import asyncio
import logging
from dataclasses import dataclass
from datetime import date, datetime, time as datetime_time, timedelta, timezone
from enum import Enum
from html import escape
from typing import Dict, List, Optional, Tuple

from zoneinfo import ZoneInfo

from aiogram import Bot
from aiogram.exceptions import TelegramBadRequest, TelegramForbiddenError
from sqlalchemy import cast, func, not_, or_, select
from sqlalchemy.dialects.postgresql import JSONB
from sqlalchemy.sql import false, true

from app.config import settings
from app.database.crud.subscription import get_subscriptions_statistics
from app.database.database import AsyncSessionLocal
from app.database.models import (
    PaymentMethod,
    Subscription,
    SubscriptionConversion,
    SubscriptionStatus,
    Ticket,
    TicketStatus,
    Transaction,
    TransactionType,
    User,
)


logger = logging.getLogger(__name__)


class ReportingServiceError(RuntimeError):
    """Base error for the reporting service."""


class ReportPeriod(Enum):
    DAILY = "daily"
    WEEKLY = "weekly"
    MONTHLY = "monthly"


@dataclass(slots=True)
class ReportPeriodRange:
    start_msk: datetime
    end_msk: datetime
    label: str


class ReportingService:
    """Generates admin summary reports (text only, no charts)."""

    def __init__(self) -> None:
        self.bot: Optional[Bot] = None
        self._task: Optional[asyncio.Task] = None
        self._moscow_tz = ZoneInfo("Europe/Moscow")

    def set_bot(self, bot: Bot) -> None:
        self.bot = bot

    def is_running(self) -> bool:
        return self._task is not None and not self._task.done()

    async def start(self) -> None:
        await self.stop()

        if not settings.ADMIN_REPORTS_ENABLED:
            logger.info("Сервис отчетов отключен настройками")
            return

        if not self.bot:
            logger.warning("Невозможно запустить сервис отчетов без экземпляра бота")
            return

        chat_id = settings.get_reports_chat_id()
        if not chat_id:
            logger.warning("Сервис отчетов не запущен: не указан чат для отправки отчетов")
            return

        send_time = settings.get_reports_send_time()
        if not send_time:
            logger.warning("Сервис отчетов не запущен: не указано время ежедневной отправки")
            return

        self._task = asyncio.create_task(self._auto_daily_loop(send_time))
        logger.info(
            "📊 Сервис отчетов запущен: ежедневная отправка в %s по МСК",
            send_time.strftime("%H:%M"),
        )

    async def stop(self) -> None:
        if self._task and not self._task.done():
            self._task.cancel()
            try:
                await self._task
            except asyncio.CancelledError:
                pass
        self._task = None

    async def send_report(
        self,
        period: ReportPeriod,
        *,
        report_date: Optional[date] = None,
        send_to_topic: bool = False,
    ) -> str:
        report_text = await self._build_report(period, report_date)

        if send_to_topic:
            await self._deliver_report(report_text)

        return report_text

    async def _auto_daily_loop(self, send_time: datetime_time) -> None:
        try:
            next_run_utc, report_date = self._calculate_next_run(send_time)

            while True:
                now_utc = datetime.now(timezone.utc)
                delay = (next_run_utc - now_utc).total_seconds()

                if delay > 0:
                    await asyncio.sleep(delay)

                try:
                    await self.send_report(
                        ReportPeriod.DAILY,
                        report_date=report_date,
                        send_to_topic=True,
                    )
                    logger.info(
                        "📊 Автоматический отчет за %s отправлен",
                        report_date.strftime("%d.%m.%Y"),
                    )
                except asyncio.CancelledError:
                    raise
                except Exception as exc:  # noqa: BLE001
                    logger.error("Ошибка автоматической отправки отчета: %s", exc)

                next_run_utc, report_date = self._calculate_next_run(send_time)

        except asyncio.CancelledError:
            logger.info("Сервис отчетов остановлен")
            raise
        except Exception as exc:  # noqa: BLE001
            logger.error("Критическая ошибка в сервисе отчетов: %s", exc)

    def _calculate_next_run(
        self,
        send_time: datetime_time,
    ) -> Tuple[datetime, date]:
        now_msk = datetime.now(self._moscow_tz)
        candidate = datetime.combine(now_msk.date(), send_time, tzinfo=self._moscow_tz)

        if now_msk >= candidate:
            candidate += timedelta(days=1)

        report_date = (candidate - timedelta(days=1)).date()
        return candidate.astimezone(timezone.utc), report_date

    async def _deliver_report(self, report_text: str) -> None:
        if not self.bot:
            raise ReportingServiceError("Бот не инициализирован для отправки отчета")

        chat_id = settings.get_reports_chat_id()
        if not chat_id:
            raise ReportingServiceError("Не задан чат для отправки отчета")

        topic_id = settings.get_reports_topic_id()

        try:
            await self.bot.send_message(
                chat_id=chat_id,
                text=report_text,
                message_thread_id=topic_id,
                parse_mode="HTML",
            )
        except (TelegramBadRequest, TelegramForbiddenError) as exc:
            logger.error("Не удалось отправить отчет: %s", exc)
            raise ReportingServiceError("Не удалось отправить отчет в чат") from exc

