import SwiftUI

/// "LAN-Scanner" tab: one table per physical Ethernet/WLAN port, each listing the
/// devices resolved onto it (name/IP/MAC/status), plus right-click actions to give a device a
/// permanent static IP (Winbox's "Make Static") or remove that reservation again.
struct DevicesView: View {
    @ObservedObject var connectionService: ConnectionService
    @StateObject private var viewModel: DevicesViewModel
    @State private var rawFieldsDevice: LanDevice?
    /// Plain, independent Bool — deliberately NOT derived from `pendingStaticAssignment`.
    /// SwiftUI's `.confirmationDialog` calls the `isPresented` binding's setter with `false` on
    /// EVERY dismissal, including tapping "Zuweisen" itself — a computed binding that reacted to
    /// that by nil-ing `pendingStaticAssignment` was found to clear it before
    /// `confirmStaticAssignment()` could read it, so the confirmed action silently ran on `nil`
    /// and did nothing. Matches this app's own established, working pattern for confirmation
    /// dialogs elsewhere (BackupListView's factory-reset dialog): the dialog's own visibility and
    /// its payload are two separate pieces of state.
    @State private var showStaticConfirmation = false
    /// Same reasoning as `showStaticConfirmation` — independent of `pendingStaticRemoval`.
    @State private var showRemovalConfirmation = false

    init(connectionService: ConnectionService) {
        self.connectionService = connectionService
        _viewModel = StateObject(wrappedValue: DevicesViewModel(connectionService: connectionService))
    }

    var body: some View {
        NavigationStack {
            Group {
                if connectionService.credentials == nil {
                    ContentUnavailableView(
                        "Nicht verbunden",
                        systemImage: "network.slash",
                        description: Text("Verbinde dich zuerst im Tab \"Verbinden\" mit deinem Router.")
                    )
                } else if viewModel.isLoading && viewModel.devices.isEmpty {
                    ProgressView("Suche Geräte im Netz…")
                        .frame(maxWidth: .infinity, maxHeight: .infinity)
                } else if let error = viewModel.loadError, viewModel.devices.isEmpty {
                    ContentUnavailableView(
                        "Konnte Geräte nicht laden", systemImage: "exclamationmark.triangle",
                        description: Text(error)
                    )
                } else if viewModel.portGroups.isEmpty {
                    ContentUnavailableView(
                        "Keine Ports gefunden", systemImage: "wifi.slash",
                        description: Text("Der Router meldet aktuell keine physischen Interfaces.")
                    )
                } else {
                    Form {
                        ForEach(viewModel.portGroups) { group in
                            Section {
                                if group.devices.isEmpty {
                                    Text("Keine Geräte").font(.caption).foregroundStyle(.secondary)
                                } else {
                                    DeviceColumnHeader()
                                    ForEach(group.devices) { device in
                                        DeviceRow(device: device)
                                            .contextMenu {
                                                deviceMenu(for: device)
                                            }
                                    }
                                }
                            } header: {
                                Text("\(group.title) (\(group.devices.count))")
                            }
                        }
                    }
                    .formStyle(.grouped)
                }
            }
            .overlay(alignment: .bottom) {
                if viewModel.isRunningNetworkTool {
                    HStack(spacing: 6) {
                        ProgressView().controlSize(.small)
                        Text("Führe Netzwerk-Test aus…").font(.caption)
                    }
                    .padding(.horizontal, 12)
                    .padding(.vertical, 6)
                    .background(.regularMaterial, in: Capsule())
                    .padding(.bottom, 12)
                }
            }
            .navigationTitle("LAN-Scanner")
            .toolbar {
                ToolbarItem {
                    Button {
                        Task { await viewModel.load() }
                    } label: {
                        if viewModel.isLoading {
                            ProgressView().controlSize(.small)
                        } else {
                            Label("Neu scannen", systemImage: "arrow.clockwise")
                        }
                    }
                    // Per explicit request: a plain icon+text toolbar button up in the corner got
                    // overlooked ("wird übersehen") — `.borderedProminent` gives it a filled,
                    // colored background so it visually stands out from the window chrome instead
                    // of blending into it.
                    .buttonStyle(.borderedProminent)
                    .disabled(viewModel.isLoading)
                }
            }
            .task {
                if viewModel.devices.isEmpty {
                    await viewModel.load()
                }
            }
            .withStaticAssignmentDialogs(
                viewModel: viewModel,
                showStaticConfirmation: $showStaticConfirmation,
                showRemovalConfirmation: $showRemovalConfirmation
            )
            .withDeviceDetailSheets(viewModel: viewModel, rawFieldsDevice: $rawFieldsDevice)
        }
    }

