"""
통계 조회 API
- 일별/월별/연도별 발전량 통계
"""

from fastapi import APIRouter, HTTPException, Depends, Query
from supabase import Client
from typing import List, Literal
from datetime import datetime, timedelta

from app.core.database import get_db

router = APIRouter(
    prefix="/plants",
    tags=["Stats"]
)


@router.get("/{plant_id}/stats")
async def get_plant_stats(
    plant_id: str,
    period: Literal["day", "month", "year"] = Query("day", description="통계 기간"),
    db: Client = Depends(get_db)
) -> dict:
    """
    발전소 통계 조회
    
    Args:
        plant_id: 발전소 ID
        period: 'day' (최근 30일), 'month' (최근 12개월), 'year' (최근 5년)
        
    Returns:
        차트 라이브러리 친화적 포맷 [{"label": "...", "value": ...}, ...]
    """
    try:
        today = datetime.now().date()
        
        if period == "day":
            # 최근 30일
            start_date = today - timedelta(days=30)
            
            result = db.table("daily_stats") \
                .select("date, total_generation") \
                .eq("plant_id", plant_id) \
                .gte("date", start_date.isoformat()) \
                .lte("date", today.isoformat()) \
                .order("date", desc=False) \
                .execute()
            
            data = [
                {"label": row["date"], "value": row["total_generation"] or 0}
                for row in result.data
            ]
            
        elif period == "month":
            # 최근 12개월 - 월별 합계
            start_date = today.replace(day=1) - timedelta(days=365)
            
            result = db.table("daily_stats") \
                .select("date, total_generation") \
                .eq("plant_id", plant_id) \
                .gte("date", start_date.isoformat()) \
                .lte("date", today.isoformat()) \
                .execute()
            
            # 월별 집계
            monthly = {}
            for row in result.data:
                date_str = row["date"]
                month_key = date_str[:7]  # YYYY-MM
                generation = row["total_generation"] or 0
                monthly[month_key] = monthly.get(month_key, 0) + generation
            
            data = [
                {"label": month, "value": round(value, 2)}
                for month, value in sorted(monthly.items())
            ][-12:]  # 최근 12개월만
            
        elif period == "year":
            # 최근 5년 - 연도별 합계
            start_year = today.year - 5
            
            result = db.table("daily_stats") \
                .select("date, total_generation") \
                .eq("plant_id", plant_id) \
                .gte("date", f"{start_year}-01-01") \
                .lte("date", today.isoformat()) \
                .execute()
            
            # 연도별 집계
            yearly = {}
            for row in result.data:
                date_str = row["date"]
                year_key = date_str[:4]  # YYYY
                generation = row["total_generation"] or 0
                yearly[year_key] = yearly.get(year_key, 0) + generation
            
            data = [
                {"label": year, "value": round(value, 2)}
                for year, value in sorted(yearly.items())
            ]
        else:
            raise HTTPException(status_code=400, detail="Invalid period parameter")
        
        return {
            "status": "success",
            "plant_id": plant_id,
            "period": period,
            "data": data,
            "count": len(data)
        }
        
    except HTTPException:
        raise
    except Exception as e:
        raise HTTPException(
            status_code=500,
            detail=f"통계 조회 실패: {str(e)}"
        )