Endpoint for cakeGraph was added

src/main/java/ntnu/idatt2016/v233/SmartMat/controller/group/WasteController.java

@@ -67,4 +67,16 @@ public class WasteController {
         return wasteService.getWasteOfCategoryByGroupId(groupId, CategoryUtil.getCategoryName(categoryNumber)).map(ResponseEntity::ok).orElseGet(() -> ResponseEntity.notFound().build());
     }
 
+    /**
+     * Retrieve information about the cake diagram for a given group ID using a GET request.
+     *
+     * @param groupId The ID of the group for which to retrieve the cake diagram information.
+     * @return A ResponseEntity containing an array of doubles representing the cake diagram information if found,
+     *         or a 404 Not Found response if not found.
+     */
+    @GetMapping("/statistic/cakeGraph/{groupId}")
+    public ResponseEntity<double[]> getInformationOfCakeGraph(@PathVariable("groupId") long groupId){
+        return wasteService.getCakeDiagram(groupId).map(ResponseEntity::ok).orElseGet(()->ResponseEntity.notFound().build());
+    }
+
 }

src/main/java/ntnu/idatt2016/v233/SmartMat/service/group/WasteService.java

@@ -10,6 +10,7 @@ import ntnu.idatt2016.v233.SmartMat.entity.product.Product;
 import ntnu.idatt2016.v233.SmartMat.repository.group.GroupRepository;
 import ntnu.idatt2016.v233.SmartMat.repository.group.WasteRepository;
 import ntnu.idatt2016.v233.SmartMat.repository.product.ProductRepository;
+import ntnu.idatt2016.v233.SmartMat.util.StatisticUtil;
 import org.springframework.stereotype.Service;
 
 import java.util.Optional;
@@ -64,4 +65,16 @@ public class WasteService {
         return wasteRepository.findAllWasteOfOneCategoryFromGroup(groupId,categoryName);
     }
 
+    /**
+     * Get the cake diagram for a group of waste.
+     *
+     * @param groupId The ID of the group for which to retrieve the cake diagram.
+     * @return An Optional containing an array of doubles representing the cake diagram for the group,
+     *         or an empty Optional if the group is not found.
+     */
+    public Optional<double[]> getCakeDiagram(long groupId){
+        Optional<Group> group = groupRepository.findByGroupId(groupId);
+        return group.map(value -> StatisticUtil.getNumberOfWasteByCategoryName(wasteRepository.findByGroupId(value).get()));
+    }
+
 }

src/main/java/ntnu/idatt2016/v233/SmartMat/util/StatisticUtil.java

+package ntnu.idatt2016.v233.SmartMat.util;
+
+import ntnu.idatt2016.v233.SmartMat.entity.Waste;
+
+import java.sql.Date;
+import java.util.List;
+
+
+/**
+ * A utility class for calculating statistics related to waste and CO2 emissions.
+ */
+public class StatisticUtil {
+
+    /**
+     * Get the annual average amount of CO2 emissions per person.
+     *
+     * @param co2List The list of CO2 emissions for a group of people.
+     * @param numberOfPerson The number of people in the group.
+     * @param firstDate The date on which the group started tracking their CO2 emissions.
+     * @return The annual average amount of CO2 emissions per person.
+     */
+    private static double getAnnualAveragePerPerson(List<Double> co2List, int numberOfPerson, Date firstDate) {
+        java.util.Date currentDate = new java.util.Date();
+        long diffInMillis = currentDate.getTime() - firstDate.getTime();
+        long diffInDays = diffInMillis / (24 * 60 * 60 * 1000);
+        double co2Sum = 0.0;
+        for (double c02 : co2List) co2Sum += c02;
+        return co2Sum / (((double) diffInDays / 365.0) * (double) numberOfPerson);
+    }
+
+    /**
+     * Get the number of waste items for each category name in a list of waste items.
+     *
+     * @param wastes The list of waste items for which to calculate the number of items by category name.
+     * @return An array of doubles representing the number of waste items for each category name.
+     */
+    public static double[] getNumberOfWasteByCategoryName(List<Waste> wastes) {
+        double[] numberOfWastes = new double[5];
+        for (Waste waste : wastes) {
+            switch (waste.getEan().getCategory().getCategoryName()) {
+                case "meat, fish and chicken" -> numberOfWastes[0] += waste.getAmount();
+                case "baked goods and grains" -> numberOfWastes[1] += waste.getAmount();
+                case "dairy and egg" -> numberOfWastes[2] += waste.getAmount();
+                case "fruit and vegetables" -> numberOfWastes[3] += waste.getAmount();
+                default -> numberOfWastes[4] += waste.getAmount();
+            }
+        }
+        return numberOfWastes;
+    }
+}
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