from __future__ import annotations

from datetime import datetime
from typing import List, Optional

from sqlalchemy import (
    Boolean,
    DateTime,
    ForeignKey,
    Integer,
    String,
    Text,
    func,
)
from sqlalchemy.orm import Mapped, Session, mapped_column, relationship

from bot.models.database import Base


class Reminder(Base):
    __tablename__ = "reminders"

    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
    user_id: Mapped[int] = mapped_column(Integer, ForeignKey("users.id"), nullable=False)

    title: Mapped[str] = mapped_column(String(256), nullable=False)
    description: Mapped[Optional[str]] = mapped_column(Text)

    # once / daily / weekly / monthly / interval
    reminder_type: Mapped[str] = mapped_column(String(32), nullable=False)

    once_time: Mapped[Optional[datetime]] = mapped_column(DateTime(timezone=True))
    daily_time: Mapped[Optional[str]] = mapped_column(String(5))   # "HH:MM"
    weekly_days: Mapped[Optional[str]] = mapped_column(String(32)) # "0,1,2" (Mon=0)
    monthly_day: Mapped[Optional[int]] = mapped_column(Integer)
    interval_minutes: Mapped[Optional[int]] = mapped_column(Integer)
    interval_start_time: Mapped[Optional[str]] = mapped_column(String(5))  # "HH:MM"
    interval_end_time: Mapped[Optional[str]] = mapped_column(String(5))    # "HH:MM"

    skip_holidays: Mapped[bool] = mapped_column(Boolean, default=False)
    is_active: Mapped[bool] = mapped_column(Boolean, default=True)

    last_sent_at: Mapped[Optional[datetime]] = mapped_column(DateTime(timezone=True))
    next_run_at: Mapped[Optional[datetime]] = mapped_column(DateTime(timezone=True))

    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), server_default=func.now()
    )
    updated_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), server_default=func.now(), onupdate=func.now()
    )

    logs: Mapped[List["ReminderLog"]] = relationship(
        "ReminderLog", back_populates="reminder", cascade="all, delete-orphan"
    )

    @classmethod
    def get_active(cls, session: Session) -> List["Reminder"]:
        return session.query(cls).filter_by(is_active=True).all()

    @classmethod
    def get_user_reminders(cls, session: Session, user_id: int) -> List["Reminder"]:
        return session.query(cls).filter_by(user_id=user_id).order_by(cls.created_at).all()

    def type_display(self) -> str:
        mapping = {
            "once": "一次性",
            "daily": "每日",
            "weekly": "每周",
            "monthly": "每月",
            "interval": "间隔",
        }
        return mapping.get(self.reminder_type, self.reminder_type)

    def schedule_summary(self) -> str:
        if self.reminder_type == "once" and self.once_time:
            return self.once_time.strftime("%Y-%m-%d %H:%M")
        if self.reminder_type == "daily" and self.daily_time:
            return f"每天 {self.daily_time}"
        if self.reminder_type == "weekly" and self.weekly_days and self.daily_time:
            day_names = ["周一", "周二", "周三", "周四", "周五", "周六", "周日"]
            days = ", ".join(day_names[int(d)] for d in self.weekly_days.split(","))
            return f"{days} {self.daily_time}"
        if self.reminder_type == "interval" and self.interval_minutes:
            return (
                f"每 {self.interval_minutes} 分钟"
                f"（{self.interval_start_time}–{self.interval_end_time}）"
            )
        return "—"


class ReminderLog(Base):
    __tablename__ = "reminder_logs"

    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
    reminder_id: Mapped[int] = mapped_column(
        Integer, ForeignKey("reminders.id"), nullable=False
    )
    sent_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), server_default=func.now()
    )
    # sent / snoozed / completed / failed
    status: Mapped[str] = mapped_column(String(32), default="sent")

    reminder: Mapped["Reminder"] = relationship("Reminder", back_populates="logs")