Implemented buildAutoChooser() in Python. (#639)

* Implemented the method 'buildAutoChooser' for the Autobuilder class in the python lib.

* Added Python Sendablechooser Usage Docs.

* fixed a folder path bug

* Added tabs to autochooser PP docs

Writerside/topics/pplib-Build-an-Auto.md

@@ -432,7 +432,7 @@ class RobotContainer:
 
 > **Note**
 >
-> This feature is only available in the Java version of PathPlannerLib
+> This feature is only available in the Java and Python versions of PathPlannerLib
 >
 {style="note"}
 
@@ -449,6 +449,9 @@ every auto in the project.
 >
 {style="warning"}
 
+<tabs group="pplib-language">
+<tab title="Java" group-key="java">
+
 ```Java
 public class RobotContainer {
   private final SendableChooser<Command> autoChooser;
@@ -471,4 +474,29 @@ public class RobotContainer {
 }
 ```
 
-</snippet>
+</tab>
+<tab title="Python" group-key="python">
+
+```Python
+from pathplannerlib.auto import AutoBuilder
+
+class RobotContainer:
+
+    def __init__():
+
+        # Build an auto chooser. This will use Commands.none() as the default option.
+        self.autoChooser = AutoBuilder.buildAutoChooser()
+
+        # Another option that allows you to specify the default auto by its name
+        # self.autoChooser = AutoBuilder.buildAutoChooser("My Default Auto")
+
+        SmartDashboard.putData("Auto Chooser", self.autoChooser)
+
+    def getAutonomousCommand():
+        return self.autoChooser.getSelected()
+```
+
+</tab>
+</tabs>
+
+</snippet>

pathplannerlib-python/pathplannerlib/auto.py

@@ -9,7 +9,7 @@
     PathfindThenFollowPathLTV
 from .geometry_util import flipFieldPose
 import os
-from wpilib import getDeployDirectory, reportError, reportWarning
+from wpilib import getDeployDirectory, reportError, reportWarning, SendableChooser
 import json
 from commands2.command import Command
 from commands2.subsystem import Subsystem
@@ -499,7 +499,34 @@ def buildAuto(auto_name: str) -> Command:
         with open(filePath, 'r') as f:
             auto_json = json.loads(f.read())
             return AutoBuilder.getAutoCommandFromJson(auto_json)
-
+
+    @staticmethod
+    def buildAutoChooser(default_auto_name: str = "") -> SendableChooser:
+        """
+        Create and populate a sendable chooser with all PathPlannerAutos in the project and the default auto name selected.
+        
+        :param default_auto_name: the name of the default auto to be selected in the chooser
+        :return: a sendable chooser object populated with all of PathPlannerAutos in the project
+        """
+        if not AutoBuilder.isConfigured():
+            raise RuntimeError('AutoBuilder was not configured before attempting to build an auto chooser')
+        auto_folder_path = os.path.join(getDeployDirectory(), 'pathplanner', 'autos')
+        auto_list = os.listdir(auto_folder_path)
+
+        chooser = SendableChooser()
+        default_auto_added = False
+
+        for auto in auto_list:
+            auto = auto.removesuffix(".auto")
+            if auto == default_auto_name:
+                default_auto_added = True
+                chooser.setDefaultOption(auto, AutoBuilder.buildAuto(auto))
+            else:
+                chooser.addOption(auto, AutoBuilder.buildAuto(auto))
+        if not default_auto_added:
+            chooser.setDefaultOption("None", cmd.none())
+        return chooser
+
 
 class PathPlannerAuto(Command):
     _autoCommand: Command