import SwiftUI

/// Einrichten eines neuen Geräts: scannen, auswählen, benennen.
struct AddDeviceView: View {
    @Environment(DeviceStore.self) private var store
    @Environment(BluetoothManager.self) private var bluetooth
    @Environment(\.dismiss) private var dismiss

    @State private var selected: Discovery?
    /// Auf einem Stellplatz sind dutzende fremde Geräte in Reichweite.
    @State private var showsAllDevices = false

    /// Nur Geräte anzeigen, die in den letzten Sekunden zu hören waren –
    /// sonst füllt sich die Liste in Wohnmobilparks endlos.
    private var visibleDiscoveries: [Discovery] {
        // Bewusst nicht nach Signalstärke sortieren: die schwankt im
        // Sekundentakt und die Liste würde unter dem Finger springen.
        bluetooth.discoveries.values
            .filter { showsAllDevices || $0.looksLikeSupported }
            .sorted { lhs, rhs in
                //if lhs.isVictron != rhs.isVictron { return lhs.isVictron }
                if lhs.looksLikeSupported != rhs.looksLikeSupported { return lhs.looksLikeSupported }
                return lhs.firstSeen < rhs.firstSeen
            }
    }

    private var alreadyAdded: Set<UUID> {
        Set(store.activeDevices.map(\.peripheralID))
    }

    var body: some View {
        NavigationStack {
            List {
                Picker("Anzeige", selection: $showsAllDevices) {
                    Text("Passende Geräte").tag(false)
                    Text("Alle").tag(true)
                }
                .pickerStyle(.segmented)
                .listRowBackground(Color.clear)

                Section {
                    if visibleDiscoveries.isEmpty {
                        Label(showsAllDevices ? "Suche…" : "Noch nichts Passendes gefunden",
                              systemImage: "antenna.radiowaves.left.and.right")
                            .foregroundStyle(.secondary)
                    }
                    ForEach(visibleDiscoveries) { discovery in
                        Button {
                            selected = discovery
                        } label: {
                            row(for: discovery)
                        }
                        .disabled(alreadyAdded.contains(discovery.id))
                    }
                } header: {
                    HStack {
                        Text("Gefundene Geräte")
                        Spacer()
                        ProgressView().controlSize(.small)
                    }
                } footer: {
                    Text("Victron-Geräte werden automatisch erkannt. Damit sie hier "
                         + "auftauchen, muss „Instant Readout“ in VictronConnect aktiv sein. "
                         + "Das BMS meldet sich meist als „DL-…“. Kühlboxen tragen oft "
                         + "einen kryptischen Namen – findest du dein Gerät nicht, auf "
                         + "„Alle“ umschalten.")
                }
            }
            .navigationTitle("Gerät für \(store.activeProfile?.name ?? "Camper")")
            .navigationBarTitleDisplayMode(.inline)
            .toolbar {
                ToolbarItem(placement: .cancellationAction) {
                    Button("Fertig") { dismiss() }
                }
            }
            .sheet(item: $selected) { discovery in
                ConfigureDeviceView(discovery: discovery) {
                    dismiss()
                }
            }
            .onAppear {
                bluetooth.clearDiscoveries()
                bluetooth.isDiscovering = true
            }
            .onDisappear {
                bluetooth.isDiscovering = false
            }
        }
    }

    private func row(for discovery: Discovery) -> some View {
        HStack(spacing: 12) {
            Image(systemName/*: discovery.isVictron ? "bolt.circle.fill"*/
                  : discovery.looksLikeSupported ? "battery.100percent" : "dot.radiowaves.left.and.right")
                .font(.title3)
                .foregroundStyle(/*discovery.isVictron || */discovery.looksLikeSupported ? Color.accentColor : Color.secondary)
                .frame(width: 28)

            VStack(alignment: .leading, spacing: 2) {
                Text(discovery.displayName)
                    .foregroundStyle(.primary)
                Text(discovery.subtitle)
                    .font(.caption)
                    .foregroundStyle(.secondary)
            }

            Spacer()

            if alreadyAdded.contains(discovery.id) {
                Text("Hinzugefügt")
                    .font(.caption)
                    .foregroundStyle(.secondary)
            } else {
                SignalBars(rssi: discovery.rssi)
            }
        }
    }
}

/// Formular für ein neu gewähltes Gerät.
private struct ConfigureDeviceView: View {
    let discovery: Discovery
    let onSaved: () -> Void

    @Environment(DeviceStore.self) private var store
    @Environment(BluetoothManager.self) private var bluetooth
    @Environment(\.dismiss) private var dismiss

