app.py

# app.py
from flask import Flask, send_from_directory, jsonify, request
import os
import json
import errno

app = Flask(__name__)

# Directory to store settings
SETTINGS_DIR = "settings"

# Ensure the settings directory exists and has the correct permissions
try:
    if not os.path.exists(SETTINGS_DIR):
        os.makedirs(SETTINGS_DIR, mode=0o775)
    os.chmod(SETTINGS_DIR, 0o775)
except OSError as e:
    print(f"Error setting up settings directory: {e}")

# Real-world simulation parameters (unscaled)
simulation_params = {
    "sun": {
        "mass": 1.989e30,  # Real mass in kg
        "position": [0, 0, 0],
        "orbital_velocity": 0,  # Sun is stationary
    },
    "earth": {
        "mass": 5.972e24,  # Real mass in kg
        "position": [149.6e6, 0, 0],  # 1 AU in km
        "orbital_velocity": 29.8,  # Real orbital velocity in km/s
    },
    "mars": {
        "mass": 6.417e23,  # Real mass in kg
        "position": [227.9e6, 0, 0],  # 1.52 AU in km
        "orbital_velocity": 24.1,  # Real orbital velocity in km/s
    },
    "fluid_speed": 0.1,
    "fluid_friction": 0.9,
    "fluid_deflection": 0.1,
}

# Serve the frontend
@app.route('/')
def serve_index():
    return send_from_directory('static', 'index.html')

# Serve static files (CSS, JS)
@app.route('/static/<path:path>')
def serve_static(path):
    return send_from_directory('static', path)

# API to get simulation parameters
@app.route('/api/params', methods=['GET'])
def get_params():
    return jsonify(simulation_params)

# API to update simulation parameters
@app.route('/api/params', methods=['POST'])
def update_params():
    global simulation_params
    data = request.get_json()
    simulation_params.update(data)
    return jsonify({"status": "success", "params": simulation_params})

# API to save settings to a JSON file
@app.route('/api/save', methods=['POST'])
def save_settings():
    try:
        filename = os.path.join(SETTINGS_DIR, "settings.json")
        with open(filename, 'w') as f:
            json.dump(simulation_params, f, indent=4)
        return jsonify({"status": "success", "message": "Settings saved successfully"})
    except PermissionError as e:
        return jsonify({"status": "error", "message": "Permission denied: Unable to save settings. Please check directory permissions."}), 500
    except Exception as e:
        return jsonify({"status": "error", "message": f"Error saving settings: {str(e)}"}), 500

# API to load settings from a JSON file
@app.route('/api/load', methods=['GET'])
def load_settings():
    global simulation_params
    try:
        filename = os.path.join(SETTINGS_DIR, "settings.json")
        if os.path.exists(filename):
            with open(filename, 'r') as f:
                simulation_params = json.load(f)
            return jsonify({"status": "success", "params": simulation_params})
        else:
            return jsonify({"status": "error", "message": "No saved settings found"}), 404
    except PermissionError as e:
        return jsonify({"status": "error", "message": "Permission denied: Unable to load settings. Please check directory permissions."}), 500
    except Exception as e:
        return jsonify({"status": "error", "message": f"Error loading settings: {str(e)}"}), 500

if __name__ == '__main__':
    port = int(os.environ.get('PORT', 7860))  # Default port for Hugging Face Spaces
    app.run(host='0.0.0.0', port=port)