package eu.ztsh.garmin.mapbox

import com.mapbox.common.location.Location
import com.mapbox.navigation.core.trip.session.LocationMatcherResult
import com.mapbox.navigation.core.trip.session.LocationObserver
import com.mapbox.navigation.ui.maps.camera.transition.NavigationCameraTransitionOptions
import eu.ztsh.garmin.Garmin

class LocationObserver(private val mapControl: MapControl) : LocationObserver {

    /**
     * Gets notified with location updates.
     *
     * Exposes raw updates coming directly from the location services
     * and the updates enhanced by the Navigation SDK (cleaned up and matched to the road).
     */
    private var firstLocationUpdateReceived = false

    override fun onNewRawLocation(rawLocation: Location) {
        // not handled
    }

    override fun onNewLocationMatcherResult(locationMatcherResult: LocationMatcherResult) {
        val enhancedLocation = locationMatcherResult.enhancedLocation
        // update location puck's position on the map
        mapControl.navigationLocationProvider.changePosition(
            location = enhancedLocation,
            keyPoints = locationMatcherResult.keyPoints,
        )

        // update camera position to account for new location
        mapControl.viewportDataSource.onLocationChanged(enhancedLocation)
        mapControl.viewportDataSource.evaluate()

        Garmin.instance.process(locationMatcherResult)

        // if this is the first location update the activity has received,
        // it's best to immediately move the camera to the current user location
        if (!firstLocationUpdateReceived) {
            firstLocationUpdateReceived = true
            mapControl.navigationCamera.requestNavigationCameraToOverview(
                stateTransitionOptions = NavigationCameraTransitionOptions.Builder()
                    .maxDuration(0) // instant transition
                    .build()
            )
        }
    }

}