//
//  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 mastodonController: MastodonController
    let subscription: PushSubscription?
    let updateSubscription: (PushSubscription.Alerts, PushSubscription.Policy) async -> Bool

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

private struct PushSubscriptionSettingsView: View {
    let account: UserAccountInfo
    let mastodonController: MastodonController
    let subscription: PushSubscription
    let updateSubscription: (PushSubscription.Alerts, PushSubscription.Policy) async -> Bool
    @State private var isLoading: [PushSubscription.Alerts: Bool] = [:]
    
    var body: some View {
        VStack {
            alertsToggles
            
            if mastodonController.instanceFeatures.pushNotificationPolicy {
                AsyncPicker("From", alignment: .trailing, value: .constant(subscription.policy)) { newPolicy in
                    await updateSubscription(subscription.alerts, newPolicy)
                } content: {
                    ForEach(PushSubscription.Policy.allCases) {
                        Text($0.displayName).tag($0)
                    }
                }
                .pickerStyle(.menu)
            }
        }
        // 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 var alertsToggles: some View {
        GroupBox("Get notifications for") {
            VStack {
                toggle("All", alert: allSupportedAlertTypes)
                toggle("Mentions", alert: .mention)
                toggle("Favorites", alert: .favorite)
                toggle("Reblogs", alert: .reblog)
                if mastodonController.instanceFeatures.pushNotificationTypeFollowRequest {
                    toggle("Follows", alert: [.follow, .followRequest])
                } else {
                    toggle("Follows", alert: .follow)
                }
                toggle("Polls finishing", alert: .poll)
                if mastodonController.instanceFeatures.pushNotificationTypeUpdate {
                    toggle("Edits", alert: .update)
                }
                // status notifications not supported until we can enable/disable them in the app
            }
        }
        .groupBoxStyle(AppBackgroundGroupBoxStyle())
    }
    
    private var allSupportedAlertTypes: PushSubscription.Alerts {
        var alerts: PushSubscription.Alerts = [.mention, .favorite, .reblog, .follow, .poll]
        if mastodonController.instanceFeatures.pushNotificationTypeFollowRequest {
            alerts.insert(.followRequest)
        }
        if mastodonController.instanceFeatures.pushNotificationTypeUpdate {
            alerts.insert(.update)
        }
        return alerts
    }
    
    private func toggle(_ titleKey: LocalizedStringKey, alert: PushSubscription.Alerts) -> some View {
        let binding: Binding<AsyncToggle.Mode> = Binding {
            isLoading[alert] == true ? .loading : subscription.alerts.contains(alert) ? .on : .off
        } set: { newValue in
            isLoading[alert] = newValue == .loading
        }
        return AsyncToggle(titleKey, mode: binding) {
            return await updateAlert(alert, isOn: $0)
        }
    }
    
    private func updateAlert(_ alert: PushSubscription.Alerts, isOn: Bool) async -> Bool {
        var newAlerts = subscription.alerts
        if isOn {
            newAlerts.insert(alert)
        } else {
            newAlerts.remove(alert)
        }
        return await updateSubscription(newAlerts, subscription.policy)
    }
}

private extension PushSubscription.Policy {
    var displayName: String {
        switch self {
        case .all:
            "Anyone"
        case .followed:
            "Accounts you follow"
        case .followers:
            "Your followers"
        }
    }
}

private struct AppBackgroundGroupBoxStyle: GroupBoxStyle {
    func makeBody(configuration: Configuration) -> some View {
        VStack(alignment: .leading, spacing: 16) {
            configuration.label
                .font(.headline)
            
            configuration.content
        }
        .padding()
        .background(Color.appGroupedBackground, in: RoundedRectangle(cornerRadius: 8))
    }
}

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