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#include "analyzerutils.h"

#include "analyzerconstants.h"

#include <coreplugin/editormanager/editormanager.h>
#include <coreplugin/icore.h>
#include <texteditor/basetexteditor.h>
#include <texteditor/itexteditor.h>
#include <utils/qtcassert.h>

#include <cplusplus/ExpressionUnderCursor.h>
#include <cplusplus/ModelManagerInterface.h>
#include <cplusplus/LookupItem.h>
#include <cplusplus/TypeOfExpression.h>

// shared/cplusplus includes
#include <Scope.h>
#include <Symbol.h>

#include <QTextDocumentFragment>
#include <QTextCursor>
#include <QWidget>

using namespace Analyzer;
using namespace Core;

static void moveCursorToEndOfName(QTextCursor *tc)
{
    QTextDocument *doc = tc->document();
    if (!doc)
        return;

    QChar ch = doc->characterAt(tc->position());
    while (ch.isLetterOrNumber() || ch == QLatin1Char('_')) {
        tc->movePosition(QTextCursor::NextCharacter);
        ch = doc->characterAt(tc->position());
    }
}

// TODO: Can this be improved? This code is ripped from CppEditor, especially CppElementEvaluater
// We cannot depend on this since CppEditor plugin code is internal and requires building the implementation files ourselves
CPlusPlus::Symbol *AnalyzerUtils::findSymbolUnderCursor()
{
    EditorManager *editorManager = EditorManager::instance();
    if (!editorManager)
        return 0;
    IEditor *editor = editorManager->currentEditor();
    if (!editor)
        return 0;
    TextEditor::ITextEditor *textEditor = qobject_cast<TextEditor::ITextEditor *>(editor);
    if (!textEditor)
        return 0;
    TextEditor::BaseTextEditorWidget *editorWidget = qobject_cast<TextEditor::BaseTextEditorWidget *>(editor->widget());
    if (!editorWidget)
        return 0;

    QPlainTextEdit *ptEdit = qobject_cast<QPlainTextEdit *>(editor->widget());
    if (!ptEdit)
        return 0;

    QTextCursor tc;
    tc = ptEdit->textCursor();
    int line = 0;
    int column = 0;
    const int pos = tc.position();
    editorWidget->convertPosition(pos, &line, &column);

    const CPlusPlus::Snapshot &snapshot = CPlusPlus::CppModelManagerInterface::instance()->snapshot();
    CPlusPlus::Document::Ptr doc = snapshot.document(editor->document()->fileName());
    QTC_ASSERT(doc, return 0)

    // fetch the expression's code
    CPlusPlus::ExpressionUnderCursor expressionUnderCursor;
    moveCursorToEndOfName(&tc);
    const QString &expression = expressionUnderCursor(tc);
    CPlusPlus::Scope *scope = doc->scopeAt(line, column);

    CPlusPlus::TypeOfExpression typeOfExpression;
    typeOfExpression.init(doc, snapshot);
    const QList<CPlusPlus::LookupItem> &lookupItems = typeOfExpression(expression.toUtf8(), scope);
    if (lookupItems.isEmpty())
        return 0;

    const CPlusPlus::LookupItem &lookupItem = lookupItems.first(); // ### TODO: select best candidate.
    return lookupItem.declaration();
}
