//
//  UpdateUserLocationTask.swift
//  Earthquake Network
//
//  Created by Andrea Busi on 16/08/23.
//  Copyright © 2023 Earthquake Network. All rights reserved.
//

import Foundation
import BackgroundTasks
import CoreLocation


final class UpdateUserLocationTask: NSObject, BackgroundTaskIdentifiable {
    
    static var identifier: String {
        "com.finazzi.distquake.update_server_position"
    }
    
    static var interval: TimeInterval {
        5 * 60
    }
    
    static let shared = UpdateUserLocationTask()
    private let debugHelper = EQNBackgroundPositionDebugHelper()
    
    // MARK: - Internal
    
    private lazy var locationManager: CLLocationManager = {
        let manager = CLLocationManager()
        manager.delegate = self
        manager.desiredAccuracy = kCLLocationAccuracyNearestTenMeters
        manager.allowsBackgroundLocationUpdates = true
        manager.pausesLocationUpdatesAutomatically = false
        return manager
    }()
    
    var appTaskCompletion: BackgroundTaskIdentifiable.TaskCompletion?
    
    func handle(_ task: BGTask, completion: @escaping (_ success: Bool) -> Void) {
        self.appTaskCompletion = completion
        
        // ricaviamo la posizione corrente dell'utente
        if let location = locationManager.location {
            complete(with: location)
        } else {
            locationManager.requestLocation()
        }
    }
    
    func exipration() {
        locationManager.stopUpdatingLocation()
        failed()
    }
    
    // MARK: - Private
    
    private func complete(with location: CLLocation) {
        // send position to cloud
        let url = EQNGeneratoreURLServer.urlPosizione(withLocation: location.coordinate)
        ServerRequest.default().inviaInformazioniAlServer(with: url, richiesta: .posizione) { result in
            if self.debugHelper.isEnabled {
                self.debugHelper.savePosition(coordinate: location.coordinate, requestSuccess: true)
            }
            self.appTaskCompletion?(true)
        } failure: { error in
            if self.debugHelper.isEnabled {
                self.debugHelper.savePosition(coordinate: location.coordinate, requestSuccess: false)
            }
            self.appTaskCompletion?(false)
        }
    }
    
    private func failed() {
        appTaskCompletion?(false)
    }
}

extension UpdateUserLocationTask: CLLocationManagerDelegate {
    
    func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
        if let location = locations.first {
            complete(with: location)
        } else {
            failed()
        }
    }
    
    func locationManager(_ manager: CLLocationManager, didFailWithError error: Error) {
        print("[UpdateUserLocationTask] Location manager failed. Error: \(error.localizedDescription)")

        // nope, but mandatory
        failed()
    }
}