    @ViewBuilder
    private func deviceMenu(for device: LanDevice) -> some View {
        if device.hasLease {
            if device.isStatic {
                Button {
                    viewModel.pendingStaticRemoval = device
                    showRemovalConfirmation = true
                } label: {
                    Label("Feste Zuweisung entfernen", systemImage: "pin.slash")
                }
            } else {
                Button {
                    viewModel.pendingStaticAssignment = device
                    showStaticConfirmation = true
                } label: {
                    Label("Feste IP zuweisen", systemImage: "pin.fill")
                }
            }
        } else {
            Text("Kein DHCP-Lease — feste Zuweisung hier nicht möglich")
        }
        Divider()
        Menu {
            Button {
                viewModel.runPing(for: device)
            } label: {
                Label("Ping", systemImage: "dot.radiowaves.left.and.right")
            }
            Button {
                viewModel.runTraceroute(for: device)
            } label: {
                Label("Traceroute", systemImage: "point.topleft.down.curvedto.point.bottomright.up")
            }
            if let hostName = device.hostName, !hostName.isEmpty {
                Button {
                    viewModel.runDnsLookup(for: device)
                } label: {
                    Label("DNS-Auflösung (nslookup)", systemImage: "magnifyingglass")
                }
            }
            Divider()
            Button {
                viewModel.runPortScan(for: device)
            } label: {
                Label("Port-Scan", systemImage: "list.bullet.rectangle.portrait")
            }
        } label: {
            Label("Netzwerk-Tools", systemImage: "stethoscope")
        }
        .disabled(viewModel.isRunningNetworkTool)
        Divider()
        Button {
            rawFieldsDevice = device
        } label: {
            Label("Rohdaten anzeigen", systemImage: "list.bullet.rectangle")
        }
    }
}

/// Split out of `body` — same reasoning as `ConnectView`'s dialog-splitting extensions (Bug 19 in
/// HANDOFF.md): too many `.alert`/`.confirmationDialog`/`.sheet` modifiers chained onto one view
/// times out the Swift type-checker with a misleading error location, not an actual logic issue.
private extension View {
    func withStaticAssignmentDialogs(
        viewModel: DevicesViewModel,
        showStaticConfirmation: Binding<Bool>,
        showRemovalConfirmation: Binding<Bool>
    ) -> some View {
        self
            .confirmationDialog(
                "Feste IP-Adresse zuweisen?",
                isPresented: showStaticConfirmation,
                titleVisibility: .visible
            ) {
                Button("Zuweisen") {
                    Task { await viewModel.confirmStaticAssignment() }
                }
                Button("Abbrechen", role: .cancel) { viewModel.cancelStaticAssignment() }
            } message: {
                if let device = viewModel.pendingStaticAssignment {
                    Text(
                        "\(device.ipAddress) wird dauerhaft an \(device.macAddress)"
                        + (device.hostName.map { " (\($0))" } ?? "")
                        + " gebunden — die Adresse ändert sich für dieses Gerät nicht mehr automatisch."
                        + "\n\nRückgängig machen: hier im LAN-Scanner-Tab per Rechtsklick auf das Gerät"
                        + " → \"Feste Zuweisung entfernen\". Das Gerät bekommt danach aber nicht sofort"
                        + " automatisch eine neue Adresse — dafür muss es die Verbindung kurz trennen und"
                        + " neu aufbauen (Netzwerkkabel kurz ziehen/stecken, WLAN aus/an, oder neu starten)."
                        + "\n\nBefehl: \(viewModel.pendingCommand?.cliLine ?? "")"
                    )
                }
            }
            .confirmationDialog(
                "Feste Zuweisung entfernen?",
                isPresented: showRemovalConfirmation,
                titleVisibility: .visible
            ) {
                Button("Entfernen", role: .destructive) {
                    Task { await viewModel.confirmStaticRemoval() }
                }
                Button("Abbrechen", role: .cancel) { viewModel.cancelStaticRemoval() }
            } message: {
                if let device = viewModel.pendingStaticRemoval {
                    Text(
                        "Die feste Zuweisung für \(device.macAddress)"
                        + (device.hostName.map { " (\($0))" } ?? "")
                        + " wird entfernt. RouterOS kennt keine direkte Umkehrung von \"Make Static\" —"
                        + " das Gerät bekommt erst beim nächsten Verbindungsaufbau (Kabel/WLAN neu"
                        + " verbinden, Neustart) automatisch wieder eine Adresse per DHCP, eventuell"
                        + " eine andere IP als bisher."
                        + "\n\nBefehl: \(viewModel.pendingRemovalCommand?.cliLine ?? "")"
                    )
                }
            }
            .alert(
                "Fehler",
                isPresented: Binding(
                    get: { viewModel.applyError != nil },
                    set: { if !$0 { viewModel.dismissApplyError() } }
                ),
                presenting: viewModel.applyError
            ) { _ in
                Button("OK") {}
            } message: { error in
                Text(error)
            }
    }

