From d04df4625ef31b2342078500ff1910ee386c517e Mon Sep 17 00:00:00 2001
From: Devon Friend <69879126+DFriend01@users.noreply.github.com>
Date: Sat, 29 Jul 2023 18:23:48 -0700
Subject: [PATCH] Change launch file to follow new convention (#31)

---
 launch/example.py     | 13 --------
 launch/main_launch.py | 75 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 75 insertions(+), 13 deletions(-)
 delete mode 100644 launch/example.py
 create mode 100644 launch/main_launch.py

diff --git a/launch/example.py b/launch/example.py
deleted file mode 100644
index c43889b..0000000
--- a/launch/example.py
+++ /dev/null
@@ -1,13 +0,0 @@
-from launch import LaunchDescription
-from launch_ros.actions import Node
-
-
-def generate_launch_description():
-    return LaunchDescription([
-        Node(
-            package='network_systems',
-            node_namespace='example',
-            node_executable='example',
-            node_name='cached_fib'
-        )
-    ])
diff --git a/launch/main_launch.py b/launch/main_launch.py
new file mode 100644
index 0000000..fc4a3db
--- /dev/null
+++ b/launch/main_launch.py
@@ -0,0 +1,75 @@
+import importlib
+import os
+from types import ModuleType
+from typing import List
+
+from launch_ros.actions import Node
+
+from launch import LaunchDescription
+from launch.substitutions import LaunchConfiguration
+
+
+def get_global_main_launch_module() -> ModuleType:
+    """Execute and return the main launch file of the `global_launch` package.
+
+    Returns:
+        ModuleType: The executed module.
+    """
+    global_main_launch = os.path.join(
+        os.getenv("ROS_WORKSPACE"), "src", "global_launch", "main_launch.py"
+    )
+    spec = importlib.util.spec_from_file_location("global_launch", global_main_launch)
+    module = importlib.util.module_from_spec(spec)
+    spec.loader.exec_module(module)
+    return module
+
+
+GLOBAL_LAUNCH = get_global_main_launch_module()
+
+
+def generate_launch_description() -> LaunchDescription:
+    """Generate the launch description for the `local_pathfinding` package.
+
+    Returns:
+        LaunchDescription: The launch description.
+    """
+    # get_nodes() arguments for the package launch
+    common_parameters = [GLOBAL_LAUNCH.GLOBAL_CONFIG]
+    common_ros_arguments = [*GLOBAL_LAUNCH.get_log_ros_arguments()]
+    mode = LaunchConfiguration("mode")
+
+    return LaunchDescription(
+        [
+            *GLOBAL_LAUNCH.GLOBAL_LAUNCH_ARGUMENTS,
+            *get_nodes(common_parameters, common_ros_arguments, mode),
+        ]
+    )
+
+
+def get_nodes(common_parameters: List, common_ros_arguments: List, mode: str) -> List[Node]:
+    """Get the nodes to be launched depending on an indicated mode.
+
+    Args:
+        common_parameters (List): Parameters that are common to all nodes.
+        common_ros_arguments (List): ROS arguments that are common to all nodes.
+        mode (str): The system mode.
+
+    Returns:
+        List[Node]: The nodes to be launched.
+    """
+    # cached_fib parameters and ROS arguments
+    cached_fib_parameters = [*common_parameters]
+    cached_fib_ros_arguments = [*common_ros_arguments]
+
+    nodes = [
+        Node(
+            package="network_systems",
+            namespace="example",
+            executable="example",
+            name="cached_fib",
+            parameters=cached_fib_parameters,
+            ros_arguments=cached_fib_ros_arguments,
+        ),
+    ]
+
+    return nodes