import SwiftUI

struct BeaconDetailScreen: View {
    let beacon: Beacon
    var onSaved: () -> Void

    @State private var name: String = ""
    @State private var uuid: String = ""
    @State private var isActive: Bool = true
    @State private var isSaving = false
    @State private var isDeleting = false
    @State private var error: String?
    @State private var showDeleteConfirm = false
    @EnvironmentObject var appState: AppState
    @Environment(\.dismiss) private var dismiss

    var body: some View {
        Form {
            Section("Beacon Info") {
                TextField("Name", text: $name)
                TextField("UUID (32 hex characters)", text: $uuid)
                    .textInputAutocapitalization(.characters)
                    .autocorrectionDisabled()
                    .font(.system(.body, design: .monospaced))
                Toggle("Active", isOn: $isActive)
            }

            Section("Details") {
                LabeledContent("ID", value: "\(beacon.id)")
                LabeledContent("Business ID", value: "\(beacon.businessId)")
                if let date = beacon.createdAt {
                    LabeledContent("Created", value: date.formatted(date: .abbreviated, time: .shortened))
                }
                if let date = beacon.updatedAt {
                    LabeledContent("Updated", value: date.formatted(date: .abbreviated, time: .shortened))
                }
            }

            if let error = error {
                Section {
                    HStack {
                        Image(systemName: "exclamationmark.circle.fill")
                            .foregroundColor(.red)
                        Text(error)
                            .foregroundColor(.red)
                    }
                }
            }

            Section {
                Button("Save Changes") { save() }
                    .frame(maxWidth: .infinity)
                    .disabled(isSaving || isDeleting || name.isEmpty || uuid.isEmpty)
            }

            Section {
                Button(isDeleting ? "Deleting..." : "Delete Beacon", role: .destructive) {
                    showDeleteConfirm = true
                }
                .frame(maxWidth: .infinity)
                .disabled(isSaving || isDeleting)
            }
        }
        .navigationTitle(beacon.name)
        .onAppear {
            name = beacon.name
            uuid = beacon.uuid
            isActive = beacon.isActive
        }
        .alert("Delete Beacon?", isPresented: $showDeleteConfirm) {
            Button("Delete", role: .destructive) { deleteBeacon() }
            Button("Cancel", role: .cancel) {}
        } message: {
            Text("This will permanently remove \"\(beacon.name)\". Service points using this beacon will be unassigned.")
        }
    }

    private func save() {
        isSaving = true
        error = nil
        Task {
            do {
                try await APIService.shared.updateBeacon(
                    beaconId: beacon.id,
                    name: name.trimmingCharacters(in: .whitespaces),
                    uuid: uuid.trimmingCharacters(in: .whitespaces),
                    isActive: isActive
                )
                onSaved()
                dismiss()
            } catch let apiError as APIError where apiError == .unauthorized {
                await appState.handleUnauthorized()
            } catch {
                self.error = error.localizedDescription
            }
            isSaving = false
        }
    }

    private func deleteBeacon() {
        isDeleting = true
        error = nil
        Task {
            do {
                try await APIService.shared.deleteBeacon(beaconId: beacon.id)
                onSaved()
                dismiss()
            } catch let apiError as APIError where apiError == .unauthorized {
                await appState.handleUnauthorized()
            } catch {
                self.error = error.localizedDescription
            }
            isDeleting = false
        }
    }
}