Refactor StatProvider to improve data fetching logic and enhance docu…

…mentation

Sources/Scout/UI/StatProvider.swift

@@ -21,58 +21,75 @@ import CloudKit
         self.eventName = eventName
     }
 
-    /// Fetches the statistical data if it has not been fetched yet.
-    /// - Parameter container: The CloudKit container from which to fetch the data.
+    /// Fetches data if needed from the provided database.
+    ///
+    /// This asynchronous function checks if the data needs to be fetched and performs the fetch operation
+    /// using the given `DatabaseController` instance.
+    ///
+    /// - Parameter database: The `DatabaseController` instance used to fetch the data.
+    /// - Returns: An asynchronous operation that fetches the data if needed.
     ///
     func fetchIfNeeded(in database: DatabaseController) async {
         if data == nil {
             await fetch(in: database)
         }
     }
+}
+
+// MARK: - Fetching Data
 
-    /// Fetches the statistical data from the CloudKit container.
-    /// - Parameter container: The CloudKit container from which to fetch the data.
+extension StatProvider {
+
+    /// Fetches data from the specified database asynchronously.
+    ///
+    /// - Parameter database: The `DatabaseController` instance from which to fetch data.
     ///
     private func fetch(in database: DatabaseController) async {
         let today = Calendar(identifier: .iso8601).startOfDay(for: Date())
         let yearAgo = today.addingYear(-1).addingWeek(-1)
 
-        let predicate = NSPredicate(
-            format: "date >= %@ AND name == %@",
-            yearAgo as NSDate,
-            eventName
-        )
-
-        let query = CKQuery(
-            recordType: "DateIntMatrix",
-            predicate: predicate
-        )
-
         do {
             let records = try await database.allRecords(
-                matching: query,
+                matching: query(from: yearAgo),
                 desiredKeys: nil
             )
 
-            let points = try records.map(Matrix.init)
+            let rawPoints = try records.map(Matrix.init)
                 .mergeDuplicates()
                 .flatMap(ChartPoint.fromIntMatrix)
 
-            let series = RawPointData(
+            let rawData = RawPointData(
                 from: yearAgo,
                 to: today.addingDay(),
-                points: points
+                points: rawPoints
             )
 
-            data = series.chartData(for: StatPeriod.components)
+            data = rawData.chartData(for: StatPeriod.components)
 
         } catch {
             print(error.localizedDescription)
             data = nil
         }
     }
+
+    private func query(from date: Date) async throws -> CKQuery {
+        let predicate = NSPredicate(
+            format: "date >= %@ AND name == %@",
+            date as NSDate,
+            eventName
+        )
+
+        let query = CKQuery(
+            recordType: "DateIntMatrix",
+            predicate: predicate
+        )
+
+        return query
+    }
 }
 
+// MARK: - Calendar Components
+
 extension StatPeriod {
 
     /// A set of calendar components used for date calculations.