from flask import Flask, request, jsonify
import random
import string
from threading import Lock

app = Flask(__name__)
lock = Lock()
transfers = {}

def generate_id():
    return ''.join(random.choices(string.ascii_letters + string.digits, k=8))

@app.route('/create_transfer', methods=['POST'])
def create_transfer():
    with lock:
        transfer_id = generate_id()
        transfers[transfer_id] = {
            'sender': None,
            'receiver': None,
            'filename': request.json['filename'],
            'filesize': request.json['filesize']
        }
        return jsonify({'transfer_id': transfer_id})

@app.route('/register_sender/<transfer_id>', methods=['POST'])
def register_sender(transfer_id):
    with lock:
        transfers[transfer_id]['sender'] = {
            'ip': request.remote_addr,
            'port': request.json['port']
        }
        return jsonify({'status': 'sender registered'})

@app.route('/register_receiver/<transfer_id>', methods=['POST'])
def register_receiver(transfer_id):
    with lock:
        transfers[transfer_id]['receiver'] = {
            'ip': request.remote_addr,
            'port': request.json['port']
        }
        return jsonify({'status': 'receiver registered'})

@app.route('/get_peer_info/<transfer_id>')
def get_peer_info(transfer_id):
    return jsonify({
        'sender': transfers.get(transfer_id, {}).get('sender'),
        'receiver': transfers.get(transfer_id, {}).get('receiver')
    })

if __name__ == '__main__':
    app.run(host='0.0.0.0', port=5000)