main.py

"""
FastAPI Simple Application
A basic but feature-rich FastAPI application demonstrating common patterns.
"""

from fastapi import FastAPI, HTTPException, Query
from fastapi.responses import JSONResponse
from pydantic import BaseModel
from typing import Optional
import uvicorn
import os

# Create FastAPI instance
app = FastAPI(
    title="Simple FastAPI Application",
    description="A basic FastAPI app with common endpoints and features",
    version="1.0.0"
)

# Pydantic models for request/response
class Item(BaseModel):
    id: int
    name: str
    price: float
    is_available: bool = True
    description: Optional[str] = None

class ItemUpdate(BaseModel):
    name: Optional[str] = None
    price: Optional[float] = None
    is_available: Optional[bool] = None
    description: Optional[str] = None

# In-memory storage (for demonstration)
items_db = {
    1: {"id": 1, "name": "Laptop", "price": 999.99, "is_available": True, "description": "Gaming laptop"},
    2: {"id": 2, "name": "Mouse", "price": 29.99, "is_available": True, "description": "Wireless mouse"},
    3: {"id": 3, "name": "Keyboard", "price": 79.99, "is_available": False, "description": "Mechanical keyboard"}
}

# Root endpoint
@app.get("/")
async def root():
    """
    Welcome endpoint
    """
    return {"message": "Welcome to Simple FastAPI Application!", "version": "1.0.0"}

# Health check endpoint
@app.get("/health")
async def health_check():
    """
    Health check endpoint
    """
    return {"status": "healthy", "service": "fastapi-simple-app"}

# Get all items
@app.get("/items")
async def get_items(
    skip: int = Query(0, ge=0, description="Number of items to skip"),
    limit: int = Query(10, ge=1, le=100, description="Number of items to return")
):
    """
    Get all items with pagination
    """
    items_list = list(items_db.values())
    return {
        "items": items_list[skip:skip + limit],
        "total": len(items_list),
        "skip": skip,
        "limit": limit
    }

# Get item by ID
@app.get("/items/{item_id}")
async def get_item(item_id: int):
    """
    Get a specific item by ID
    """
    if item_id not in items_db:
        raise HTTPException(status_code=404, detail="Item not found")
    return items_db[item_id]

# Create new item
@app.post("/items")
async def create_item(item: Item):
    """
    Create a new item
    """
    if item.id in items_db:
        raise HTTPException(status_code=400, detail="Item already exists")

    items_db[item.id] = item.dict()
    return {"message": "Item created successfully", "item": items_db[item.id]}

# Update item
@app.put("/items/{item_id}")
async def update_item(item_id: int, item_update: ItemUpdate):
    """
    Update an existing item
    """
    if item_id not in items_db:
        raise HTTPException(status_code=404, detail="Item not found")

    # Update only provided fields
    for field, value in item_update.dict(exclude_unset=True).items():
        items_db[item_id][field] = value

    return {"message": "Item updated successfully", "item": items_db[item_id]}

# Delete item
@app.delete("/items/{item_id}")
async def delete_item(item_id: int):
    """
    Delete an item
    """
    if item_id not in items_db:
        raise HTTPException(status_code=404, detail="Item not found")

    deleted_item = items_db.pop(item_id)
    return {"message": "Item deleted successfully", "deleted_item": deleted_item}

# Search items
@app.get("/search")
async def search_items(q: str = Query(..., description="Search query")):
    """
    Search items by name or description
    """
    results = []
    for item in items_db.values():
        if (q.lower() in item["name"].lower() or 
            (item["description"] and q.lower() in item["description"].lower())):
            results.append(item)

    return {"query": q, "results": results, "count": len(results)}

# Get available items only
@app.get("/items/available")
async def get_available_items():
    """
    Get only available items
    """
    available_items = [item for item in items_db.values() if item["is_available"]]
    return {"available_items": available_items, "count": len(available_items)}

# Run the application (for development)
if __name__ == "__main__":
    uvicorn.run(
        "main:app", 
        host="127.0.0.1", 
        port=8000, 
        reload=True,
        log_level="info"
    )