"""Simple wrapper for mode change via fc_network ROS2 service.

Reference CLI command:
ros2 service call /fc_network/vehicle/send_command_long \
  fc_interfaces/srv/MavCommandLong \
  "{target_sysid: 3, target_compid: 0, command: 176, confirmation: 0, \
    param1: 1, param2: 4, param3: 0, param4: 0, param5: 0, param6: 0, \
    param7: 0, timeout_sec: 2}"
"""

from __future__ import annotations

from dataclasses import dataclass
from typing import Optional

import rclpy
from rclpy.node import Node

from fc_interfaces.srv import MavCommandLong

COMMAND_DO_SET_MODE = 176
DEFAULT_SERVICE_NAME = "/fc_network/vehicle/send_command_long"
DEFAULT_TIMEOUT_SEC = 2.0

@dataclass
class ChangeModeResult:
    """Return value for mode change requests."""

    success: bool
    message: str
    ack_result: int

def change_mode(
    *,
    target_sysid: int,
    custom_mode: float,
    target_compid: int = 0,
    base_mode: float = 1.0,
    confirmation: int = 0,
    timeout_sec: float = DEFAULT_TIMEOUT_SEC,
    service_name: str = DEFAULT_SERVICE_NAME,
) -> ChangeModeResult:

    """One-shot helper for collaborators who want minimal code."""
    rclpy.init(args=None)
    node: Optional[Node] = None
    try:
        node = Node("fc_change_mode_client_once")
        client = node.create_client(MavCommandLong, service_name)

        if not client.wait_for_service(timeout_sec=timeout_sec):
            return ChangeModeResult(
                success=False,
                message=f"Service not available: {service_name}",
                ack_result=-1,
            )

        req = MavCommandLong.Request()
        req.target_sysid = target_sysid
        req.target_compid = target_compid
        req.command = COMMAND_DO_SET_MODE
        req.confirmation = confirmation
        req.param1 = float(base_mode)
        req.param2 = float(custom_mode)
        req.param3 = 0.0
        req.param4 = 0.0
        req.param5 = 0.0
        req.param6 = 0.0
        req.param7 = 0.0
        req.timeout_sec = float(timeout_sec)

        future = client.call_async(req)
        rclpy.spin_until_future_complete(node, future, timeout_sec=timeout_sec + 1.0)
        if not future.done() or future.result() is None:
            return ChangeModeResult(
                success=False,
                message="Service call timeout or no response.",
                ack_result=-1,
            )

        response = future.result()
        return ChangeModeResult(
            success=response.success,
            message=response.message,
            ack_result=response.ack_result,
        )
    finally:
        if node is not None:
            node.destroy_node()
        rclpy.shutdown()


if __name__ == "__main__":
    # Example values are aligned with your terminal command.
    result = change_mode(target_sysid=3, custom_mode=4)
    print(
        f"change_mode success={result.success}, "
        f"ack_result={result.ack_result}, message='{result.message}'"
    )