Firebase App - Parte 2

package ...

import android.os.Bundle
import android.util.Log
import android.view.LayoutInflater
import android.view.Menu
import android.view.MenuInflater
import android.view.MenuItem
import android.view.View
import android.view.ViewGroup
import androidx.core.view.MenuHost
import androidx.core.view.MenuProvider
import androidx.fragment.app.Fragment
import androidx.fragment.app.viewModels
import androidx.lifecycle.Lifecycle
import androidx.navigation.Navigation.findNavController
import androidx.recyclerview.widget.LinearLayoutManager
import br.edu.ifsc.fulano.minhastarefas.databinding.FragmentHomeBinding
import com.google.android.material.snackbar.Snackbar
import com.google.firebase.auth.FirebaseAuth
import com.google.firebase.auth.ktx.auth
import com.google.firebase.ktx.Firebase

class HomeFragment : Fragment() {
    //binding das views automatizado
    private var _binding: FragmentHomeBinding? = null
    private val binding get() = _binding!!
    //firebase
    private lateinit var mAuth: FirebaseAuth //acessa os recursos de autenticação do Firebase

    companion object {
        fun newInstance() = HomeFragment()
    }

    private val viewModel: HomeViewModel by viewModels()
    //adaptador da recyclerview
    private var listaTarefaAdapter: ListaTarefaAdapter? = null

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        // TODO: Use the ViewModel
    }

    override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View {
        //configura a vinculação
        _binding = FragmentHomeBinding.inflate(inflater, container, false)

        //Configura a recyclerView
        val recyclerView = binding.tarefasRecyclerView
        recyclerView.layoutManager = LinearLayoutManager(context)
        //inicializa o adaptar com uma lista vazia
        listaTarefaAdapter = ListaTarefaAdapter(ArrayList<Tarefa>())
        recyclerView.adapter = listaTarefaAdapter

        //Configura a ação do FAB
        binding.addFAB.setOnClickListener{
            addTarefa()
        }

        return binding.root
    }

    override fun onStart() {
        super.onStart()
        //inicializa o serviço de autenticação do Firebase
        mAuth = Firebase.auth
        //obtem os dados do usuário atual
        val currentUser = mAuth.currentUser
        //verifica se o usuário existe
        if (currentUser != null) {
            view?.let{
                Snackbar.make(it, "Usuário logado: " + currentUser.email, Snackbar.LENGTH_LONG).show()
            }
            getTarefas()
        }
        //caso contrário encaminha para a página de login
        else {
            Log.d("TODO2024", "Usuário deslogado")
            findNavController(requireView()).navigate(R.id.action_homeFragment_to_loginFragment)
        }
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)

        val menuHost: MenuHost = requireActivity()

        menuHost.addMenuProvider(object : MenuProvider {
            override fun onCreateMenu(menu: Menu, menuInflater: MenuInflater) {
                menuInflater.inflate(R.menu.menu_main, menu)
            }

            override fun onMenuItemSelected(menuItem: MenuItem): Boolean {
                return when (menuItem.itemId) {
                    R.id.action_logout -> {
                        logOut()
                        true
                    }
                    else -> false
                }
            }
        }, viewLifecycleOwner, Lifecycle.State.RESUMED)
    }

    fun logOut(){
        //faz logout e vai para a página de login
        mAuth.signOut()
        view?.let{
            Snackbar.make(it, "Usuário deslogado.", Snackbar.LENGTH_LONG).show()
        }
        findNavController(requireView()).navigate(R.id.action_homeFragment_to_loginFragment)
    }

    fun getTarefas() {
        view?.let{
            Snackbar.make(it, "Lendo tarefas...", Snackbar.LENGTH_LONG).show()
        }
        //usa a LiveData da viewModel para escutar mudanças
        //ao ouvir mudanças atualiza a lista de tarefas do adaptador
        viewModel.listaTarefas.observe(this) { tarefas ->
            listaTarefaAdapter?.updateData(tarefas)
        }
   }

    fun addTarefa() {
        //faz a leitura dos dados
        val descricao = binding.nomeTarefaTextInputLayout.editText?.text.toString().trim()
        //se o campo estiver em branco encerra a operação
        if (descricao == "")
            return
        //envia os dados a ViewModel para adicionar uma nova tarefa
        viewModel.addTarefa(descricao, false)
        //limpa os campos
        binding.nomeTarefaTextInputLayout.editText?.text?.clear()
    }
}