"""Shared Agent install/upgrade paths and shell fragments (aligned with web/agent/install.sh)."""

from __future__ import annotations

from server.application.server_batch_common import agent_files_curl_cmds, sudo_wrap

# Must match web/agent/install.sh
AGENT_INSTALL_DIR = "/opt/nexus-agent"
AGENT_PIP_PACKAGES = (
    "fastapi==0.115.6",
    "uvicorn==0.34.0",
    "httpx==0.28.1",
    "psutil",
    "python-multipart==0.0.19",
)


def agent_venv_python(install_dir: str = AGENT_INSTALL_DIR) -> str:
    return f"{install_dir}/.venv/bin/python"


def agent_pip_install_cmd(venv_python: str | None = None) -> str:
    py = venv_python or agent_venv_python()
    pkgs = " ".join(AGENT_PIP_PACKAGES)
    return f"{py} -m pip install -q {pkgs}"


def agent_python_version_check_cmd(venv_python: str | None = None) -> str:
    py = venv_python or agent_venv_python()
    return (
        f"{py} -c '"
        "import sys; v=sys.version_info; "
        "print(f\"py_ok_{v.major}.{v.minor}.{v.micro}\") "
        "if v.major==3 and v.minor>=10 else sys.exit(1)'"
    )


def agent_rsync_install_cmd() -> str:
    return (
        "(command -v rsync >/dev/null 2>&1 || "
        "(apt-get update -qq && apt-get install -y -qq rsync) || "
        "(yum install -y -q rsync) || (dnf install -y -q rsync))"
    )


def agent_kill_port_cmd(agent_port: int) -> str:
    return f"fuser -k {int(agent_port)}/tcp 2>/dev/null || true; "


def build_agent_upgrade_cmd(
    *,
    base_url: str,
    ssh_user: str,
    install_dir: str = AGENT_INSTALL_DIR,
    agent_port: int = 8601,
) -> str:
    """Shell pipeline: rsync → py check → pip → backup → download → restart → verify."""
    venv_python = agent_venv_python(install_dir)
    systemctl_prefix = "sudo " if ssh_user != "root" else ""
    return sudo_wrap(
        f"{agent_rsync_install_cmd()} "
        f"&& {agent_python_version_check_cmd(venv_python)} "
        f"&& {agent_pip_install_cmd(venv_python)} "
        f"&& cp {install_dir}/agent.py {install_dir}/agent.py.bak "
        f"&& {agent_files_curl_cmds(base_url, install_dir)} "
        f"&& {agent_kill_port_cmd(agent_port)}{systemctl_prefix}systemctl restart nexus-agent "
        f"&& sleep 2 "
        f"&& {systemctl_prefix}systemctl is-active nexus-agent "
        f"&& echo 'upgrade_ok'",
        ssh_user,
    )


def build_agent_upgrade_rollback_cmd(
    *,
    ssh_user: str,
    install_dir: str = AGENT_INSTALL_DIR,
) -> str:
    systemctl_prefix = "sudo " if ssh_user != "root" else ""
    return sudo_wrap(
        f"cp {install_dir}/agent.py.bak {install_dir}/agent.py "
        f"&& {systemctl_prefix}systemctl restart nexus-agent",
        ssh_user,
    )