From 7ae49d35e4feee804a95209b930a33b8f9983e7b Mon Sep 17 00:00:00 2001
From: Khalim Conn-Kowlessar <kconnkowlessar@gmail.com>
Date: Fri, 17 Nov 2023 10:43:14 +0000
Subject: [PATCH] Adding flat roof insulation

---
 .idea/misc.xml                                |  3 +
 recommendations/RoofRecommendations.py        | 55 +++++++++++++++----
 .../tests/test_roof_recommendations.py        | 25 +++++++++
 3 files changed, 73 insertions(+), 10 deletions(-)

diff --git a/.idea/misc.xml b/.idea/misc.xml
index 3b05c6ac..6f308057 100644
--- a/.idea/misc.xml
+++ b/.idea/misc.xml
@@ -1,5 +1,8 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
+  <component name="Black">
+    <option name="sdkName" value="Python 3.10 (backend)" />
+  </component>
   <component name="ProjectRootManager" version="2" project-jdk-name="Python 3.10 (backend)" project-jdk-type="Python SDK" />
   <component name="PythonCompatibilityInspectionAdvertiser">
     <option name="version" value="3" />
diff --git a/recommendations/RoofRecommendations.py b/recommendations/RoofRecommendations.py
index a33a709b..5a011d82 100644
--- a/recommendations/RoofRecommendations.py
+++ b/recommendations/RoofRecommendations.py
@@ -54,29 +54,54 @@ class RoofRecommendations:
         u_value = get_roof_u_value(**{**self.property.roof, "age_band": self.property.age_band})
 
         if self.property.roof["is_pitched"]:
-            self.recommend_loft_insulation(u_value, insulation_thickness)
+            self.recommend_roof_insulation(u_value, insulation_thickness, self.property.roof)
             return
 
         if self.property.roof["is_roof_room"]:
             self.recommend_room_roof_insulation(u_value, insulation_thickness)
             return
 
+        if self.property.roof["is_flat"]:
+            self.recommend_flat_roof_insulation(u_value, insulation_thickness)
+            return
+
         raise NotImplementedError("Implement me")
 
     @staticmethod
     def make_loft_insulation_description(material, depth):
-        return f"Install {depth}{material['depth_unit']} of {material['description']}"
+        return f"Install {depth}{material['depth_unit']} of {material['description']} in your loft"
 
     @staticmethod
-    def make_room_roof_insulation(material, depth):
+    def make_room_roof_insulation_description(material, depth):
         return f"Insulate your room roof with {depth}{material['depth_unit']} of {material['description']}"
 
-    def recommend_loft_insulation(self, u_value, insulation_thickness):
+    @staticmethod
+    def make_flat_roof_insulation_description(material, depth):
+        return f"Insulate the home's flat roof with {depth}{material['depth_unit']} of {material['description']}"
+
+    def recommend_roof_insulation(self, u_value, insulation_thickness, roof):
 
         """
         This method will recommend which insulation materials to use
+        This function handles both the case of loft insulation and flat roof insulation
+
+        We also follow advide provided in this article on the Energy Saving Trust website, providing
+        high level guidance around roof insulation:
+        https://energysavingtrust.org.uk/advice/roof-and-loft-insulation/
+
+        The process roughly looks like the following:
+        - Remove the Existing Weatherproof Layer: If the roof is being replaced, remove the old weatherproof layer to
+        expose the timber roof surface.
+        - Install Insulation Boards: Lay the rigid insulation boards directly on the timber roof surface.
+        Ensure the boards fit tightly together to prevent thermal bridging (heat loss through the gaps).
+        - Add a Vapour Control Layer (VCL): This is crucial to prevent moisture from entering the insulation layer,
+        which can lead to dampness and rot. The VCL is placed over the insulation.
+        - Install a New Weatherproof Layer: On top of the insulation and VCL, install a new weatherproof layer. This
+        could be traditional roofing materials like bitumen-based felt, rubber membranes like EPDM, or fiberglass.
+
         :param u_value: U-value of the roof before any retrofit measures have been installed
         :param insulation_thickness: Existing Insulation thickness of the loft
+        :param roof: dictionary describing the make-up of the roof
         :return:
         """
 