    # ---------- referral helpers ----------

    def _referral_markers(self) -> List:
        """
        Набор условий, по которым операция помечается как реферальная (если вдруг записана типом DEPOSIT).
        """
        clauses = []

        # Явные флаги
        if hasattr(Transaction, "is_referral_bonus"):
            clauses.append(Transaction.is_referral_bonus == true())
        if hasattr(Transaction, "is_bonus"):
            clauses.append(Transaction.is_bonus == true())

        # Источник/причина
        if hasattr(Transaction, "source"):
            clauses.append(Transaction.source == "referral")
            clauses.append(Transaction.source == "referral_bonus")
        if hasattr(Transaction, "reason"):
            clauses.append(Transaction.reason == "referral")
            clauses.append(Transaction.reason == "referral_bonus")
            clauses.append(Transaction.reason == "referral_reward")

        # Текстовые поля
        like_patterns = ["%реферал%", "%реферальн%", "%referral%"]
        if hasattr(Transaction, "description"):
            for pattern in like_patterns:
                try:
                    clauses.append(Transaction.description.ilike(pattern))
                except Exception:  # noqa: BLE001 - best effort
                    pass
        if hasattr(Transaction, "comment"):
            for pattern in like_patterns:
                try:
                    clauses.append(Transaction.comment.ilike(pattern))
                except Exception:  # noqa: BLE001 - best effort
                    pass

        return [clause for clause in clauses if clause is not None]

    def _exclude_referral_deposits_condition(self):
        """
        Условие «это НЕ реферальный бонус».
        Если нет ни одного маркера — ничего не исключаем.
        """
        markers = self._referral_markers()
        if not markers:
            return true()
        return not_(or_(*markers))

    # --------------------------------------

    async def _build_report(
        self,
        period: ReportPeriod,
        report_date: Optional[date],
    ) -> str:
        period_range = self._get_period_range(period, report_date)
        start_utc = period_range.start_msk.astimezone(timezone.utc).replace(tzinfo=None)
        end_utc = period_range.end_msk.astimezone(timezone.utc).replace(tzinfo=None)

        async with AsyncSessionLocal() as session:
            totals = await self._collect_current_totals(session)
            stats = await self._collect_period_stats(session, start_utc, end_utc)
            top_referrers = await self._get_top_referrers(session, start_utc, end_utc, limit=5)
            usage = await self._get_user_usage_stats(session)

        conversion_rate = (
            (stats["trial_to_paid_conversions"] / stats["new_trials"] * 100)
            if stats["new_trials"] > 0
            else 0.0
        )

        lines: List[str] = []
        header = (
            f"📊 <b>Отчет за {period_range.label}</b>"
            if period == ReportPeriod.DAILY
            else f"📊 <b>Отчет за период {period_range.label}</b>"
        )
        lines += [header, ""]

        # TL;DR
        lines += [
            "🧭 <b>Итог по периоду</b>",
            f"• Новых пользователей: <b>{stats['new_users']}</b>",
            f"• Новых триалов: <b>{stats['new_trials']}</b>",
            (
                f"• Конверсий триал → платная: <b>{stats['trial_to_paid_conversions']}</b> "
                f"(<i>{conversion_rate:.1f}%</i>)"
            ),
            f"• Новых платных (всего): <b>{stats['new_paid_subscriptions']}</b>",
            f"• Поступления всего (только пополнения): <b>{self._format_amount(stats['deposits_amount'])}</b>",
            "",
        ]

        # Подписки
        lines += [
            "💎 <b>Подписки</b>",
            f"• Активные триалы сейчас: {totals['active_trials']}",
            f"• Активные платные сейчас: {totals['active_paid']}",
            "",
        ]

        # Финансы
        lines += [
            "💰 <b>Финансы</b>",
            (
                "• Оплаты подписок: "
                f"{stats['subscription_payments_count']} на сумму {self._format_amount(stats['subscription_payments_amount'])}"
            ),
            (
                "• Пополнения: "
                f"{stats['deposits_count']} на сумму {self._format_amount(stats['deposits_amount'])}"
            ),
            (
                "<i>Примечание: «Поступления всего» учитывают только пополнения; покупки подписок и реферальные бонусы "
                "исключены.</i>"
            ),
            "",
        ]