    func withDeviceDetailSheets(viewModel: DevicesViewModel, rawFieldsDevice: Binding<LanDevice?>) -> some View {
        self
            .sheet(item: rawFieldsDevice) { device in
                RawFieldsSheet(device: device) { rawFieldsDevice.wrappedValue = nil }
            }
            .sheet(item: Binding(
                get: { viewModel.networkToolResult },
                set: { if $0 == nil { viewModel.networkToolResult = nil } }
            )) { result in
                NetworkToolResultSheet(result: result) { viewModel.networkToolResult = nil }
            }
            .sheet(item: Binding(
                get: { viewModel.portScanResult },
                set: { if $0 == nil { viewModel.portScanResult = nil } }
            )) { result in
                PortScanResultSheet(result: result) { viewModel.portScanResult = nil }
            }
            .alert(
                "Netzwerk-Test fehlgeschlagen",
                isPresented: Binding(
                    get: { viewModel.networkToolError != nil },
                    set: { if !$0 { viewModel.dismissNetworkToolError() } }
                ),
                presenting: viewModel.networkToolError
            ) { _ in
                Button("OK") {}
            } message: { error in
                Text(error)
            }
    }
}

/// Column widths shared between the header and each row so they line up like a real table.
private enum DeviceColumn {
    static let icon: CGFloat = 16
    static let name: CGFloat = 130
    static let ip: CGFloat = 110
    static let mac: CGFloat = 140
    static let status: CGFloat = 80
}

private struct DeviceColumnHeader: View {
    var body: some View {
        HStack(spacing: 8) {
            Spacer().frame(width: DeviceColumn.icon)
            Text("Name").frame(width: DeviceColumn.name, alignment: .leading)
            Text("IP-Adresse").frame(width: DeviceColumn.ip, alignment: .leading)
            Text("MAC-Adresse").frame(width: DeviceColumn.mac, alignment: .leading)
            Text("Status").frame(width: DeviceColumn.status, alignment: .leading)
            Spacer()
        }
        .font(.caption2.bold())
        .foregroundStyle(.secondary)
    }
}

private struct DeviceRow: View {
    let device: LanDevice

    /// Three distinct states, not two — a device with no matching DHCP lease at all is neither
    /// "Fest" (a real static reservation) nor "Dynamisch" (a real active lease); conflating it
    /// with "Fest" previously mislabeled every ARP-only device, DHCP clients included whenever
    /// their lease didn't get matched.
    private var statusIcon: String {
        guard device.hasLease else { return "questionmark.circle" }
        return device.isStatic ? "pin.fill" : "circle.fill"
    }

    private var statusColor: Color {
        guard device.hasLease else { return .secondary }
        return device.isStatic ? .orange : .green
    }

    private var statusText: String {
        guard device.hasLease else { return "Kein DHCP" }
        return device.isStatic ? "Fest" : "Dynamisch"
    }

    var body: some View {
        HStack(spacing: 8) {
            Image(systemName: statusIcon)
                .foregroundStyle(statusColor)
                .font(.system(size: 8))
                .frame(width: DeviceColumn.icon)
                .help(statusText)
            Text(device.hostName?.isEmpty == false ? device.hostName! : "-")
                .font(.system(size: 12))
                .lineLimit(1)
                .frame(width: DeviceColumn.name, alignment: .leading)
            Text(device.ipAddress)
                .font(.system(size: 12))
                .frame(width: DeviceColumn.ip, alignment: .leading)
            Text(device.macAddress)
                .font(.system(size: 11, design: .monospaced))
                .frame(width: DeviceColumn.mac, alignment: .leading)
            Text(statusText)
                .font(.caption)
                .foregroundStyle(.secondary)
                .frame(width: DeviceColumn.status, alignment: .leading)
            Spacer()
        }
        .padding(.vertical, 1)
    }
}

