from fastapi import FastAPI, HTTPException
from fastapi.middleware.cors import CORSMiddleware
from models import DiagramItem
import json
import os

app = FastAPI()

app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],  # בהמשך תוכל לצמצם לכתובת הפרונטאנד
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

DATA_FILE = "diagram.json"

@app.get("/diagram/fetch")
def fetch_diagram():
    if not os.path.exists(DATA_FILE):
        return {"nodes": [], "edges": []}
    with open(DATA_FILE, "r") as f:
        return json.load(f)

@app.post("/diagram/save")
def save_diagram(payload: DiagramItem):
    try:
        with open(DATA_FILE, "w") as f:
            json.dump(payload.dict(), f, indent=2)
        return {"status": "ok"}
    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e))