"""PAM_NODE MCP 工具的 action runner 封装。"""

from __future__ import annotations

from typing import Any, Protocol

from .models import ActionResult
from .output_parser import parse_mcp_result


class McpToolClient(Protocol):
    """MCP 工具客户端需要实现的最小同步接口。"""

    def call_tool(self, tool_name: str, arguments: dict[str, Any]) -> Any:
        """调用指定 MCP tool，并返回工具原始输出。"""
        ...

    def list_tools(self) -> list[str]:
        """返回 MCP server 暴露的 tool 名称列表。"""
        ...


DEFAULT_NODE_MCP_TOOLS = {
    "get-online-ips": "pam_get_online_ips",
    "create-download-task": "pam_create_download_task",
    "poll-download-progress": "pam_poll_download_progress",
    "upgrade-ip": "pam_upgrade_ip",
    "poll-upgrade-progress": "pam_poll_upgrade_progress",
    "start-ip": "pam_start_ip",
    "stop-ip": "pam_stop_ip",
    "verify-ip": "pam_verify_ip",
    "download-log": "pam_download_log",
    "rollback-ip": "pam_rollback_ip",
}


class McpActionRunner:
    """把 Agent action 转换为 MCP tool 调用。"""

    def __init__(
        self,
        client: McpToolClient | None = None,
        tool_names: dict[str, str] | None = None,
    ) -> None:
        """保存 MCP client 和 action 到 tool name 的映射。"""
        self.client = client
        self.tool_names = tool_names or {}
        self._discovered_tools: list[str] | None = None

    def run(
        self,
        action: str,
        *,
        params: dict[str, Any],
        ip: str | None = None,
        hash_code: str | None = None,
        stop_first: bool = False,
        **_: Any,
    ) -> ActionResult:
        """执行一个 PAM_NODE action，并归一化为 ActionResult。"""
        if self.client is None:
            raise RuntimeError("尚未配置 MCP client")
        tool_name = self._resolve_tool_name(action)
        arguments = self._build_arguments(
            action,
            params=params,
            ip=ip,
            hash_code=hash_code,
            stop_first=stop_first,
        )
        try:
            payload = self.client.call_tool(tool_name, arguments)
        except Exception as exc:  # pragma: no cover - 防御性异常包装
            return parse_mcp_result(action, {}, ok=False, tool_name=tool_name, error=str(exc))
        return parse_mcp_result(action, payload, ok=True, tool_name=tool_name)

    def _resolve_tool_name(self, action: str) -> str:
        """根据显式映射、server tools 自动发现和默认约定解析 tool name。"""
        explicit = self.tool_names.get(action)
        if explicit:
            return explicit

        discovered = self._list_discovered_tools()
        if discovered:
            candidates = _tool_name_candidates(action)
            by_lower = {name.lower(): name for name in discovered}
            for candidate in candidates:
                matched = by_lower.get(candidate.lower())
                if matched:
                    return matched
            available = ", ".join(discovered)
            raise ValueError(f"MCP server 未发现 action 对应 tool: {action}; 已发现: {available}")

        fallback = DEFAULT_NODE_MCP_TOOLS.get(action)
        if fallback:
            return fallback
        raise ValueError(f"action 未映射 MCP tool: {action}")

    def _list_discovered_tools(self) -> list[str]:
        """读取并缓存 MCP server 暴露的 tool 名称。"""
        if self._discovered_tools is not None:
            return self._discovered_tools
        if self.client is None or not hasattr(self.client, "list_tools"):
            self._discovered_tools = []
            return self._discovered_tools
        try:
            self._discovered_tools = list(self.client.list_tools())
        except Exception:
            self._discovered_tools = []
        return self._discovered_tools

    def _build_arguments(
        self,
        action: str,
        *,
        params: dict[str, Any],
        ip: str | None,
        hash_code: str | None,
        stop_first: bool,
    ) -> dict[str, Any]:
        """把 Agent 参数转换为 MCP tool 所需的入参。"""
        arguments = {
            "homeBaseUrl": params.get("HOME_BASE_URL"),
            "airportCode": params.get("AIRPORT_CODE"),
            "applicationName": params.get("APP_NAME"),
            "moduleName": params.get("MODULE_NAME"),
            "versionNumber": params.get("VERSION_NUMBER"),
            "actionType": params.get("ACTION_TYPE"),
            "timeOut": params.get("TIMEOUT"),
            "logName": params.get("LOG_NAME"),
        }
        if ip:
            arguments["targetIp"] = ip
        if hash_code:
            arguments["hashCode"] = hash_code
        if action == "rollback-ip":
            arguments["stopFirst"] = stop_first
        return {key: value for key, value in arguments.items() if value not in (None, "")}


def _tool_name_candidates(action: str) -> list[str]:
    """生成 action 自动匹配 MCP tool 的候选名称。"""
    snake = action.replace("-", "_")
    return [
        action,
        snake,
        f"pam_{snake}",
        f"pam_node_{snake}",
        f"pam.node.{snake}",
        f"pam-node.{action}",
    ]