# services/external/app/cache/redis_cache.py
"""
Redis cache layer for fast training data access
"""

from typing import List, Dict, Any, Optional
import json
from datetime import datetime, timedelta
import structlog
import redis.asyncio as redis

from app.core.config import settings

logger = structlog.get_logger()


class ExternalDataCache:
    """Redis cache for external data service"""

    def __init__(self):
        self.redis_client = redis.from_url(
            settings.REDIS_URL,
            encoding="utf-8",
            decode_responses=True
        )
        self.ttl = 86400 * 7

    def _weather_cache_key(
        self,
        city_id: str,
        start_date: datetime,
        end_date: datetime
    ) -> str:
        """Generate cache key for weather data"""
        return f"weather:{city_id}:{start_date.date()}:{end_date.date()}"

    async def get_cached_weather(
        self,
        city_id: str,
        start_date: datetime,
        end_date: datetime
    ) -> Optional[List[Dict[str, Any]]]:
        """Get cached weather data"""
        try:
            key = self._weather_cache_key(city_id, start_date, end_date)
            cached = await self.redis_client.get(key)

            if cached:
                logger.debug("Weather cache hit", city_id=city_id, key=key)
                return json.loads(cached)

            logger.debug("Weather cache miss", city_id=city_id, key=key)
            return None

        except Exception as e:
            logger.error("Error reading weather cache", error=str(e))
            return None

    async def set_cached_weather(
        self,
        city_id: str,
        start_date: datetime,
        end_date: datetime,
        data: List[Dict[str, Any]]
    ):
        """Set cached weather data"""
        try:
            key = self._weather_cache_key(city_id, start_date, end_date)

            serializable_data = []
            for record in data:
                # Handle both dict and Pydantic model objects
                if hasattr(record, 'model_dump'):
                    record_dict = record.model_dump()
                elif hasattr(record, 'dict'):
                    record_dict = record.dict()
                else:
                    record_dict = record.copy() if isinstance(record, dict) else dict(record)

                # Convert any datetime fields to ISO format strings
                for key_name, value in record_dict.items():
                    if isinstance(value, datetime):
                        record_dict[key_name] = value.isoformat()

                serializable_data.append(record_dict)

            await self.redis_client.setex(
                key,
                self.ttl,
                json.dumps(serializable_data)
            )

            logger.debug("Weather data cached", city_id=city_id, records=len(data))

        except Exception as e:
            logger.error("Error caching weather data", error=str(e))

    def _traffic_cache_key(
        self,
        city_id: str,
        start_date: datetime,
        end_date: datetime
    ) -> str:
        """Generate cache key for traffic data"""
        return f"traffic:{city_id}:{start_date.date()}:{end_date.date()}"

    async def get_cached_traffic(
        self,
        city_id: str,
        start_date: datetime,
        end_date: datetime
    ) -> Optional[List[Dict[str, Any]]]:
        """Get cached traffic data"""
        try:
            key = self._traffic_cache_key(city_id, start_date, end_date)
            cached = await self.redis_client.get(key)

            if cached:
                logger.debug("Traffic cache hit", city_id=city_id, key=key)
                return json.loads(cached)

            logger.debug("Traffic cache miss", city_id=city_id, key=key)
            return None

        except Exception as e:
            logger.error("Error reading traffic cache", error=str(e))
            return None

    async def set_cached_traffic(
        self,
        city_id: str,
        start_date: datetime,
        end_date: datetime,
        data: List[Dict[str, Any]]
    ):
        """Set cached traffic data"""
        try:
            key = self._traffic_cache_key(city_id, start_date, end_date)

            serializable_data = []
            for record in data:
                # Handle both dict and Pydantic model objects
                if hasattr(record, 'model_dump'):
                    record_dict = record.model_dump()
                elif hasattr(record, 'dict'):
                    record_dict = record.dict()
                else:
                    record_dict = record.copy() if isinstance(record, dict) else dict(record)

                # Convert any datetime fields to ISO format strings
                for key_name, value in record_dict.items():
                    if isinstance(value, datetime):
                        record_dict[key_name] = value.isoformat()

                serializable_data.append(record_dict)

            await self.redis_client.setex(
                key,
                self.ttl,
                json.dumps(serializable_data)
            )

            logger.debug("Traffic data cached", city_id=city_id, records=len(data))

        except Exception as e:
            logger.error("Error caching traffic data", error=str(e))

    async def invalidate_city_cache(self, city_id: str):
        """Invalidate all cache entries for a city"""
        try:
            pattern = f"*:{city_id}:*"
            async for key in self.redis_client.scan_iter(match=pattern):
                await self.redis_client.delete(key)

            logger.info("City cache invalidated", city_id=city_id)

        except Exception as e:
            logger.error("Error invalidating cache", error=str(e))