import SwiftUI

struct BusinessSelectionScreen: View {
    @EnvironmentObject var appState: AppState
    @State private var businesses: [Employment] = []
    @State private var myTaskBusinessIds: Set<Int> = []
    @State private var isLoading = true
    @State private var error: String?
    @State private var showingTaskList = false
    @State private var showingMyTasks = false
    @State private var showingAccount = false
    @State private var showingDebug = false
    @State private var selectedBusiness: Employment?
    @State private var debugText = ""

    private let refreshTimer = Timer.publish(every: 2, on: .main, in: .common).autoconnect()

    var body: some View {
        NavigationStack {
            ZStack(alignment: .bottomTrailing) {
                Group {
                    if isLoading {
                        ProgressView()
                    } else if let error = error {
                        errorView(error)
                    } else if businesses.isEmpty {
                        emptyView
                    } else {
                        businessList
                    }
                }
                .frame(maxWidth: .infinity, maxHeight: .infinity)

                myTasksFAB
            }
            .navigationTitle("Select Business")
            .toolbar {
                ToolbarItem(placement: .navigationBarTrailing) {
                    Menu {
                        Label(appState.userName ?? "Worker", systemImage: "person.circle.fill")

                        Divider()

                        Button { showingMyTasks = true } label: {
                            Label("My Tasks", systemImage: "checkmark.circle")
                        }

                        Button { showingAccount = true } label: {
                            Label("Account", systemImage: "person.crop.circle")
                        }

                        Button { loadDebugInfo() } label: {
                            Label("Debug API", systemImage: "ladybug")
                        }

                        Button(role: .destructive) { logout() } label: {
                            Label("Logout", systemImage: "rectangle.portrait.and.arrow.right")
                        }
                    } label: {
                        Image(systemName: "ellipsis.circle")
                    }
                }

                ToolbarItem(placement: .navigationBarTrailing) {
                    Button { loadBusinesses() } label: {
                        Image(systemName: "arrow.clockwise")
                    }
                }
            }
            .navigationDestination(isPresented: $showingTaskList) {
                if let biz = selectedBusiness {
                    TaskListScreen(businessName: biz.businessName)
                        .onAppear {
                            Task { await APIService.shared.setBusinessId(biz.businessId) }
                            appState.setBusinessId(biz.businessId)
                        }
                }
            }
            .navigationDestination(isPresented: $showingMyTasks) {
                MyTasksScreen()
            }
            .navigationDestination(isPresented: $showingAccount) {
                AccountScreen()
            }
            .onChange(of: appState.shouldPopToRoot) { shouldPop in
                if shouldPop {
                    showingTaskList = false
                    showingMyTasks = false
                    showingAccount = false
                    appState.shouldPopToRoot = false
                }
            }
            .onChange(of: appState.needsRefresh) { needsRefresh in
                if needsRefresh {
                    loadBusinesses()
                    appState.needsRefresh = false
                }
            }
        }
        .sheet(isPresented: $showingDebug) {
            NavigationStack {
                ScrollView {
                    Text(debugText)
                        .font(.system(.caption2, design: .monospaced))
                        .padding()
                        .frame(maxWidth: .infinity, alignment: .leading)
                }
                .navigationTitle("API Debug")
                .toolbar {
                    ToolbarItem(placement: .navigationBarTrailing) {
                        Button("Done") { showingDebug = false }
                    }
                }
            }
        }
        .task { loadBusinesses() }
        .onReceive(refreshTimer) { _ in loadBusinesses(silent: true) }
    }

    // MARK: - Business List

    private var businessList: some View {
        ScrollView {
            LazyVStack(spacing: 12) {
                ForEach(businesses) { emp in
                    let hasActivity = emp.pendingTaskCount > 0 || myTaskBusinessIds.contains(emp.businessId)
                    if hasActivity {
                        Button { selectBusiness(emp) } label: {
                            businessCard(emp)
                        }
                        .buttonStyle(.plain)
                    } else {
                        businessCard(emp)
                            .opacity(0.5)
                    }
                }
            }
            .padding(.horizontal, 16)
            .padding(.top, 8)
            .padding(.bottom, 80) // space for FAB
        }
        .refreshable { loadBusinesses() }
    }

    private func businessCard(_ emp: Employment) -> some View {
        HStack(spacing: 14) {
            // Initial letter
            Text(String(emp.businessName.prefix(1)).uppercased())
                .font(.system(size: 32, weight: .bold))
                .foregroundColor(.primary.opacity(0.7))
                .frame(width: 50)

            // Name + status
            VStack(alignment: .leading, spacing: 4) {
                Text(emp.businessName)
                    .font(.body.weight(.semibold))
                    .foregroundColor(.primary)
                    .lineLimit(1)

                Text(emp.statusName)
                    .font(.caption.weight(.medium))
                    .foregroundColor(.white)
                    .padding(.horizontal, 8)
                    .padding(.vertical, 2)
                    .background(statusColor(emp.employeeStatusId))
                    .clipShape(Capsule())
            }

            Spacer()

            // Task indicators
            HStack(spacing: 8) {
                // Red indicator if user has active tasks with this business
                if myTaskBusinessIds.contains(emp.businessId) {
                    HStack(spacing: 4) {
                        Image(systemName: "exclamationmark.circle.fill")
                            .font(.body)
                            .foregroundColor(.red)
                        Text("active")
                            .font(.caption2.weight(.medium))
                            .foregroundColor(.red)
                    }
                }

                // Pending task count or clear checkmark
                if emp.pendingTaskCount > 0 {
                    Text("\(emp.pendingTaskCount)")
                        .font(.title3.bold())
                        .foregroundColor(.payfritGreen)
                } else if !myTaskBusinessIds.contains(emp.businessId) {
                    VStack(spacing: 2) {
                        Image(systemName: "checkmark.circle.fill")
                            .font(.title2)
                            .foregroundColor(.payfritGreen)
                        Text("clear")
                            .font(.caption2)
                            .foregroundColor(.secondary)
                    }
                }
            }

