Feature/craig/fix overflow menu state upon navigating back home (#846)

* Ensure overflow menu state in sync when navigating back home

* Fix forward navigation

* Set navigation state to null when returning to empty tab state

This ensures that when you navigate forwards, the state is correctly identified as having changed from the previous state. Without this, the states are compared and we conclude the state is unchanged, and the `site` is never rebuilt so remains null.

Author: CDRussell

app/src/androidTest/java/com/duckduckgo/app/browser/BrowserTabViewModelTest.kt

@@ -1831,6 +1831,110 @@ class BrowserTabViewModelTest {
         verify(mockPixel).fire(Pixel.PixelName.FIREPROOF_WEBSITE_UNDO)
     }
 
+    @Test
+    fun whenUserBrowsingPressesBackThenCannotAddBookmark() {
+        setupNavigation(skipHome = false, isBrowsing = true, canGoBack = false)
+        assertTrue(testee.onUserPressedBack())
+        assertFalse(browserViewState().canAddBookmarks)
+    }
+
+    @Test
+    fun whenUserBrowsingPressesBackThenCannotSharePage() {
+        setupNavigation(skipHome = false, isBrowsing = true, canGoBack = false)
+        assertTrue(testee.onUserPressedBack())
+        assertFalse(browserViewState().canSharePage)
+    }
+
+    @Test
+    fun whenUserBrowsingPressesBackThenCannotReportSite() {
+        setupNavigation(skipHome = false, isBrowsing = true, canGoBack = false)
+        assertTrue(testee.onUserPressedBack())
+        assertFalse(browserViewState().canReportSite)
+    }
+
+    @Test
+    fun whenUserBrowsingPressesBackThenCannotAddToHome() {
+        setupNavigation(skipHome = false, isBrowsing = true, canGoBack = false)
+        assertTrue(testee.onUserPressedBack())
+        assertFalse(browserViewState().addToHomeEnabled)
+    }
+
+    @Test
+    fun whenUserBrowsingPressesBackThenCannotWhitelist() {
+        setupNavigation(skipHome = false, isBrowsing = true, canGoBack = false)
+        assertTrue(testee.onUserPressedBack())
+        assertFalse(browserViewState().canWhitelist)
+    }
+
+    @Test
+    fun whenUserBrowsingPressesBackThenCannotNavigateBack() {
+        setupNavigation(skipHome = false, isBrowsing = true, canGoBack = false)
+        assertTrue(testee.onUserPressedBack())
+        assertFalse(browserViewState().canGoBack)
+    }
+
+    @Test
+    fun whenUserBrowsingPressesBackThenCannotFindInPage() {
+        setupNavigation(skipHome = false, isBrowsing = true, canGoBack = false)
+        assertTrue(testee.onUserPressedBack())
+        assertFalse(findInPageViewState().canFindInPage)
+    }
+
+    @Test
+    fun whenUserBrowsingPressesBackThenCanGoForward() {
+        setupNavigation(skipHome = false, isBrowsing = true, canGoBack = false)
+        assertTrue(testee.onUserPressedBack())
+        assertTrue(browserViewState().canGoForward)
+    }
+
+    @Test
+    fun whenUserBrowsingPressesBackAndForwardThenCanAddBookmark() {
+        setupNavigation(skipHome = false, isBrowsing = true, canGoBack = false)
+        testee.onUserPressedBack()
+        testee.onUserPressedForward()
+        assertTrue(browserViewState().canAddBookmarks)
+    }
+
+    @Test
+    fun whenUserBrowsingPressesBackAndForwardThenCanWhitelist() {
+        setupNavigation(skipHome = false, isBrowsing = true, canGoBack = false)
+        testee.onUserPressedBack()
+        testee.onUserPressedForward()
+        assertTrue(browserViewState().canWhitelist)
+    }
+
+    @Test
+    fun whenUserBrowsingPressesBackAndForwardThenCanShare() {
+        setupNavigation(skipHome = false, isBrowsing = true, canGoBack = false)
+        testee.onUserPressedBack()
+        testee.onUserPressedForward()
+        assertTrue(browserViewState().canSharePage)
+    }
+
+    @Test
+    fun whenUserBrowsingPressesBackAndForwardThenCanReportSite() {
+        setupNavigation(skipHome = false, isBrowsing = true, canGoBack = false)
+        testee.onUserPressedBack()
+        testee.onUserPressedForward()
+        assertTrue(browserViewState().canReportSite)
+    }
+
+    @Test
+    fun whenUserBrowsingPressesBackAndForwardThenCanAddToHome() {
+        setupNavigation(skipHome = false, isBrowsing = true, canGoBack = false)
+        testee.onUserPressedBack()
+        testee.onUserPressedForward()
+        assertTrue(browserViewState().addToHomeEnabled)
+    }
+
+    @Test
+    fun whenUserBrowsingPressesBackAndForwardThenCanFindInPage() {
+        setupNavigation(skipHome = false, isBrowsing = true, canGoBack = false)
+        testee.onUserPressedBack()
+        testee.onUserPressedForward()
+        assertTrue(findInPageViewState().canFindInPage)
+    }
+
     private inline fun <reified T : Command> assertCommandIssued(instanceAssertions: T.() -> Unit = {}) {
         verify(mockCommandObserver, atLeastOnce()).onChanged(commandCaptor.capture())
         val issuedCommand = commandCaptor.allValues.find { it is T }

