From 498a1ad1aa096cc01bd3484727032db9225dd21c Mon Sep 17 00:00:00 2001
From: Nanuke Rynyk <4591126+naNuke@users.noreply.github.com>
Date: Sun, 7 Jun 2026 21:20:11 +0200
Subject: [PATCH] PackageEditor: Compare package to installed package (shows
 droplist of viable files)

---
 .../Packages/SharedPackageTools.cs            | 60 +++++++++++++++++++
 .../PackageEditor/PackageEditorWindow.xaml    |  3 +
 .../PackageEditor/PackageEditorWindow.xaml.cs |  6 +-
 3 files changed, 68 insertions(+), 1 deletion(-)

diff --git a/LegendaryExplorer/LegendaryExplorer/Packages/SharedPackageTools.cs b/LegendaryExplorer/LegendaryExplorer/Packages/SharedPackageTools.cs
index b39491a009..be014ccd25 100644
--- a/LegendaryExplorer/LegendaryExplorer/Packages/SharedPackageTools.cs
+++ b/LegendaryExplorer/LegendaryExplorer/Packages/SharedPackageTools.cs
@@ -190,6 +190,66 @@ public static void ComparePackageToAnother(WPFBase wpfBase, Action<EntryStringPa
             }
         }
 
+        public static void ComparePackageToInstalledPackage(WPFBase wpfBase, Action<EntryStringPair> entryDoubleClickCallback, bool structuralCompare = false)
+        {
+            // no pcc no joy
+            if (wpfBase?.Pcc == null) return;
+
+            if (!wpfBase.Pcc.Game.IsMEGame())
+            {
+                MessageBox.Show(wpfBase, "Can only compare packages from the Original Trilogy or Legendary Edition.",
+                    "Can't compare", MessageBoxButton.OK, MessageBoxImage.Error);
+                return;
+            }
+
+            Task.Run(() =>
+            {
+                wpfBase.BusyText = "Finding installed candidates...";
+                wpfBase.IsBusy = true;
+
+                CaseInsensitiveDictionary<string> dlcFiles = [];
+
+                string pccFileName = Path.GetFileName(wpfBase.Pcc.FilePath);
+                foreach (string file in MELoadedFiles.GetAllGameFiles(null, wpfBase.Pcc.Game))
+                {
+                    string fileName = Path.GetFileName(file);
+                    if (fileName == null) continue;
+                    if (fileName != pccFileName) continue; // only files of same name
+                    if (file == wpfBase.Pcc.FilePath) continue; // skip same file as current opened
+
+                    string dlcFolder = file.Split(Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar)
+                        .FirstOrDefault(p => p.StartsWith("DLC_"));
+                    dlcFolder ??= "basegame";
+
+                    // save file
+                    dlcFiles.Add(dlcFolder, file);
+                }
+
+                return dlcFiles;
+            }).ContinueWithOnUIThread(foundCandidates =>
+            {
+                wpfBase.IsBusy = false;
+                if (!foundCandidates.Result.Any())
+                {
+                    MessageBox.Show(wpfBase, "Cannot find any candidates for this file!");
+                    return;
+                }
+
+                var choice = InputComboBoxDialog.GetValue(wpfBase, "Choose installation source to compare to:",
+                    "Installed file comparison", foundCandidates.Result.Keys, foundCandidates.Result.Keys.Last());
+                if (string.IsNullOrEmpty(choice)) return;
+
+                foundCandidates.Result.TryGetValue(choice, out string selectedFile);
+                if (selectedFile == null)
+                {
+                    MessageBox.Show("Selected candidate not found in the lists! This is a bug", "OH NO");
+                    return;
+                }
+
+                CompareToPackageWrapper(wpfBase, entryDoubleClickCallback, structuralCompare: structuralCompare, diskPath: selectedFile);
+            });
+        }
+
         public static bool CanCompareToUnmodded(WPFBase wpfBase) => wpfBase.Pcc != null && wpfBase.Pcc.Game != MEGame.UDK && (!(wpfBase.Pcc.IsInBasegame() || wpfBase.Pcc.IsInOfficialDLC()) || ME3TweaksBackups.GetGameBackupPath(wpfBase.Pcc.Game) != null);
 
