import SwiftUI

/// Business selector screen (matches Android MainActivity)
struct BusinessListView: View {
    @EnvironmentObject var appState: AppState

    @State private var businesses: [Business] = []
    @State private var isLoading = true
    @State private var errorMessage: String?

    var body: some View {
        NavigationStack {
            Group {
                if isLoading {
                    ProgressView("Loading businesses…")
                } else if let error = errorMessage {
                    if #available(iOS 17.0, *) {
                        ContentUnavailableView {
                            Label("Error", systemImage: "exclamationmark.triangle")
                        } description: {
                            Text(error)
                        } actions: {
                            Button("Retry") { Task { await loadBusinesses() } }
                        }
                    } else {
                        VStack(spacing: 12) {
                            Image(systemName: "exclamationmark.triangle")
                                .font(.system(size: 48))
                                .foregroundStyle(Color.warningOrange)
                            Text("Error")
                                .font(.headline)
                            Text(error)
                                .font(.subheadline)
                                .foregroundStyle(.secondary)
                                .multilineTextAlignment(.center)
                            Button("Retry") { Task { await loadBusinesses() } }
                                .buttonStyle(.borderedProminent)
                        }
                        .padding()
                    }
                } else if businesses.isEmpty {
                    if #available(iOS 17.0, *) {
                        ContentUnavailableView(
                            "No Businesses",
                            systemImage: "building.2",
                            description: Text("You don't have any businesses yet.")
                        )
                    } else {
                        VStack(spacing: 12) {
                            Image(systemName: "building.2")
                                .font(.system(size: 48))
                                .foregroundStyle(.secondary)
                            Text("No Businesses")
                                .font(.headline)
                            Text("You don't have any businesses yet.")
                                .font(.subheadline)
                                .foregroundStyle(.secondary)
                        }
                        .frame(maxHeight: .infinity)
                        .padding()
                    }
                } else {
                    List(businesses) { business in
                        Button {
                            appState.selectBusiness(business)
                        } label: {
                            BusinessRow(business: business)
                        }
                    }
                    .listStyle(.insetGrouped)
                }
            }
            .navigationTitle("Select Business")
            .toolbar(content: {
                ToolbarItem(placement: .topBarTrailing) {
                    Button("Logout") {
                        appState.logout()
                    }
                }
            })
        }
        .task {
            await loadBusinesses()
        }
    }

    private func loadBusinesses() async {
        guard let token = appState.token else { return }

        isLoading = true
        errorMessage = nil

        do {
            let list = try await APIClient.shared.listBusinesses(token: token)
            businesses = list

            // Skip auto-navigation if user explicitly tapped Back
            if !appState.skipAutoNav {
                // Auto-navigate if only one business (like Android)
                if list.count == 1, let only = list.first {
                    appState.selectBusiness(only)
                    return
                }

                // Auto-navigate to last used business
                if let lastId = AppPrefs.lastBusinessId,
                   let last = list.first(where: { $0.id == lastId }) {
                    appState.selectBusiness(last)
                    return
                }
            }
            appState.skipAutoNav = false
        } catch let e as APIError where e.errorDescription == APIError.unauthorized.errorDescription {
            appState.logout()
        } catch {
            errorMessage = error.localizedDescription
        }

        isLoading = false
    }
}

// MARK: - Business Row

struct BusinessRow: View {
    let business: Business

    var body: some View {
        HStack(spacing: 12) {
            // Business header image
            AsyncImage(url: business.headerImageURL) { image in
                image.resizable().aspectRatio(contentMode: .fill)
            } placeholder: {
                Image(systemName: "building.2")
                    .font(.title2)
                    .foregroundStyle(.secondary)
            }
            .frame(width: 56, height: 56)
            .clipShape(RoundedRectangle(cornerRadius: 8))

            VStack(alignment: .leading, spacing: 4) {
                Text(business.name)
                    .font(.headline)
                Text("ID: \(business.id)")
                    .font(.caption)
                    .foregroundStyle(.secondary)
            }

            Spacer()

            Image(systemName: "chevron.right")
                .foregroundStyle(.tertiary)
        }
        .padding(.vertical, 4)
    }
}