from __future__ import annotations

import re
from dataclasses import dataclass
from pathlib import Path


PROFILE_ID_RE = re.compile(r"^[a-z0-9][a-z0-9_-]{0,63}$")


@dataclass(frozen=True)
class AgentProfile:
    id: str
    name: str


class InvalidAgentId(ValueError):
    pass


class UnknownAgent(ValueError):
    pass


class ProfileDiscovery:
    def __init__(self, profiles_dir: str | Path = "Hermes/profiles") -> None:
        self.profiles_dir = Path(profiles_dir)

    def list_agents(self) -> list[AgentProfile]:
        if not self.profiles_dir.exists():
            return []

        agents: list[AgentProfile] = []
        for child in sorted(self.profiles_dir.iterdir(), key=lambda item: item.name):
            if child.is_dir() and PROFILE_ID_RE.fullmatch(child.name):
                agents.append(AgentProfile(id=child.name, name=child.name))
        return agents

    def validate_agent_id(self, agent_id: str) -> str:
        if not PROFILE_ID_RE.fullmatch(agent_id):
            raise InvalidAgentId("Invalid agent_id.")

        path = (self.profiles_dir / agent_id).resolve()
        root = self.profiles_dir.resolve()
        if path.parent != root or not path.is_dir():
            raise UnknownAgent("Unknown agent_id.")
        return agent_id