from typing import Optional


class MqttTopic:
    """
    封装 MQTT topic，根据规则:
    project/domain/deviceType/deviceId/resource
    """

    LEVELS = 5

    def __init__(self, topic: str):
        self.raw = str(topic)
        parts = self.raw.split("/")

        # 不足的层级用 None 补齐，避免属性缺失
        parts += [None] * (self.LEVELS - len(parts))

        self.dept_id: Optional[str] = parts[0]
        self.domain: Optional[str] = parts[1]
        self.device_type: Optional[str] = parts[2]
        self.device_id: Optional[str] = parts[3]
        self.resource: Optional[str] = parts[4]

    @classmethod
    def from_parts(
        cls,
        dept_id: Optional[str] = None,
        domain: Optional[str] = None,
        device_type: Optional[str] = None,
        device_id: Optional[str] = None,
        resource: Optional[str] = None,
    ) -> "MqttTopic":
        """
        通过结构化参数构造 topic
        None -> '+'
        """

        def _v(v: Optional[str]) -> str:
            return "+" if v is None else str(v)

        topic = "/".join(
            map(
                _v,
                [
                    dept_id,
                    domain,
                    device_type,
                    device_id,
                    resource,
                ],
            )
        )
        return cls(topic)

    def to_topic(self) -> str:
        """
        根据当前字段生成 topic（允许 '+')
        """

        def _v(v: Optional[str]) -> str:
            return "+" if v is None else v

        return "/".join(
            map(
                _v,
                [
                    self.dept_id,
                    self.domain,
                    self.device_type,
                    self.device_id,
                    self.resource,
                ],
            )
        )

    def build(self) -> str:
        """
        生成严格 topic（不允许 None / '+'）
        用于 publish 场景
        """
        parts = [
            self.dept_id,
            self.domain,
            self.device_type,
            self.device_id,
            self.resource,
        ]

        if any(p in (None, "+") for p in parts):
            raise ValueError(
                f"Cannot build strict topic, wildcard exists: {self.to_topic()}"
            )

        return "/".join(parts)

    def is_wildcard(self) -> bool:
        return "+" in self.to_topic() or "#" in self.to_topic()

    def __repr__(self):
        return f"<MqttTopic {self.to_topic()}>"

    def is_status(self) -> bool:
        return self.domain == "status" and self.resource == "info"

    def is_cmd(self) -> bool:
        return self.domain == "cmd"