/*
   This file is part of the clazy static checker.

  Copyright (C) 2015 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com
  Author: Sérgio Martins <sergio.martins@kdab.com>

  Copyright (C) 2015,2018 Sergio Martins <smartins@kde.org>

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Library General Public
  License as published by the Free Software Foundation; either
  version 2 of the License, or (at your option) any later version.

  This library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  Library General Public License for more details.

  You should have received a copy of the GNU Library General Public License
  along with this library; see the file COPYING.LIB.  If not, write to
  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  Boston, MA 02110-1301, USA.
*/

#include "function-args-by-ref.h"
#include "Utils.h"
#include "FixItUtils.h"
#include "TypeUtils.h"
#include "ClazyContext.h"
#include "StringUtils.h"

#include <clang/AST/AST.h>
#include <clang/Lex/Lexer.h>

using namespace clang;
using namespace std;

static bool shouldIgnoreClass(CXXRecordDecl *record)
{
    if (!record)
        return false;

    if (Utils::isSharedPointer(record))
        return true;

    static const vector<string> ignoreList = {"QDebug", // Too many warnings
                                              "QGenericReturnArgument",
                                              "QColor", // TODO: Remove in Qt6
                                              "QStringRef", // TODO: Remove in Qt6
                                              "QList::const_iterator", // TODO: Remove in Qt6
                                              "QJsonArray::const_iterator", // TODO: Remove in Qt6
                                              "QList<QString>::const_iterator",  // TODO: Remove in Qt6
                                              "QtMetaTypePrivate::QSequentialIterableImpl",
                                              "QtMetaTypePrivate::QAssociativeIterableImpl",
                                              "QVariantComparisonHelper",
                                              "QHashDummyValue", "QCharRef", "QString::Null"
                                             };
    return clazy::contains(ignoreList, record->getQualifiedNameAsString());
}

static bool shouldIgnoreOperator(FunctionDecl *function)
{
    // Too many warnings in operator<<
    static const vector<StringRef> ignoreList = { "operator<<" };

    return clazy::contains(ignoreList, clazy::name(function));
}

static bool shouldIgnoreFunction(clang::FunctionDecl *function)
{
    static const vector<string> qualifiedIgnoreList = {"QDBusMessage::createErrorReply", // Fixed in Qt6
                                                       "QMenu::exec", // Fixed in Qt6
                                                       "QTextFrame::iterator", // Fixed in Qt6
                                                       "QGraphicsWidget::addActions", // Fixed in Qt6
                                                       "QListWidget::mimeData", // Fixed in Qt6
                                                       "QTableWidget::mimeData", // Fixed in Qt6
                                                       "QTreeWidget::mimeData", // Fixed in Qt6
                                                       "QWidget::addActions", // Fixed in Qt6
                                                       "QSslCertificate::verify", // Fixed in Qt6
                                                       "QSslConfiguration::setAllowedNextProtocols" // Fixed in Qt6
                                                      };

    return clazy::contains(qualifiedIgnoreList, function->getQualifiedNameAsString());
}

FunctionArgsByRef::FunctionArgsByRef(const std::string &name, ClazyContext *context)
    : CheckBase(name, context, Option_CanIgnoreIncludes)
{
}

static std::string warningMsgForSmallType(int sizeOf, const std::string &typeName)
{
    std::string sizeStr = std::to_string(sizeOf);
    return "Missing reference on large type (sizeof " + typeName + " is " + sizeStr + " bytes)";
}

void FunctionArgsByRef::processFunction(FunctionDecl *func)
{
    if (!func || !func->isThisDeclarationADefinition() || func->isDeleted() || shouldIgnoreOperator(func))
        return;

    if (m_context->isQtDeveloper() && shouldIgnoreFunction(func))
        return;

    const bool warnForOverriddenMethods = isOptionSet("warn-for-overridden-methods");
    if (!warnForOverriddenMethods && Utils::methodOverrides(dyn_cast<CXXMethodDecl>(func))) {
        // When overriding you can't change the signature. You should fix the base classes first
        return;
    }

    Stmt *body = func->getBody();

    int i = -1;
    for (auto param : Utils::functionParameters(func)) {
        i++;
        QualType paramQt = TypeUtils::unrefQualType(param->getType());
        const Type *paramType = paramQt.getTypePtrOrNull();
        if (!paramType || paramType->isIncompleteType() || paramType->isDependentType())
            continue;

        if (shouldIgnoreClass(paramType->getAsCXXRecordDecl()))
            continue;

        TypeUtils::QualTypeClassification classif;
        bool success = TypeUtils::classifyQualType(m_context, param, classif, body);
        if (!success)
            continue;

        vector<CXXCtorInitializer *> ctorInits = Utils::ctorInitializer(dyn_cast<CXXConstructorDecl>(func), param);
        if (Utils::ctorInitializerContainsMove(ctorInits))
            continue;

        if (classif.passBigTypeByConstRef || classif.passNonTriviallyCopyableByConstRef) {
            string error;
            std::vector<FixItHint> fixits;
            const string paramStr = param->getType().getAsString();
            if (classif.passBigTypeByConstRef) {
                error = warningMsgForSmallType(classif.size_of_T, paramStr);
            } else if (classif.passNonTriviallyCopyableByConstRef) {
                error = "Missing reference on non-trivial type (" + paramStr + ')';
            }

            emitWarning(getLocStart(param), error.c_str(), fixits);
        }
    }
}

void FunctionArgsByRef::VisitDecl(Decl *decl)
{
    processFunction(dyn_cast<FunctionDecl>(decl));
}

void FunctionArgsByRef::VisitStmt(Stmt *stmt)
{
    if (auto lambda = dyn_cast<LambdaExpr>(stmt)) {
        if (!shouldIgnoreFile(getLocStart(stmt)))
            processFunction(lambda->getCallOperator());
    }
}

clang::FixItHint FunctionArgsByRef::fixit(const ParmVarDecl *, TypeUtils::QualTypeClassification)
{
    FixItHint fixit;
    return fixit;
}
