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** GNU General Public License Usage
**
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** Public License versions 2.0 or 3.0 as published by the Free Software
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#include "cpphoverhandler.h"
#include "cppmodelmanager.h"

#include <coreplugin/icore.h>
#include <coreplugin/uniqueidmanager.h>
#include <texteditor/itexteditor.h>
#include <debugger/debuggerconstants.h>

#include <CoreTypes.h>
#include <FullySpecifiedType.h>
#include <Literals.h>
#include <Names.h>
#include <Scope.h>
#include <Symbol.h>
#include <Symbols.h>
#include <cplusplus/ExpressionUnderCursor.h>
#include <cplusplus/Overview.h>
#include <cplusplus/TypeOfExpression.h>

#include <QtGui/QToolTip>
#include <QtGui/QPlainTextEdit>
#include <QtGui/QTextCursor>
#include <QtGui/QTextBlock>
#include <QtHelp/QHelpEngineCore>
#include <QtCore/QtCore>

using namespace CppTools::Internal;

CppHoverHandler::CppHoverHandler(CppModelManager *manager, QObject *parent)
    : QObject(parent), m_manager(manager)
{
    QFileInfo fi(ExtensionSystem::PluginManager::instance()->getObject<Core::ICore>()->settings()->fileName());
    m_helpEngine = new QHelpEngineCore(fi.absolutePath()
                                       + QLatin1String("/helpcollection.qhc"), this);
    //m_helpEngine->setAutoSaveFilter(false);
    m_helpEngine->setupData();
    m_helpEngine->setCurrentFilter(tr("Unfiltered"));
}

void CppHoverHandler::updateContextHelpId(TextEditor::ITextEditor *editor, int pos)
{
    updateHelpIdAndTooltip(editor, pos);
}

void CppHoverHandler::showToolTip(TextEditor::ITextEditor *editor, const QPoint &point, int pos)
{
    const int dbgcontext = m_manager->core()->
        uniqueIDManager()->uniqueIdentifier(Debugger::Constants::C_GDBDEBUGGER);

    if (m_manager->core()->hasContext(dbgcontext))
        return;

    if (! editor)
        return;

    updateHelpIdAndTooltip(editor, pos);

    if (m_toolTip.isEmpty())
        QToolTip::hideText();
    else {
        const QPoint pnt = point - QPoint(0,
#ifdef Q_WS_WIN
        24
#else
        16
#endif
        );

        QToolTip::showText(pnt, m_toolTip);
    }
}

static QString buildHelpId(const CPlusPlus::FullySpecifiedType &type,
                           const CPlusPlus::Symbol *symbol)
{
    using namespace CPlusPlus;

    Name *name = 0;
    Scope *scope = 0;

    if (const Function *f = type->asFunction()) {
        name = f->name();
        scope = f->scope();
    } else if (const Class *c = type->asClass()) {
        name = c->name();
        scope = c->scope();
    } else if (const Enum *e = type->asEnum()) {
        name = e->name();
        scope = e->scope();
    } else if (const NamedType *t = type->asNamedType()) {
        name = t->name();
    } else if (const Declaration *d = symbol->asDeclaration()) {
        if (d->scope() && d->scope()->owner()->isEnum()) {
            name = d->name();
            scope = d->scope();
        }
    }

    Overview overview;
    overview.setShowArgumentNames(false);
    overview.setShowReturnTypes(false);

    QStringList qualifiedNames;
    qualifiedNames.prepend(overview.prettyName(name));

    for (; scope; scope = scope->enclosingScope()) {
        if (scope->owner() && scope->owner()->name() && !scope->isEnumScope()) {
            Name *name = scope->owner()->name();
            Identifier *id = 0;
            if (NameId *nameId = name->asNameId()) {
                id = nameId->identifier();
            } else if (TemplateNameId *nameId = name->asTemplateNameId()) {
                id = nameId->identifier();
            }
            if (id)
                qualifiedNames.prepend(QString::fromLatin1(id->chars(), id->size()));
        }
    }

    return qualifiedNames.join(QLatin1String("::"));
}

void CppHoverHandler::updateHelpIdAndTooltip(TextEditor::ITextEditor *editor, int pos)
{
    using namespace CPlusPlus;

    m_helpId.clear();
    m_toolTip.clear();

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

    QTextCursor tc(edit->document());
    tc.setPosition(pos);

    const int lineNumber = tc.block().blockNumber() + 1;

    QString fileName = editor->file()->fileName();
    Document::Ptr doc = m_manager->document(fileName);
    if (doc) {
        foreach (Document::DiagnosticMessage m, doc->diagnosticMessages()) {
            if (m.line() == lineNumber) {
                m_toolTip = m.text();
                break;
            }
        }
    }

    if (m_toolTip.isEmpty()) {
        // Move to the end of a qualified name
        bool stop = false;
        while (!stop) {
            const QChar ch = editor->characterAt(tc.position());
            if (ch.isLetterOrNumber() || ch == QLatin1Char('_'))
                tc.setPosition(tc.position() + 1);
            else if (ch == QLatin1Char(':') && editor->characterAt(tc.position() + 1) == QLatin1Char(':')) {
                tc.setPosition(tc.position() + 2);
            } else {
                stop = true;
            }
        }

        // Fetch the expression's code.
        ExpressionUnderCursor expressionUnderCursor;
        const QString expression = expressionUnderCursor(tc);

        if (doc) {
            // Find the last symbol up to the cursor position
            int line = 0, column = 0;
            editor->convertPosition(tc.position(), &line, &column);
            Symbol *lastSymbol = doc->findSymbolAt(line, column);

            TypeOfExpression typeOfExpression;
            typeOfExpression.setDocuments(m_manager->documents());
            QList<TypeOfExpression::Result> types = typeOfExpression(expression, doc, lastSymbol);

            if (!types.isEmpty()) {
                FullySpecifiedType firstType = types.first().first;
                FullySpecifiedType docType = firstType;

                if (const PointerType *pt = firstType->asPointerType()) {
                    docType = pt->elementType();
                } else if (const ReferenceType *rt = firstType->asReferenceType()) {
                    docType = rt->elementType();
                }


                m_helpId = buildHelpId(docType, types.first().second);
                QString displayName = buildHelpId(firstType, types.first().second);

                if (!firstType->isClass() && !firstType->isNamedType()) {
                    Overview overview;
                    overview.setShowArgumentNames(true);
                    overview.setShowReturnTypes(true);
                    m_toolTip = overview.prettyType(firstType, displayName);
                } else {
                    m_toolTip = m_helpId;
                }
            }
        }
    }

    if (!m_helpId.isEmpty() && !m_helpEngine->linksForIdentifier(m_helpId).isEmpty()) {
        m_toolTip = QString(QLatin1String("<table><tr><td valign=middle><nobr>%1</td>"
                                          "<td><img src=\":/cpptools/images/f1.svg\"></td></tr></table>")).arg(Qt::escape(m_toolTip));
        editor->setContextHelpId(m_helpId);
    } else if (!m_toolTip.isEmpty()) {
        m_toolTip = QString(QLatin1String("<nobr>%1")).arg(Qt::escape(m_toolTip));
    }
}