"""
Volatile cache router for Library Desk API.

Endpoints for ephemeral cached data with TTL - weather, news, financial, etc.
"""

from fastapi import APIRouter, HTTPException, Depends, Query
import logging

from src.models.volatile import (
    VolatileRecordCreate,
    VolatileRecordResponse,
    VolatileListResponse,
    VolatileScheduledResponse,
    VolatileStatsResponse,
    VolatileDeleteResponse,
    VolatileBulkDeleteResponse,
    VolatileNamespace,
)
from src.services.volatile_service import VolatileCacheService
from src.core.dependencies import verify_api_key, RedisDep
from src.core.multi_tenancy import DEFAULT_USER
from src.config import get_settings

logger = logging.getLogger(__name__)

router = APIRouter(prefix="/volatile", tags=["Volatile Cache"])


def get_volatile_service(redis: RedisDep) -> VolatileCacheService:
    """Get volatile cache service instance."""
    settings = get_settings()
    return VolatileCacheService(redis_client=redis, settings=settings)


@router.get("/stats", response_model=VolatileStatsResponse)
async def get_stats(
    user: str = Query(default=DEFAULT_USER, description="User identifier"),
    redis: RedisDep = None,
    api_key: str = Depends(verify_api_key)
):
    """
    Get volatile cache statistics.

    Returns counts of records by namespace and scheduled refresh info.
    """
    service = get_volatile_service(redis)
    stats = await service.get_stats(user)

    return VolatileStatsResponse(
        total_records=stats["total_records"],
        by_namespace=stats["by_namespace"],
        scheduled_count=stats["scheduled_count"],
        total_memory_bytes=stats.get("total_memory_bytes"),
        user=user,
    )


@router.get("/scheduled", response_model=VolatileScheduledResponse)
async def get_scheduled(
    user: str = Query(default=DEFAULT_USER, description="User identifier"),
    redis: RedisDep = None,
    api_key: str = Depends(verify_api_key)
):
    """
    Get records with refresh schedules.

    Used by scheduler to determine what volatile data needs refreshing.
    Returns all records that have a refresh_schedule cron expression set.
    """
    service = get_volatile_service(redis)
    records = await service.get_scheduled(user)

    return VolatileScheduledResponse(
        records=records,
        count=len(records),
        user=user,
    )


@router.get("/namespaces")
async def list_namespaces(
    api_key: str = Depends(verify_api_key)
):
    """
    List available namespaces and their default TTLs.

    Returns predefined namespaces with their default TTL values.
    Custom namespaces can also be used with the default TTL.
    """
    from src.models.volatile import NAMESPACE_DEFAULT_TTL

    return {
        "namespaces": [
            {
                "name": ns.value,
                "default_ttl": NAMESPACE_DEFAULT_TTL.get(ns, 3600),
                "description": _get_namespace_description(ns),
            }
            for ns in VolatileNamespace
        ]
    }


def _get_namespace_description(ns: VolatileNamespace) -> str:
    """Get human-readable description for namespace."""
    descriptions = {
        VolatileNamespace.WEATHER: "Weather conditions and forecasts",
        VolatileNamespace.NEWS: "Headlines and breaking news",
        VolatileNamespace.FINANCIAL: "Stock prices, exchange rates, crypto",
        VolatileNamespace.TRANSIT: "Train/bus schedules, delays",
        VolatileNamespace.TRAFFIC: "Commute times, road conditions",
        VolatileNamespace.AIR_QUALITY: "Pollution levels, pollen counts",
        VolatileNamespace.SPORTS: "Live scores, upcoming matches",
        VolatileNamespace.SOCIAL: "Social media mentions, notifications",
        VolatileNamespace.SYSTEM: "Service health, infrastructure status",
        VolatileNamespace.CONTEXT: "Conversation context, session state",
        VolatileNamespace.CUSTOM: "User-defined volatile data",
    }
    return descriptions.get(ns, "Custom namespace")


@router.get("/{namespace}", response_model=VolatileListResponse)
async def list_keys(
    namespace: str,
    user: str = Query(default=DEFAULT_USER, description="User identifier"),
    redis: RedisDep = None,
    api_key: str = Depends(verify_api_key)
):
    """
    List all keys in a namespace.

    Returns the list of keys stored in the specified namespace.
    """
    service = get_volatile_service(redis)
    keys = await service.list_namespace(user, namespace)

    return VolatileListResponse(
        namespace=namespace,
        keys=keys,
        count=len(keys),
        user=user,
    )


@router.delete("/{namespace}", response_model=VolatileBulkDeleteResponse)
async def delete_namespace(
    namespace: str,
    user: str = Query(default=DEFAULT_USER, description="User identifier"),
    redis: RedisDep = None,
    api_key: str = Depends(verify_api_key)
):
    """
    Delete all records in a namespace.

    Removes all volatile data for the specified namespace.
    """
    service = get_volatile_service(redis)
    deleted = await service.delete_namespace(user, namespace)

    return VolatileBulkDeleteResponse(
        namespace=namespace,
        deleted_count=deleted,
        user=user,
    )


@router.get("/{namespace}/{key}", response_model=VolatileRecordResponse)
async def get_record(
    namespace: str,
    key: str,
    user: str = Query(default=DEFAULT_USER, description="User identifier"),
    redis: RedisDep = None,
    api_key: str = Depends(verify_api_key)
):
    """
    Get a volatile record.

    Returns the record if it exists and has not expired.

    **Example:**
    ```
    GET /volatile/weather/rotterdam?user=jpmschweitzer
    ```
    """
    service = get_volatile_service(redis)
    record = await service.get(user, namespace, key)

    if not record:
        raise HTTPException(
            status_code=404,
            detail=f"Record '{key}' not found in namespace '{namespace}'"
        )

    return record


@router.post("/{namespace}/{key}", response_model=VolatileRecordResponse)
async def set_record(
    namespace: str,
    key: str,
    request: VolatileRecordCreate,
    user: str = Query(default=DEFAULT_USER, description="User identifier"),
    redis: RedisDep = None,
    api_key: str = Depends(verify_api_key)
):
    """
    Store or update a volatile record.

    Creates or updates a record with the specified TTL.
    If TTL is not provided, the namespace default is used.

    **Example Request:**
    ```json
    {
        "data": {
            "temperature": 18,
            "conditions": "Partly cloudy",
            "humidity": 65
        },
        "source": "openweathermap",
        "ttl": 1800,
        "refresh_schedule": "0 * * * *"
    }
    ```

    **Refresh Schedule:**
    Optional cron expression for automatic refresh. The scheduler
    will query `/volatile/scheduled` and trigger refreshes.
    """
    service = get_volatile_service(redis)

    try:
        record = await service.set(
            user=user,
            namespace=namespace,
            key=key,
            data=request.data,
            source=request.source,
            ttl=request.ttl,
            refresh_schedule=request.refresh_schedule,
        )
        return record

    except Exception as e:
        logger.error(f"Failed to store volatile record: {e}")
        raise HTTPException(status_code=500, detail="Failed to store record")


@router.delete("/{namespace}/{key}", response_model=VolatileDeleteResponse)
async def delete_record(
    namespace: str,
    key: str,
    user: str = Query(default=DEFAULT_USER, description="User identifier"),
    redis: RedisDep = None,
    api_key: str = Depends(verify_api_key)
):
    """
    Delete a volatile record.

    Removes the record from the cache.
    """
    service = get_volatile_service(redis)
    deleted = await service.delete(user, namespace, key)

    return VolatileDeleteResponse(
        key=key,
        namespace=namespace,
        deleted=deleted,
        user=user,
    )