import SwiftUI

enum AppSection: String, CaseIterable, Hashable, Identifiable {
    var id: String { rawValue }
    case dashboard = "Dashboard"
    case clients = "Clients"
    case imports = "Imports"
    case communications = "Communications"
    case calendar = "Calendar"
    case oracle    = "Oracle"
    case sentinel  = "Sentinel"
    case inventory = "Inventory"
    case settings  = "Settings"

    var displayTitle: String {
        switch self {
        case .sentinel:
            return SentinelScope.navigationTitle
        default:
            return rawValue
        }
    }

    var systemImage: String {
        switch self {
        case .dashboard: return "square.grid.2x2"
        case .clients: return "person.text.rectangle"
        case .imports: return "tray.and.arrow.down"
        case .communications: return "phone.connection"
        case .calendar: return "calendar.badge.clock"
        case .oracle:    return "message.and.waveform"
        case .sentinel:  return "person.crop.rectangle"
        case .inventory: return "shippingbox"
        case .settings:  return "gearshape"
        }
    }

    var accentColor: Color {
        switch self {
        case .dashboard: return VelocityTheme.accent
        case .clients: return Color(red: 0.22, green: 0.78, blue: 0.96)
        case .imports: return Color(red: 0.94, green: 0.70, blue: 0.25)
        case .communications: return Color(red: 0.19, green: 0.84, blue: 0.63)
        case .calendar: return Color(red: 0.96, green: 0.67, blue: 0.16)
        case .oracle:    return Color(red: 0.13, green: 0.83, blue: 0.93)  // cyan
        case .sentinel:  return Color(red: 0.60, green: 0.57, blue: 0.99)  // indigo
        case .inventory: return VelocityTheme.warning
        case .settings:  return VelocityTheme.mutedFg
        }
    }
}

struct ContentView: View {
    @State private var selectedSection: AppSection? = .dashboard
    @State private var session = SessionStore.shared

    var body: some View {
        Group {
            if session.isConfigured {
                NavigationSplitView(columnVisibility: .constant(.all)) {
                    sidebarContent
                } detail: {
                    detailContent
                }
                .navigationSplitViewStyle(.balanced)
            } else {
                ConfigurationGateView()
            }
        }
    }

    // MARK: – Sidebar
    private var sidebarContent: some View {
        ZStack {
            VelocityTheme.sidebarBg.ignoresSafeArea()

            VStack(spacing: 0) {
                // App title
                HStack(spacing: 10) {
                    ZStack {
                        RoundedRectangle(cornerRadius: 9)
                            .fill(VelocityTheme.accent.opacity(0.18))
                            .frame(width: 34, height: 34)
                        Image(systemName: "bolt.fill")
                            .font(.system(size: 15, weight: .semibold))
                            .foregroundStyle(VelocityTheme.accent)
                    }
                    VStack(alignment: .leading, spacing: 1) {
                        Text("Velocity")
                            .font(.system(size: 16, weight: .semibold))
                            .foregroundStyle(VelocityTheme.foreground)
                        Text("Project Velocity · v1.1")
                            .font(.system(size: 10))
                            .foregroundStyle(VelocityTheme.mutedFg)
                    }
                    Spacer()
                }
                .padding(.horizontal, 16)
                .padding(.top, 20)
                .padding(.bottom, 16)

                Divider()
                    .background(VelocityTheme.borderSubtle)
                    .padding(.bottom, 8)

                // Nav items
                VStack(spacing: 2) {
                    ForEach(AppSection.allCases) { section in
                        Button {
                            selectedSection = section
                        } label: {
                            SidebarRow(section: section, isSelected: selectedSection == section)
                        }
                        .buttonStyle(.plain)
                        .accessibilityLabel(section.displayTitle)
                        .accessibilityAddTraits(selectedSection == section ? [.isSelected] : [])
                    }
                }
                .padding(.horizontal, 8)

                Spacer()

                // User footer
                Divider()
                    .background(VelocityTheme.borderSubtle)
                HStack(spacing: 10) {
                    ZStack {
                        RoundedRectangle(cornerRadius: 8)
                            .fill(VelocityTheme.accent)
                            .frame(width: 32, height: 32)
                        Text(operatorInitials)
                            .font(.system(size: 11, weight: .bold))
                            .foregroundStyle(.white)
                    }
                    VStack(alignment: .leading, spacing: 2) {
                        Text(operatorName)
                            .font(.system(size: 12, weight: .medium))
                            .foregroundStyle(VelocityTheme.foreground)
                        Text(session.authModeDescription)
                            .font(.system(size: 10))
                            .foregroundStyle(VelocityTheme.mutedFg)
                    }
                    Spacer()
                }
                .padding(16)
            }
        }
        .navigationTitle("")
        .toolbar(.hidden, for: .navigationBar)
    }

    // MARK: – Detail
    private var detailContent: some View {
        ZStack {
            VelocityTheme.background.ignoresSafeArea()

            Group {
                switch selectedSection {
                case .dashboard: DashboardView()
                case .clients: ClientsView()
                case .imports: ImportsView()
                case .communications: CommunicationsView()
                case .calendar: CalendarView()
                case .oracle:    OracleView()
                case .sentinel:  SentinelView()
                case .inventory: InventoryView()
                case .settings:  SettingsView()
                case .none:      DashboardView()
                }
            }
            .frame(maxWidth: .infinity, maxHeight: .infinity)
        }
    }

    private var operatorName: String {
        session.operatorIdentity
    }

    private var operatorInitials: String {
        let source = session.operatorIdentity
        let parts = source
            .replacingOccurrences(of: "@", with: " ")
            .split(separator: ".")
            .flatMap { $0.split(separator: " ") }
        let initials = parts.prefix(2).compactMap(\.first)
        return initials.isEmpty ? "VO" : String(initials)
    }
}

// MARK: – Sidebar Row
private struct SidebarRow: View {
    let section: AppSection
    let isSelected: Bool

    var body: some View {
        HStack(spacing: 11) {
            Image(systemName: section.systemImage)
                .font(.system(size: 14, weight: .medium))
                .foregroundStyle(isSelected ? section.accentColor : VelocityTheme.mutedFg)
                .frame(width: 20)

            Text(section.displayTitle)
                .font(.system(size: 14, weight: isSelected ? .semibold : .regular))
                .foregroundStyle(isSelected ? VelocityTheme.foreground : VelocityTheme.mutedFg)

            Spacer()
        }
        .padding(.horizontal, 12)
        .padding(.vertical, 9)
        .background(
            RoundedRectangle(cornerRadius: 10)
                .fill(isSelected ? section.accentColor.opacity(0.12) : .clear)
                .overlay(
                    RoundedRectangle(cornerRadius: 10)
                        .stroke(isSelected ? section.accentColor.opacity(0.25) : .clear, lineWidth: 1)
                )
        )
        .contentShape(Rectangle())
    }
}

#Preview {
    ContentView()
}