private struct RawFieldsSheet: View {
    let device: LanDevice
    let onClose: () -> Void

    var body: some View {
        VStack(alignment: .leading, spacing: 12) {
            Text("Rohdaten: \(device.macAddress)")
                .font(.headline)
            Text("Alle Felder, die RouterOS für diesen Eintrag zurückgegeben hat — hilfreich, falls Status/Port hier falsch aussieht.")
                .font(.caption)
                .foregroundStyle(.secondary)
            Divider()
            ScrollView {
                VStack(alignment: .leading, spacing: 4) {
                    ForEach(device.rawFields, id: \.key) { pair in
                        HStack(alignment: .top) {
                            Text(pair.key).font(.caption.monospaced()).foregroundStyle(.secondary)
                            Spacer()
                            Text(pair.value).font(.caption.monospaced()).multilineTextAlignment(.trailing)
                        }
                    }
                }
            }
            HStack {
                Spacer()
                Button("Schließen") { onClose() }
            }
        }
        .padding()
        .frame(minWidth: 380, minHeight: 300)
    }
}

/// Raw text output of a ping/traceroute/DNS-Auflösung run against a device — see
/// `NetworkToolResult`'s doc comment for why this isn't parsed into a nicer structured view.
private struct NetworkToolResultSheet: View {
    let result: NetworkToolResult
    let onClose: () -> Void

    var body: some View {
        VStack(alignment: .leading, spacing: 12) {
            Text(result.title)
                .font(.headline)
            Text("Ausgeführt vom Router aus (eigene SSH-Verbindung) — testet die Erreichbarkeit vom Router zu diesem Gerät, nicht von diesem Mac.")
                .font(.caption)
                .foregroundStyle(.secondary)
            Divider()
            ScrollView {
                Text(result.output.isEmpty ? "(keine Ausgabe)" : result.output)
                    .font(.system(.caption, design: .monospaced))
                    .frame(maxWidth: .infinity, alignment: .leading)
                    .textSelection(.enabled)
            }
            HStack {
                Spacer()
                Button("Schließen") { onClose() }
            }
        }
        .padding()
        .frame(minWidth: 420, minHeight: 320)
    }
}

/// Colored per-port result of a `PortScanner` run — red (open), green (closed), grey
/// (unreachable/no response), per explicit request. Run directly from this Mac, not the router
/// (see `PortScanner`'s doc comment), so the caption here says so — different from
/// `NetworkToolResultSheet`'s "run from the router" caption right above it in this same file.
private struct PortScanResultSheet: View {
    let result: PortScanResult
    let onClose: () -> Void

    var body: some View {
        VStack(alignment: .leading, spacing: 12) {
            Text("Port-Scan: \(result.deviceLabel)")
                .font(.headline)
            Text("TCP-Verbindungsversuch auf gängige Ports, ausgeführt von diesem Mac aus (nicht vom Router) — rot = offen, grün = geschlossen (Gerät antwortet, aber nichts lauscht dort), grau = keine Antwort (Firewall, Gerät aus, oder Port gefiltert).")
                .font(.caption)
                .foregroundStyle(.secondary)
            Divider()
            ScrollView {
                VStack(spacing: 0) {
                    ForEach(Array(result.entries.enumerated()), id: \.element.id) { index, entry in
                        if index > 0 { Divider() }
                        PortScanRow(entry: entry)
                    }
                }
            }
            HStack {
                Spacer()
                Button("Schließen") { onClose() }
            }
        }
        .padding()
        .frame(minWidth: 420, minHeight: 420)
    }
}

private struct PortScanRow: View {
    let entry: PortScanResult.Entry

    private var color: Color {
        switch entry.status {
        case .open: return .red
        case .closed: return .green
        case .unreachable: return .secondary
        }
    }

    private var statusText: String {
        switch entry.status {
        case .open: return "Offen"
        case .closed: return "Geschlossen"
        case .unreachable: return "Keine Antwort"
        }
    }

    var body: some View {
        HStack {
            Circle().fill(color).frame(width: 8, height: 8)
            Text("\(entry.port)")
                .font(.system(.caption, design: .monospaced))
                .frame(width: 50, alignment: .leading)
            Text(entry.serviceName ?? "-")
                .font(.caption)
                .foregroundStyle(.secondary)
                .frame(width: 140, alignment: .leading)
            Spacer()
            Text(statusText)
                .font(.caption)
                .foregroundStyle(color)
        }
        .padding(.vertical, 3)
    }
}

#Preview {
    DevicesView(connectionService: ConnectionService())
}