fix: convert MultiPolygons to Polygons (LAN-794)

Water Body: Leaflet Draw doesn't support editing the MutiPolygons (imported
from the former GIS), so we need to convert them to Polygons.

landa/patches.txt

@@ -28,3 +28,4 @@ landa.patches.set_hide_custom_in_user_workspaces
 landa.patches.cleanup_addresses_and_contacts
 landa.patches.lease_rent_per_year
 landa.patches.add_water_body_title_in_stocking
+landa.patches.multi_to_polygon

landa/patches/multi_to_polygon.py

@@ -0,0 +1,40 @@
+import json
+
+import frappe
+
+
+def execute():
+	"""
+	Water Body: convert all MultiPolygons to Polygons in the geo shapes.
+
+	Leaflet Draw doesn't support editing the MutiPolygons (imported from the
+	former GIS), so we need to convert them to Polygons.
+	"""
+	for wb_name in frappe.get_all(
+		"Water Body", filters={"location": ("like", "%MultiPolygon%")}, pluck="name"
+	):
+		geojson_str = frappe.db.get_value("Water Body", wb_name, "location")
+		geojson = json.loads(geojson_str)
+
+		if "features" not in geojson:
+			continue
+
+		features = []
+		modified = False
+		for feature in geojson["features"]:
+			if feature["geometry"]["type"] != "MultiPolygon":
+				features.append(feature)
+			else:
+				features.extend(
+					{
+						"type": "Feature",
+						"geometry": {"type": "Polygon", "coordinates": polygon},
+						"properties": feature["properties"],
+					}
+					for polygon in feature["geometry"]["coordinates"]
+				)
+				modified = True
+
+		if modified:
+			geojson["features"] = features
+			frappe.db.set_value("Water Body", wb_name, "location", json.dumps(geojson))