import Library
import SkyRenderer
import SwiftUI
import UserNotifications

/// UserDefaults keys shared by the settings screen and the models that read them.
enum SettingsKey {
    static let locationMode = "locationMode" // "current" or "city"
    static let cityName = "cityName"
    static let cityLatitude = "cityLatitude"
    static let cityLongitude = "cityLongitude"
    static let nightMode = "nightMode" // "off", "on" or "auto"
    static let onboarded = "onboarded"
    /// Whether the Sky tab is currently drawn in night mode (written by the Sky tab).
    static let nightActive = "nightActive"
    static let dailySummary = "dailySummary"
    /// Sky culture id, or "western" for the IAU constellations.
    static let skyCulture = "skyCulture"
    /// Minutes after local midnight.
    static let dailySummaryMinutes = "dailySummaryMinutes"
}

struct City: Hashable, Identifiable {
    var name: String
    var latitude: Double
    var longitude: Double
    var id: String { name }

    static let all: [City] = [
        City(name: "Anchorage", latitude: 61.218, longitude: -149.900),
        City(name: "Auckland", latitude: -36.849, longitude: 174.763),
        City(name: "Berlin", latitude: 52.520, longitude: 13.405),
        City(name: "Buenos Aires", latitude: -34.604, longitude: -58.382),
        City(name: "Cairo", latitude: 30.044, longitude: 31.236),
        City(name: "Cape Town", latitude: -33.925, longitude: 18.424),
        City(name: "Chicago", latitude: 41.878, longitude: -87.630),
        City(name: "Denver", latitude: 39.739, longitude: -104.990),
        City(name: "Honolulu", latitude: 21.307, longitude: -157.858),
        City(name: "Houston", latitude: 29.760, longitude: -95.370),
        City(name: "London", latitude: 51.507, longitude: -0.128),
        City(name: "Los Angeles", latitude: 34.052, longitude: -118.244),
        City(name: "Mexico City", latitude: 19.433, longitude: -99.133),
        City(name: "Mumbai", latitude: 19.076, longitude: 72.878),
        City(name: "New York", latitude: 40.713, longitude: -74.006),
        City(name: "Paris", latitude: 48.857, longitude: 2.352),
        City(name: "Reykjavík", latitude: 64.147, longitude: -21.942),
        City(name: "Santiago", latitude: -33.449, longitude: -70.669),
        City(name: "São Paulo", latitude: -23.551, longitude: -46.633),
        City(name: "Seattle", latitude: 47.606, longitude: -122.332),
        City(name: "Singapore", latitude: 1.352, longitude: 103.820),
        City(name: "Stockholm", latitude: 59.329, longitude: 18.069),
        City(name: "Sydney", latitude: -33.869, longitude: 151.209),
        City(name: "Tokyo", latitude: 35.676, longitude: 139.650),
        City(name: "Toronto", latitude: 43.653, longitude: -79.383),
    ]
}

/// Privacy policy served by the backend.
let privacyPolicyURL = URL(string: "https://moonrise-server.audit-labs.workers.dev/privacy")!

struct SettingsScreen: View {
    @AppStorage(SettingsKey.locationMode) private var locationMode = "current"
    @AppStorage(SettingsKey.cityName) private var cityName = "Chicago"
    @AppStorage(SettingsKey.cityLatitude) private var cityLatitude = 41.878
    @AppStorage(SettingsKey.cityLongitude) private var cityLongitude = -87.630
    @AppStorage(SettingsKey.nightMode) private var nightMode = "auto"
    @AppStorage(SettingsKey.skyCulture) private var skyCulture = "western"
    @AppStorage(SettingsKey.onboarded) private var onboarded = true
    @Environment(\.dismiss) private var dismiss
    @State private var alerts = AuroraAlerts.shared
    @AppStorage(SettingsKey.dailySummary) private var dailySummary = false
    @AppStorage(SettingsKey.dailySummaryMinutes) private var dailySummaryMinutes = DailySummaryNotifications.defaultMinutes
    @State private var summaryStatus: String?
    var onChange: () -> Void

