From c2837850e356deaa85c8f386068874a6291166ba Mon Sep 17 00:00:00 2001
From: Juha <juha@lazarus-ide.org>
Date: Sun, 6 Jul 2025 18:05:58 +0300
Subject: [PATCH] IDE: Accept a dropped project info file to Project Wizard.
 Solves issue #41536.

(cherry picked from commit 63933a901f0879488f64c5893e431e27c6da8ae1)
---
 ide/main.pp              |  2 +-
 ide/projectwizarddlg.lfm |  7 +++++-
 ide/projectwizarddlg.pas | 53 ++++++++++++++++++++++++++++++++++++----
 3 files changed, 55 insertions(+), 7 deletions(-)

diff --git a/ide/main.pp b/ide/main.pp
index 2bda25328b..652810589c 100644
--- a/ide/main.pp
+++ b/ide/main.pp
@@ -6527,7 +6527,7 @@ begin
       mnuNewProjectClicked(Sender);
     tpws_open:
       mnuOpenProjectClicked(Sender);
-    tpws_openRecent:
+    tpws_openRecent, tpws_droppedProject:
       begin
         ARecentProject := ExpandFileNameUTF8(ARecentProject);
         if DoOpenProjectFile(ARecentProject, [ofAddToRecent]) <> mrOk then
diff --git a/ide/projectwizarddlg.lfm b/ide/projectwizarddlg.lfm
index d30ef54cd2..26f7f05b83 100644
--- a/ide/projectwizarddlg.lfm
+++ b/ide/projectwizarddlg.lfm
@@ -4,14 +4,19 @@ object ProjectWizardDialog: TProjectWizardDialog
   Top = 322
   Width = 572
   ActiveControl = btnNewProject
+  AllowDropFiles = True
   BorderIcons = [biSystemMenu]
   Caption = 'Project Wizard '
   ClientHeight = 294
   ClientWidth = 572
+  DragMode = dmAutomatic
   Position = poScreenCenter
-  LCLVersion = '3.99.0.0'
+  LCLVersion = '4.99.0.0'
   OnClose = FormClose
   OnCreate = FormCreate
+  OnDragDrop = FormDragDrop
+  OnDragOver = FormDragOver
+  OnDropFiles = FormDropFiles
   object btnNewProject: TBitBtn
     AnchorSideTop.Control = Owner
     AnchorSideRight.Side = asrBottom
diff --git a/ide/projectwizarddlg.pas b/ide/projectwizarddlg.pas
index 98f8fdc762..8d074ac812 100644
--- a/ide/projectwizarddlg.pas
+++ b/ide/projectwizarddlg.pas
@@ -31,6 +31,8 @@ uses
   Classes, SysUtils,
   // LCL
   Forms, Controls, StdCtrls, Graphics, Dialogs, Buttons,
+  // LazUtils
+  LazFileUtils, LazLoggerBase,
   // BuildIntf
   PackageIntf,
   // IdeIntf
@@ -43,6 +45,7 @@ type
     tpws_new,
     tpws_open,
     tpws_openRecent,
+    tpws_droppedProject,
     tpws_examples,
     tpws_convert,
     tpws_closeIDE
@@ -66,24 +69,30 @@ type
     procedure cbRecentProjectsSelect(Sender: TObject);
     procedure FormClose(Sender: TObject; var CloseAction: TCloseAction);
     procedure FormCreate(Sender: TObject);
+    procedure FormDragDrop(Sender, Source: TObject; X, Y: Integer);
+    procedure FormDragOver(Sender, Source: TObject; X, Y: Integer;
+      State: TDragState; var Accept: Boolean);
+    procedure FormDropFiles(Sender: TObject; const FileNames: array of string);
   private
     FResult: TProjectWizardSelectionType;
+    FDroppedProjectInfo: string;
   public
     property Result: TProjectWizardSelectionType read FResult;
-  end; 
+    property DroppedProjectInfo: string read FDroppedProjectInfo;
+  end;
 
-function ShowProjectWizardDlg(out ARecentProject: String): TProjectWizardSelectionType;
+function ShowProjectWizardDlg(out AProjectToOpen: String): TProjectWizardSelectionType;
 
 implementation
 
 {$R *.lfm}
 
-function ShowProjectWizardDlg(out ARecentProject: String): TProjectWizardSelectionType;
+function ShowProjectWizardDlg(out AProjectToOpen: String): TProjectWizardSelectionType;
 var
   ProjectWizardDialog: TProjectWizardDialog;
 begin
   Result := tpws_closeIDE;
-  ARecentProject := '';
+  AProjectToOpen := '';
   ProjectWizardDialog := TProjectWizardDialog.create(nil);
   with ProjectWizardDialog do
   begin
@@ -110,7 +119,12 @@ begin
     if ProjectWizardDialog.ShowModal <> mrOk then
       Exit;
     Result := ProjectWizardDialog.Result;
-    ARecentProject := ProjectWizardDialog.cbRecentProjects.Text;
+    case Result of
+      tpws_openRecent:
+        AProjectToOpen := ProjectWizardDialog.cbRecentProjects.Text;
+      tpws_droppedProject:
+        AProjectToOpen := ProjectWizardDialog.DroppedProjectInfo;
+    end;
   finally
     ProjectWizardDialog.free;
   end;
@@ -160,5 +174,34 @@ begin
   IDEDialogLayoutList.ApplyLayout(self);
 end;
 
+// How are FormDragDrop and FormDragOver triggered? Nothing is shown.
+procedure TProjectWizardDialog.FormDragDrop(Sender, Source: TObject; X, Y: Integer);
+begin
+  //ShowMessage('TProjectWizardDialog.FormDragDrop: Source=' + Source.ClassName);
+  debugln(['TProjectWizardDialog.FormDragDrop: XY=', X,':',Y, ', Sender', Sender, ', Source=', Source]);
+end;
+
+procedure TProjectWizardDialog.FormDragOver(Sender, Source: TObject; X,
+  Y: Integer; State: TDragState; var Accept: Boolean);
+begin
+  //ShowMessage('TProjectWizardDialog.FormDragOver: Source=' + Source.ClassName + ', State=' + IntToStr(Ord(State)));
+  debugln(['TProjectWizardDialog.FormDragOver: XY=', X,':',Y, ', Sender', Sender,
+           ', Source=', Source, ', State=', State, ', Accept=', Accept]);
+  Accept := True;
+end;
+
+// This works when AllowDropFiles is enabled.
+procedure TProjectWizardDialog.FormDropFiles(Sender: TObject;
+  const FileNames: array of string);
+begin
+  Assert(Length(FileNames)>0, 'TProjectWizardDialog.FormDropFiles: FileNames is empty.');
+  debugln(['TProjectWizardDialog.FormDropFiles File[0]=', FileNames[0]]);
+  if FilenameExtIs(FileNames[0], 'lpi') then begin
+    FDroppedProjectInfo := FileNames[0];
+    FResult := tpws_droppedProject;
+    ModalResult := mrOK;
+  end;
+end;
+
 end.