from __future__ import annotations

import enum
from datetime import datetime

from sqlalchemy import Boolean, Column, DateTime, Enum, ForeignKey, Integer, String, Text
from sqlalchemy.orm import relationship

from app.db.base_class import Base


class DifficultyLevel(enum.Enum):
    EASY = "easy"
    MEDIUM = "medium"
    HARD = "hard"


class Subject(Base):
    """
    Subject model representing a learning area (e.g., Math, Science, Language).
    """

    id = Column(Integer, primary_key=True, index=True)
    name = Column(String, index=True, nullable=False)
    description = Column(Text, nullable=True)
    image_url = Column(String, nullable=True)
    order = Column(Integer, default=0)
    is_active = Column(Boolean, default=True)
    created_at = Column(DateTime, default=datetime.utcnow)
    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)

    # Relationships
    lessons = relationship("Lesson", back_populates="subject", cascade="all, delete-orphan")


class Lesson(Base):
    """
    Lesson model representing a specific learning unit within a subject.
    """

    id = Column(Integer, primary_key=True, index=True)
    subject_id = Column(Integer, ForeignKey("subject.id"), nullable=False)
    title = Column(String, index=True, nullable=False)
    description = Column(Text, nullable=True)
    content = Column(Text, nullable=False)
    image_url = Column(String, nullable=True)
    order = Column(Integer, default=0)
    difficulty = Column(Enum(DifficultyLevel), default=DifficultyLevel.EASY)
    points = Column(Integer, default=10)  # Points awarded for completing the lesson
    duration_minutes = Column(Integer, default=15)  # Estimated time to complete the lesson
    is_active = Column(Boolean, default=True)
    created_at = Column(DateTime, default=datetime.utcnow)
    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)

    # Relationships
    subject = relationship("Subject", back_populates="lessons")
    quizzes = relationship("Quiz", back_populates="lesson", cascade="all, delete-orphan")
    progress = relationship("UserProgress", back_populates="lesson")


class Quiz(Base):
    """
    Quiz model representing a set of questions related to a lesson.
    """

    id = Column(Integer, primary_key=True, index=True)
    lesson_id = Column(Integer, ForeignKey("lesson.id"), nullable=False)
    title = Column(String, index=True, nullable=False)
    description = Column(Text, nullable=True)
    time_limit_minutes = Column(Integer, default=10)  # Time limit to complete the quiz
    pass_percentage = Column(Integer, default=70)  # Percentage required to pass
    points = Column(Integer, default=20)  # Points awarded for passing the quiz
    is_active = Column(Boolean, default=True)
    created_at = Column(DateTime, default=datetime.utcnow)
    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)

    # Relationships
    lesson = relationship("Lesson", back_populates="quizzes")
    questions = relationship("Question", back_populates="quiz", cascade="all, delete-orphan")


class Question(Base):
    """
    Question model representing a single quiz question.
    """

    id = Column(Integer, primary_key=True, index=True)
    quiz_id = Column(Integer, ForeignKey("quiz.id"), nullable=False)
    text = Column(Text, nullable=False)
    image_url = Column(String, nullable=True)
    explanation = Column(Text, nullable=True)  # Explanation of the correct answer
    points = Column(Integer, default=5)  # Points for this question
    order = Column(Integer, default=0)
    is_active = Column(Boolean, default=True)
    created_at = Column(DateTime, default=datetime.utcnow)
    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)

    # Relationships
    quiz = relationship("Quiz", back_populates="questions")
    answers = relationship("Answer", back_populates="question", cascade="all, delete-orphan")
    user_answers = relationship("UserAnswer", back_populates="question")


class Answer(Base):
    """
    Answer model representing a possible answer to a question.
    """

    id = Column(Integer, primary_key=True, index=True)
    question_id = Column(Integer, ForeignKey("question.id"), nullable=False)
    text = Column(Text, nullable=False)
    is_correct = Column(Boolean, default=False)
    explanation = Column(Text, nullable=True)
    order = Column(Integer, default=0)
    created_at = Column(DateTime, default=datetime.utcnow)
    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)

    # Relationships
    question = relationship("Question", back_populates="answers")
    user_answers = relationship("UserAnswer", back_populates="answer")