from typing import Dict, Any, Optional
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy import select
from app.models.translation_quota import TranslationQuota
from datetime import datetime
import logging

logger = logging.getLogger(__name__)


class TranslationQuotaService:
    def __init__(self, db: AsyncSession):
        self.db = db

    async def _get_or_create(self, version: str) -> TranslationQuota:
        result = await self.db.execute(
            select(TranslationQuota).where(TranslationQuota.version == version)
        )
        quota = result.scalar_one_or_none()
        if not quota:
            now = datetime.utcnow()
            quota = TranslationQuota(
                version=version,
                monthly_limit=1000000,
                used_chars=0,
                current_month=now.strftime("%Y-%m"),
                enabled=True,
                description=f"阿里云翻译{version}版",
            )
            self.db.add(quota)
            await self.db.flush()
        return quota

    async def check_quota(self, version: str) -> bool:
        quota = await self._get_or_create(version)
        now = datetime.utcnow()
        current = now.strftime("%Y-%m")
        if quota.current_month != current:
            quota.current_month = current
            quota.used_chars = 0
            await self.db.flush()
        return quota.enabled and quota.used_chars < quota.monthly_limit

    async def consume(self, version: str, chars: int):
        quota = await self._get_or_create(version)
        if not quota.enabled:
            raise ValueError(f"Translation API [{version}] is disabled")
        now = datetime.utcnow()
        current = now.strftime("%Y-%m")
        if quota.current_month != current:
            quota.current_month = current
            quota.used_chars = 0
        quota.used_chars += chars
        await self.db.flush()
        remaining = max(0, quota.monthly_limit - quota.used_chars)
        logger.info(f"Quota [{version}] consumed {chars} chars, remaining {remaining} this month")
        return remaining

    async def get_all_quotas(self) -> list:
        default_versions = ["ecommerce", "general"]
        for v in default_versions:
            await self._get_or_create(v)

        result = await self.db.execute(select(TranslationQuota).order_by(TranslationQuota.version))
        quotas = result.scalars().all()
        rows = []
        for q in quotas:
            now = datetime.utcnow()
            current = now.strftime("%Y-%m")
            if q.current_month != current:
                q.current_month = current
                q.used_chars = 0
                await self.db.flush()
            rows.append({
                "version": q.version,
                "monthly_limit": q.monthly_limit,
                "used_chars": q.used_chars,
                "current_month": q.current_month,
                "enabled": q.enabled,
                "description": q.description,
            })
        return rows

    async def update_quota(self, version: str, data: Dict[str, Any]) -> Optional[Dict[str, Any]]:
        quota = await self._get_or_create(version)
        if "monthly_limit" in data:
            quota.monthly_limit = int(data["monthly_limit"])
        if "enabled" in data:
            quota.enabled = bool(data["enabled"])
        if "description" in data:
            quota.description = str(data["description"])
        await self.db.flush()
        return {
            "version": quota.version,
            "monthly_limit": quota.monthly_limit,
            "used_chars": quota.used_chars,
            "current_month": quota.current_month,
            "enabled": quota.enabled,
            "description": quota.description,
        }

    async def reset_usage(self, version: str) -> Optional[Dict[str, Any]]:
        quota = await self._get_or_create(version)
        quota.used_chars = 0
        quota.current_month = datetime.utcnow().strftime("%Y-%m")
        await self.db.flush()
        return {
            "version": quota.version,
            "monthly_limit": quota.monthly_limit,
            "used_chars": quota.used_chars,
            "current_month": quota.current_month,
            "enabled": quota.enabled,
        }