         public static UnmoddedCandidatesLookup GetUnmoddedCandidatesForPackage(WPFBase wpfBase)
diff --git a/LegendaryExplorer/LegendaryExplorer/Tools/PackageEditor/PackageEditorWindow.xaml b/LegendaryExplorer/LegendaryExplorer/Tools/PackageEditor/PackageEditorWindow.xaml
index 4565705572..2c942a77cb 100644
--- a/LegendaryExplorer/LegendaryExplorer/Tools/PackageEditor/PackageEditorWindow.xaml
+++ b/LegendaryExplorer/LegendaryExplorer/Tools/PackageEditor/PackageEditorWindow.xaml
@@ -166,8 +166,11 @@
                 <MenuItem Header="Tools" Padding="4">
                     <MenuItem Header="Package file header info" ToolTip="View information stored in package header" Command="{Binding PackageHeaderViewerCommand}"/>
                     <MenuItem Header="LECL Data Editor" ToolTip="Edits metadata stored in this package that is used in mod development tools" Command="{Binding LECLEditorCommand}"/>
+                    <MenuItem Header="Compare with another package (installed)" ToolTip="Compare another version of this package from installed packages in the game folder to see what exports and imports have changed" Command="{Binding CompareToInstalledCommand}"/>
                     <MenuItem Header="Compare with another package" ToolTip="Compare another version of this package to see what exports and imports have changed" Command="{Binding ComparePackagesCommand}"/>
                     <MenuItem Header="Compare with unmodded" ToolTip="Compare with the (hopefully) unmodded version of this package to see what exports and imports have changed" Command="{Binding CompareToUnmoddedCommand}"/>
+                    <MenuItem Header="Structural Compare with another package (installed)" Command="{Binding StructuralCompareToInstalledCommand}"
+                              ToolTip="Compare another version of this package from installed packages in the game folder to see what exports and imports have changed. This comparison method tries to match entries based on their paths, not their indexes." />
                     <MenuItem Header="Structural Compare with another package" Command="{Binding StructuralComparePackagesCommand}"
                               ToolTip="Compare another version of this package to see what exports and imports have changed. This comparison method tries to match entries based on their paths, not their indexes." />
                     <MenuItem Header="Structural Compare with unmodded" Command="{Binding StructuralCompareToUnmoddedCommand}"
diff --git a/LegendaryExplorer/LegendaryExplorer/Tools/PackageEditor/PackageEditorWindow.xaml.cs b/LegendaryExplorer/LegendaryExplorer/Tools/PackageEditor/PackageEditorWindow.xaml.cs
index c1405bbdd7..5b65359f2e 100644
--- a/LegendaryExplorer/LegendaryExplorer/Tools/PackageEditor/PackageEditorWindow.xaml.cs
+++ b/LegendaryExplorer/LegendaryExplorer/Tools/PackageEditor/PackageEditorWindow.xaml.cs
@@ -185,6 +185,8 @@ public bool ShowExperiments
         public ICommand ForceReloadPackageCommand { get; set; }
         public ICommand ComparePackagesCommand { get; set; }
         public ICommand StructuralComparePackagesCommand { get; set; }
+        public ICommand CompareToInstalledCommand { get; set; }
+        public ICommand StructuralCompareToInstalledCommand { get; set; }
         public ICommand OpenOtherVersionCommand { get; set; }
         public ICommand OpenHighestMountedCommand { get; set; }
         public ICommand CompareToUnmoddedCommand { get; set; }
@@ -264,6 +266,8 @@ private void LoadCommands()
             StructuralCompareToUnmoddedCommand = new GenericCommand(() => SharedPackageTools.ComparePackageToUnmodded(this, entryDoubleClickToTreeview, true), () => SharedPackageTools.CanCompareToUnmodded(this));
             ComparePackagesCommand = new GenericCommand(() => SharedPackageTools.ComparePackageToAnother(this, entryDoubleClickToTreeview), PackageIsLoaded);
             StructuralComparePackagesCommand = new GenericCommand(() => SharedPackageTools.ComparePackageToAnother(this, entryDoubleClickToTreeview, true), PackageIsLoaded);
+            CompareToInstalledCommand = new GenericCommand(() => SharedPackageTools.ComparePackageToInstalledPackage(this, entryDoubleClickToTreeview), PackageIsLoaded);
+            StructuralCompareToInstalledCommand = new GenericCommand(() => SharedPackageTools.ComparePackageToInstalledPackage(this, entryDoubleClickToTreeview, true), PackageIsLoaded);
             ExportAllDataCommand = new GenericCommand(ExportAllData, ExportIsSelected);
             ExportBinaryDataCommand = new GenericCommand(ExportBinaryData, ExportIsSelected);
             ImportAllDataCommand = new GenericCommand(ImportAllData, ExportIsSelected);
@@ -4686,4 +4690,4 @@ public void PropogateRecentsChange(string propogationSource, IEnumerable<Recents
 
         public string Toolname => "PackageEditor";
     }
-}
\ No newline at end of file
+}