Add fuel_check plugin

plugins/__init__.py

@@ -1 +1,2 @@
-plugins = []
+from . import fuel_check
+plugins = [fuel_check]

plugins/fuel_check.py

@@ -0,0 +1,26 @@
+import time
+
+start = time.monotonic()
+last_message = None
+threshold = 5
+
+def check(data, emit):
+    "Checks if the fuel ratio is below a certain threshold"
+    global last_message
+    if "FuelRatio" not in data:
+        return
+
+    ratio = data["FuelRatio"]
+    if ratio <= threshold:
+        if last_message is None:
+            emit("switchPlugin", {
+                "plugin": "warning",
+                "data": {
+                    "title": "Low Fuel",
+                    "description": f"Only {int(ratio)}% fuel left. Please refill the tank."
+                },
+                "time": 5000
+            })
+            last_message = time.monotonic()
+    else:
+        last_message = None