    id = Column(String(36), primary_key=True, default=lambda: str(uuid4()))
    title = Column(String(255), nullable=False)
    slug = Column(String(255), unique=True, nullable=False, index=True)
    description = Column(Text, nullable=True)
    thumbnail_url = Column(String(500), nullable=True)
    difficulty = Column(Enum(DifficultyLevel), default=DifficultyLevel.BEGINNER)
    is_published = Column(Boolean, default=False)
    is_featured = Column(Boolean, default=False)
    estimated_hours = Column(Integer, default=0)
    order_index = Column(Integer, default=0)

    # Creator
    created_by = Column(String(36), ForeignKey("users.id"), nullable=True)

    # Timestamps
    created_at = Column(DateTime, default=datetime.utcnow)
    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)

    # Relationships
    modules = relationship("Module", back_populates="course", cascade="all, delete-orphan", order_by="Module.order_index")
    enrollments = relationship("Enrollment", back_populates="course", cascade="all, delete-orphan")

    def __repr__(self):
        return f"<Course {self.title}>"


class Module(Base):
    __tablename__ = "modules"

    id = Column(String(36), primary_key=True, default=lambda: str(uuid4()))
    course_id = Column(String(36), ForeignKey("courses.id"), nullable=False)
    title = Column(String(255), nullable=False)
    description = Column(Text, nullable=True)
    order_index = Column(Integer, default=0)
    is_published = Column(Boolean, default=False)

    # Unlock requirements
    prerequisite_module_id = Column(String(36), ForeignKey("modules.id"), nullable=True)

    # Timestamps
    created_at = Column(DateTime, default=datetime.utcnow)
    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)

    # Relationships
    course = relationship("Course", back_populates="modules")
    lessons = relationship("Lesson", back_populates="module", cascade="all, delete-orphan", order_by="Lesson.order_index")
    prerequisite = relationship("Module", remote_side="Module.id")

    def __repr__(self):
        return f"<Module {self.title}>"


class Lesson(Base):
    __tablename__ = "lessons"

    id = Column(String(36), primary_key=True, default=lambda: str(uuid4()))
    module_id = Column(String(36), ForeignKey("modules.id"), nullable=False)
    title = Column(String(255), nullable=False)
    description = Column(Text, nullable=True)
    content_type = Column(Enum(ContentType), nullable=False)
    content_url = Column(String(500), nullable=True)  # File URL or external link
    content_text = Column(Text, nullable=True)  # For markdown content
    duration_minutes = Column(Integer, default=0)
    order_index = Column(Integer, default=0)
    is_published = Column(Boolean, default=False)

    # Vector store reference
    vector_namespace = Column(String(255), nullable=True)

    # Timestamps
    created_at = Column(DateTime, default=datetime.utcnow)
    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)

    # Relationships
    module = relationship("Module", back_populates="lessons")
    progress_records = relationship("Progress", back_populates="lesson", cascade="all, delete-orphan")
    quizzes = relationship("Quiz", back_populates="lesson", cascade="all, delete-orphan")

    def __repr__(self):
        return f"<Lesson {self.title}>"