"""工具注册中心。

职责很单一：
1. 保存当前可用工具实例；
2. 向 LLM 暴露 function schema；
3. 在执行前做基础参数校验，并把异常统一转成文本结果。
"""

from typing import Any

from nanobot.agent.tools.base import Tool


class ToolRegistry:
    """
    Registry for agent tools.

    Allows dynamic registration and execution of tools.
    """

    def __init__(self):
        # 工具名到实例的映射表；工具名在整个 registry 内必须唯一。
        self._tools: dict[str, Tool] = {}

    def register(self, tool: Tool) -> None:
        """注册一个工具实例。"""
        self._tools[tool.name] = tool

    def clone(self) -> "ToolRegistry":
        """创建一个浅拷贝，复用同一批工具实例。"""
        # 这里不深拷贝工具对象，因为很多工具本身持有运行时状态或外部连接。
        # 当前需求只是“在一个请求里临时附加额外工具”，复用实例即可。
        other = ToolRegistry()
        other._tools = dict(self._tools)
        return other

    def unregister(self, name: str) -> None:
        """Unregister a tool by name."""
        self._tools.pop(name, None)

    def get(self, name: str) -> Tool | None:
        """Get a tool by name."""
        return self._tools.get(name)

    def has(self, name: str) -> bool:
        """Check if a tool is registered."""
        return name in self._tools

    def get_definitions(self) -> list[dict[str, Any]]:
        """Get all tool definitions in OpenAI format."""
        return [tool.to_schema() for tool in self._tools.values()]

    async def execute(self, name: str, params: dict[str, Any]) -> str:
        """
        Execute a tool by name with given parameters.

        Args:
            name: Tool name.
            params: Tool parameters.

        Returns:
            Tool execution result as string.

        Raises:
            KeyError: If tool not found.
        """
        _hint = "\n\n[Analyze the error above and try a different approach.]"

        tool = self._tools.get(name)
        if not tool:
            return f"Error: Tool '{name}' not found. Available: {', '.join(self.tool_names)}"

        try:
            # schema 级参数校验放在真正调用前做，尽量把错误反馈成模型能自修复的文本。
            errors = tool.validate_params(params)
            if errors:
                return f"Error: Invalid parameters for tool '{name}': " + "; ".join(errors) + _hint
            result = await tool.execute(**params)
            # 约定：工具若返回以 Error 开头的文本，说明是业务失败而非程序崩溃。
            if isinstance(result, str) and result.startswith("Error"):
                return result + _hint
            return result
        except Exception as e:
            # 保持“不抛异常到模型层”的接口语义，统一回成可读文本。
            return f"Error executing {name}: {str(e)}" + _hint

    @property
    def tool_names(self) -> list[str]:
        """Get list of registered tool names."""
        return list(self._tools.keys())

    def __len__(self) -> int:
        return len(self._tools)

    def __contains__(self, name: str) -> bool:
        return name in self._tools