/****************************************************************************
**
** Copyright (C) 2015 The Qt Company Ltd.
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** This file is part of the QtDeclarative module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL21$
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** accordance with the commercial license agreement provided with the
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** Alternatively, this file may be used under the terms of the GNU Lesser
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****************************************************************************/

#include "private/qdeclarativerewrite_p.h"

#include "private/qdeclarativeglobal_p.h"

#include <QtCore/qdebug.h>

QT_BEGIN_NAMESPACE

DEFINE_BOOL_CONFIG_OPTION(rewriteDump, QML_REWRITE_DUMP);

namespace QDeclarativeRewrite {

bool SharedBindingTester::isSharable(const QString &code)
{
    Engine engine;
    NodePool pool(QString(), &engine);
    Lexer lexer(&engine);
    Parser parser(&engine);
    lexer.setCode(code, 0);
    parser.parseStatement();
    if (!parser.statement())
        return false;

    return isSharable(parser.statement());
}

bool SharedBindingTester::isSharable(AST::Node *node)
{
    _sharable = true;
    AST::Node::acceptChild(node, this);
    return _sharable;
}

QString RewriteBinding::operator()(const QString &code, bool *ok, bool *sharable)
{
    Engine engine;
    NodePool pool(QString(), &engine);
    Lexer lexer(&engine);
    Parser parser(&engine);
    lexer.setCode(code, 0);
    parser.parseStatement();
    if (!parser.statement()) {
        if (ok) *ok = false;
        return QString();
    } else {
        if (ok) *ok = true;
        if (sharable) {
            SharedBindingTester tester;
            *sharable = tester.isSharable(parser.statement());
        }
    }
    return rewrite(code, 0, parser.statement());
}

QString RewriteBinding::operator()(QDeclarativeJS::AST::Node *node, const QString &code, bool *sharable)
{
    if (!node)
        return code;

    if (sharable) {
        SharedBindingTester tester;
        *sharable = tester.isSharable(node);
    }

    QDeclarativeJS::AST::ExpressionNode *expression = node->expressionCast();
    QDeclarativeJS::AST::Statement *statement = node->statementCast();
    if(!expression && !statement)
        return code;

    TextWriter w;
    _writer = &w;
    _position = expression ? expression->firstSourceLocation().begin() : statement->firstSourceLocation().begin();
    _inLoop = 0;

    accept(node);

    unsigned startOfStatement = 0;
    unsigned endOfStatement = (expression ? expression->lastSourceLocation().end() : statement->lastSourceLocation().end()) - _position;

    QString startString = QLatin1String("(function ") + QString::fromUtf8(_name) + QLatin1String("() { ");
    if (expression)
        startString += QLatin1String("return ");
    _writer->replace(startOfStatement, 0, startString);
    _writer->replace(endOfStatement, 0, QLatin1String(" })"));

    if (rewriteDump()) {
        qWarning() << "=============================================================";
        qWarning() << "Rewrote:";
        qWarning() << qPrintable(code);
    }

    QString codeCopy = code;
    w.write(&codeCopy);

    if (rewriteDump()) {
        qWarning() << "To:";
        qWarning() << qPrintable(code);
        qWarning() << "=============================================================";
    }

    return codeCopy;
}

void RewriteBinding::accept(AST::Node *node)
{
    AST::Node::acceptChild(node, this);
}

QString RewriteBinding::rewrite(QString code, unsigned position,
                                AST::Statement *node)
{
    TextWriter w;
    _writer = &w;
    _position = position;
    _inLoop = 0;

    accept(node);

    unsigned startOfStatement = node->firstSourceLocation().begin() - _position;
    unsigned endOfStatement = node->lastSourceLocation().end() - _position;

    _writer->replace(startOfStatement, 0, QLatin1String("(function ") + QString::fromUtf8(_name) + QLatin1String("() { "));
    _writer->replace(endOfStatement, 0, QLatin1String(" })"));

    if (rewriteDump()) {
        qWarning() << "=============================================================";
        qWarning() << "Rewrote:";
        qWarning() << qPrintable(code);
    }

    w.write(&code);

    if (rewriteDump()) {
        qWarning() << "To:";
        qWarning() << qPrintable(code);
        qWarning() << "=============================================================";
    }

    return code;
}

bool RewriteBinding::visit(AST::Block *ast)
{
    for (AST::StatementList *it = ast->statements; it; it = it->next) {
        if (! it->next) {
            // we need to rewrite only the last statement of a block.
            accept(it->statement);
        }
    }

    return false;
}

bool RewriteBinding::visit(AST::ExpressionStatement *ast)
{
    if (! _inLoop) {
        unsigned startOfExpressionStatement = ast->firstSourceLocation().begin() - _position;
        _writer->replace(startOfExpressionStatement, 0, QLatin1String("return "));
    }

    return false;
}

bool RewriteBinding::visit(AST::DoWhileStatement *)
{
    ++_inLoop;
    return true;
}

void RewriteBinding::endVisit(AST::DoWhileStatement *)
{
    --_inLoop;
}

bool RewriteBinding::visit(AST::WhileStatement *)
{
    ++_inLoop;
    return true;
}

void RewriteBinding::endVisit(AST::WhileStatement *)
{
    --_inLoop;
}

bool RewriteBinding::visit(AST::ForStatement *)
{
    ++_inLoop;
    return true;
}

void RewriteBinding::endVisit(AST::ForStatement *)
{
    --_inLoop;
}

bool RewriteBinding::visit(AST::LocalForStatement *)
{
    ++_inLoop;
    return true;
}

void RewriteBinding::endVisit(AST::LocalForStatement *)
{
    --_inLoop;
}

bool RewriteBinding::visit(AST::ForEachStatement *)
{
    ++_inLoop;
    return true;
}

void RewriteBinding::endVisit(AST::ForEachStatement *)
{
    --_inLoop;
}

bool RewriteBinding::visit(AST::LocalForEachStatement *)
{
    ++_inLoop;
    return true;
}

void RewriteBinding::endVisit(AST::LocalForEachStatement *)
{
    --_inLoop;
}

} // namespace QDeclarativeRewrite

QT_END_NAMESPACE
