# Copyright (c) 2018 Intel Corporation
#
# 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.

import os

from ament_index_python.packages import get_package_share_directory

from launch import LaunchDescription
from launch.actions import DeclareLaunchArgument, GroupAction, SetEnvironmentVariable
from launch.conditions import IfCondition
from launch.substitutions import LaunchConfiguration, PythonExpression
from launch_ros.actions import LoadComposableNodes
from launch_ros.actions import Node
from launch_ros.descriptions import ComposableNode, ParameterFile
from nav2_common.launch import RewrittenYaml


def generate_launch_description():
    # Get the launch directory
    bringup_dir = get_package_share_directory("nav2_bringup")

    namespace = LaunchConfiguration("namespace")
    map_yaml_file = LaunchConfiguration("map")
    use_sim_time = LaunchConfiguration("use_sim_time")
    autostart = LaunchConfiguration("autostart")
    params_file = LaunchConfiguration("params_file")
    use_composition = LaunchConfiguration("use_composition")
    container_name = LaunchConfiguration("container_name")
    container_name_full = (namespace, "/", container_name)
    use_respawn = LaunchConfiguration("use_respawn")
    log_level = LaunchConfiguration("log_level")

    lifecycle_nodes = ["map_server", "amcl"]

    # Create our own temporary YAML files that include substitutions
    param_substitutions = {"use_sim_time": use_sim_time, "yaml_filename": map_yaml_file}

    configured_params = ParameterFile(
        RewrittenYaml(
            source_file=params_file,
            root_key=namespace,
            param_rewrites=param_substitutions,
            convert_types=True,
        ),
        allow_substs=True,
    )

    stdout_linebuf_envvar = SetEnvironmentVariable("RCUTILS_LOGGING_BUFFERED_STREAM", "1")

    declare_namespace_cmd = DeclareLaunchArgument(
        "namespace", default_value="", description="Top-level namespace"
    )

    declare_map_yaml_cmd = DeclareLaunchArgument(
        "map", description="Full path to map yaml file to load"
    )

    declare_use_sim_time_cmd = DeclareLaunchArgument(
        "use_sim_time", default_value="false", 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="False", description="Use composed bringup if True"
    )

    declare_container_name_cmd = DeclareLaunchArgument(
        "container_name",
        default_value="nav2_container",
        description="the name of container that nodes will load in if use composition",
    )

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

    declare_log_level_cmd = DeclareLaunchArgument(
        "log_level", default_value="info", description="log level"
    )

    load_nodes = GroupAction(
        condition=IfCondition(PythonExpression(["not ", use_composition])),
        actions=[
            Node(
                package="nav2_map_server",
                executable="map_server",
                name="map_server",
                output="screen",
                respawn=use_respawn,
                respawn_delay=2.0,
                parameters=[configured_params],
                arguments=["--ros-args", "--log-level", log_level],
            ),
            Node(
                package="nav2_amcl",
                executable="amcl",
                name="amcl",
                output="screen",
                respawn=use_respawn,
                respawn_delay=2.0,
                parameters=[configured_params],
                arguments=["--ros-args", "--log-level", log_level],
            ),
            Node(
                package="nav2_lifecycle_manager",
                executable="lifecycle_manager",
                name="lifecycle_manager_localization",
                output="screen",
                arguments=["--ros-args", "--log-level", log_level],
                parameters=[
                    {"use_sim_time": use_sim_time},
                    {"autostart": autostart},
                    {"node_names": lifecycle_nodes},
                ],
            ),
        ],
    )

    load_composable_nodes = LoadComposableNodes(
        condition=IfCondition(use_composition),
        target_container=container_name_full,
        composable_node_descriptions=[
            ComposableNode(
                package="nav2_map_server",
                plugin="nav2_map_server::MapServer",
                name="map_server",
                parameters=[configured_params],
            ),
            ComposableNode(
                package="nav2_amcl",
                plugin="nav2_amcl::AmclNode",
                name="amcl",
                parameters=[configured_params],
            ),
            ComposableNode(
                package="nav2_lifecycle_manager",
                plugin="nav2_lifecycle_manager::LifecycleManager",
                name="lifecycle_manager_localization",
                parameters=[
                    {
                        "use_sim_time": use_sim_time,
                        "autostart": autostart,
                        "node_names": lifecycle_nodes,
                    }
                ],
            ),
        ],
    )

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

    # Set environment variables
    ld.add_action(stdout_linebuf_envvar)

    # Declare the launch options
    ld.add_action(declare_namespace_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_container_name_cmd)
    ld.add_action(declare_use_respawn_cmd)
    ld.add_action(declare_log_level_cmd)

    # Add the actions to launch all of the localiztion nodes
    ld.add_action(load_nodes)
    ld.add_action(load_composable_nodes)

    return ld