first commit

internal/handlers/dashboard.go

@@ -0,0 +1,151 @@
+package handlers
+
+import (
+	"log"
+	"net/http"
+
+	"tankstopp/internal/models"
+	"tankstopp/internal/views/pages"
+)
+
+// HomeHandler serves the main dashboard page
+func (h *Handler) HomeHandler(w http.ResponseWriter, r *http.Request) {
+	userID, username := h.getCurrentUser(r)
+	if userID == 0 {
+		http.Redirect(w, r, "/login", http.StatusSeeOther)
+		return
+	}
+
+	// Get the user object
+	user, err := h.db.GetUserByID(userID)
+	if err != nil {
+		log.Printf("Error getting user: %v", err)
+		http.Error(w, "Internal server error", http.StatusInternalServerError)
+		return
+	}
+
+	// Get fuel stops for the user
+	stops, err := h.db.GetFuelStops(userID)
+	if err != nil {
+		log.Printf("Error getting fuel stops: %v", err)
+		http.Error(w, "Internal server error", http.StatusInternalServerError)
+		return
+	}
+
+	// Get fuel stop statistics
+	stats, err := h.db.GetFuelStopStats(userID)
+	if err != nil {
+		log.Printf("Error getting fuel stop stats: %v", err)
+		http.Error(w, "Internal server error", http.StatusInternalServerError)
+		return
+	}
+
+	// Get vehicles for the user
+	vehicles, err := h.db.GetVehicles(userID)
+	if err != nil {
+		log.Printf("Error getting vehicles: %v", err)
+		http.Error(w, "Internal server error", http.StatusInternalServerError)
+		return
+	}
+
+	// Calculate dashboard statistics
+	totalStops := len(stops)
+	totalCost := stats.TotalSpent
+
+	// Calculate detailed consumption statistics
+	avgConsumption, _, _ := h.calculateConsumptionStats(stops)
+	if avgConsumption == 0 {
+		avgConsumption = stats.AverageConsumption // Fallback to basic stats
+	}
+
+	var lastFillUp *models.FuelStop
+	if len(stops) > 0 {
+		lastFillUp = &stops[0]
+	}
+
+	// Render dashboard using templ
+	component := pages.DashboardPage(user, username, stops, vehicles, totalStops, totalCost, avgConsumption, lastFillUp)
+
+	w.Header().Set("Content-Type", "text/html")
+	err = component.Render(r.Context(), w)
+	if err != nil {
+		log.Printf("Error rendering template: %v", err)
+		http.Error(w, "Internal server error", http.StatusInternalServerError)
+	}
+}
+
+// calculateConsumptionStats calculates consumption-related statistics
+func (h *Handler) calculateConsumptionStats(stops []models.FuelStop) (float64, float64, float64) {
+	if len(stops) == 0 {
+		return 0, 0, 0
+	}
+
+	var totalLiters, totalKm float64
+	var consumptionReadings []float64
+
+	for _, stop := range stops {
+		totalLiters += stop.Liters
+
+		if stop.TripLength > 0 {
+			totalKm += stop.TripLength
+
+			// Calculate consumption for this stop (L/100km)
+			consumption := (stop.Liters / stop.TripLength) * 100
+			if consumption > 0 && consumption < 50 { // Filter out unrealistic values
+				consumptionReadings = append(consumptionReadings, consumption)
+			}
+		}
+	}
+
+	// Average consumption from individual readings
+	var avgConsumption float64
+	if len(consumptionReadings) > 0 {
+		var sum float64
+		for _, consumption := range consumptionReadings {
+			sum += consumption
+		}
+		avgConsumption = sum / float64(len(consumptionReadings))
+	}
+
+	// Overall consumption from totals
+	var overallConsumption float64
+	if totalKm > 0 {
+		overallConsumption = (totalLiters / totalKm) * 100
+	}
+
+	return avgConsumption, overallConsumption, totalKm
+}
+
+// calculateEfficiencyTrend calculates fuel efficiency trend over time
+func (h *Handler) calculateEfficiencyTrend(stops []models.FuelStop) string {
+	if len(stops) < 2 {
+		return "insufficient_data"
+	}
+
+	// Get consumption for recent stops (last 5) vs older stops
+	recentStops := stops[:min(5, len(stops))]
+	olderStops := stops[min(5, len(stops)):]
+
+	recentAvg, _, _ := h.calculateConsumptionStats(recentStops)
+	olderAvg, _, _ := h.calculateConsumptionStats(olderStops)
+
+	if recentAvg == 0 || olderAvg == 0 {
+		return "insufficient_data"
+	}
+
+	diff := recentAvg - olderAvg
+	if diff < -0.5 {
+		return "improving" // Lower consumption is better
+	} else if diff > 0.5 {
+		return "worsening"
+	}
+	return "stable"
+}
+
+// min helper function
+func min(a, b int) int {
+	if a < b {
+		return a
+	}
+	return b
+}