# D:\GNPL-Private\TimeCraft\backend\main.py

import os
from fastapi import FastAPI
from fastapi.middleware.cors import CORSMiddleware
from dotenv import load_dotenv # For loading environment variables

from app.api import endpoints # Import your API router

# Load environment variables from the .env file.
# This should be called early in your application's lifecycle.
load_dotenv()

# Initialize the FastAPI application instance
# Add additional metadata for professional API documentation
app = FastAPI(
    title="AI-Powered Schedule and Task Planning Backend",
    description="FastAPI backend for ingesting user tasks, using an LLM for intelligent scheduling, and returning structured schedules.",
    version="1.0.0",
    docs_url="/docs",       # Enable interactive API documentation (Swagger UI)
    redoc_url="/redoc",     # Enable ReDoc documentation
    openapi_url="/openapi.json" # Specify the OpenAPI schema URL
)

# Configure CORS (Cross-Origin Resource Sharing) middleware.
# This is crucial for allowing your React frontend (running on a different port/domain)
# to make requests to your FastAPI backend.
origins = [
    os.getenv("FRONTEND_URL", "http://localhost:3000"),  # Get frontend URL from .env, default to React's development port
    # Add other origins if your frontend is deployed elsewhere or has multiple access points
    # e.g., "https://your-production-frontend.com",
    # "http://localhost:8080" # If testing with another local frontend setup
]

app.add_middleware(
    CORSMiddleware,
    allow_origins=origins,          # List of allowed origins
    allow_credentials=True,         # Allow cookies and authentication headers to be sent
    allow_methods=["*"],            # Allow all HTTP methods (GET, POST, PUT, DELETE, etc.)
    allow_headers=["*"],            # Allow all headers in the request
)

# Include the API router defined in app.api.endpoints.
# All routes defined in endpoints.py will be prefixed with "/api/v1".
app.include_router(endpoints.router, prefix="/api/v1")

# Define a root endpoint for basic health check or welcome message
@app.get("/", summary="Root Endpoint", description="Provides a welcome message for the API.")
async def root():
    """
    Root endpoint for the API.
    Returns a simple welcome message to indicate the API is running.
    """
    return {"message": "Welcome to the AI-Powered Schedule and Task Planning API! Access docs at /docs"}