    var body: some View {
        NavigationStack {
            Form {
                Section("Location") {
                    Picker("Sky for", selection: $locationMode) {
                        Text("Current location").tag("current")
                        Text("A city").tag("city")
                    }
                    if locationMode == "city" {
                        Picker("City", selection: $cityName) {
                            ForEach(City.all) { Text($0.name).tag($0.name) }
                        }
                    }
                }
                Section {
                    Toggle("Aurora alerts", isOn: Binding(
                        get: { alerts.enabled },
                        set: { on in Task { await alerts.setEnabled(on) } }
                    ))
                    Toggle("News alerts", isOn: Binding(
                        get: { alerts.news },
                        set: { on in Task { await alerts.setNews(on) } }
                    ))
                    if alerts.enabled || alerts.news {
                        Button("Send a test alert") { Task { await alerts.sendTest() } }
                    }
                    if let status = alerts.status {
                        Text(status).font(.footnote).foregroundStyle(.secondary)
                    }
                } header: {
                    Text("Alerts")
                } footer: {
                    Text("Aurora alerts tell you when the aurora may be visible from your area at night. News alerts send three of the day's space headlines at 9 a.m. For these, Moonrise sends our server this device's notification token, a 5° band of geomagnetic latitude, your time zone offset and which alerts are on, not your location.")
                }
                Section {
                    Toggle("Daily summary", isOn: Binding(
                        get: { dailySummary },
                        set: { on in Task { await setDailySummary(on) } }
                    ))
                    if dailySummary {
                        DatePicker("Time", selection: summaryTime, displayedComponents: .hourAndMinute)
                    }
                    if let summaryStatus {
                        Text(summaryStatus).font(.footnote).foregroundStyle(.secondary)
                    }
                } footer: {
                    Text("A note each day with the Moon, the planets up that night, the best satellite pass and any events. It is worked out on this device; nothing is sent to our server.")
                }
                Section {
                    Picker("Constellations", selection: $skyCulture) {
                        Text("Western (IAU)").tag("western")
                        ForEach(Catalog.skyCultures) { Text($0.name).tag($0.id) }
                    }
                    Picker("Night mode", selection: $nightMode) {
                        Text("Off").tag("off")
                        Text("On").tag("on")
                        Text("After dark").tag("auto")
                    }
                } header: {
                    Text("Display")
                } footer: {
                    Text("Constellations from other cultures come from Stellarium's sky cultures and are drawn over the same stars; figures with stars fainter than the app's catalogue are shortened. Night mode draws the sky in red to keep your eyes adapted to the dark. After dark turns it on once the Sun is 12° below the horizon.")
                }
                Section("About") {
                    LabeledContent("Version", value: Bundle.main.versionString)
                    Button("Show the introduction again") {
                        dismiss()
                        // After the sheet has gone, so the full-screen introduction can present.
                        Task { try? await Task.sleep(for: .milliseconds(600)); onboarded = false }
                    }
                    NavigationLink("Credits and licences") { CreditsScreen() }
                    Link("Privacy policy", destination: privacyPolicyURL)
                }
            }
            .navigationTitle("Settings")
            .navigationBarTitleDisplayMode(.inline)
            .toolbar {
                ToolbarItem(placement: .confirmationAction) { Button("Done") { dismiss() } }
            }
            .onChange(of: cityName) {
                if let c = City.all.first(where: { $0.name == cityName }) {
                    cityLatitude = c.latitude
                    cityLongitude = c.longitude
                }
                onChange()
            }
            .onChange(of: locationMode) { onChange() }
        }
    }

    private var summaryTime: Binding<Date> {
        Binding(
            get: { Calendar.current.startOfDay(for: .now).addingTimeInterval(Double(dailySummaryMinutes) * 60) },
            set: { d in
                let c = Calendar.current.dateComponents([.hour, .minute], from: d)
                dailySummaryMinutes = (c.hour ?? 0) * 60 + (c.minute ?? 0)
            }
        )
    }

