from fastapi import APIRouter, HTTPException, status, Depends, Query
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy import select
from typing import List, Optional
from ..core.dependencies import get_current_active_user
from ..db.database import get_db
from ..db.models import Product, User
from ..db.schemas import ProductCreate, ProductInDB

router = APIRouter()

@router.post("/", response_model=ProductInDB)
async def create_product(
    product: ProductCreate,
    current_user: User = Depends(get_current_active_user),
    db: AsyncSession = Depends(get_db)
) -> ProductInDB:
    # Ensure user belongs to the branch they're creating the product for
    if current_user.branch_id != product.branch_id and not current_user.is_superuser:
        raise HTTPException(
            status_code=403,
            detail="You can only create products for your own branch"
        )
    
    # Create product with current user as seller
    product_data = product.dict()
    product_data["seller_id"] = current_user.id
    db_product = Product(**product_data)
    db.add(db_product)
    await db.commit()
    await db.refresh(db_product)
    return db_product

@router.get("/", response_model=List[ProductInDB])
async def list_products(
    skip: int = 0,
    limit: int = 10,
    category: Optional[str] = None,
    branch_id: Optional[int] = Query(None, description="Filter products by branch"),
    current_user: User = Depends(get_current_active_user),
    db: AsyncSession = Depends(get_db)
) -> List[ProductInDB]:
    query = select(Product)
    
    # Filter by category if provided
    if category:
        query = query.where(Product.category == category)
    
    # Filter by branch if provided, otherwise use user's branch
    if branch_id:
        if not current_user.is_superuser and branch_id != current_user.branch_id:
            raise HTTPException(
                status_code=403,
                detail="You can only view products from your own branch"
            )
        query = query.where(Product.branch_id == branch_id)
    elif not current_user.is_superuser:
        # Non-superusers can only see products from their branch
        query = query.where(Product.branch_id == current_user.branch_id)
    
    query = query.offset(skip).limit(limit)
    result = await db.execute(query)
    return result.scalars().all()

@router.get("/{product_id}", response_model=ProductInDB)
async def get_product(
    product_id: int,
    current_user: User = Depends(get_current_active_user),
    db: AsyncSession = Depends(get_db)
) -> ProductInDB:
    stmt = select(Product).where(Product.id == product_id)
    result = await db.execute(stmt)
    product = result.scalar_one_or_none()
    
    if not product:
        raise HTTPException(status_code=404, detail="Product not found")
    
    # Check if user has access to this product's branch
    if not current_user.is_superuser and product.branch_id != current_user.branch_id:
        raise HTTPException(status_code=403, detail="You cannot access products from other branches")
    
    return product

@router.put("/{product_id}", response_model=ProductInDB)
async def update_product(
    product_id: int,
    product_update: ProductCreate,
    current_user: User = Depends(get_current_active_user),
    db: AsyncSession = Depends(get_db)
) -> ProductInDB:
    stmt = select(Product).where(Product.id == product_id)
    result = await db.execute(stmt)
    product = result.scalar_one_or_none()
    
    if not product:
        raise HTTPException(status_code=404, detail="Product not found")
    
    # Check if user has access to this product's branch
    if not current_user.is_superuser and product.branch_id != current_user.branch_id:
        raise HTTPException(status_code=403, detail="You cannot modify products from other branches")
    
    # Ensure the branch isn't being changed to a different branch
    if product_update.branch_id != product.branch_id:
        raise HTTPException(status_code=400, detail="Cannot change product's branch")
    
    # Update product fields
    update_data = product_update.dict(exclude_unset=True)
    for field, value in update_data.items():
        setattr(product, field, value)
    
    await db.commit()
    await db.refresh(product)
    return product

@router.delete("/{product_id}")
async def delete_product(
    product_id: int,
    current_user: User = Depends(get_current_active_user),
    db: AsyncSession = Depends(get_db)
):
    stmt = select(Product).where(Product.id == product_id)
    result = await db.execute(stmt)
    product = result.scalar_one_or_none()
    
    if not product:
        raise HTTPException(status_code=404, detail="Product not found")
    
    # Check if user has access to this product's branch
    if not current_user.is_superuser and product.branch_id != current_user.branch_id:
        raise HTTPException(status_code=403, detail="You cannot delete products from other branches")
    
    await db.delete(product)
    await db.commit()
    return {"status": "success", "message": "Product deleted"}