        # Поддержка
        lines += [
            "🎟️ <b>Поддержка</b>",
            f"• Новых тикетов: {stats['new_tickets']}",
            f"• Активных тикетов сейчас: {totals['open_tickets']}",
            "",
        ]

        # Активность пользователей
        lines += [
            "👤 <b>Активность пользователей</b>",
            f"• Пользователей с активной платной подпиской: {usage['active_paid_users']}",
            f"• Пользователей, ни разу не подключившихся: {usage['never_connected_users']}",
            "",
        ]

        # Топ по рефералам
        lines += ["🤝 <b>Топ по рефералам (за период)</b>"]
        if top_referrers:
            for index, row in enumerate(top_referrers, 1):
                referrer_label = escape(row["referrer_label"], quote=False)
                lines.append(
                    f"{index}. {referrer_label}: {row['count']} приглашений"
                )
        else:
            lines.append("— данных нет")

        return "\n".join(lines)

    def _get_period_range(
        self,
        period: ReportPeriod,
        report_date: Optional[date],
    ) -> ReportPeriodRange:
        now_msk = datetime.now(self._moscow_tz)

        if period == ReportPeriod.DAILY:
            target_date = report_date or (now_msk.date() - timedelta(days=1))
            start = datetime.combine(target_date, datetime_time.min, tzinfo=self._moscow_tz)
            end = start + timedelta(days=1)
        elif period == ReportPeriod.WEEKLY:
            end_date = report_date or now_msk.date()
            start_date = end_date - timedelta(days=7)
            start = datetime.combine(start_date, datetime_time.min, tzinfo=self._moscow_tz)
            end = datetime.combine(end_date, datetime_time.min, tzinfo=self._moscow_tz)
        elif period == ReportPeriod.MONTHLY:
            end_date = report_date or now_msk.date()
            start_date = end_date - timedelta(days=30)
            start = datetime.combine(start_date, datetime_time.min, tzinfo=self._moscow_tz)
            end = datetime.combine(end_date, datetime_time.min, tzinfo=self._moscow_tz)
        else:  # pragma: no cover - defensive branch
            raise ReportingServiceError(f"Неизвестный период отчета: {period}")

        label = self._format_period_label(start, end)
        return ReportPeriodRange(start, end, label)

    async def _collect_current_totals(self, session) -> dict:
        stats = await get_subscriptions_statistics(session)
        open_tickets_result = await session.execute(
            select(func.count(Ticket.id)).where(
                Ticket.status.in_(
                    [
                        TicketStatus.OPEN.value,
                        TicketStatus.ANSWERED.value,
                        TicketStatus.PENDING.value,
                    ]
                )
            )
        )
        open_tickets = int(open_tickets_result.scalar() or 0)
        return {
            "active_trials": stats.get("trial_subscriptions", 0) or 0,
            "active_paid": stats.get("paid_subscriptions", 0) or 0,
            "open_tickets": open_tickets,
        }

    async def _collect_period_stats(
        self,
        session,
        start_utc: datetime,
        end_utc: datetime,
    ) -> dict:
        new_users = int(
            (
                await session.execute(
                    select(func.count(User.id)).where(
                        User.created_at >= start_utc,
                        User.created_at < end_utc,
                    )
                )
            ).scalar()
            or 0
        )

        new_trials = int(
            (
                await session.execute(
                    select(func.count(Subscription.id)).where(
                        Subscription.created_at >= start_utc,
                        Subscription.created_at < end_utc,
                        Subscription.is_trial == true(),
                    )
                )
            ).scalar()
            or 0
        )

        direct_paid = int(
            (
                await session.execute(
                    select(func.count(Subscription.id)).where(
                        Subscription.created_at >= start_utc,
                        Subscription.created_at < end_utc,
                        Subscription.is_trial == false(),
                    )
                )
            ).scalar()
            or 0
        )

        trial_to_paid_conversions = int(
            (
                await session.execute(
                    select(func.count(SubscriptionConversion.id)).where(
                        SubscriptionConversion.converted_at >= start_utc,
                        SubscriptionConversion.converted_at < end_utc,
                    )
                )
            ).scalar()
            or 0
        )

        subscription_payments_count, subscription_payments_amount = (
            (
                await session.execute(
                    self._txn_query_base(
                        TransactionType.SUBSCRIPTION_PAYMENT.value,
                        start_utc,
                        end_utc,
                    )
                )
            ).one()
        )

        deposits_count, deposits_amount = (
            (
                await session.execute(
                    self._deposit_query_excluding_referrals(start_utc, end_utc)
                )
            ).one()
        )

        new_tickets = int(
            (
                await session.execute(
                    select(func.count(Ticket.id)).where(
                        Ticket.created_at >= start_utc,
                        Ticket.created_at < end_utc,
                    )
                )
            ).scalar()
            or 0
        )

