import enum
from datetime import datetime, timezone

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

from database import Base


class MicroStepStatus(enum.Enum):
    pending = "pending"
    in_progress = "in_progress"
    completed = "completed"
    skipped = "skipped"


class Subject(Base):
    __tablename__ = "subjects"

    id = Column(Integer, primary_key=True, index=True)
    name = Column(String(200), nullable=False)
    semester = Column(String(50))
    is_active = Column(Boolean, default=True)
    is_parked = Column(Boolean, default=False)
    created_at = Column(DateTime, default=lambda: datetime.now(timezone.utc).replace(tzinfo=None))

    deadlines = relationship("Deadline", back_populates="subject", cascade="all, delete-orphan")
    study_sessions = relationship("StudySession", back_populates="subject", cascade="all, delete-orphan")


class Deadline(Base):
    __tablename__ = "deadlines"

    id = Column(Integer, primary_key=True, index=True)
    subject_id = Column(Integer, ForeignKey("subjects.id"), nullable=False)
    title = Column(String(200), nullable=False)
    description = Column(Text)
    due_date = Column(DateTime, nullable=False)
    created_at = Column(DateTime, default=lambda: datetime.now(timezone.utc).replace(tzinfo=None))

    subject = relationship("Subject", back_populates="deadlines")
    micro_steps = relationship("MicroStep", back_populates="deadline", cascade="all, delete-orphan")


class MicroStep(Base):
    __tablename__ = "micro_steps"

    id = Column(Integer, primary_key=True, index=True)
    deadline_id = Column(Integer, ForeignKey("deadlines.id"), nullable=False)
    title = Column(String(300), nullable=False)
    context = Column(Text)  # what exactly to do — fresh-start framing
    order_num = Column(Integer, default=0)
    duration_minutes = Column(Integer, default=5)
    status = Column(Enum(MicroStepStatus), default=MicroStepStatus.pending)
    created_at = Column(DateTime, default=lambda: datetime.now(timezone.utc).replace(tzinfo=None))

    deadline = relationship("Deadline", back_populates="micro_steps")


class StudySession(Base):
    __tablename__ = "study_sessions"

    id = Column(Integer, primary_key=True, index=True)
    subject_id = Column(Integer, ForeignKey("subjects.id"), nullable=False)
    started_at = Column(DateTime, default=lambda: datetime.now(timezone.utc).replace(tzinfo=None))
    ended_at = Column(DateTime)
    steps_completed = Column(Integer, default=0)
    notes = Column(Text)

    subject = relationship("Subject", back_populates="study_sessions")