Implement new widget prompt in onboarding (#6256)

Task/Issue
URL:https://app.asana.com/1/137249556945/project/1200581511062568/task/1210403485354664?focus=true

### Description
Added an experimental home screen widget bottom sheet dialog to promote
adding the DuckDuckGo search widget to the user's home screen. The
dialog includes a visual preview of the widget, explanatory text, and
two action buttons: "Add Widget" and "Not Now".

### Steps to test this PR

_Home Screen Widget Promotion_
- [x] Install from this branch.
- [x] Apply the patch attached to the Asana task.
- [x] Go through the Onboarding until you reach the Widget Promo step.
- [x] Verify the experimental home screen widget bottom sheet appears
when triggered.
- [x] Confirm the "Add Widget" button dismisses the dialog and launches
the widget addition flow.
- [x] Verify the "Not Now" button properly dismisses the dialog.
- [x] Check that the dialog shows a preview image of the widget and
explanatory text.

### UI changes
| Light  | Dark |
| ------ | ----- |

|![Screenshot_20250607_115414](https://github.com/user-attachments/assets/cede9a93-3436-4720-aaf9-3a59c590a2a9)|![Screenshot_20250607_120058](https://github.com/user-attachments/assets/12f099c8-86ed-4ff1-a484-a01145b3ad6d)|

Author: anikiki

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

@@ -125,6 +125,7 @@ import com.duckduckgo.app.browser.customtabs.CustomTabPixelNames
 import com.duckduckgo.app.browser.customtabs.CustomTabViewModel.Companion.CUSTOM_TAB_NAME_PREFIX
 import com.duckduckgo.app.browser.databinding.FragmentBrowserTabBinding
 import com.duckduckgo.app.browser.databinding.HttpAuthenticationBinding
+import com.duckduckgo.app.browser.defaultbrowsing.prompts.ui.experiment.ExperimentalHomeScreenWidgetBottomSheetDialog
 import com.duckduckgo.app.browser.downloader.BlobConverterInjector
 import com.duckduckgo.app.browser.favicon.FaviconManager
 import com.duckduckgo.app.browser.filechooser.FileChooserIntentBuilder
@@ -581,6 +582,7 @@ class BrowserTabFragment :
 
     private lateinit var popupMenu: BrowserPopupMenu
     private lateinit var ctaBottomSheet: PromoBottomSheetDialog
+    private lateinit var experimentalBottomSheet: ExperimentalHomeScreenWidgetBottomSheetDialog
 
     private lateinit var autoCompleteSuggestionsAdapter: BrowserAutoCompleteSuggestionsAdapter
 
@@ -4394,6 +4396,45 @@ class BrowserTabFragment :
             )
         }
 
+        private fun showExperimentalHomeWidget(
+            configuration: HomePanelCta,
+        ) {
+            hideDaxCta()
+
+            if (!::experimentalBottomSheet.isInitialized) {
+                experimentalBottomSheet = ExperimentalHomeScreenWidgetBottomSheetDialog(
+                    context = requireContext(),
+                    isLightModeEnabled = appTheme.isLightModeEnabled(),
+                )
+                experimentalBottomSheet.eventListener = object : ExperimentalHomeScreenWidgetBottomSheetDialog.EventListener {
+                    override fun onShown() {
+                        viewModel.onExperimentalHomeScreenWidgetBottomSheetDialogShown()
+                        viewModel.onCtaShown()
+                    }
+
+                    override fun onCanceled() {
+                        viewModel.onExperimentalHomeScreenWidgetBottomSheetDialogCancelled()
+                        viewModel.onUserClickCtaSecondaryButton(configuration)
+                    }
+
+                    override fun onAddWidgetButtonClicked() {
+                        viewModel.onExperimentalHomeScreenWidgetBottomSheetDialogAddWidgetClicked()
+                        viewModel.onUserClickCtaOkButton(configuration)
+                    }
+
+                    override fun onNotNowButtonClicked() {
+                        viewModel.onExperimentalHomeScreenWidgetBottomSheetDialogNotNowClicked()
+                        viewModel.onUserClickCtaSecondaryButton(configuration)
+                    }
+                }
+                experimentalBottomSheet.show()
+            } else {
+                if (!experimentalBottomSheet.isShowing) {
+                    experimentalBottomSheet.show()
+                }
+            }
+        }
+
         private fun showHomeCta(
             configuration: HomePanelCta,
         ) {

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

@@ -4186,6 +4186,23 @@ class BrowserTabViewModel @Inject constructor(
         lastSubmittedUserQuery = query
     }
 
