from flask import Flask, request, jsonify

app = Flask(__name__)

accounts = {
    '1': {'amount': 1000},
    '2': {'amount': 1000},
}

transactions = []


# POST endpoint
@app.route('/transfer', methods = ['POST'])
def transfer():
    new_balance = request.get_json()
    from_account = new_balance.get('from_account')
    to_account = new_balance.get('to_account')
    desired_amount = new_balance.get('desired_amount')

    # validate input
    if from from_account not in accounts or to_account not in accounts:
        return jsontify({"error: Invalid account"}), 404

    # transfer process
    accounts[from_account]['amount'] -= desired_amount
    accounts[to_account]['amount'] += desired_amount
    transactions.append(accounts)

# GET endpoint
@app.route ('/transfer', method=['GET'])
def get_information():
    new_balance = request.get_json()
    from_account = new_balance.get('from_account')
    to_account = new_balance.get('to_account')

    # validate input
    if from from_account not in accounts or to_account not in accounts:
        return jsontify({"error: Unknown account"}), 404

    # get the information
    return jsontify(transactions)