import json
from datetime import datetime, timezone, date
from fastapi import APIRouter, Depends, HTTPException
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy import select, func
from app.database import get_db
from app.models.user import User
from app.models.product import Product
from app.models.scan import Scan
from app.schemas.scan import ScanRequest, ScanResult, ScanHistoryItem
from app.utils.security import get_current_user
from app.integrations.open_food_facts import fetch_product
from app.integrations.openai_client import analyze_product
from app.config import settings
from app.services.seed import SEED_PRODUCTS

router = APIRouter(prefix="/api", tags=["scan"])

@router.post("/scan", response_model=ScanResult)
async def scan_product(req: ScanRequest, user: User = Depends(get_current_user), db: AsyncSession = Depends(get_db)):
    # Rate limit check
    if not user.is_premium:
        today_start = datetime.now(timezone.utc).replace(hour=0, minute=0, second=0, microsecond=0)
        result = await db.execute(
            select(func.count(Scan.id)).where(Scan.user_id == user.id, Scan.scanned_at >= today_start)
        )
        count = result.scalar()
        if count >= settings.FREE_SCAN_LIMIT:
            raise HTTPException(status_code=429, detail=f"Limite de {settings.FREE_SCAN_LIMIT} scans/dia atingido. Faça upgrade para Premium!")

    # Check local cache
    result = await db.execute(select(Product).where(Product.barcode == req.barcode))
    product = result.scalar_one_or_none()
    
    product_data = None
    source = "cache"
    
    if product:
        product_data = {
            "name": product.name, "brand": product.brand, "category": product.category,
            "ingredients_text": product.ingredients_text, "nutri_score": product.nutri_score,
            "nova_group": product.nova_group, "nutrition": json.loads(product.nutrition_json or "{}"),
            "image_url": product.image_url,
        }
    else:
        # Check seed data
        if req.barcode in SEED_PRODUCTS:
            product_data = SEED_PRODUCTS[req.barcode].copy()
            source = "seed"
        else:
            # Fetch from Open Food Facts
            product_data = await fetch_product(req.barcode)
            source = "open_food_facts"
        
        if product_data:
            new_product = Product(
                barcode=req.barcode, name=product_data.get("name"), brand=product_data.get("brand"),
                category=product_data.get("category"), ingredients_text=product_data.get("ingredients_text"),
                nutri_score=product_data.get("nutri_score"), nova_group=product_data.get("nova_group"),
                nutrition_json=json.dumps(product_data.get("nutrition", {})),
                image_url=product_data.get("image_url", ""),
            )
            db.add(new_product)
            await db.commit()
    
    if not product_data:
        raise HTTPException(status_code=404, detail="Produto não encontrado. Tente inserir manualmente.")

    # AI Analysis
    analysis = await analyze_product(product_data)
    
    # Save scan
    scan = Scan(
        user_id=user.id, barcode=req.barcode, product_name=product_data.get("name"),
        brand=product_data.get("brand"), score=analysis.get("score", 50),
        summary=analysis.get("summary", ""), analysis_json=json.dumps(analysis),
    )
    db.add(scan)
    await db.commit()

    return ScanResult(
        barcode=req.barcode,
        product_name=product_data.get("name"),
        brand=product_data.get("brand"),
        category=product_data.get("category"),
        image_url=product_data.get("image_url"),
        score=analysis.get("score", 50),
        summary=analysis.get("summary", ""),
        positives=analysis.get("positives", []),
        negatives=analysis.get("negatives", []),
        ingredients=analysis.get("ingredients", []),
        nutri_score=product_data.get("nutri_score"),
        nova_group=product_data.get("nova_group"),
        source=source,
    )

@router.get("/history", response_model=list[ScanHistoryItem])
async def get_history(user: User = Depends(get_current_user), db: AsyncSession = Depends(get_db)):
    result = await db.execute(
        select(Scan).where(Scan.user_id == user.id).order_by(Scan.scanned_at.desc()).limit(50)
    )
    scans = result.scalars().all()
    return [ScanHistoryItem(
        id=s.id, barcode=s.barcode, product_name=s.product_name,
        brand=s.brand, score=s.score, scanned_at=s.scanned_at
    ) for s in scans]