"""stm32_cmd.launch.py — Launch the binary-framed STM32 command node (Issue #119).

Usage:
  # Default (binary protocol, bidirectional):
  ros2 launch saltybot_bridge stm32_cmd.launch.py

  # Override serial port:
  ros2 launch saltybot_bridge stm32_cmd.launch.py serial_port:=/dev/ttyACM1

  # Custom velocity scales:
  ros2 launch saltybot_bridge stm32_cmd.launch.py speed_scale:=800.0 steer_scale:=-400.0
"""

import os
from ament_index_python.packages import get_package_share_directory
from launch import LaunchDescription
from launch.actions import DeclareLaunchArgument
from launch.substitutions import LaunchConfiguration
from launch_ros.actions import Node


def generate_launch_description() -> LaunchDescription:
    pkg = get_package_share_directory("saltybot_bridge")
    params_file = os.path.join(pkg, "config", "stm32_cmd_params.yaml")

    return LaunchDescription([
        DeclareLaunchArgument("serial_port",      default_value="/dev/ttyACM0"),
        DeclareLaunchArgument("baud_rate",         default_value="921600"),
        DeclareLaunchArgument("speed_scale",       default_value="1000.0"),
        DeclareLaunchArgument("steer_scale",       default_value="-500.0"),
        DeclareLaunchArgument("watchdog_timeout",  default_value="0.5"),
        DeclareLaunchArgument("heartbeat_period",  default_value="0.2"),

        Node(
            package="saltybot_bridge",
            executable="stm32_cmd_node",
            name="stm32_cmd_node",
            output="screen",
            emulate_tty=True,
            parameters=[
                params_file,
                {
                    "serial_port":      LaunchConfiguration("serial_port"),
                    "baud_rate":        LaunchConfiguration("baud_rate"),
                    "speed_scale":      LaunchConfiguration("speed_scale"),
                    "steer_scale":      LaunchConfiguration("steer_scale"),
                    "watchdog_timeout": LaunchConfiguration("watchdog_timeout"),
                    "heartbeat_period": LaunchConfiguration("heartbeat_period"),
                },
            ],
        ),
    ])