# Copyright (C) 2023 Open Source Robotics Foundation
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"""This is all-in-one launch script intended for use by nav2 developers."""

import os
import tempfile

from ament_index_python.packages import get_package_share_directory

from launch import LaunchDescription
from launch.actions import (
    DeclareLaunchArgument,
    ExecuteProcess,
    IncludeLaunchDescription,
    OpaqueFunction,
    RegisterEventHandler,
)
from launch.conditions import IfCondition
from launch.event_handlers import OnShutdown
from launch.launch_description_sources import PythonLaunchDescriptionSource
from launch.substitutions import LaunchConfiguration, PythonExpression

from launch_ros.actions import Node


def generate_launch_description():
    # Get the launch directory
    bringup_dir = get_package_share_directory('nav2_bringup')
    launch_dir = os.path.join(bringup_dir, 'launch')
    sim_dir = get_package_share_directory('nav2_minimal_tb3_sim')

    # Create the launch configuration variables
    slam = LaunchConfiguration('slam')
    namespace = LaunchConfiguration('namespace')
    use_namespace = LaunchConfiguration('use_namespace')
    map_yaml_file = LaunchConfiguration('map')
    use_sim_time = LaunchConfiguration('use_sim_time')
    params_file = LaunchConfiguration('params_file')
    autostart = LaunchConfiguration('autostart')
    use_composition = LaunchConfiguration('use_composition')
    use_respawn = LaunchConfiguration('use_respawn')

    # Launch configuration variables specific to simulation
    rviz_config_file = LaunchConfiguration('rviz_config_file')
    use_simulator = LaunchConfiguration('use_simulator')
    use_robot_state_pub = LaunchConfiguration('use_robot_state_pub')
    use_rviz = LaunchConfiguration('use_rviz')
    headless = LaunchConfiguration('headless')
    world = LaunchConfiguration('world')
    pose = {
        'x': LaunchConfiguration('x_pose', default='-2.00'),
        'y': LaunchConfiguration('y_pose', default='-0.50'),
        'z': LaunchConfiguration('z_pose', default='0.01'),
        'R': LaunchConfiguration('roll', default='0.00'),
        'P': LaunchConfiguration('pitch', default='0.00'),
        'Y': LaunchConfiguration('yaw', default='0.00'),
    }
    robot_name = LaunchConfiguration('robot_name')
    robot_sdf = LaunchConfiguration('robot_sdf')

    remappings = [('/tf', 'tf'), ('/tf_static', 'tf_static')]

    # Declare the launch arguments
    declare_namespace_cmd = DeclareLaunchArgument(
        'namespace', default_value='', description='Top-level namespace'
    )

    declare_use_namespace_cmd = DeclareLaunchArgument(
        'use_namespace',
        default_value='false',
        description='Whether to apply a namespace to the navigation stack',
    )

    declare_slam_cmd = DeclareLaunchArgument(
        'slam', default_value='False', description='Whether run a SLAM'
    )

    declare_map_yaml_cmd = DeclareLaunchArgument(
        'map',
        default_value=os.path.join(bringup_dir, 'maps', 'tb3_sandbox.yaml'),
    )

    declare_use_sim_time_cmd = DeclareLaunchArgument(
        'use_sim_time',
        default_value='true',
        description='Use simulation (Gazebo) clock if true',
    )

    declare_params_file_cmd = DeclareLaunchArgument(
        'params_file',
        default_value=os.path.join(bringup_dir, 'params', 'nav2_params.yaml'),
        description='Full path to the ROS2 parameters file to use for all launched nodes',
    )

    declare_autostart_cmd = DeclareLaunchArgument(
        'autostart',
        default_value='true',
        description='Automatically startup the nav2 stack',
    )

    declare_use_composition_cmd = DeclareLaunchArgument(
        'use_composition',
        default_value='True',
        description='Whether to use composed bringup',
    )

    declare_use_respawn_cmd = DeclareLaunchArgument(
        'use_respawn',
        default_value='False',
        description='Whether to respawn if a node crashes. Applied when composition is disabled.',
    )

    declare_rviz_config_file_cmd = DeclareLaunchArgument(
        'rviz_config_file',
        default_value=os.path.join(bringup_dir, 'rviz', 'nav2_default_view.rviz'),
        description='Full path to the RVIZ config file to use',
    )

    declare_use_simulator_cmd = DeclareLaunchArgument(
        'use_simulator',
        default_value='True',
        description='Whether to start the simulator',
    )

    declare_use_robot_state_pub_cmd = DeclareLaunchArgument(
        'use_robot_state_pub',
        default_value='True',
        description='Whether to start the robot state publisher',
    )

    declare_use_rviz_cmd = DeclareLaunchArgument(
        'use_rviz', default_value='True', description='Whether to start RVIZ'
    )

    declare_simulator_cmd = DeclareLaunchArgument(
        'headless', default_value='True', description='Whether to execute gzclient)'
    )

    declare_world_cmd = DeclareLaunchArgument(
        'world',
        default_value=os.path.join(sim_dir, 'worlds', 'tb3_sandbox.sdf.xacro'),
        description='Full path to world model file to load',
    )

