Added stat methods and anomaly detection algorithm

model/statisticsModel.go

@@ -2,7 +2,10 @@ package model
 
 import (
 	"errors"
+	"slices"
+	"strconv"
 
+	"github.com/ceticamarco/zephyr/statistics"
 	"github.com/ceticamarco/zephyr/types"
 )
 
@@ -11,7 +14,45 @@ func GetStatistics(cityName string, statDB *types.StatDB) (types.StatResult, err
 	if statDB.IsKeyInvalid(cityName) {
 		return types.StatResult{}, errors.New("Insufficient or outdated data to perform statistical analysis")
 	}
-	// TODO: we have enough data, do the math!
 
-	return types.StatResult{}, nil
+	extractTemps := func(weatherArr []types.Weather) ([]float64, error) {
+		temps := make([]float64, 0, len(weatherArr))
+
+		for _, weather := range weatherArr {
+			temperature, err := strconv.ParseFloat(weather.Temperature, 64)
+			if err != nil {
+				return nil, err
+			}
+			temps = append(temps, temperature)
+		}
+
+		return temps, nil
+	}
+
+	// Extract records from the database
+	stats := statDB.GetCityStatistics(cityName)
+
+	// Extract temperatures from weather statistics
+	temps, err := extractTemps(stats)
+	if err != nil {
+		return types.StatResult{}, err
+	}
+
+	// Detect anomalies
+	anomalies := statistics.DetectAnomalies(stats)
+	if len(anomalies) == 0 {
+		anomalies = nil
+	}
+
+	// Compute statistics
+	return types.StatResult{
+		Min:     slices.Min(temps),
+		Max:     slices.Max(temps),
+		Count:   len(stats),
+		Mean:    statistics.Mean(temps),
+		StdDev:  statistics.StdDev(temps),
+		Median:  statistics.Median(temps),
+		Mode:    statistics.Mode(temps),
+		Anomaly: &anomalies,
+	}, nil
 }