Tusker/Tusker/Screens/Preferences/Notifications/PushSubscriptionView.swift

//
//  PushSubscriptionView.swift
//  Tusker
//
//  Created by Shadowfacts on 4/7/24.
//  Copyright © 2024 Shadowfacts. All rights reserved.
//

import SwiftUI
import UserAccounts
import PushNotifications
import TuskerComponents

struct PushSubscriptionView: View {
    let account: UserAccountInfo
    let subscription: PushSubscription?
    let updateSubscription: (PushSubscription.Alerts, PushSubscription.Policy) async -> Void

    var body: some View {
        if let subscription {
            PushSubscriptionSettingsView(account: account, subscription: subscription, updateSubscription: updateSubscription)
        } else {
            Text("No notifications")
                .foregroundStyle(.secondary)
        }
    }
}

private struct PushSubscriptionSettingsView: View {
    let account: UserAccountInfo
    let subscription: PushSubscription
    let updateSubscription: (PushSubscription.Alerts, PushSubscription.Policy) async -> Void
    @State private var isLoading: [PushSubscription.Alerts: Bool] = [:]
    
    init(account: UserAccountInfo, subscription: PushSubscription, updateSubscription: @escaping (PushSubscription.Alerts, PushSubscription.Policy) async -> Void) {
        self.account = account
        self.subscription = subscription
        self.updateSubscription = updateSubscription
    }
    
    var body: some View {
        VStack(alignment: .prefsAvatar) {
            AsyncToggle("Mentions", mode: alertsBinding(for: .mention)) {
                await onChange(alert: .mention, value: $0)
            }
        }
        // this is the default value of the alignment guide, but this modifier is loading bearing
        .alignmentGuide(.prefsAvatar, computeValue: { dimension in
            dimension[.leading]
        })
        // otherwise the flexible view makes the containing stack extend under the edge of the list row
        .padding(.leading, 38)
    }
    
    private func alertsBinding(for alert: PushSubscription.Alerts) -> Binding<AsyncToggle.Mode> {
        return Binding {
            isLoading[alert] == true ? .loading : subscription.alerts.contains(alert) ? .on : .off
        } set: { newValue in
            isLoading[alert] = newValue == .loading
        }
    }
    
    private func onChange(alert: PushSubscription.Alerts, value: Bool) async {
        var newAlerts = subscription.alerts
        if value {
            newAlerts.insert(alert)
        } else {
            newAlerts.remove(alert)
        }
        await updateSubscription(newAlerts, subscription.policy)
    }
}

//#Preview {
//    PushSubscriptionView()
//}