import os

user_staus = {'username': None}


def ad_credit(username, amount):
  """
  充值功能
  :param username:
  :param amount:
  :return:
  """
  if user_staus['username'] is None:
    login()
  with open('db.txt', 'rt', encoding='utf-8')as f1, \
      open('db.txt.swap', 'wt', encoding='utf-8')as f2:
    while True:
      cont = f1.readline()
      if len(cont) == 0:
        break
      name, remain = cont.strip().split(':')
      if username in name:
        remain = int(remain) + int(amount)
        f2.write('{}:{}\n'.format(name, remain))
        print('充值成功，{}的余額為{}'.format(username, remain))
      else:
        f2.write(cont)
  os.remove('db.txt')
  os.rename('db.txt.swap', 'db.txt')


def transfer(user_out, user_in, amount):
  '''3
  轉(zhuǎn)賬功能
  :param user_out:
  :param user_in:
  :param amount:
  :return:
  '''
  if user_staus['username'] is None:
    login()
  with open('db.txt', 'rt', encoding='utf-8')as f1, \
      open('db.txt.swap', 'wt', encoding='utf-8')as f2:

    userinfo = {}
    for line in f1:
      name, remind = line.strip().split(':')
      userinfo[name] = int(remind)
    if user_out not in userinfo:
      print('用戶不存在')
      return
    if user_in not in userinfo:
      print('收款方不存在')
      return
    if user_out in userinfo and user_in in userinfo:
      if userinfo[user_out] >= int(amount):
        userinfo[user_out] -= int(amount)
        userinfo[user_in] += int(amount)
        print('轉(zhuǎn)賬成功，已成功從{}向{}匯款{}'.format(user_out, user_in, amount))
      elif userinfo[user_out] < amount:
        print('余額不足')
        return
    for name, remind in userinfo.items():
      f2.write('{}:{}\n'.format(name, remind))

  os.remove('db.txt')
  os.rename('db.txt.swap', 'db.txt')


def cashon(username, amount):
  '''
  提現(xiàn)功能
  :param username:
  :param amount:
  :return:
  '''
  if user_staus['username'] is None:
    login()
  with open('db.txt', 'rt', encoding='utf-8')as f1, \
      open('db.txt.swap', 'wt', encoding='utf-8')as f2:
    userinfo = {}
    for line in f1:
      name, remind = line.strip().split(':')
      userinfo[name] = int(remind)
    if username not in userinfo:
      print('用戶不存在')
      return
    if username in userinfo and userinfo[username] >= int(amount):
      userinfo[username] -= int(amount)
      print('已從余額中取出{}，現(xiàn)余額為{}'.format(amount, userinfo[username]))
    elif userinfo[username] < amount:
      print('余額不足，提現(xiàn)失敗')
      return
    for name, remind in userinfo.items():
      f2.write('{}:{}\n'.format(name, remind))
  os.remove('db.txt')
  os.rename('db.txt.swap', 'db.txt')


def check(username):
  '''
  余額查詢功能
  :param username:
  :return:
  '''
  if user_staus['username'] is None:
    login()
  with open('db.txt', 'rt', encoding='utf-8')as f:
    userinfo = {}
    for line in f:
      name, remind = line.strip().split(':')
      userinfo[name] = remind
    if username not in userinfo:
      print('用戶不存在')
      return
    if username in userinfo:
      print('當(dāng)前余額為：{}'.format(userinfo[username]))


def login():
  username = input('輸入用戶名')
  userpassword = input('輸入密碼')
  with open('login.txt', 'rt', encoding='utf-8')as login_f:
    login = {}
    for line in login_f:
      name, psd = line.strip().split(':')
      login[name] = psd
      if username in login:
        if login[username] == userpassword:
          print('登陸成功')
          user_staus['username'] = username
          break
      elif username not in login:
        print('用戶名不存在')
        return


def logout():
  user_staus['username'] = None
  print('已成功登出')
  return


login()
tag = True
while tag:
  cmd = input('''
  請輸入你想使用的功能序號
  1：充值
  2：轉(zhuǎn)賬
  3：提現(xiàn)
  4：查詢余額
  0：登出
  ''')
  if cmd == '1':
    username = input('輸入用戶名：')
    amount = input('輸入充值金額：')
    ad_credit(username, amount)
  elif cmd == '2':
    user_out = input('請輸入轉(zhuǎn)賬方：')
    user_in = input('請輸入接收方：')
    amount = input('輸入轉(zhuǎn)賬金額：')
    transfer(user_out, user_in, amount)
  elif cmd == '3':
    username = input('輸入用戶名：')
    amount = input('輸入提現(xiàn)金額')
    cashon(username, amount)
  elif cmd == '4':
    username = input('輸入用戶名：')
    check(username)
  elif cmd == '0':
    logout()
    tag = False
  else:
    print('請正確輸入序號')