@@ -84,13 +109,19 @@ class RoofRecommendations:
         # Therefore the price is 100mm + whatever thickness is rolled on top, rolled at a 90 degree angle
         # from the base layer
 
-        loft_insulation_materials = [m for m in self.materials if m["type"] == "loft_insulation"]
-        if not loft_insulation_materials:
+        if roof["is_pitched"]:
+            materials = [m for m in self.materials if m["type"] == "loft_insulation"]
+        elif roof["is_flat"]:
+            materials = [m for m in self.materials if m["type"] == "flat_roof_insulation"]
+        else:
+            raise ValueError("Roof is not pitched or flat")
+
+        if not materials:
             raise ValueError("No loft insulation materials found")
 
         lowest_selected_u_value = None
         recommendations = []
-        for material in loft_insulation_materials:
+        for material in materials:
 
             for depth, cost_per_unit in zip(material["depths"], material["cost"]):
                 # We make sure we hit a depth of 270mm. We should factor in any existing insulation if the
@@ -120,6 +151,11 @@ class RoofRecommendations:
 
                     estimated_cost = cost_per_unit * self.property.floor_area
 
+                    if roof["is_pitched"]:
+                        description = self.make_loft_insulation_description(material, depth)
+                    else:
+                        description = self.make_flat_roof_insulation_description(material, depth)
+
                     recommendations.append(
                         {
                             "parts": [
@@ -132,7 +168,7 @@ class RoofRecommendations:
                                 )
                             ],
                             "type": "roof_insulation",
-                            "description": self.make_loft_insulation_description(material, depth),
+                            "description": description,
                             "starting_u_value": u_value,
                             "new_u_value": new_u_value,
                             "sap_points": None,
@@ -179,7 +215,6 @@ class RoofRecommendations:
            but with a layer of plasterboard on the inside of the insulation.
          - Vertical walls can be insulated in the same way.
          - Flat ceilings can be insulated like a standard loft.
-         "
 
         :param u_value:  Current u-value of the roof
         :param insulation_thickness:   Current insulation thickness of the roof
@@ -236,7 +271,7 @@ class RoofRecommendations:
                                 )
                             ],
                             "type": "roof_insulation",
-                            "description": self.make_room_roof_insulation(material, depth),
+                            "description": self.make_room_roof_insulation_description(material, depth),
                             "starting_u_value": u_value,
                             "new_u_value": new_u_value,
                             "sap_points": None,
diff --git a/recommendations/tests/test_roof_recommendations.py b/recommendations/tests/test_roof_recommendations.py
index 3f99535c..5be4c6a7 100644
--- a/recommendations/tests/test_roof_recommendations.py
+++ b/recommendations/tests/test_roof_recommendations.py
@@ -328,3 +328,28 @@ class TestRoofRecommendations:
                "Insulate your room roof with 220mm of Example room roof insulation"
         assert roof_recommender10.recommendations[1]["description"] == \
                "Insulate your room roof with 270mm of Example room roof insulation"
+
+    def test_flat_no_insulation(self):
+        # Desriptions to handle:
+        # 'Flat, limited insulation (assumed)',
+        #
+        # 'Flat, insulated (assumed)'
+
+        property_instance11 = Property(id=11, address1="fake", postcode="fake", epc_client=Mock())
+        property_instance11.age_band = "D"
+        property_instance11.floor_area = 150
+        property_instance11.roof = {
+            'original_description': 'Flat, no insulation (assumed)',
+            'clean_description': 'Flat, no insulation',
+            'thermal_transmittance': None, 'thermal_transmittance_unit': None, 'is_pitched': False,
+            'is_roof_room': False, 'is_loft': False, 'is_flat': True, 'is_thatched': False, 'is_at_rafters': False,
+            'is_assumed': True, 'has_dwelling_above': False, 'is_valid': True, 'insulation_thickness': 'none'
+        }
+
+        roof_recommender11 = RoofRecommendations(
+            property_instance=property_instance11, materials=room_roof_insulation_materials
+        )
+
+        assert not roof_recommender11.recommendations
+
+        roof_recommender11.recommend()