    private func setDailySummary(_ on: Bool) async {
        if on {
            let granted = (try? await UNUserNotificationCenter.current().requestAuthorization(options: [.alert, .sound])) ?? false
            guard granted else {
                summaryStatus = "Notifications are off for Moonrise. Turn them on in the Settings app."
                return
            }
        }
        summaryStatus = nil
        dailySummary = on
    }
}

struct CreditsScreen: View {
    private struct Credit: Hashable {
        var name: String
        var detail: String
    }

    private let software: [Credit] = [
        Credit(name: "Astronomy Engine", detail: "Don Cross. MIT licence."),
        Credit(name: "Yale Bright Star Catalogue, 5th ed.", detail: "Hoffleit & Warren (1991), via VizieR V/50."),
        Credit(name: "Constellation lines", detail: "Marc van der Sluys, ConstellationLines (doi:10.5281/zenodo.10397192). CC BY 4.0."),
        Credit(name: "Coastlines", detail: "Natural Earth. Public domain."),
        Credit(name: "Spacecraft trajectories", detail: "NASA/JPL Horizons."),
    ]

    private let feeds: [Credit] = [
        Credit(name: "Space weather and aurora forecast", detail: "NOAA Space Weather Prediction Center."),
        Credit(name: "Images of the Sun", detail: "Courtesy of NASA/SDO and the AIA, EVE, and HMI science teams."),
        Credit(name: "Launch schedule", detail: "The Space Devs, Launch Library 2."),
        Credit(name: "Deep Space Network status", detail: "NASA/JPL, DSN Now."),
        Credit(name: "Satellite orbits", detail: "CelesTrak."),
        Credit(name: "Mars rover raw images", detail: "NASA/JPL-Caltech, with MSSS and ASU for some cameras."),
        Credit(name: "Space news headlines", detail: "Spaceflight News API, The Space Devs. Articles belong to their publishers."),
    ]

    /// Every distinct image credit used by the Library, grouped by licence.
    private var imageCredits: [(licence: String, credits: [String])] {
        let images = Library.pages.compactMap(\.image)
        let grouped = Dictionary(grouping: images, by: \.licence)
        return grouped.keys.sorted().map { licence in
            (licence, Array(Set(grouped[licence]!.map(\.credit))).sorted())
        }
    }

    var body: some View {
        List {
            Section("Data and software") {
                ForEach(software, id: \.self) { row($0) }
            }
            Section("Live data") {
                ForEach(feeds, id: \.self) { row($0) }
            }
            Section("Sky cultures") {
                ForEach(Catalog.skyCultures) { c in
                    Link(destination: c.source) {
                        VStack(alignment: .leading, spacing: 2) {
                            Text(c.name)
                            Text("Stellarium sky cultures. \(c.licence)").font(.footnote).foregroundStyle(.secondary)
                        }
                    }
                }
            }
            ForEach(imageCredits, id: \.licence) { group in
                Section("Library images: \(group.licence)") {
                    ForEach(group.credits, id: \.self) { Text($0).font(.footnote) }
                }
            }
            Section {
                Text("Each Library page lists its sources, and each image links to the page it is published on. CC BY images are used under the Creative Commons Attribution 4.0 licence; ESA images marked CC BY-SA 3.0 IGO under that licence. NASA does not endorse this app.")
                    .font(.footnote)
            }
        }
        .navigationTitle("Credits and licences")
    }

    private func row(_ c: Credit) -> some View {
        VStack(alignment: .leading, spacing: 2) {
            Text(c.name)
            Text(c.detail).font(.footnote).foregroundStyle(.secondary)
        }
    }
}

extension Bundle {
    var versionString: String {
        let v = object(forInfoDictionaryKey: "CFBundleShortVersionString") as? String ?? "?"
        let b = object(forInfoDictionaryKey: "CFBundleVersion") as? String ?? "?"
        return "\(v) (\(b))"
    }
}