Close #19045: Dismiss tabstray when last tab in a page is closed

app/src/main/java/org/mozilla/fenix/tabstray/CloseOnLastTabBinding.kt

@@ -0,0 +1,50 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.fenix.tabstray
+
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.collect
+import kotlinx.coroutines.flow.drop
+import kotlinx.coroutines.flow.map
+import mozilla.components.browser.state.selector.normalTabs
+import mozilla.components.browser.state.selector.privateTabs
+import mozilla.components.browser.state.state.BrowserState
+import mozilla.components.browser.state.store.BrowserStore
+import mozilla.components.support.ktx.kotlinx.coroutines.flow.ifChanged
+import org.mozilla.fenix.components.AbstractBinding
+
+/**
+ * A binding that closes the tabs tray when the last tab is closed.
+ */
+class CloseOnLastTabBinding(
+    browserStore: BrowserStore,
+    private val tabsTrayStore: TabsTrayStore,
+    private val navigationInteractor: NavigationInteractor
+) : AbstractBinding<BrowserState>(browserStore) {
+    override suspend fun onState(flow: Flow<BrowserState>) {
+        flow.map { it }
+            // Ignore the initial state; we don't want to close immediately.
+            .drop(1)
+            .ifChanged { it.tabs }
+            .collect { state ->
+                val selectedPage = tabsTrayStore.state.selectedPage
+                val tabs = when (selectedPage) {
+                    Page.NormalTabs -> {
+                        state.normalTabs
+                    }
+                    Page.PrivateTabs -> {
+                        state.privateTabs
+                    }
+                    else -> {
+                        // Do nothing if we're on any other non-browser page.
+                        null
+                    }
+                }
+                if (tabs?.isEmpty() == true) {
+                    navigationInteractor.onCloseAllTabsClicked(selectedPage == Page.PrivateTabs)
+                }
+            }
+    }
+}

app/src/main/java/org/mozilla/fenix/tabstray/TabsTrayFragment.kt

@@ -59,6 +59,7 @@ class TabsTrayFragment : AppCompatDialogFragment(), TabsTrayInteractor {
     private val selectionBannerBinding = ViewBoundFeatureWrapper<SelectionBannerBinding>()
     private val selectionHandleBinding = ViewBoundFeatureWrapper<SelectionHandleBinding>()
     private val tabsTrayCtaBinding = ViewBoundFeatureWrapper<TabsTrayInfoBannerBinding>()
+    private val closeOnLastTabBinding = ViewBoundFeatureWrapper<CloseOnLastTabBinding>()
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
@@ -228,6 +229,16 @@ class TabsTrayFragment : AppCompatDialogFragment(), TabsTrayInteractor {
             owner = this,
             view = view
         )
+
+        closeOnLastTabBinding.set(
+            feature = CloseOnLastTabBinding(
+                browserStore = requireComponents.core.store,
+                tabsTrayStore = tabsTrayStore,
+                navigationInteractor = navigationInteractor
+            ),
+            owner = this,
+            view = view
+        )
     }
 
     override fun setCurrentTrayPosition(position: Int, smoothScroll: Boolean) {

app/src/test/java/org/mozilla/fenix/tabstray/CloseOnLastTabBindingTest.kt

@@ -0,0 +1,115 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.fenix.tabstray
+
+import io.mockk.Called
+import io.mockk.mockk
+import io.mockk.verify
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.test.TestCoroutineDispatcher
+import mozilla.components.browser.state.action.TabListAction
+import mozilla.components.browser.state.state.BrowserState
+import mozilla.components.browser.state.state.createTab
+import mozilla.components.browser.state.store.BrowserStore
+import mozilla.components.support.test.libstate.ext.waitUntilIdle
+import mozilla.components.support.test.rule.MainCoroutineRule
+import org.junit.Rule
+import org.junit.Test
+
+class CloseOnLastTabBindingTest {
+
+    @OptIn(ExperimentalCoroutinesApi::class)
+    @get:Rule
+    val coroutinesTestRule = MainCoroutineRule(TestCoroutineDispatcher())
+
+    @Test
+    fun `WHEN the binding starts THEN do nothing`() {
+        val browserStore = BrowserStore()
+        val tabsTrayStore = TabsTrayStore()
+        val interactor = mockk<NavigationInteractor>(relaxed = true)
+        val binding = CloseOnLastTabBinding(browserStore, tabsTrayStore, interactor)
+
+        binding.start()
+
+        verify { interactor wasNot Called }
+    }
+
+    @Test
+    fun `WHEN a tab is closed THEN invoke the interactor`() {
+        val browserStore = BrowserStore(
+            BrowserState(
+                tabs = listOf(
+                    createTab(
+                        "https://mozilla.org",
+                        id = "tab1"
+                    )
+                )
+            )
+        )
+        val tabsTrayStore = TabsTrayStore()
+        val interactor = mockk<NavigationInteractor>(relaxed = true)
+        val binding = CloseOnLastTabBinding(browserStore, tabsTrayStore, interactor)
+
+        binding.start()
+
+        browserStore.dispatch(TabListAction.RemoveTabAction("tab1"))
+
+        browserStore.waitUntilIdle()
+
+        verify { interactor.onCloseAllTabsClicked(false) }
+    }
+
+    @Test
+    fun `WHEN a private tab is closed THEN invoke the interactor`() {
+        val browserStore = BrowserStore(
+            BrowserState(
+                tabs = listOf(
+                    createTab(
+                        "https://mozilla.org",
+                        id = "tab1",
+                        private = true
+                    )
+                )
+            )
+        )
+        val tabsTrayStore = TabsTrayStore(TabsTrayState(selectedPage = Page.PrivateTabs))
+        val interactor = mockk<NavigationInteractor>(relaxed = true)
+        val binding = CloseOnLastTabBinding(browserStore, tabsTrayStore, interactor)
+
+        binding.start()
+
+        browserStore.dispatch(TabListAction.RemoveTabAction("tab1"))
+
+        browserStore.waitUntilIdle()
+
+        verify { interactor.onCloseAllTabsClicked(true) }
+    }
+
+    @Test
+    fun `WHEN on the synced tabs page THEN nothing is invoked`() {
+        val browserStore = BrowserStore(
+            BrowserState(
+                tabs = listOf(
+                    createTab(
+                        "https://mozilla.org",
+                        id = "tab1",
+                        private = true
+                    )
+                )
+            )
+        )
+        val tabsTrayStore = TabsTrayStore(TabsTrayState(selectedPage = Page.SyncedTabs))
+        val interactor = mockk<NavigationInteractor>(relaxed = true)
+        val binding = CloseOnLastTabBinding(browserStore, tabsTrayStore, interactor)
+
+        binding.start()
+
+        browserStore.dispatch(TabListAction.RemoveAllTabsAction)
+
+        browserStore.waitUntilIdle()
+
+        verify { interactor wasNot Called }
+    }
+}