import SwiftUI

struct PreferencesView: View {
    private enum Tab: CaseIterable {
        case monitor, notifications, alerts

        var title: String {
            switch self {
            case .monitor: return "Monitor"
            case .notifications: return "Notifications"
            case .alerts: return "Alerts"
            }
        }

        var icon: String {
            switch self {
            case .monitor: return "waveform.path.ecg"
            case .notifications: return "bell.badge"
            case .alerts: return "exclamationmark.triangle"
            }
        }
    }

    @AppStorage("pingInterval") private var storedPingInterval: Int = 10
    @AppStorage("refreshInterval") private var storedRefreshInterval: Int = 60
    @AppStorage("showIntervalIndicator") private var showIntervalIndicator: Bool = true

    @State private var pingIntervalSlider: Double = 10
    @State private var refreshIntervalSlider: Double = 60
    @State private var selection: Tab = .monitor

    private let minimumInterval: Double = 10
    private let maximumPingInterval: Double = 600
    private let maximumRefreshInterval: Double = 600

    var body: some View {
        HStack(spacing: 0) {
            sidebar
            Divider()
            ScrollView {
                detailContent(for: selection)
                    .frame(maxWidth: .infinity, alignment: .leading)
                    .padding()
            }
            .frame(minWidth: 360, maxWidth: .infinity, maxHeight: .infinity)
        }
        .frame(minWidth: 560, minHeight: 360)
        .onAppear {
            pingIntervalSlider = Double(storedPingInterval)
            refreshIntervalSlider = Double(storedRefreshInterval)
        }
        .onChange(of: pingIntervalSlider) { _, newValue in
            storedPingInterval = Int(newValue)
        }
        .onChange(of: refreshIntervalSlider) { _, newValue in
            storedRefreshInterval = Int(newValue)
        }
    }

    private var sidebar: some View {
        VStack(alignment: .leading, spacing: 12) {
            Text("Preferences")
                .font(.headline)
                .padding(.bottom, 8)

            ForEach(Tab.allCases, id: \.self) { tab in
                Button {
                    selection = tab
                } label: {
                    HStack(spacing: 10) {
                        Image(systemName: tab.icon)
                            .frame(width: 20)
                        Text(tab.title)
                        Spacer()
                    }
                    .padding(.vertical, 8)
                    .padding(.horizontal, 6)
                    .background(
                        RoundedRectangle(cornerRadius: 10, style: .continuous)
                            .fill(selection == tab ? Color.accentColor.opacity(0.25) : Color.clear)
                    )
                }
                .buttonStyle(.plain)
            }

            Spacer()
        }
        .padding()
        .frame(width: 180, alignment: .top)
    }

    @ViewBuilder
    private func detailContent(for tab: Tab) -> some View {
        VStack(alignment: .leading, spacing: 12) {
            Text(tab.title)
                .font(.title2)
                .padding(.bottom, 12)

            switch tab {
            case .monitor:
                MonitorPreferencesView(
                    pingIntervalSlider: $pingIntervalSlider,
                    refreshIntervalSlider: $refreshIntervalSlider,
                    showIntervalIndicator: $showIntervalIndicator,
                    minimumInterval: minimumInterval,
                    maximumPingInterval: maximumPingInterval,
                    maximumRefreshInterval: maximumRefreshInterval,
                    pingChanged: handlePingSliderEditing(_:),
                    refreshChanged: handleRefreshSliderEditing(_:)
                )
            case .notifications:
                NotificationsPreferencesView()
            case .alerts:
                AlertsPreferencesView()
            }
        }
    }

    private func handlePingSliderEditing(_ editing: Bool) {
        if !editing {
            storedPingInterval = Int(pingIntervalSlider)
        }
    }

    private func handleRefreshSliderEditing(_ editing: Bool) {
        if !editing {
            storedRefreshInterval = Int(refreshIntervalSlider)
        }
    }
}

private struct MonitorPreferencesView: View {
    @Binding var pingIntervalSlider: Double
    @Binding var refreshIntervalSlider: Double
    @Binding var showIntervalIndicator: Bool

    let minimumInterval: Double
    let maximumPingInterval: Double
    let maximumRefreshInterval: Double
    let pingChanged: (Bool) -> Void
    let refreshChanged: (Bool) -> Void

    var body: some View {
        VStack(alignment: .leading, spacing: 18) {
            Group {
                Text("Ping interval")
                    .font(.headline)
                Slider(
                    value: $pingIntervalSlider,
                    in: minimumInterval...maximumPingInterval,
                    step: 5
                ) {
                    Text("Ping interval")
                } minimumValueLabel: {
                    Text("\(Int(minimumInterval))s")
                        .font(.caption)
                        .foregroundColor(.secondary)
                } maximumValueLabel: {
                    Text("\(Int(maximumPingInterval))s")
                        .font(.caption)
                        .foregroundColor(.secondary)
                } onEditingChanged: { editing in
                    pingChanged(editing)
                }
                Text("Current: \(Int(pingIntervalSlider)) seconds")
                    .font(.caption)
                    .foregroundColor(.secondary)
            }

            Group {
                Text("Refresh interval")
                    .font(.headline)
                Slider(
                    value: $refreshIntervalSlider,
                    in: minimumInterval...maximumRefreshInterval,
                    step: 5
                ) {
                    Text("Refresh interval")
                } minimumValueLabel: {
                    Text("\(Int(minimumInterval))s")
                        .font(.caption)
                        .foregroundColor(.secondary)
                } maximumValueLabel: {
                    Text("\(Int(maximumRefreshInterval))s")
                        .font(.caption)
                        .foregroundColor(.secondary)
                } onEditingChanged: { editing in
                    refreshChanged(editing)
                }
                Text("Current: \(Int(refreshIntervalSlider)) seconds")
                    .font(.caption)
                    .foregroundColor(.secondary)
            }

            Divider()

            Toggle("Show interval indicator", isOn: $showIntervalIndicator)
                .toggleStyle(.switch)

            Spacer()
        }
        .frame(maxWidth: .infinity, alignment: .leading)
    }
}

private struct NotificationsPreferencesView: View {
    var body: some View {
        VStack(alignment: .leading, spacing: 12) {
            Text("Notifications")
                .font(.headline)
                .padding(.bottom)

            Text("Configure notification behavior here.")
                .foregroundColor(.secondary)

            Spacer()
        }
        .frame(maxWidth: .infinity, alignment: .leading)
        .padding()
    }
}

private struct AlertsPreferencesView: View {
    var body: some View {
        VStack(alignment: .leading, spacing: 12) {
            Text("Alerts")
                .font(.headline)
                .padding(.bottom)

            Text("Configure alert thresholds and behavior.")
                .foregroundColor(.secondary)

            Spacer()
        }
        .frame(maxWidth: .infinity, alignment: .leading)
        .padding()
    }
}

#Preview {
    PreferencesView()
}