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


class CommandLongClient(Node):
    """Small ROS2 client dedicated to change flight mode."""

    def __init__(self, service_name: str = DEFAULT_SERVICE_NAME) -> None:
        rclpy.init()
        super().__init__("fc_change_mode_client")
        self._client = self.create_client(MavCommandLong, service_name)

    def wait_for_service(self, timeout_sec: float = 3.0) -> bool:
        return self._client.wait_for_service(timeout_sec=timeout_sec)

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

        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 = self._client.call_async(req)
        rclpy.spin_until_future_complete(self, 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,
        )