import {EventEmitter, Injectable} from '@angular/core';
import {BehaviorSubject, combineLatest} from "rxjs";
import {PermissionsService} from "../components/permissions/permissions.service";

@Injectable({
    providedIn: 'root'
})
export class PhysicsService {
    private motionTimestamp;

    requireCalibration = new EventEmitter();
    calibrate = new BehaviorSubject<number>(Infinity);

    info = new BehaviorSubject(null);
    motion = new BehaviorSubject<DeviceMotionEvent>(null);
    orientation = new BehaviorSubject<DeviceOrientationEvent>(null);
    position = new BehaviorSubject<Position>(null);

    constructor(permissionsService: PermissionsService) {

        permissionsService.requestPermission('geolocation', 'gps_fixed', 'Can we use your location?').then(granted => {
            if(granted) {
                // Gather physical data
                window.addEventListener('deviceorientation', orientation => {
                    console.log('Orientation:', orientation);
                    this.orientation.next(orientation);
                });
                window.addEventListener('devicemotion', motion => {
                    console.log('Motion:', motion);
                    this.motion.next(motion);
                });
                navigator.geolocation.watchPosition(position => {
                    console.log('GPS:', position);
                    this.position.next(position);
                });

                // Combine data into one nice package
                combineLatest(this.position, this.orientation, this.calibrate).subscribe(data => {
                    console.log('Combine:', data);
                    if(!data[0]) return;

                    let info = {
                        accuracy: data[0].coords.accuracy,
                        altitude: data[0].coords.altitude,
                        altitudeAccuracy: data[0].coords.altitudeAccuracy,
                        heading: data[0].coords.heading,
                        latitude: data[0].coords.latitude,
                        longitude: data[0].coords.longitude,
                        speed: data[0].coords.speed
                    };

                    if(info.heading == null && data[1]) {
                        if(!data[1].absolute && data[2] == Infinity) {
                            this.calibrate.next(0);
                            this.requireCalibration.emit();
                        }

                        info.heading = -data[1].alpha + (data[2] == Infinity ? 0 : data[2]);
                        if(info.heading < 0) info.heading += 360;
                        if(info.heading >= 360) info.heading -= 360;
                    }

                    this.info.next(info);
                    console.log('Out:', info);
                })
            }
        });
    }
}