            Image(systemName: "chevron.right")
                .font(.caption.weight(.semibold))
                .foregroundColor(.secondary)
        }
        .padding(.horizontal, 16)
        .padding(.vertical, 14)
        .background(Color.payfritGreen.opacity(0.08))
        .clipShape(RoundedRectangle(cornerRadius: 12, style: .continuous))
        .contentShape(Rectangle())
    }

    private var myTasksFAB: some View {
        Button { showingMyTasks = true } label: {
            HStack(spacing: 8) {
                Image(systemName: "checkmark.square.fill")
                    .font(.title3)
                Text("My Tasks")
                    .font(.body.weight(.semibold))
            }
            .padding(.horizontal, 20)
            .padding(.vertical, 14)
            .background(Color.payfritGreen)
            .foregroundColor(.white)
            .clipShape(RoundedRectangle(cornerRadius: 16, style: .continuous))
            .shadow(color: .black.opacity(0.15), radius: 6, x: 0, y: 3)
        }
        .padding(.trailing, 16)
        .padding(.bottom, 16)
    }

    // MARK: - Empty / Error

    private var emptyView: some View {
        VStack(spacing: 16) {
            Image(systemName: "briefcase")
                .font(.system(size: 64))
                .foregroundColor(.secondary)
            Text("No businesses found")
                .font(.title3)
                .foregroundColor(.secondary)
            Text("You are not currently employed at any business")
                .foregroundColor(.secondary)
                .multilineTextAlignment(.center)
        }
        .padding()
    }

    private func errorView(_ message: String) -> some View {
        VStack(spacing: 16) {
            Image(systemName: "exclamationmark.circle")
                .font(.system(size: 48))
                .foregroundColor(.red)
            Text(message)
                .multilineTextAlignment(.center)
            Button("Retry") { loadBusinesses() }
                .buttonStyle(.borderedProminent)
        }
        .padding()
    }

    // MARK: - Actions

    private func loadBusinesses(silent: Bool = false) {
        if !silent {
            isLoading = true
            error = nil
        }
        Task {
            do {
                let result = try await APIService.shared.getMyBusinesses()
                businesses = result

                // Fetch user's active tasks to show indicator
                let myTasks = try? await APIService.shared.listMyTasks(filterType: "active")
                if let tasks = myTasks {
                    myTaskBusinessIds = Set(tasks.map { $0.businessId })
                }

                isLoading = false
            } catch {
                if !silent {
                    self.error = error.localizedDescription
                    isLoading = false
                }
            }
        }
    }

    private func selectBusiness(_ emp: Employment) {
        selectedBusiness = emp
        showingTaskList = true
    }

    private func logout() {
        Task {
            await APIService.shared.logout()
            await AuthStorage.shared.clearAuth()
            appState.clearAuth()
        }
    }

    private func loadDebugInfo() {
        debugText = "Loading..."
        showingDebug = true
        Task {
            let uid = await APIService.shared.getUserId() ?? 0
            let bid = await APIService.shared.getBusinessId()
            var text = "=== RAW API RESPONSES ===\n\n"
            text += "UserID: \(uid), BusinessID: \(bid)\n\n"

            text += "--- /workers/myBusinesses.cfm ---\n"
            let bizRaw = await APIService.shared.debugRawJSON(
                "/workers/myBusinesses.cfm", payload: ["UserID": uid])
            text += bizRaw + "\n\n"

            if bid > 0 {
                text += "--- /tasks/listPending.cfm ---\n"
                let taskRaw = await APIService.shared.debugRawJSON(
                    "/tasks/listPending.cfm", payload: ["BusinessID": bid])
                text += taskRaw + "\n\n"
            }

            debugText = text
        }
    }

    private func statusColor(_ id: Int) -> Color {
        switch id {
        case 0: return .payfritGreen
        case 1: return .green
        case 2: return .gray
        default: return .gray
        }
    }
}

// MARK: - Business Header Image

struct BusinessHeaderImage: View {
    let businessId: Int

    @State private var loadedImage: UIImage?
    @State private var isLoading = true

    private var imageURLs: [URL] {
        let domain = IS_DEV ? "https://dev.payfrit.com" : "https://biz.payfrit.com"
        return [
            "\(domain)/uploads/headers/\(businessId).png",
            "\(domain)/uploads/headers/\(businessId).jpg",
        ].compactMap { URL(string: $0) }
    }

    var body: some View {
        ZStack {
            Color(.systemGray6)

            if let image = loadedImage {
                Image(uiImage: image)
                    .resizable()
                    .aspectRatio(contentMode: .fit)
                    .frame(maxWidth: .infinity)
            } else if isLoading {
                ProgressView()
                    .tint(.payfritGreen)
                    .frame(maxWidth: .infinity)
                    .frame(height: 100)
            } else {
                // No image fallback
                Image(systemName: "building.2")
                    .font(.system(size: 30))
                    .foregroundColor(.secondary)
                    .frame(maxWidth: .infinity)
                    .frame(height: 100)
            }
        }
        .task {
            await loadImage()
        }
    }

    private func loadImage() async {
        for url in imageURLs {
            do {
                let (data, response) = try await URLSession.shared.data(from: url)
                if let httpResponse = response as? HTTPURLResponse,
                   httpResponse.statusCode == 200,
                   let image = UIImage(data: data) {
                    await MainActor.run {
                        loadedImage = image
                        isLoading = false
                    }
                    return
                }
            } catch {
                continue
            }
        }
        await MainActor.run {
            isLoading = false
        }
    }
}