from fastapi import APIRouter, Depends, HTTPException, status
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy.future import select
from typing import List
from database.session import get_db
from database.models import Order as OrderModel, User as UserModel, Service as ServiceModel
from auth import get_current_user
import schemas

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

@router.post("/", response_model=schemas.Order, status_code=status.HTTP_201_CREATED)
async def create_order(
    order: schemas.OrderCreate, 
    current_user: UserModel = Depends(get_current_user),
    db: AsyncSession = Depends(get_db)
):
    """
    Create a new order. Deducts balance from user.
    """
    # 1. Check if service exists and is active
    result = await db.execute(select(ServiceModel).where(ServiceModel.id == order.service_id))
    service = result.scalar_one_or_none()
    
    if not service or not service.is_active:
        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="Service not found or inactive")
        
    # 2. Validate quantity limits
    if order.quantity < service.min_quantity or order.quantity > service.max_quantity:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST, 
            detail=f"Quantity must be between {service.min_quantity} and {service.max_quantity}"
        )
        
    # 3. Calculate charge
    charge = (service.price / 1000) * order.quantity
    
    # 4. Check user balance
    if current_user.balance < charge:
        raise HTTPException(status_code=status.HTTP_402_PAYMENT_REQUIRED, detail="Insufficient balance")
        
    # 5. Deduct balance
    current_user.balance -= charge
    current_user.spent += charge
    
    # 6. Create order
    new_order = OrderModel(
        user_id=current_user.id,
        service_id=service.id,
        link=order.link,
        quantity=order.quantity,
        charge=charge,
        remains=order.quantity,
        status="Pending",
        api_provider_id=service.api_provider_id
    )
    
    db.add(new_order)
    
    # 7. Update service stats
    service.total_orders += 1
    
    await db.commit()
    await db.refresh(new_order)
    
    return new_order

@router.get("/", response_model=List[schemas.Order])
async def get_orders(
    skip: int = 0, 
    limit: int = 100, 
    current_user: UserModel = Depends(get_current_user),
    db: AsyncSession = Depends(get_db)
):
    """
    Get user's orders.
    """
    result = await db.execute(
        select(OrderModel)
        .where(OrderModel.user_id == current_user.id)
        .order_by(OrderModel.created_at.desc())
        .offset(skip)
        .limit(limit)
    )
    return result.scalars().all()

@router.get("/{order_id}", response_model=schemas.Order)
async def get_order(
    order_id: int, 
    current_user: UserModel = Depends(get_current_user),
    db: AsyncSession = Depends(get_db)
):
    """
    Get specific order details.
    """
    result = await db.execute(
        select(OrderModel)
        .where(OrderModel.id == order_id)
        .where(OrderModel.user_id == current_user.id)
    )
    order = result.scalar_one_or_none()
    
    if not order:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Order not found")
        
    return order