From 8483f8d42cdbcf95c48223f328c6bbbe905a3673 Mon Sep 17 00:00:00 2001
From: inthewaves <26474149+inthewaves@users.noreply.github.com>
Date: Mon, 13 Jan 2025 23:02:18 -0800
Subject: [PATCH] OutlineListFragment: validate node id argument

---
 .../pdfviewer/outline/OutlineFragment.kt      |  5 +++--
 .../pdfviewer/outline/OutlineListFragment.kt  | 19 +++++++++++++++----
 .../pdfviewer/viewModel/OutlineViewModel.kt   |  2 ++
 3 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/app/src/main/java/app/grapheneos/pdfviewer/outline/OutlineFragment.kt b/app/src/main/java/app/grapheneos/pdfviewer/outline/OutlineFragment.kt
index df6a6a29..6a2f56c7 100644
--- a/app/src/main/java/app/grapheneos/pdfviewer/outline/OutlineFragment.kt
+++ b/app/src/main/java/app/grapheneos/pdfviewer/outline/OutlineFragment.kt
@@ -10,8 +10,8 @@ import android.widget.TextView
 import androidx.core.os.bundleOf
 import androidx.fragment.app.Fragment
 import androidx.fragment.app.FragmentContainerView
+import androidx.fragment.app.activityViewModels
 import androidx.fragment.app.viewModels
-import app.grapheneos.pdfviewer.PdfViewer
 import app.grapheneos.pdfviewer.R
 import app.grapheneos.pdfviewer.applySystemBarMargins
 import app.grapheneos.pdfviewer.databinding.OutlineFragmentBinding
@@ -26,6 +26,7 @@ class OutlineFragment : Fragment() {
     private lateinit var topBar: MaterialToolbar
     private lateinit var listContainer: FragmentContainerView
 
+    private val activityViewModel by activityViewModels<PdfViewModel>()
     private val viewModel by viewModels<OutlineViewModel>()
 
     private fun dismissOutlineFragment(pageNumber: Int? = null) {
@@ -84,7 +85,6 @@ class OutlineFragment : Fragment() {
 
         val docTitle = arguments?.getString(ARG_DOC_TITLE_KEY, "") ?: ""
 
-        val activityViewModel = (requireActivity() as PdfViewer).viewModel
         activityViewModel.requestOutlineIfNotAvailable()
         activityViewModel.outline.observe(viewLifecycleOwner) { outlineState ->
             if (outlineState is PdfViewModel.OutlineStatus.Loaded) {
@@ -122,6 +122,7 @@ class OutlineFragment : Fragment() {
                 is OutlineViewModel.Action.ViewChildren -> {
                     val parent = action.parent
                     val fragment = OutlineListFragment.makeInstance(parent.id)
+                    // could be replaced with androidx.navigation
                     if (childFragmentManager.findFragmentByTag(parent.id.toString()) == null) {
                         listContainer.visibility = View.VISIBLE
                         childFragmentManager.beginTransaction()
diff --git a/app/src/main/java/app/grapheneos/pdfviewer/outline/OutlineListFragment.kt b/app/src/main/java/app/grapheneos/pdfviewer/outline/OutlineListFragment.kt
index 52b89b64..bb0f223a 100644
--- a/app/src/main/java/app/grapheneos/pdfviewer/outline/OutlineListFragment.kt
+++ b/app/src/main/java/app/grapheneos/pdfviewer/outline/OutlineListFragment.kt
@@ -1,6 +1,7 @@
 package app.grapheneos.pdfviewer.outline
 
 import android.os.Bundle
+import android.util.Log
 import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
@@ -18,8 +19,8 @@ import com.google.android.material.divider.MaterialDividerItemDecoration
 class OutlineListViewModel : ViewModel() {
     val outlineContents = MutableLiveData<List<OutlineNode>?>(null)
 
-    fun updateOutlineContents(contents: List<OutlineNode>) {
-        if (outlineContents.value == null) {
+    fun updateOutlineContents(contents: List<OutlineNode>?) {
+        if (contents != null && outlineContents.value == null) {
             outlineContents.value = contents
         }
     }
@@ -48,9 +49,18 @@ class OutlineListFragment : Fragment() {
         list.addItemDecoration(dividerItemDecoration)
         list.layoutManager = layoutManager
 
+        val parentNodeId = arguments?.getInt(ARG_OUTLINE_ID, -2) ?: -2
+
         outlineViewModel.currentChild.observe(viewLifecycleOwner) { child ->
-            if (child != null) {
-                viewModel.updateOutlineContents(child.children)
+            val contents = if (child?.id == parentNodeId) {
+                child.children
+            } else {
+                outlineViewModel.findNodeOrNull(parentNodeId)?.children
+            }
+            viewModel.updateOutlineContents(contents)
+            if (contents == null) {
+                Log.d(TAG, "unable to find child with id $parentNodeId")
+                outlineViewModel.submitAction(OutlineViewModel.Action.Back)
             }
         }
 
@@ -70,6 +80,7 @@ class OutlineListFragment : Fragment() {
     }
 
     companion object {
+        private const val TAG = "OutlineListFragment"
         private const val ARG_OUTLINE_ID = "outlinenodeid"
 
         fun makeInstance(outlineId: Int) = OutlineListFragment().apply {
diff --git a/app/src/main/java/app/grapheneos/pdfviewer/viewModel/OutlineViewModel.kt b/app/src/main/java/app/grapheneos/pdfviewer/viewModel/OutlineViewModel.kt
index 640bde52..574df2d9 100644
--- a/app/src/main/java/app/grapheneos/pdfviewer/viewModel/OutlineViewModel.kt
+++ b/app/src/main/java/app/grapheneos/pdfviewer/viewModel/OutlineViewModel.kt
@@ -44,6 +44,8 @@ class OutlineViewModel : ViewModel() {
 
     val currentChild = MutableLiveData<OutlineNode?>(null)
 
+    fun findNodeOrNull(id: Int): OutlineNode? = outlineStack.find { it.id == id }
+
     fun getSubtitleString() = outlineStack.lastOrNull()?.title?.trim() ?: docTitle
 
     private var docTitle = ""