wip

packages/racing/domain/services/StrengthOfFieldCalculator.ts

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+/**
+ * Domain Service: StrengthOfFieldCalculator
+ * 
+ * Calculates the Strength of Field (SOF) for a race based on participant ratings.
+ * SOF is the average rating of all participants in a race.
+ */
+
+export interface DriverRating {
+  driverId: string;
+  rating: number;
+}
+
+export interface StrengthOfFieldCalculator {
+  /**
+   * Calculate SOF from a list of driver ratings
+   * Returns null if no valid ratings are provided
+   */
+  calculate(driverRatings: DriverRating[]): number | null;
+}
+
+/**
+ * Default implementation using simple average
+ */
+export class AverageStrengthOfFieldCalculator implements StrengthOfFieldCalculator {
+  calculate(driverRatings: DriverRating[]): number | null {
+    if (driverRatings.length === 0) {
+      return null;
+    }
+
+    const validRatings = driverRatings.filter(dr => dr.rating > 0);
+    
+    if (validRatings.length === 0) {
+      return null;
+    }
+
+    const sum = validRatings.reduce((acc, dr) => acc + dr.rating, 0);
+    return Math.round(sum / validRatings.length);
+  }
+}