+    fun onExperimentalHomeScreenWidgetBottomSheetDialogShown() {
+        logcat { "Experimental Home Screen Widget bottom sheet shown" }
+    }
+
+    fun onExperimentalHomeScreenWidgetBottomSheetDialogCancelled() {
+        logcat { "Experimental Home Screen Widget bottom sheet dismissed" }
+    }
+
+    fun onExperimentalHomeScreenWidgetBottomSheetDialogAddWidgetClicked() {
+        logcat { "Add Widget clicked on the Experimental Home Screen Widget bottom sheet" }
+        command.value = LaunchAddWidget
+    }
+
+    fun onExperimentalHomeScreenWidgetBottomSheetDialogNotNowClicked() {
+        logcat { "Not Now clicked on the Experimental Home Screen Widget bottom sheet" }
+    }
+
     companion object {
         private const val FIXED_PROGRESS = 50
 

app/src/main/java/com/duckduckgo/app/browser/defaultbrowsing/prompts/ui/experiment/ExperimentalHomeScreenWidgetBottomSheetDialog.kt

@@ -0,0 +1,97 @@
+/*
+ * Copyright (c) 2025 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.defaultbrowsing.prompts.ui.experiment
+
+import android.annotation.SuppressLint
+import android.content.Context
+import android.content.DialogInterface
+import android.view.LayoutInflater
+import android.widget.FrameLayout
+import com.duckduckgo.app.browser.databinding.BottomSheetExperimentHomeScreenWidgetBinding
+import com.google.android.material.R
+import com.google.android.material.bottomsheet.BottomSheetBehavior
+import com.google.android.material.bottomsheet.BottomSheetDialog
+import com.google.android.material.shape.CornerFamily
+import com.google.android.material.shape.MaterialShapeDrawable
+
+@SuppressLint("NoBottomSheetDialog")
+class ExperimentalHomeScreenWidgetBottomSheetDialog(
+    private val context: Context,
+    isLightModeEnabled: Boolean,
+) : BottomSheetDialog(context) {
+
+    private val binding: BottomSheetExperimentHomeScreenWidgetBinding =
+        BottomSheetExperimentHomeScreenWidgetBinding.inflate(LayoutInflater.from(context))
+
+    var eventListener: EventListener? = null
+
+    init {
+        setContentView(binding.root)
+        // We need the dialog to always be expanded and not draggable because the content takes up a lot of vertical space and requires a scroll view,
+        // especially in landscape aspect-ratios. If the dialog started as collapsed, the drag would interfere with internal scroll.
+        this.behavior.state = BottomSheetBehavior.STATE_EXPANDED
+        this.behavior.isDraggable = false
+
+        setOnShowListener { dialogInterface ->
+            setRoundCorners(dialogInterface)
+            eventListener?.onShown()
+        }
+        setOnCancelListener {
+            eventListener?.onCanceled()
+            dismiss()
+        }
+        binding.experimentHomeScreenWidgetBottomSheetDialogImage.setImageResource(
+            if (isLightModeEnabled) {
+                com.duckduckgo.app.browser.R.drawable.experiment_widget_promo_light
+            } else {
+                com.duckduckgo.app.browser.R.drawable.experiment_widget_promo_dark
+            },
+        )
+        binding.experimentHomeScreenWidgetBottomSheetDialogPrimaryButton.setOnClickListener {
+            eventListener?.onAddWidgetButtonClicked()
+            dismiss()
+        }
+        binding.experimentHomeScreenWidgetBottomSheetDialogGhostButton.setOnClickListener {
+            eventListener?.onNotNowButtonClicked()
+            dismiss()
+        }
+    }
+
+    /**
+     * By default, when bottom sheet dialog is expanded, the corners become squared.
+     * This function ensures that the bottom sheet dialog will have rounded corners even when in an expanded state.
+     */
+    private fun setRoundCorners(dialogInterface: DialogInterface) {
+        val bottomSheetDialog = dialogInterface as BottomSheetDialog
+        val bottomSheet = bottomSheetDialog.findViewById<FrameLayout>(R.id.design_bottom_sheet)
+
+        val shapeDrawable = MaterialShapeDrawable.createWithElevationOverlay(context)
+        shapeDrawable.shapeAppearanceModel = shapeDrawable.shapeAppearanceModel
+            .toBuilder()
+            .setTopLeftCorner(CornerFamily.ROUNDED, context.resources.getDimension(com.duckduckgo.mobile.android.R.dimen.dialogBorderRadius))
+            .setTopRightCorner(CornerFamily.ROUNDED, context.resources.getDimension(com.duckduckgo.mobile.android.R.dimen.dialogBorderRadius))
+            .build()
+        bottomSheet?.background = shapeDrawable
+    }
+
+    interface EventListener {
+        fun onShown()
+        fun onCanceled()
+        fun onAddWidgetButtonClicked()
+        fun onNotNowButtonClicked()
+    }
+}