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package http
import (
"math"
"strconv"
"strings"
"time"
"github.com/mpolden/atb/atb"
"github.com/mpolden/atb/entur"
)
// BusStops represents a list of bus stops.
type BusStops struct {
Stops []BusStop `json:"stops"`
nodeIDs map[int]*BusStop
}
// BusStop represents a single bus stop.
type BusStop struct {
URL string `json:"url"`
StopID int `json:"stopId"`
NodeID int `json:"nodeId"`
Description string `json:"description"`
Longitude float64 `json:"longitude"`
Latitude float64 `json:"latitude"`
MobileCode string `json:"mobileCode"`
MobileName string `json:"mobileName"`
}
// GeoJSON represents the top-level object of the GeoJSON format.
type GeoJSON struct {
Type string `json:"type"`
Geometry `json:"geometry"`
Properties map[string]interface{} `json:"properties"`
}
// Geometry represents the geometry object of the GeoJSON format.
type Geometry struct {
Type string `json:"type"`
Coordinates []float64 `json:"coordinates"`
}
// GeoJSONCollection represents a collection of GeoJSON feature objects.
type GeoJSONCollection struct {
Type string `json:"type"`
Features []GeoJSON `json:"features"`
}
// Departures represents a list of departures, from a given bus stop.
type Departures struct {
URL string `json:"url"`
TowardsCentrum *bool `json:"isGoingTowardsCentrum,omitempty"`
Departures []Departure `json:"departures"`
}
// Departure represents a single departure in a given direction.
type Departure struct {
LineID string `json:"line"`
RegisteredDepartureTime string `json:"registeredDepartureTime,omitempty"`
ScheduledDepartureTime string `json:"scheduledDepartureTime"`
Destination string `json:"destination"`
IsRealtimeData bool `json:"isRealtimeData"`
TowardsCentrum *bool `json:"isGoingTowardsCentrum,omitempty"`
}
// Error represents an error in the API, which is returned to the user.
type Error struct {
err error
Status int `json:"status"`
Message string `json:"message"`
}
func convertBusStop(s atb.BusStop) (BusStop, error) {
nodeID, err := strconv.Atoi(s.NodeID)
if err != nil {
return BusStop{}, err
}
longitude, err := strconv.Atoi(s.Longitude)
if err != nil {
return BusStop{}, err
}
lat, lon := ConvertCoordinates(s.Latitude, longitude)
return BusStop{
StopID: s.StopID,
NodeID: nodeID,
Description: s.Description,
Longitude: ceilN(lon, 6),
Latitude: ceilN(lat, 6),
MobileCode: s.MobileCode,
MobileName: s.MobileName,
}, nil
}
func convertBusStops(s atb.BusStops) (BusStops, error) {
stops := make([]BusStop, 0, len(s.Stops))
for _, stop := range s.Stops {
converted, err := convertBusStop(stop)
if err != nil {
return BusStops{}, err
}
stops = append(stops, converted)
}
return BusStops{Stops: stops}, nil
}
// ConvertTime converts time from AtBs format to ISO 8601.
func ConvertTime(src string) (string, error) {
t, err := time.Parse("02.01.2006 15:04", src)
if err != nil {
return "", err
}
return t.Format("2006-01-02T15:04:05.000"), nil
}
// IsRealtime returns a boolean indicating whether stationForecast is realtime.
func IsRealtime(stationForecast string) bool {
return strings.EqualFold(stationForecast, "prev")
}
func convertForecast(f atb.Forecast) (Departure, error) {
registeredDeparture, err := ConvertTime(f.RegisteredDepartureTime)
if err != nil {
return Departure{}, err
}
scheduledDeparture, err := ConvertTime(f.ScheduledDepartureTime)
if err != nil {
return Departure{}, err
}
return Departure{
LineID: f.LineID,
Destination: f.Destination,
RegisteredDepartureTime: registeredDeparture,
ScheduledDepartureTime: scheduledDeparture,
IsRealtimeData: IsRealtime(f.StationForecast),
}, nil
}
// IsTowardsCentrum returns a boolean indicating whether a bus stop, identified
// by nodeID, is going to the centrum.
func IsTowardsCentrum(nodeID int) bool {
return (nodeID/1000)%2 == 1
}
// ConvertCoordinates converts latitude and longitude from EPSG:3785 to
// EPSG:4326.
func ConvertCoordinates(latitude, longitude int) (float64, float64) {
const earthRadius = 6378137
originShift := (2 * math.Pi * earthRadius) / 2
lat := (float64(latitude) / originShift) * 180
lon := (float64(longitude) / originShift) * 180
lat = 180 / math.Pi * (2*math.Atan(
math.Exp(lat*math.Pi/180)) - math.Pi/2)
return lat, lon
}
func ceilN(f float64, n int) float64 {
shift := math.Pow(10, float64(n))
return math.Ceil(f*shift) / shift
}
func convertForecasts(f atb.Forecasts) (Departures, error) {
towardsCentrum := false
if len(f.Nodes) > 0 {
nodeID, err := strconv.Atoi(f.Nodes[0].NodeID)
if err != nil {
return Departures{}, err
}
towardsCentrum = IsTowardsCentrum(nodeID)
}
departures := make([]Departure, 0, len(f.Forecasts))
for _, forecast := range f.Forecasts {
departure, err := convertForecast(forecast)
if err != nil {
return Departures{}, err
}
departures = append(departures, departure)
}
return Departures{
TowardsCentrum: &towardsCentrum,
Departures: departures,
}, nil
}
func convertDepartures(enturDepartures []entur.Departure) Departures {
departures := make([]Departure, 0, len(enturDepartures))
const timeLayout = "2006-01-02T15:04:05.000"
for _, d := range enturDepartures {
scheduledDepartureTime := d.ScheduledDepartureTime.Format(timeLayout)
registeredDepartureTime := ""
if !d.RegisteredDepartureTime.IsZero() {
registeredDepartureTime = d.RegisteredDepartureTime.Format(timeLayout)
}
towardsCentrum := d.Inbound
departure := Departure{
LineID: d.Line,
ScheduledDepartureTime: scheduledDepartureTime,
RegisteredDepartureTime: registeredDepartureTime,
Destination: d.Destination,
IsRealtimeData: d.IsRealtime,
TowardsCentrum: &towardsCentrum,
}
departures = append(departures, departure)
}
return Departures{
Departures: departures,
}
}
// GeoJSON converts BusStop into the GeoJSON format.
func (s *BusStop) GeoJSON() GeoJSON {
geometry := Geometry{
Type: "Point",
Coordinates: []float64{s.Longitude, s.Latitude},
}
properties := map[string]interface{}{
"name": s.Description,
"busstop": s,
}
return GeoJSON{
Type: "Feature",
Geometry: geometry,
Properties: properties,
}
}
// GeoJSON converts BusStops into a GeoJSON feature collection.
func (s *BusStops) GeoJSON() GeoJSONCollection {
features := make([]GeoJSON, 0, len(s.Stops))
for i := range s.Stops {
geoJSON := s.Stops[i].GeoJSON()
features = append(features, geoJSON)
}
return GeoJSONCollection{
Type: "FeatureCollection",
Features: features,
}
}
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