Removed current tab property from presenter interface

app/src/main/java/com/sirekanyan/knigopis/feature/MainActivity.kt

@@ -25,7 +25,6 @@ import com.sirekanyan.knigopis.feature.profile.createProfileIntent
 import com.sirekanyan.knigopis.feature.user.createUserIntent
 import com.sirekanyan.knigopis.feature.users.MainPresenterState
 import com.sirekanyan.knigopis.model.BookDataModel
-import com.sirekanyan.knigopis.model.CurrentTab.HOME_TAB
 import com.sirekanyan.knigopis.repository.*
 import com.tbruyelle.rxpermissions2.RxPermissions
 import kotlinx.android.synthetic.main.activity_main.*
@@ -112,7 +111,9 @@ class MainActivity : BaseActivity(), Router, MainPresenter.Router {
 
     override fun onSaveInstanceState(outState: Bundle?) {
         super.onSaveInstanceState(outState)
-        outState?.putInt(CURRENT_TAB_KEY, presenter.currentTab.itemId)
+        presenter.state?.let { state ->
+            outState?.putInt(CURRENT_TAB_KEY, state.currentTab)
+        }
     }
 
     override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
@@ -142,10 +143,8 @@ class MainActivity : BaseActivity(), Router, MainPresenter.Router {
     }
 
     override fun onBackPressed() {
-        if (presenter.currentTab == HOME_TAB || !auth.isAuthorized()) {
+        if (!presenter.back()) {
             super.onBackPressed()
-        } else {
-            presenter.refresh(HOME_TAB)
         }
     }
 

app/src/main/java/com/sirekanyan/knigopis/feature/MainPresenter.kt

@@ -19,9 +19,10 @@ import io.reactivex.Flowable
 
 interface MainPresenter : Presenter {
 
-    var currentTab: CurrentTab
+    val state: MainPresenterState?
     fun init(state: MainPresenterState?)
     fun start()
+    fun back(): Boolean
     fun refresh(tab: CurrentTab? = null, isForce: Boolean = false)
     fun refreshNavigation()
     fun refreshOptionsMenu()
@@ -48,8 +49,9 @@ class MainPresenterImpl(
     private val resources: ResourceProvider
 ) : BasePresenter<MainView>(), MainPresenter, MainView.Callbacks {
 
-    override lateinit var currentTab: CurrentTab
     private val loadedTabs = mutableSetOf<CurrentTab>()
+    private var currentTab: CurrentTab? = null
+    override val state get() = currentTab?.let { MainPresenterState(it.itemId) }
 
     override fun init(state: MainPresenterState?) {
         val currentTab = state?.currentTab?.let { CurrentTab.getByItemId(it) }
@@ -60,14 +62,24 @@ class MainPresenterImpl(
     override fun start() {
     }
 
+    override fun back(): Boolean =
+        if (currentTab == HOME_TAB || !auth.isAuthorized()) {
+            false
+        } else {
+            refresh(HOME_TAB)
+            true
+        }
+
     override fun refresh(tab: CurrentTab?, isForce: Boolean) {
         if (!auth.isAuthorized()) {
             currentTab = NOTES_TAB
         } else if (tab != null) {
             currentTab = tab
         }
-        showPage(currentTab, isForce)
-        view.setNavigation(currentTab.itemId)
+        currentTab?.let {
+            showPage(it, isForce)
+            view.setNavigation(it.itemId)
+        }
     }
 
     override fun refreshNavigation() {
@@ -99,8 +111,10 @@ class MainPresenterImpl(
     }
 
     override fun onNavigationClicked(itemId: Int) {
-        currentTab = CurrentTab.getByItemId(itemId)
-        showPage(currentTab, false)
+        CurrentTab.getByItemId(itemId).let { tab ->
+            currentTab = tab
+            showPage(tab, false)
+        }
     }
 
     override fun onToolbarClicked() {