make it work for my tram board

adds webserer with endpoint /line?number=3

you need to specify a post body text using b64-encoded, semicolon-separated names of the stops

index of stop name corresponds to returned value (led index)

cmd/web/main.go

@@ -0,0 +1,98 @@
+package main
+
+import (
+	"encoding/base64"
+	"encoding/json"
+	"io"
+	"log"
+	"maps"
+	"net/http"
+	trmaps "shellixa/puvetra/internal/maps"
+	"shellixa/puvetra/internal/types"
+	"slices"
+	"strings"
+	"time"
+)
+
+func main() {
+
+	mux := http.NewServeMux()
+
+	server := &http.Server{
+		Handler: mux,
+		Addr:    ":8080",
+	}
+
+	mux.HandleFunc("POST /line", GetLineTrams)
+
+	err := server.ListenAndServe()
+	if err != nil {
+		log.Println(err)
+	}
+}
+
+func GetLineTrams(w http.ResponseWriter, r *http.Request) {
+
+	// log.Printf("%+v\n", r)
+	b64Body := base64.NewDecoder(base64.StdEncoding, r.Body)
+	defer r.Body.Close()
+
+	body, _ := io.ReadAll(b64Body)
+
+	stationSeq := strings.Split(string(body), ";")
+
+	tramLine := r.URL.Query().Get("number")
+
+	trams := trmaps.GetTrips()
+
+	var allTrams []types.MapTrip
+
+	for _, t := range trams {
+		if t.Mode == "TRAM" && t.Trips[0].RouteShortName == tramLine {
+			allTrams = append(allTrams, t)
+		}
+	}
+
+
+	var traminfo = make(map[string]types.MapTrip)
+
+	now := time.Now()
+	for _, tr := range allTrams {
+		// Überschreibe [tripId] nur, wenn (OR)
+		// - [tripId] == nil
+		// - departure < now && arrival > [tripId].departure
+		storedTram := traminfo[tr.Trips[0].TripId]
+
+		if tr.Departure.Sub(now).Abs() < storedTram.Departure.Sub(now).Abs() {
+			// Current is past now, Stored is future now
+			traminfo[tr.Trips[0].TripId] = tr
+		}
+	}
+
+	stationLookupTable := make(map[string]int)
+	for i, v := range stationSeq {
+		stationLookupTable[strings.ToLower(v)] = i
+	}
+
+	activeLights := make(map[int]bool)
+	for _, tram := range slices.Collect(maps.Values(traminfo)) {
+		// Calculate current Station name depending on current time
+		realStation := tram.From
+		if tram.Departure.Sub(now).Abs() > tram.Arrival.Sub(now).Abs() {
+			//		log.Printf(">  %v, %v\n", now.Sub(depTime), arrTime.Sub(now))
+			realStation = tram.To
+		}
+		// log.Printf("From='%s' To='%s' Real='%s'\n", tram.From.Name, tram.To.Name, realStation.Name)
+		activeLights[stationLookupTable[strings.ToLower(realStation.Name)]] = true
+
+	}
+
+	lightIds := slices.Collect(maps.Keys(activeLights))
+	// log.Println(lightIds)
+
+	enc := json.NewEncoder(w)
+	err := enc.Encode(lightIds)
+	if err != nil {
+		log.Println(err)
+	}
+}