import traceback, re, asyncio
from pymud import Command, IConfig

class CmdDelVar(Command, IConfig):
    _help = """
    通过命令行删除废弃变量的命令：
        正常指令      含义
        delvar xxx:    删除变量名为'xxx'的变量
        delvar :      删除所有变量
    """
    def __init__(self, session, *args, **kwargs):
        # delvar命令后，删除所有变量
        pattern = r"^(\bdelvar\b)(?:\s+([a-zA-Z_][a-zA-Z0-9_]*))?$"
        kwargs.setdefault("id", "cmd_delvar")
        super().__init__(session, patterns = pattern, *args, **kwargs)
    def __unload__(self):
        super().__unload__()

    async def execute(self, cmd, *args, **kwargs):
        """
        执行delvar命令，删除所有变量或指定变量
        """
        try:
            m = re.match(self.patterns, cmd)
            if m:
                para = list()
                for i in range(1, 3):
                    if m[i] != None:
                        para.append(m[i])
                if (len(para) == 2):
                    self.session.delVariable(para[1])
                    self.session.info(f"变量 {para[1]} 已删除")
                else:
                    var_list = list()
                    for var in self.session.vars.keys():
                        var_list.append(var)
                    for var in var_list:
                        self.session.delVariable(var)
                    self.session.info("所有变量已删除")
        except Exception as e:
            self.error(f"异步执行中遇到异常, {e}, 类型为 {type(e)}")
            self.error(f"异常追踪为： {traceback.format_exc()}")