From e27653219b397c4fbae88ddcaf460efee55a2dea Mon Sep 17 00:00:00 2001
From: Adam Treat <treat.adam@gmail.com>
Date: Thu, 21 Dec 2023 13:59:33 -0500
Subject: [PATCH] Fix bugs with the context link text for localdocs to make the
 context links persistently work across application loads and fix scrolling
 bug with context links.

Signed-off-by: Adam Treat <treat.adam@gmail.com>
---
 gpt4all-chat/responsetext.cpp | 57 +++++++++++++++++++++++++++++------
 gpt4all-chat/responsetext.h   | 16 ++++++++++
 2 files changed, 64 insertions(+), 9 deletions(-)

diff --git a/gpt4all-chat/responsetext.cpp b/gpt4all-chat/responsetext.cpp
index 9bdc9a38..3e2f51f9 100644
--- a/gpt4all-chat/responsetext.cpp
+++ b/gpt4all-chat/responsetext.cpp
@@ -7,6 +7,7 @@
 #include <QTextTableCell>
 #include <QGuiApplication>
 #include <QClipboard>
+#include <QPainter>
 
 enum Language {
     None,
@@ -845,11 +846,36 @@ void SyntaxHighlighter::highlightBlock(const QString &text)
     }
 }
 
+const int ContextLinkFormat = QTextFormat::UserObject + 1;
+const int ContextLinkHref = QTextFormat::UserProperty + 1;
+const int ContextLinkText = QTextFormat::UserProperty + 2;
+
+void ContextLinkInterface::drawObject(QPainter *painter, const QRectF &rect, QTextDocument *doc,
+    int posInDocument, const QTextFormat &format)
+{
+    const QString &href = format.property(ContextLinkHref).toString();
+    const QString &text = format.property(ContextLinkText).toString();
+    painter->setFont(doc->defaultFont());
+    painter->setPen(format.foreground().color());
+    painter->drawText(rect.bottomLeft(), text);
+}
+
+QSizeF ContextLinkInterface::intrinsicSize(QTextDocument *doc, int posInDocument,
+    const QTextFormat &format)
+{
+    const QString &href = format.property(ContextLinkHref).toString();
+    const QString &text = format.property(ContextLinkText).toString();
+    const QFontMetricsF metrics(doc->defaultFont());
+    const QSizeF textSize = metrics.size(Qt::TextSingleLine, text);
+    return textSize;
+}
+
 ResponseText::ResponseText(QObject *parent)
     : QObject{parent}
     , m_textDocument(nullptr)
     , m_syntaxHighlighter(new SyntaxHighlighter(this))
     , m_isProcessingText(false)
+    , m_contextLink(new ContextLinkInterface(this))
 {
 }
 
@@ -864,6 +890,7 @@ void ResponseText::setTextDocument(QQuickTextDocument* textDocument)
         disconnect(m_textDocument->textDocument(), &QTextDocument::contentsChanged, this, &ResponseText::handleTextChanged);
 
     m_textDocument = textDocument;
+    m_textDocument->textDocument()->documentLayout()->registerHandler(ContextLinkFormat, m_contextLink);
     m_syntaxHighlighter->setDocument(m_textDocument->textDocument());
     connect(m_textDocument->textDocument(), &QTextDocument::contentsChanged, this, &ResponseText::handleTextChanged);
     handleTextChanged();
@@ -871,10 +898,20 @@ void ResponseText::setTextDocument(QQuickTextDocument* textDocument)
 
 QString ResponseText::getLinkAtPosition(int position) const
 {
-    int i = 0;
-    for (const auto &link : m_links) {
-        if (position >= link.startPos && position < link.endPos)
-            return link.href;
+    QTextCursor cursor(m_textDocument->textDocument());
+    cursor.setPosition(position);
+    QTextCharFormat format = cursor.charFormat();
+    if (format.objectType() == ContextLinkFormat) {
+        QString href = format.property(ContextLinkHref).toString();
+        if (!href.isEmpty())
+            return href;
+    }
+    cursor.movePosition(QTextCursor::Right, QTextCursor::MoveAnchor);
+    format = cursor.charFormat();
+    if (format.objectType() == ContextLinkFormat) {
+        QString href = format.property(ContextLinkHref).toString();
+        if (!href.isEmpty())
+            return href;
     }
     return QString();
 }
@@ -912,9 +949,6 @@ void ResponseText::handleContextLinks()
 {
     QTextDocument* doc = m_textDocument->textDocument();
     QTextCursor cursor(doc);
-    QTextCharFormat linkFormat;
-    linkFormat.setForeground(m_linkColor);
-    linkFormat.setFontUnderline(true);
 
     // Regex for context links
     static const QRegularExpression reLink("\\[Context\\]\\((context://\\d+)\\)");
@@ -943,8 +977,13 @@ void ResponseText::handleContextLinks()
         cursor.setPosition(matchesLink.at(index).capturedStart());
         cursor.setPosition(matchesLink.at(index).capturedEnd(), QTextCursor::KeepAnchor);
         cursor.removeSelectedText();
-        cursor.setCharFormat(linkFormat);
-        cursor.insertText(newLinks.at(index).text);
+        QTextCharFormat objectFormat;
+        objectFormat.setForeground(m_linkColor);
+        objectFormat.setFontUnderline(true);
+        objectFormat.setProperty(ContextLinkHref, newLinks.at(index).href);
+        objectFormat.setProperty(ContextLinkText, newLinks.at(index).text);
+        objectFormat.setObjectType(ContextLinkFormat);
+        cursor.insertText(QString(QChar::ObjectReplacementCharacter), objectFormat);
         cursor.setCharFormat(QTextCharFormat());
     }
 
diff --git a/gpt4all-chat/responsetext.h b/gpt4all-chat/responsetext.h
index a5588bd6..216fe3fd 100644
--- a/gpt4all-chat/responsetext.h
+++ b/gpt4all-chat/responsetext.h
@@ -6,6 +6,7 @@
 #include <QQuickTextDocument>
 #include <QSyntaxHighlighter>
 #include <QRegularExpression>
+#include <QTextObjectInterface>
 
 class SyntaxHighlighter : public QSyntaxHighlighter {
     Q_OBJECT
@@ -28,6 +29,20 @@ struct CodeCopy {
     QString text;
 };
 
+class ContextLinkInterface : public QObject, public QTextObjectInterface
+{
+    Q_OBJECT
+    Q_INTERFACES(QTextObjectInterface)
+
+public:
+    explicit ContextLinkInterface(QObject *parent) : QObject(parent) {}
+    void drawObject(QPainter *painter, const QRectF &rect, QTextDocument *doc, int posInDocument,
+                    const QTextFormat &format) override;
+
+    QSizeF intrinsicSize(QTextDocument *doc, int posInDocument, const QTextFormat &format) override;
+};
+
+
 class ResponseText : public QObject
 {
     Q_OBJECT
@@ -61,6 +76,7 @@ private:
     QColor m_linkColor;
     QColor m_headerColor;
     bool m_isProcessingText = false;
+    ContextLinkInterface *m_contextLink;
 };
 
 #endif // RESPONSETEXT_H