app/src/main/java/com/duckduckgo/app/browser/BrowserStateModifier.kt

@@ -0,0 +1,50 @@
+/*
+ * Copyright (c) 2020 DuckDuckGo
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.duckduckgo.app.browser
+
+import com.duckduckgo.app.browser.BrowserTabViewModel.BrowserViewState
+import io.reactivex.annotations.CheckReturnValue
+
+class BrowserStateModifier {
+
+    @CheckReturnValue
+    fun copyForBrowserShowing(original: BrowserViewState): BrowserViewState {
+        return original.copy(
+            browserShowing = true,
+            canWhitelist = true,
+            canFireproofSite = true,
+            canReportSite = true,
+            canSharePage = true,
+            canAddBookmarks = true,
+            addToHomeEnabled = true
+        )
+    }
+
+    @CheckReturnValue
+    fun copyForHomeShowing(original: BrowserViewState): BrowserViewState {
+        return original.copy(
+            browserShowing = false,
+            canWhitelist = false,
+            canFireproofSite = false,
+            canReportSite = false,
+            canSharePage = false,
+            canAddBookmarks = false,
+            addToHomeEnabled = false,
+            canGoBack = false
+        )
+    }
+}

app/src/main/java/com/duckduckgo/app/browser/BrowserTabViewModel.kt

@@ -249,6 +249,7 @@ class BrowserTabViewModel(
     private lateinit var tabId: String
     private var webNavigationState: WebNavigationState? = null
     private var httpsUpgraded = false
+    private val browserStateModifier = BrowserStateModifier()
     private val fireproofWebsitesObserver = Observer<List<FireproofWebsiteEntity>> {
         browserViewState.value = currentBrowserViewState().copy(canFireproofSite = canFireproofWebsite())
     }
@@ -417,7 +418,8 @@ class BrowserTabViewModel(
 
     fun onUserPressedForward() {
         if (!currentBrowserViewState().browserShowing) {
-            browserViewState.value = currentBrowserViewState().copy(browserShowing = true)
+            browserViewState.value = browserStateModifier.copyForBrowserShowing(currentBrowserViewState())
+            findInPageViewState.value = currentFindInPageViewState().copy(canFindInPage = true)
             command.value = Refresh
         } else {
             command.value = NavigateForward
@@ -466,13 +468,14 @@ class BrowserTabViewModel(
     private fun navigateHome() {
         site = null
         onSiteChanged()
+        webNavigationState = null
 
-        browserViewState.value = currentBrowserViewState().copy(
-            browserShowing = false,
-            canGoBack = false,
-            canFireproofSite = false,
+        val browserState = browserStateModifier.copyForHomeShowing(currentBrowserViewState()).copy(
             canGoForward = currentGlobalLayoutState() !is Invalidated
         )
+        browserViewState.value = browserState
+
+        findInPageViewState.value = FindInPageViewState()
         omnibarViewState.value = currentOmnibarViewState().copy(omnibarText = "", shouldMoveCaretToEnd = false)
         loadingViewState.value = currentLoadingViewState().copy(isLoading = false)