home.page.ts

import { Component } from '@angular/core';
import { Platform } from '@ionic/angular';
import { NativeStorage } from '@ionic-native/native-storage/ngx';

import BackgroundGeolocation, {
  Location,
  GeofenceEvent,
  ConnectivityChangeEvent,
  HttpEvent,
} from 'cordova-background-geolocation';

@Component({
  selector: 'app-home',
  templateUrl: 'home.page.html',
  styleUrls: ['home.page.scss'],
})

export class HomePage {
	HuskyTrack_ID: number;

	isTracking: boolean = false;
	Tracking_UI_Text: string = "Begin Tracking";

  DB_URL: string = 'http://sdp40.cse.uconn.edu/api/locationdata';
                    
	constructor(public platform: Platform, private nativeStorage: NativeStorage) {
    platform.ready().then(() => {
      this.load_or_generate_unique_id().then(() => {
        this.configureBackgroundGeolocation();
      });
    });
  }

  onHttp(event:HttpEvent) {
    console.log('[http] -', event.success, event.status, event.responseText);
  }

  onConnectivityChange(event:ConnectivityChangeEvent) {
    console.log('[connectivitychange] - connected?', event.connected);
  }

  onGeofence(event:GeofenceEvent) {
      console.log('[onGeofence] ', event);
      if (event.action == "ENTER") {
        console.log("User has entered UCONN tracking radius. Begin Location Tracking.");
        BackgroundGeolocation.start();
      }

      if (event.action == "EXIT") {
        console.log("User has left UCONN tracking radius. Disable Location Tracking.");
        BackgroundGeolocation.startGeofences(); 
      }
  }

  onLocation(location:Location) {
    console.log('[location].latitude ', location.coords.latitude);
    console.log('[location].longitude ', location.coords.longitude);
  }

  configureBackgroundGeolocation() {
    BackgroundGeolocation.onLocation(this.onLocation.bind(this));
    BackgroundGeolocation.onGeofence(this.onGeofence.bind(this));
    BackgroundGeolocation.onHttp(this.onHttp.bind(this));
    BackgroundGeolocation.onConnectivityChange(this.onConnectivityChange.bind(this));

    BackgroundGeolocation.addGeofence({
      identifier: "UCONN Campus",
      radius: 500,
      latitude: 41.807757,//LAT-LONG of UCONN Campus : 41.807757, -72.253990 from http://www.latitude-longitude.net
      longitude: -72.253990,
      notifyOnEntry: true,
      notifyOnExit: true,
    }).then((success) => {
      console.log('[addGeofence] UCONN Campus Geofence added.');
    }).catch((error) => {
      console.log('[addGeofence] FAILURE: ', error);
    });

    BackgroundGeolocation.reset();

    BackgroundGeolocation.ready({
      reset: true,
      debug: false,
      logLevel: BackgroundGeolocation.LOG_LEVEL_DEBUG,
      distanceFilter: 1,
      stopTimeout: 1,
      url: this.DB_URL,
      autoSync: true,
      batchSync: true,
      autoSyncThreshold: 1, // HTTP requests drain battery far quicker than GPS tracking according to docs.
      params: {
        'user_id' : this.HuskyTrack_ID
      }, 
    }, (state) => {
      console.log('- Configure success: ', state);
    });
  }

	async load_or_generate_unique_id() {
		await this.nativeStorage.getItem('HuskyTrack_ID').then((data) => { //The reason I'm using HuskyTrack_ID instead of just ID is to effectively namespace 'ID' on local storage.
			this.HuskyTrack_ID = data;
			console.log(`UserID was already set to: ${this.HuskyTrack_ID}`);
		},
		(error) => {
			console.log("ID not set. First time ran? Generating ID.");
			var max = 9007199254740992; // largest *consequative* integer represented by doubles.
			this.HuskyTrack_ID = Math.floor(Math.random() * max);

			this.nativeStorage.setItem('HuskyTrack_ID', this.HuskyTrack_ID).then( 
				()      => console.log(`ID Set to: ${this.nativeStorage.getItem('HuskyTrack_ID')}`), //NOTE(Jesse): If we fail here then something really off has happened.
				(error) => console.log(`error: ${error}. Could not set ID. Consult https://github.com/TheCocoaProject/cordova-plugin-nativestorage`)
			);
	      }
		);
	}

  toggle_tracking() {
  	this.isTracking = !this.isTracking;
  	this.isTracking ? this.Tracking_UI_Text = "Stop Tracking" : this.Tracking_UI_Text = "Start Tracking";

    if (this.isTracking){
      console.log("Begun Tracking");
      BackgroundGeolocation.startGeofences();
    }
    else {
      console.log("Ended Tracking");
      BackgroundGeolocation.stop();
    }
  }

}