//
//  PasquakesMapViewController.swift
//  Earthquake Network
//
//  Created by Andrea Busi on 10/03/21.
//  Copyright © 2021 Earthquake Network. All rights reserved.
//

import Foundation
import MapKit

class PasquakesMapViewController: EQNBaseMapViewController {
    
    override var availableFilters: [EQNBaseMapFilter] {
        [ .oneMonth, .oneWeek, .oneDay, .oneHour ]
    }
    
    // MARK: - Internal
    
    /// Pasquakes currently showned on the map
    private var filteredPastquakes = [EQNPastquakes]()
    /// Keep track of the evaluated center, to show circles around it
    private var centerLocation: CLLocation?
    /// Contains circles drawed on the map
    private var mapCircles = [MKCircle]()
    
    // MARK: - View Lifecycle
    
    override func viewDidLoad() {
        super.viewDidLoad()
    }
    
    // MARK: - Public
    
    override func registerMapAnnotationViews() {
        mapView.register(EQNCustomAnnotationView.self, forAnnotationViewWithReuseIdentifier: EQNCustomAnnotationView.SingleLineIdentifier)
    }
    
    override func loadDataSource() {
        guard let list = EQNManager.manager().datiPastQuakes else { return }

        // set the base filter
        setDefaultFilter(for: list)
        
        // filter report based on selected filter
        let filterDate = filter.date
        filteredPastquakes = list.filter { $0.date > filterDate }
        
        // create annotations to display on the map
        let annotations = filteredPastquakes.compactMap { EQNMapAnnotationPastquake(pastquake: $0) }
        // elaborate the center
        centerLocation = elaborateCenter(for: filteredPastquakes)
        
        // update map and center
        updateMap(with: annotations)
        if let centerLocation = centerLocation {
            addCircles(for: centerLocation)
        }
    }
    
    override func elaborateMapCenter() {
        guard let centerLocation = centerLocation else { return }
        
        setMapCenter(for: centerLocation)
    }
    
    override func didTapAnnotation(_ annotation: MKAnnotation) {
        mapView.deselectAnnotation(annotation, animated: true)
        
        guard let annotation = annotation as? EQNMapAnnotationPastquake, let pastquake = annotation.pastquake else {
            return
        }
        
        let difference = Int(Date().timeIntervalSince(pastquake.date) / 60.0)
        let title = EQNUtility.formattedString(forTimeDifference: difference)
        
        let message = ""
            + "📱 " + String(format: NSLocalizedString("map_number", comment: ""), "\(pastquake.users)")
            + "\n⏱ " + EQNUtility.formattedDate(from: pastquake.date) + " \(NSLocalizedString("share_yourtime", comment: ""))"
        
        let alert = UIAlertController(title: title, message: message, preferredStyle: .alert)
        alert.addAction(UIAlertAction(title: NSLocalizedString("official_close", comment: ""), style: .cancel, handler: nil))
        present(alert, animated: true, completion: nil)
    }
    
    // MARK: - Private

    private func elaborateCenter(for pastquakes: [EQNPastquakes]) -> CLLocation? {
        var center: CLLocation?

        // Se c'è un rilevamento distante dall'utente meno del raggio di notifica,
        // allora il centro è su quel rilevamento
        if let userPosition = CLLocationManager().location {
            let nearestPastquake = filteredPastquakes
                .sorted(by: { (pastquake1, pastquake2) -> Bool in
                    abs(userPosition.distance(from: pastquake1.coordinate)) < abs(userPosition.distance(from: pastquake2.coordinate))
                })
                .first
            
            // controlliamo che sia inferiore al raggio massimo impostato per le notifiche
            if let radiusLow = Double(EQNSettingRealTimeAlert.shared.raggioSismiLievi),
               let radiusStrong = Double(EQNSettingRealTimeAlert.shared.raggioSismiForti),
               let nearestPastquake = nearestPastquake {
                let radius = max(radiusLow, radiusStrong)
                if abs(nearestPastquake.coordinate.distance(from: userPosition)) < radius {
                    center = nearestPastquake.coordinate
                }
            }
        }
        
        // altrimenti il centro è sul rilevamento più recente
        if center == nil, let newestPastquake = filteredPastquakes.sorted(by: { $0.date > $1.date }).first {
            center = newestPastquake.coordinate
        }
        
        return center
    }
    
    private func addCircles(for location: CLLocation) {
        // aggiungiamo 3 cerchi concentrici per il punto specificato
        // li inseriamo a a 50, 100 e 200 km.
             
        let circles = [
            MKCircle(center: location.coordinate, radius: 25_000),
            MKCircle(center: location.coordinate, radius: 100_000),
            MKCircle(center: location.coordinate, radius: 200_000)
        ]

        // elimino vecchie circonferenze
        mapView.removeOverlays(mapCircles)
        
        // !!note: is important to assign here the circles
        // otherwise `addOverlays` will not work
        mapCircles = circles
        
        // creo nuovi cerchi
        mapView.addOverlays(circles)
    }
    
    // MARK: - Map
    
    override func setupAnnotationView(for annotation: MKAnnotation, on mapView: MKMapView) -> MKAnnotationView? {
        guard let annotation = annotation as? EQNMapAnnotationPastquake else {
            return nil
        }
        
        let annotationView = mapView.dequeueReusableAnnotationView(withIdentifier: EQNCustomAnnotationView.SingleLineIdentifier, for: annotation) as! EQNCustomAnnotationView
        
        annotationView.image = annotation.image
        annotationView.title = annotation.title
        
        return annotationView
    }
    
    func mapView(_ mapView: MKMapView, rendererFor overlay: MKOverlay) -> MKOverlayRenderer {
        guard let circleOverlay = overlay as? MKCircle else {
            return MKOverlayRenderer(overlay: overlay)
        }
        
        let circle = MKCircleRenderer(overlay: circleOverlay)
        circle.strokeColor = AppTheme.Colors.darkGray
        circle.lineWidth = 1.0
        return circle
    }
}