From db61432d36c409072f6f23bbd446ad4ebc8c48d3 Mon Sep 17 00:00:00 2001
From: Roy Qu <royqh1979@gmail.com>
Date: Fri, 26 Nov 2021 19:54:05 +0800
Subject: [PATCH] - fix: dragging text from lines in the front to lines back
 will cause error  - fix: dragging text onto itself should do nothing

---
 NEWS.md                          |  2 +
 RedPandaIDE/qsynedit/SynEdit.cpp | 63 +++++++++++++++++++++++++-------
 RedPandaIDE/qsynedit/Types.cpp   | 29 +++++++++++++++
 RedPandaIDE/qsynedit/Types.h     |  5 +++
 4 files changed, 85 insertions(+), 14 deletions(-)

diff --git a/NEWS.md b/NEWS.md
index 0f3c1bbc..26e49e80 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,6 +1,8 @@
 Version 0.10.2 For Dev-C++ 7 Beta
  - fix: select by mouse can't correctly set mouse's column position
  - fix: dragging out of the editor and back will cause error
+ - fix: dragging text from lines in the front to lines back will cause error
+ - fix: dragging text onto itself should do nothing
 
 Version 0.10.1 For Dev-C++ 7 Beta
  - fix: can't correctly expand watch expression that has spaces in it
diff --git a/RedPandaIDE/qsynedit/SynEdit.cpp b/RedPandaIDE/qsynedit/SynEdit.cpp
index 201874c0..9c733be6 100644
--- a/RedPandaIDE/qsynedit/SynEdit.cpp
+++ b/RedPandaIDE/qsynedit/SynEdit.cpp
@@ -6203,23 +6203,58 @@ void SynEdit::dragEnterEvent(QDragEnterEvent *event)
 void SynEdit::dropEvent(QDropEvent *event)
 {
     //mScrollTimer->stop();
-    mUndoList->BeginBlock();
-    auto action = finally([this] {
-        mUndoList->EndBlock();
-    });
+
     BufferCoord coord = displayToBufferPos(pixelsToNearestRowColumn(event->pos().x(),
                                                                     event->pos().y()));
-    int topLine = mTopLine;
-    int leftChar = mLeftChar;
-    if (event->proposedAction() == Qt::DropAction::MoveAction) {
-        setBlockBegin(mDragSelBeginSave);
-        setBlockEnd(mDragSelEndSave);
-        setSelText("");
-    }
-    setTopLine(topLine);
-    setLeftChar(leftChar);
     setCaretXY(coord);
-    setSelText(event->mimeData()->text());
+    if (coord>=mDragSelBeginSave && coord<=mDragSelEndSave) {
+        //do nothing if drag onto itself
+    } else if (event->proposedAction() == Qt::DropAction::CopyAction) {
+        //just copy it
+        setSelText(event->mimeData()->text());
+    } else if (event->proposedAction() == Qt::DropAction::MoveAction)  {
+        int topLine = mTopLine;
+        int leftChar = mLeftChar;
+        mUndoList->BeginBlock();
+        if (coord < mDragSelBeginSave ) {
+            //delete old
+            setBlockBegin(mDragSelBeginSave);
+            setBlockEnd(mDragSelEndSave);
+            setSelText("");
+            //paste to new position
+            setTopLine(topLine);
+            setLeftChar(leftChar);
+            setCaretXY(coord);
+            setSelText(event->mimeData()->text());
+        } else {
+            //paste to new position
+            setTopLine(topLine);
+            setLeftChar(leftChar);
+            setCaretXY(coord);
+            setSelText(event->mimeData()->text());
+            //delete old
+            setBlockBegin(mDragSelBeginSave);
+            setBlockEnd(mDragSelEndSave);
+            setSelText("");
+            //set caret to right pos
+            if (mDragSelBeginSave.Line == mDragSelEndSave.Line) {
+                if (coord.Line == mDragSelEndSave.Line) {
+                    coord.Char -= mDragSelEndSave.Char-mDragSelBeginSave.Char;
+                }
+            } else {
+                if (coord.Line == mDragSelEndSave.Line) {
+                    coord.Char -= mDragSelEndSave.Char-1;
+                } else {
+                    coord.Line -= mDragSelEndSave.Line-mDragSelBeginSave.Line;
+                    topLine -= mDragSelEndSave.Line-mDragSelBeginSave.Line;
+                }
+            }
+            setTopLine(topLine);
+            setLeftChar(leftChar);
+            setCaretXY(coord);
+        }
+        mUndoList->EndBlock();
+    }
     event->acceptProposedAction();
 
 }
diff --git a/RedPandaIDE/qsynedit/Types.cpp b/RedPandaIDE/qsynedit/Types.cpp
index e4e985eb..0de4c4bf 100644
--- a/RedPandaIDE/qsynedit/Types.cpp
+++ b/RedPandaIDE/qsynedit/Types.cpp
@@ -239,3 +239,32 @@ bool BufferCoord::operator==(const BufferCoord &coord)
 {
     return coord.Char == Char && coord.Line == Line;
 }
+
+bool BufferCoord::operator>=(const BufferCoord &coord)
+{
+    return (Line > coord.Line)
+            || (Line == coord.Line && Char >= coord.Char);
+}
+
+bool BufferCoord::operator>(const BufferCoord &coord)
+{
+    return (Line > coord.Line)
+            || (Line == coord.Line && Char > coord.Char);
+}
+
+bool BufferCoord::operator<(const BufferCoord &coord)
+{
+    return (Line < coord.Line)
+            || (Line == coord.Line && Char < coord.Char);
+}
+
+bool BufferCoord::operator<=(const BufferCoord &coord)
+{
+    return (Line < coord.Line)
+            || (Line == coord.Line && Char <= coord.Char);
+}
+
+bool BufferCoord::operator!=(const BufferCoord &coord)
+{
+    return coord.Char != Char || coord.Line != Line;
+}
diff --git a/RedPandaIDE/qsynedit/Types.h b/RedPandaIDE/qsynedit/Types.h
index ce7fe313..5df31c40 100644
--- a/RedPandaIDE/qsynedit/Types.h
+++ b/RedPandaIDE/qsynedit/Types.h
@@ -11,6 +11,11 @@ struct BufferCoord {
     int Char;
     int Line;
     bool operator==(const BufferCoord& coord);
+    bool operator>=(const BufferCoord& coord);
+    bool operator>(const BufferCoord& coord);
+    bool operator<(const BufferCoord& coord);
+    bool operator<=(const BufferCoord& coord);
+    bool operator!=(const BufferCoord& coord);
 };
 
 class SynEdit;