    @State private var name: String = ""
    @State private var role: DeviceRole = .leveling
    @State private var key: String = ""

    //private var needsKey: Bool { role.transport == .advertisement }
    //private var keyIsValid: Bool { key.hexBytes?.count == 16 }
    private var canSave: Bool {
        !name.trimmingCharacters(in: .whitespaces).isEmpty /*&& (!needsKey || key.isEmpty || keyIsValid)*/
    }

    var body: some View {
        NavigationStack {
            Form {
                Section("Gerät") {
                    LabeledContent("Gefunden als", value: discovery.displayName)
                    TextField("Name", text: $name)
                    Picker("Art", selection: $role) {
                        ForEach(DeviceRole.allCases) { role in
                            Text(role.title).tag(role)
                        }
                    }
                }

                /*if needsKey {
                    Section {
                        TextField("32 Hex-Zeichen", text: $key)
                            .font(.system(.body, design: .monospaced))
                            .textInputAutocapitalization(.never)
                            .autocorrectionDisabled()
                        if !key.isEmpty && !keyIsValid {
                            Label("Der Schlüssel muss 16 Byte (32 Hex-Zeichen) haben.",
                                  systemImage: "exclamationmark.circle")
                                .font(.caption)
                                .foregroundStyle(.orange)
                        }
                    } header: {
                        Text("Verschlüsselungsschlüssel")
                    } footer: {
                        Text("VictronConnect → Gerät → Zahnrad → ⋮ → Produkt-Info → "
                             + "„Instant Readout“ aktivieren → Verschlüsselungsdaten anzeigen. "
                             + "Kann auch später nachgetragen werden.")
                    }
                }*/
            }
            .navigationTitle("Einrichten")
            .navigationBarTitleDisplayMode(.inline)
            .toolbar {
                ToolbarItem(placement: .cancellationAction) {
                    Button("Abbrechen") { dismiss() }
                }
                ToolbarItem(placement: .confirmationAction) {
                    Button("Sichern", action: save).disabled(!canSave)
                }
            }
            .onAppear(perform: prefill)
        }
    }

    /// Aus dem Advertisement lässt sich Art und Name oft schon erraten.
    private func prefill() {
        /*if let recordType = discovery.victronRecordType {
            switch VictronAdvertisement.RecordType(rawValue: recordType) {
            case .solarCharger:                 role = .solarCharger
            case .dcdcConverter, .orionXS:      role = .chargeBooster
            case .batteryMonitor:               role = .batteryMonitor
            default:                            role = .solarCharger
            }
        } else*/ if discovery.isLevelSensor {
            role = .leveling
        } else if discovery.isVotronicSolarESPSensor {
            role = .solar
        } /*else if let name = discovery.name?.lowercased(),
                  ["alpicool", "icecube", "ice cube", "fridge", "cool"].contains(where: name.contains) {
            role = .fridge
        } else if discovery.looksLikeSupported {
            role = .bms
        }*/
        // Funknamen wie "WTaEaAA25342229" taugen nicht als Anzeigename. Die
        // Art des Geräts ist der bessere Vorschlag; der Funkname steht
        // ohnehin darüber unter "Gefunden als".
        if discovery.isLevelSensor {
            name = "Nivellierung"
        } else if discovery.isVotronicSolarESPSensor {
            name = role.title
        } else if let advertised = discovery.name, advertised.count <= 20,
           advertised.contains(" ") || advertised.rangeOfCharacter(from: .decimalDigits) == nil {
            name = advertised
        } else {
            name = role.title
        }
    }

    private func save() {
        let device = ConfiguredDevice(
            name: name.trimmingCharacters(in: .whitespaces),
            role: role,
            profileID: store.activeProfileID,
            peripheralID: discovery.id,
            advertisedName: discovery.name
        )
        store.add(device/*, victronKey: needsKey && keyIsValid ? key : nil*/)
        bluetooth.refreshConfiguration()
        dismiss()
        onSaved()
    }
}

/// Signalstärke als drei Balken.
struct SignalBars: View {
    let rssi: Int

    private var level: Int {
        switch rssi {
        case (-60)...:      return 3
        case (-75)..<(-60): return 2
        case (-90)..<(-75): return 1
        default:            return 0
        }
    }

    var body: some View {
        HStack(alignment: .bottom, spacing: 2) {
            ForEach(1...3, id: \.self) { bar in
                RoundedRectangle(cornerRadius: 1)
                    .fill(bar <= level ? Color.accentColor : Color.secondary.opacity(0.25))
                    .frame(width: 3, height: CGFloat(bar) * 4 + 2)
            }
        }
        .accessibilityLabel("Signalstärke \(level) von 3")
    }
}