    declare_robot_name_cmd = DeclareLaunchArgument(
        'robot_name', default_value='turtlebot3_waffle', description='name of the robot'
    )

    declare_robot_sdf_cmd = DeclareLaunchArgument(
        'robot_sdf',
        default_value=os.path.join(sim_dir, 'urdf', 'gz_waffle.sdf.xacro'),
        description='Full path to robot sdf file to spawn the robot in gazebo',
    )

    urdf = os.path.join(sim_dir, 'urdf', 'turtlebot3_waffle.urdf')
    with open(urdf, 'r') as infp:
        robot_description = infp.read()

    start_robot_state_publisher_cmd = Node(
        condition=IfCondition(use_robot_state_pub),
        package='robot_state_publisher',
        executable='robot_state_publisher',
        name='robot_state_publisher',
        namespace=namespace,
        output='screen',
        parameters=[
            {'use_sim_time': use_sim_time, 'robot_description': robot_description}
        ],
        remappings=remappings,
    )

    rviz_cmd = IncludeLaunchDescription(
        PythonLaunchDescriptionSource(os.path.join(launch_dir, 'rviz_launch.py')),
        condition=IfCondition(use_rviz),
        launch_arguments={
            'namespace': namespace,
            'use_namespace': use_namespace,
            'use_sim_time': use_sim_time,
            'rviz_config': rviz_config_file,
        }.items(),
    )

    bringup_cmd = IncludeLaunchDescription(
        PythonLaunchDescriptionSource(os.path.join(launch_dir, 'bringup_launch.py')),
        launch_arguments={
            'namespace': namespace,
            'use_namespace': use_namespace,
            'slam': slam,
            'map': map_yaml_file,
            'use_sim_time': use_sim_time,
            'params_file': params_file,
            'autostart': autostart,
            'use_composition': use_composition,
            'use_respawn': use_respawn,
        }.items(),
    )
    # The SDF file for the world is a xacro file because we wanted to
    # conditionally load the SceneBroadcaster plugin based on wheter we're
    # running in headless mode. But currently, the Gazebo command line doesn't
    # take SDF strings for worlds, so the output of xacro needs to be saved into
    # a temporary file and passed to Gazebo.
    world_sdf = tempfile.mktemp(prefix='nav2_', suffix='.sdf')
    world_sdf_xacro = ExecuteProcess(
        cmd=['xacro', '-o', world_sdf, ['headless:=', headless], world])
    gazebo_server = ExecuteProcess(
        cmd=['gz', 'sim', '-r', '-s', world_sdf],
        output='screen',
        condition=IfCondition(use_simulator)
    )

    remove_temp_sdf_file = RegisterEventHandler(event_handler=OnShutdown(
        on_shutdown=[
            OpaqueFunction(function=lambda _: os.remove(world_sdf))
        ]))

    gazebo_client = IncludeLaunchDescription(
        PythonLaunchDescriptionSource(
            os.path.join(get_package_share_directory('ros_gz_sim'),
                         'launch',
                         'gz_sim.launch.py')
        ),
        condition=IfCondition(PythonExpression(
            [use_simulator, ' and not ', headless])),
        launch_arguments={'gz_args': ['-v4 -g ']}.items(),
    )

    gz_robot = IncludeLaunchDescription(
        PythonLaunchDescriptionSource(
            os.path.join(sim_dir, 'launch', 'spawn_tb3.launch.py')),
        launch_arguments={'namespace': namespace,
                          'use_sim_time': use_sim_time,
                          'robot_name': robot_name,
                          'robot_sdf': robot_sdf,
                          'x_pose': pose['x'],
                          'y_pose': pose['y'],
                          'z_pose': pose['z'],
                          'roll': pose['R'],
                          'pitch': pose['P'],
                          'yaw': pose['Y']}.items())

    # Create the launch description and populate
    ld = LaunchDescription()

    # Declare the launch options
    ld.add_action(declare_namespace_cmd)
    ld.add_action(declare_use_namespace_cmd)
    ld.add_action(declare_slam_cmd)
    ld.add_action(declare_map_yaml_cmd)
    ld.add_action(declare_use_sim_time_cmd)
    ld.add_action(declare_params_file_cmd)
    ld.add_action(declare_autostart_cmd)
    ld.add_action(declare_use_composition_cmd)

    ld.add_action(declare_rviz_config_file_cmd)
    ld.add_action(declare_use_simulator_cmd)
    ld.add_action(declare_use_robot_state_pub_cmd)
    ld.add_action(declare_use_rviz_cmd)
    ld.add_action(declare_simulator_cmd)
    ld.add_action(declare_world_cmd)
    ld.add_action(declare_robot_name_cmd)
    ld.add_action(declare_robot_sdf_cmd)
    ld.add_action(declare_use_respawn_cmd)

    ld.add_action(world_sdf_xacro)
    ld.add_action(remove_temp_sdf_file)
    ld.add_action(gz_robot)
    ld.add_action(gazebo_server)
    ld.add_action(gazebo_client)

    # Add the actions to launch all of the navigation nodes
    ld.add_action(start_robot_state_publisher_cmd)
    ld.add_action(rviz_cmd)
    ld.add_action(bringup_cmd)

    return ld