feat(config.py): add Config type

This allows folks to just do `config.stuff()` instead of fallibly-indexing into the ConfigParser dictionary each time.

In other words, there's a single point of failure, which is something I'd like to get rid of.

libs/config.py

@@ -0,0 +1,99 @@
+from configparser import ConfigParser
+
+from dataclasses import dataclass
+
+@dataclass(kw_only=True)
+class Config:
+    """
+    A container for the rover's configuration.
+    """
+    config: ConfigParser
+
+    ##### MBED, for controlling the LEDs #####
+
+    def mbed_ip(self) -> str:
+        """
+        Returns the IP address of the MBED micro-controller.
+        """
+        return str(self.config["CONFIG"]["MBED_IP"])
+
+    def mbed_port(self) -> int:
+        """
+        Returns the port number of the MBED micro-controller.
+        """
+        return int(self.config["CONFIG"]["MBED_PORT"])
+
+    ##### Swift, for getting GPS coordinates #####
+
+    def gps_ip(self) -> str:
+        """
+        Returns the IP address of the Swift GPS module.
+        """
+        return str(self.config["CONFIG"]["SWIFT_IP"])
+
+    def gps_port(self) -> int:
+        """
+        Returns the port number of the Swift GPS module.
+        """
+        return int(self.config["CONFIG"]["SWIFT_PORT"])
+
+    ##### OpenCV format #####
+
+    def opencv_format(self) -> str:
+        """
+        Returns the OpenCV format string for camera initialization.
+        """
+        return self.config["ARTRACKER"]["FORMAT"]
+
+    ##### Camera traits, for object distances and angles #####
+
+    def camera_hdegrees_per_pixel(self) -> float:
+        """
+        Returns the horizontal degrees per pixel for the camera.
+        """
+        return float(self.config["ARTRACKER"]["DEGREES_PER_PIXEL"])
+
+    def camera_vdegrees_per_pixel(self) -> float:
+        """
+        Returns the vertical degrees per pixel for the camera.
+        """
+        return float(self.config["ARTRACKER"]["VDEGREES_PER_PIXEL"])
+
+    def camera_frame_width(self) -> int:
+        """
+        Returns the width of the camera frame.
+        """
+        return int(self.config["ARTRACKER"]["FRAME_WIDTH"])
+
+    def camera_frame_height(self) -> int:
+        """
+        Returns the height of the camera frame.
+        """
+        return int(self.config["ARTRACKER"]["FRAME_HEIGHT"])
+
+    def camera_focal_length(self) -> float:
+        """
+        The focal length of the camera.
+        """
+        return float(self.config["ARTRACKER"]["FOCAL_LENGTH"])
+
+    ## TODO: remove these if we use the OpenCV distance/angle function
+
+    def camera_known_marker_size(self) -> float:
+        """
+        The real-world width/height of an ARUCO marker. This helps calculate 
+        the distance/angle to the marker.
+        """
+        return float(self.config["ARTRACKER"]["KNOWN_TAG_WIDTH"])
+
+    def camera_focal_length30h(self) -> float:
+        """
+        The focal length of the camera at 30 degrees horizontal.
+        """
+        return float(self.config["ARTRACKER"]["FOCAL_LENGTH30H"])
+
+    def camera_focal_length30v(self) -> float:
+        """
+        The focal length of the camera at 30 degrees vertical.
+        """
+        return float(self.config["ARTRACKER"]["FOCAL_LENGTH30V"])