/**
 * TrackerMap
 * Copyright (C) 2021-2022  Iván Ávalos <avalos@disroot.org>, Henoch Ojeda <imhenoch@protonmail.com>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */
import SwiftUI
import Combine
import WhirlyGlobeMaplyComponent
import shared

struct BaseMapView: UIViewControllerRepresentable {
    typealias UIViewControllerType = MaplyViewController
    
    @Binding var mapLayer: MapLayer
    var link: BaseMapLink
    
    class Coordinator: NSObject, MaplyViewControllerDelegate {
        var parent: BaseMapView
        var uiViewController: MaplyViewController?
        var loader: MaplyQuadImageLoader? = nil
        
        // Source: https://stackoverflow.com/questions/65923718
        var cancellable: AnyCancellable?
        var link: BaseMapLink? {
            didSet {
                cancellable = link?.$action.sink(receiveValue: { action in
                    guard let action = action else {
                        return
                    }
                    self.uiViewController?.action(action)
                })
            }
        }
        
        init(_ uiViewController: BaseMapView) {
            self.parent = uiViewController
        }
        
        func maplyViewController(_ viewC: MaplyViewController, didClick annotation: MaplyAnnotation) {
            print("Clicked map! :D")
        }
    }
    
    func makeCoordinator() -> Coordinator {
        Coordinator(self)
    }
    
    func makeUIViewController(context: Context) -> MaplyViewController {
        let mapViewController = MaplyViewController(mapType: .typeFlat)
        mapViewController.delegate = context.coordinator
        
        let tileInfo = Utils.tileInfoFrom(layer: mapLayer)
        mapViewController.setZoomLimits(minZoom: mapLayer.minZoom,
                                        maxZoom: mapLayer.maxZoom)
        
        let sampleParams = MaplySamplingParams()
        sampleParams.coordSys = MaplySphericalMercator(webStandard: ())
        sampleParams.coverPoles = true
        sampleParams.edgeMatching = true
        sampleParams.minZoom = tileInfo.minZoom
        sampleParams.maxZoom = tileInfo.maxZoom
        sampleParams.singleLevel = true
        sampleParams.maxTiles = 25
        
        let loader = MaplyQuadImageLoader(params: sampleParams, tileInfo: tileInfo, viewC: mapViewController)
        loader?.baseDrawPriority = kMaplyImageLayerDrawPriorityDefault
        loader?.imageFormat = .imageUShort565
        context.coordinator.loader = loader
        
        DispatchQueue.main.async {
            let point = MaplyCoordinateMakeWithDegrees(-100.36, 23.191)
            mapViewController.focusOn(point: point, height: 0.4)
        }
        
        return mapViewController
    }
    
    func updateUIViewController(_ uiViewController: MaplyViewController, context: Context) {
        context.coordinator.uiViewController = uiViewController
        context.coordinator.link = link
        
        // MARK: - Set map layer
        context.coordinator.loader?.changeTileInfo(Utils.tileInfoFrom(layer: mapLayer))
        uiViewController.setZoomLimits(minZoom: mapLayer.minZoom,
                                       maxZoom: mapLayer.maxZoom)
    }
    
    static func dismantleUIViewController(_ uiViewController: MaplyViewController, coordinator: Coordinator) {
        coordinator.loader?.shutdown()
        uiViewController.teardown()
    }
}

extension MaplyViewController {
    enum Action {
        case zoomIn
        case zoomOut
    }
    
    func action(_ action: Action) {
        DispatchQueue.main.async {
            switch action {
            case .zoomIn:
                self.zoomIn()
            case .zoomOut:
                self.zoomOut()
            }
        }
    }
    
    func focusOn(point: MaplyCoordinate, height: Float = 0.0000264, animated: Bool = true) {
        let z = max(height, getMinZoom())
        if animated {
            animate(toPosition: point, height: z, time: 0.2)
        } else {
            setPosition(point, height: z)
        }
    }
    
    func zoomIn() {
        let pos = getPosition()
        let zoom = currentMapScale() / 2
        focusOn(point: pos, height: height(forMapScale: zoom))
    }
    
    func zoomOut() {
        let pos = getPosition()
        let zoom = currentMapScale() * 2
        focusOn(point: pos, height: height(forMapScale: zoom))
    }
    
    func setZoomLimits(minZoom: Int32, maxZoom: Int32) {
        setZoomLimitsMin(
            height(forMapScale: Float(truncating:
                MapCalculus.companion.zoomLevelToScale(zoom: maxZoom)
                ?? MapCalculus.companion.zoomLevelToScale(zoom: 21)!
            )),
            max: height(forMapScale: Float(truncating:
                MapCalculus.companion.zoomLevelToScale(zoom: minZoom)
                ?? MapCalculus.companion.zoomLevelToScale(zoom: 1)!
            )))
    }
}

// Source: https://stackoverflow.com/questions/65923718
class BaseMapLink: ObservableObject {
    @Published var action: MaplyViewController.Action?
    
    func zoomIn() {
        action = .zoomIn
    }
    
    func zoomOut() {
        action = .zoomOut
    }
}