import enum
from datetime import datetime, time

from sqlalchemy import Enum, ForeignKey, Integer, SmallInteger, String, Time
from sqlalchemy.orm import Mapped, mapped_column, relationship
from sqlalchemy.sql import func

from app.database import Base

ALL_WEEKDAYS_MASK = 0b1111111  # 월~일 전부 (bit0=월 ... bit6=일)


class HabitType(str, enum.Enum):
    BUILD = "build"  # 만들고 싶은 습관
    QUIT = "quit"  # 멈추고 싶은 습관


class HabitStatus(str, enum.Enum):
    ACTIVE = "active"
    COMPLETED = "completed"


class Habit(Base):
    __tablename__ = "habit"

    id: Mapped[int] = mapped_column(Integer, primary_key=True)
    user_id: Mapped[int | None] = mapped_column(
        ForeignKey("user.id", ondelete="CASCADE"), nullable=True
    )
    name: Mapped[str] = mapped_column(String(200), nullable=False)
    habit_type: Mapped[HabitType] = mapped_column(Enum(HabitType, native_enum=False, length=20), nullable=False)
    status: Mapped[HabitStatus] = mapped_column(
        Enum(HabitStatus, native_enum=False, length=20), nullable=False, default=HabitStatus.ACTIVE
    )
    weekdays_mask: Mapped[int] = mapped_column(SmallInteger, nullable=False, default=ALL_WEEKDAYS_MASK)
    condition_text: Mapped[str | None] = mapped_column(String(300), nullable=True)
    reminder_time: Mapped[time | None] = mapped_column(Time, nullable=True)
    sort_order: Mapped[int | None] = mapped_column(Integer, nullable=True)
    created_at: Mapped[datetime] = mapped_column(server_default=func.now(), nullable=False)
    completed_at: Mapped[datetime | None] = mapped_column(nullable=True)

    logs: Mapped[list["HabitLog"]] = relationship(
        back_populates="habit", cascade="all, delete-orphan", passive_deletes=True
    )

    def is_scheduled_on(self, weekday: int) -> bool:
        """weekday: Python date.weekday() 기준 (월=0 ... 일=6)"""
        return bool(self.weekdays_mask & (1 << weekday))