        return {
            "new_users": new_users,
            "new_trials": new_trials,
            "new_paid_subscriptions": direct_paid + trial_to_paid_conversions,
            "trial_to_paid_conversions": trial_to_paid_conversions,
            "subscription_payments_count": int(subscription_payments_count or 0),
            "subscription_payments_amount": int(subscription_payments_amount or 0),
            "deposits_count": int(deposits_count or 0),
            "deposits_amount": int(deposits_amount or 0),
            "new_tickets": new_tickets,
        }

    def _txn_query_base(self, txn_type: str, start_utc: datetime, end_utc: datetime):
        return select(
            func.count(Transaction.id),
            func.coalesce(func.sum(Transaction.amount_kopeks), 0),
        ).where(
            Transaction.type == txn_type,
            Transaction.is_completed == true(),
            Transaction.created_at >= start_utc,
            Transaction.created_at < end_utc,
        )

    def _deposit_query_excluding_referrals(self, start_utc: datetime, end_utc: datetime):
        return select(
            func.count(Transaction.id),
            func.coalesce(func.sum(Transaction.amount_kopeks), 0),
        ).where(
            Transaction.type == TransactionType.DEPOSIT.value,
            Transaction.is_completed == true(),
            Transaction.created_at >= start_utc,
            Transaction.created_at < end_utc,
            self._exclude_referral_deposits_condition(),
            # Исключаем ручные (админские) пополнения из статистики
            or_(
                Transaction.payment_method.is_(None),
                Transaction.payment_method != PaymentMethod.MANUAL.value,
            ),
        )

    async def _get_top_referrers(
        self,
        session,
        start_utc: datetime,
        end_utc: datetime,
        limit: int = 5,
    ) -> List[Dict]:
        rows = await session.execute(
            select(
                User.referred_by_id,
                func.count(User.id).label("cnt"),
            )
            .where(
                User.created_at >= start_utc,
                User.created_at < end_utc,
                User.referred_by_id.isnot(None),
            )
            .group_by(User.referred_by_id)
            .order_by(func.count(User.id).desc())
            .limit(limit)
        )
        rows = rows.all()
        if not rows:
            return []
        ref_ids = [row[0] for row in rows if row[0] is not None]
        users_map: Dict[int, str] = {}
        if ref_ids:
            urows = await session.execute(select(User).where(User.id.in_(ref_ids)))
            for user in urows.scalars().all():
                users_map[user.id] = self._user_label(user)
        return [
            {"referrer_label": users_map.get(ref_id, f"User #{ref_id}"), "count": int(count or 0)}
            for ref_id, count in rows
        ]

    async def _get_user_usage_stats(self, session) -> Dict[str, int]:
        now_utc = datetime.now(timezone.utc).replace(tzinfo=None)

        active_paid_q = await session.execute(
            select(func.count(func.distinct(Subscription.user_id))).where(
                Subscription.is_trial == false(),
                Subscription.status == SubscriptionStatus.ACTIVE.value,
                Subscription.end_date > now_utc,
            )
        )
        active_paid_users = int(active_paid_q.scalar() or 0)

        never_connected_q = await session.execute(
            select(func.count(func.distinct(Subscription.user_id))).where(
                or_(
                    Subscription.connected_squads.is_(None),
                    cast(Subscription.connected_squads, JSONB) == cast('[]', JSONB),
                    func.jsonb_typeof(cast(Subscription.connected_squads, JSONB)) != 'array',
                )
            )
        )
        never_connected_users = int(never_connected_q.scalar() or 0)

        return {
            "active_paid_users": active_paid_users,
            "never_connected_users": never_connected_users,
        }

    def _user_label(self, user: User) -> str:
        if getattr(user, "username", None):
            return f"@{user.username}"
        parts = []
        if getattr(user, "first_name", None):
            parts.append(user.first_name)
        if getattr(user, "last_name", None):
            parts.append(user.last_name)
        if parts:
            return " ".join(parts)
        return f"User #{getattr(user, 'id', '?')}"

    def _format_period_label(self, start: datetime, end: datetime) -> str:
        start_date = start.astimezone(self._moscow_tz).date()
        end_boundary = (end - timedelta(seconds=1)).astimezone(self._moscow_tz)
        end_date = end_boundary.date()

        if start_date == end_date:
            return start_date.strftime("%d.%m.%Y")

        return f"{start_date.strftime('%d.%m.%Y')} - {end_date.strftime('%d.%m.%Y')}"

    def _format_amount(self, amount_kopeks: int) -> str:
        rubles = (amount_kopeks or 0) / 100
        return f"{rubles:,.2f} ₽".replace(",", " ")


reporting_service = ReportingService()