//
// Copyright Amazon.com Inc. or its affiliates.
// All Rights Reserved.
//
// SPDX-License-Identifier: Apache-2.0
//

import SwiftUI
import Amplify
import AWSLocationGeoPlugin
import Mapbox
import AmplifyMapLibreAdapter

/// The `SwiftUI` wrapper for `MGLMapView`
public struct AMLMapView: View {
    /// Object to track state changes in the map.
    @ObservedObject var mapState: AMLMapViewState

    /// Map configuration settings. Accessible through view modifiers.
    @ObservedObject var mapSettings: AMLMapViewSettings

    /// Loading state for track asynchronous loading of map
    @State private var mapLoadingState = MapCreationStateMachine(state: .begin)

    /// Create an instance of `AMLMapView`
    /// - Parameter mapState: Object to track state changes.
    public init(mapState: AMLMapViewState = .init()) {
        self.mapState = mapState
        self.mapSettings = AMLMapViewSettings()
        if let mapView = mapState.mapView {
            mapLoadingState.state = .complete(mapView)
        }
    }

    /// Create an instance of `AMLMapView`.
    ///
    /// Internal initializer to pass mapSettings in from composite view.
    /// - Parameters:
    ///   - mapState: Object to track state changes.
    ///   - mapSettings: Configurable settings for the map. Set through view modfiiers.
    internal init(mapState: AMLMapViewState, mapSettings: AMLMapViewSettings) {
        self.mapState = mapState
        self.mapSettings = mapSettings
        if let mapView = mapState.mapView {
            mapLoadingState.state = .complete(mapView)
        }
    }

    public var body: some View {
        switch mapLoadingState.state {
        case .complete(let mapView):
            ZStack {
                _MGLMapViewWrapper(
                    mapView: mapView,
                    zoomLevel: $mapState.zoomLevel,
                    bounds: $mapState.bounds,
                    center: $mapState.center,
                    heading: $mapState.heading,
                    userLocation: $mapState.userLocation,
                    showUserLocation: mapSettings.showUserLocation,
                    features: $mapState.features,
                    attribution: $mapState.attribution,
                    featureImage: mapSettings.featureImage,
                    clusteringBehavior: mapSettings.clusteringBehavior,
                    proxyDelegate: mapSettings.proxyDelegate
                )
                    .showUserLocation(mapSettings.showUserLocation)
                    .compassPosition(mapSettings.compassPosition)
                    .minZoomLevel(mapSettings.minZoomLevel)
                    .maxZoomLevel(mapSettings.maxZoomLevel)
                    .accessibility(label: Text("Map"))
                    .accessibility(identifier: "amlmapview")

                VStack {
                    Spacer()
                    AMLMapAttributionView(
                        isAttributionTextDisplayed: $mapState.isAttributionTextDisplayed,
                        attributionText: mapState.attribution
                    )
                }
            }
        case .error(let error):
            Text("Error loading view: \(error.localizedDescription)")
        case .begin:
            AMLActivityIndicator()
                .onAppear(perform: createMap)
        }
    }

    /// Handle aysnchronous request to create map from `AmplifyMapLibre`.
    private func createMap() {
        Task {
            do {
                let mapView = try await AmplifyMapLibre.createMap()
                mapLoadingState.transition(input: .success(mapView), assign: &mapState.mapView)
            } catch {
                mapLoadingState.transition(input: .failure(error as! Geo.Error), assign: &mapState.mapView)
            }
        }
    }
}