aog.js

const app = new DialogflowApp({request: request, response: response});

const INTENT_AVAILABILITY_USER_LOCATION = 'availability-user-location';
const INTENT_AVAILABILITY_USER_LOCATION_PERMISSION_RESPONSE = 'availability-user-location.response';
const ARG_ASSET_TYPE = 'asset_type';

const actionMap = new Map();
actionMap.set(INTENT_AVAILABILITY_USER_LOCATION, availabilityUserLocation);
actionMap.set(INTENT_AVAILABILITY_USER_LOCATION_PERMISSION_RESPONSE, availabilityUserLocationPermissionResponse)

app.handleRequest(actionMap);

function availabilityUserLocation(){
    let assetType = app.getArgument('assetType');

    let preciseLocationPermission = app.SupportedPermissions.DEVICE_PRECISE_LOCATION
    if (app.isPermissionGranted(preciseLocationPermission)){
        getAvailabilityForUserLocation(app);     
    } else {
        app.askForPermission(`To look for available ${assetType}s`, preciseLocationPermission);
    }         
}

function availabilityUserLocationPermissionResponse(){
    getAvailabilityForUserLocation(app);
}

function fallback(){
    saySimpleResponse("I'm sorry, I didn't quite get that. Please try again.")
}

function getAvailabilityForUserLocation(app){ 
    let assetType = app.getContextArgument('availability', 'assetType').value;
    
    if (!app.isPermissionGranted(app.SupportedPermissions.DEVICE_PRECISE_LOCATION)){
        saySimpleResponse(`I unfortunately cannot find nearest available ${assetType}s without knowing your location.`,
            `I need to know your location to find available ${assetType}s`);
        return;
    }        

    if (assetType != null){
        CityBikeAPI.getStationsSortedByDistance(app.getDeviceLocation().coordinates, assetType)
            .then(stations => {   
                if (stations != null && stations.length > 0){
                    let availability = (assetType == "bike" ? stations[0].availability.bikes : stations[0].availability.locks);

                    let speechResponse = `There are ${availability} ${assetType}s available at ${stations[0].title}, 
                        ${stations[0].distanceString} from you.`
                    let textResponse = `${availability} ${assetType}s available at ${stations[0].title}`

                    let googleResponse = app.buildRichResponse().addSimpleResponse({
                            speech: speechResponse,
                            displayText: textResponse
                        }).addBasicCard(app.buildBasicCard(textResponse)
                            .setSubtitle(`${stations[0].distanceString} away`)
                            .setTitle(stations[0].title)                            
                            .setImage(getGoogleMapsUri(availability, stations[0].center), stations[0].title, 400, 200)
                            .addButton("Unlock bike", "https://someurl")
                        );
                    app.ask(googleResponse);                    

                } else {
                    saySimpleResponse(`I'm sorry, but I wasn't able to find any available ${assetType}s at the moment.`,
                        `No available ${assetType}s at the moment.`);                    
                }            
            });   
    } else {
        saySimpleResponse("I'm sorry, I didn't understand what you meant. Please try again.",
            "I didn't understand. Please try again.")
    }                         
}