"""MCP 传输层工厂。

根据 server 的 transport 字段创建对应的 TransportProtocol 实例。
"""

from __future__ import annotations

import json
from typing import Any

import httpx

from app.integrations.mcp.transports.base import TransportProtocol
from app.integrations.mcp.transports.http import StreamableHttpTransport
from app.integrations.mcp.transports.stdio import StdioTransport


def get_transport(
    server: Any,
    http_client: httpx.AsyncClient | None = None,
) -> TransportProtocol:
    """根据 server 的 transport 字段创建传输层实例。"""
    transport = server.transport if hasattr(server, "transport") else "streamable-http"

    if transport == "stdio":
        args: list[str] = []
        if hasattr(server, "args_json") and server.args_json:
            try:
                parsed = json.loads(server.args_json)
                if isinstance(parsed, list):
                    args = [str(a) for a in parsed]
            except (json.JSONDecodeError, TypeError):
                pass

        env: dict[str, str] | None = None
        if hasattr(server, "env_json") and server.env_json:
            try:
                parsed = json.loads(server.env_json)
                if isinstance(parsed, dict):
                    env = {str(k): str(v) for k, v in parsed.items()}
            except (json.JSONDecodeError, TypeError):
                pass

        cwd: str | None = None
        if hasattr(server, "cwd") and server.cwd:
            cwd = server.cwd

        cmd = getattr(server, "command", None) or ""
        return StdioTransport(
            server_id=server.id,
            server_name=server.name,
            command=cmd,
            args=args,
            env=env,
            cwd=cwd,
        )

    # 默认 streamable-http
    endpoint_url = getattr(server, "endpoint_url", None) or ""
    auth_token = getattr(server, "auth_token", None)
    return StreamableHttpTransport(
        server_id=server.id,
        server_name=server.name,
        endpoint_url=endpoint_url,
        auth_token=auth_token,
        http_client=http_client,
    )