from datetime import datetime, timedelta, timezone

from sqlalchemy import select
from sqlalchemy.orm import Session

from app.config import get_settings
from app.db.base import SessionLocal
from app.db.models import ChatSession, FitnessReminder, Message
from app.fitness.service import FitnessService

KIND_LABELS = {
    "water": "Вода",
    "meal": "Еда",
    "workout": "Тренировка",
    "weigh_in": "Взвешивание",
}


def _post_fitness_notice(content: str) -> None:
    db = SessionLocal()
    try:
        session = db.scalar(
            select(ChatSession).order_by(ChatSession.updated_at.desc()).limit(1)
        )
        if not session:
            session = ChatSession(title="Фитнес")
            db.add(session)
            db.commit()
            db.refresh(session)
        db.add(Message(session_id=session.id, role="notice", content=content))
        db.commit()
    finally:
        db.close()


def _build_notice(kind: str, summary: dict) -> str:
    label = KIND_LABELS.get(kind, kind)
    totals = summary.get("totals") or {}
    targets = summary.get("targets") or {}
    water_l = totals.get("water_ml", 0) / 1000
    water_target = targets.get("water_ml", 2500) / 1000
    cals = totals.get("calories", 0)
    cal_target = targets.get("calories", 2000)

    if kind == "water":
        return (
            f"💪 **{label}** · выпито {water_l:.1f}/{water_target:.1f} л сегодня. "
            "Пора выпить стакан воды."
        )
    if kind == "meal":
        return (
            f"💪 **{label}** · {cals:.0f}/{cal_target:.0f} ккал за день. "
            "Не забудь залогировать приём пищи."
        )
    if kind == "workout":
        workouts = summary.get("workouts") or []
        if workouts:
            return f"💪 **{label}** · сегодня уже была тренировка. Отдыхай или лёгкая активность."
        return "💪 **Тренировка** · запланирована на сегодня. Время двигаться!"
    if kind == "weigh_in":
        return "💪 **Взвешивание** · пора записать вес (log_weight)."
    return f"💪 **{label}** · напоминание"


def check_reminders(db: Session) -> list[str]:
    if not get_settings().fitness_reminders_enabled:
        return []

    now = datetime.now(timezone.utc)
    service = FitnessService(db)
    summary = service.get_daily_summary()
    fired: list[str] = []

    reminders = db.scalars(
        select(FitnessReminder).where(FitnessReminder.enabled.is_(True))
    ).all()

    for rem in reminders:
        should_fire = False

        if rem.interval_hours:
            if rem.last_fired_at is None:
                should_fire = now.hour >= rem.hour
            else:
                delta = now - rem.last_fired_at.replace(tzinfo=timezone.utc)
                should_fire = delta >= timedelta(hours=rem.interval_hours)
        else:
            if rem.kind == "weigh_in":
                if rem.last_fired_at:
                    delta = now - rem.last_fired_at.replace(tzinfo=timezone.utc)
                    should_fire = delta >= timedelta(days=7)
                else:
                    should_fire = now.hour == rem.hour and now.minute >= rem.minute
            else:
                if rem.last_fired_at:
                    last = rem.last_fired_at.replace(tzinfo=timezone.utc)
                    already_today = last.date() == now.date()
                    if already_today:
                        continue
                should_fire = now.hour == rem.hour and now.minute >= rem.minute

        if not should_fire:
            continue

        notice = _build_notice(rem.kind, summary)
        rem.last_fired_at = now
        fired.append(notice)

    if fired:
        db.commit()
        for notice in fired:
            _post_fitness_notice(notice)

    return fired