from fastapi import FastAPI, APIRouter, HTTPException
from pydantic import BaseModel
from typing import List

app = FastAPI()

# Router instance
router = APIRouter()

# Sample data model
class Item(BaseModel):
    id: int
    name: str
    description: str = None
    price: float
    available: bool

# In-memory database (for demonstration)
items_db = []

# GET route to fetch all items
@router.get("/items", response_model=List[Item])
async def get_items():
    return items_db

# GET route to fetch a single item by ID
@router.get("/items/{item_id}", response_model=Item)
async def get_item(item_id: int):
    item = next((item for item in items_db if item.id == item_id), None)
    if not item:
        raise HTTPException(status_code=404, detail="Item not found")
    return item

# POST route to create a new item
@router.post("/items", response_model=Item)
async def create_item(item: Item):
    items_db.append(item)
    return item

# PUT route to update an existing item by ID
@router.put("/items/{item_id}", response_model=Item)
async def update_item(item_id: int, updated_item: Item):
    for index, item in enumerate(items_db):
        if item.id == item_id:
            items_db[index] = updated_item
            return updated_item
    raise HTTPException(status_code=404, detail="Item not found")

# DELETE route to delete an item by ID
@router.delete("/items/{item_id}")
async def delete_item(item_id: int):
    global items_db
    items_db = [item for item in items_db if item.id != item_id]
    return {"detail": "Item deleted successfully"}

# Include the router in the main FastAPI app
app.include_router(router, prefix="/api/v1", tags=["items"])

# Root endpoint
@app.get("/")
async def root():
    return {"message": "Welcome to the FastAPI app!"}