/****************************************************************************
**
** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
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**
** This file is part of the QtQml module of the Qt Toolkit.
**
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** Software or, alternatively, in accordance with the terms contained in
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** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file.  Please review the following information to
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** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.  Please review the following information to
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****************************************************************************/
#ifndef QMLJS_VALUE_H
#define QMLJS_VALUE_H

#include <cmath> // this HAS to come

#include <QtCore/QString>
#include <QtCore/qnumeric.h>
#include "qv4global_p.h"
#include "qv4string_p.h"
#include <QtCore/QDebug>
#include "qv4managed_p.h"
#include <private/qtqmlglobal_p.h>

//#include <wtf/MathExtras.h>

#include "qv4value_def_p.h"

QT_BEGIN_NAMESPACE

namespace QV4 {

QV4::Object *__qmljs_convert_to_object(QV4::ExecutionContext *ctx, const QV4::Value &value);

inline Managed *Value::asManaged() const
{
    if (isManaged())
        return managed();
    return 0;
}

inline ExecutionEngine *Value::engine() const {
    Managed *m = asManaged();
    return m ? m->engine() : 0;
}

inline void Value::mark() const {
    Managed *m = asManaged();
    if (m)
        m->mark();
}

inline Value Value::undefinedValue()
{
    Value v;
#if QT_POINTER_SIZE == 8
    v.val = quint64(_Undefined_Type) << Tag_Shift;
#else
    v.tag = _Undefined_Type;
    v.int_32 = 0;
#endif
    return v;
}

inline Value Value::nullValue()
{
    Value v;
#if QT_POINTER_SIZE == 8
    v.val = quint64(_Null_Type) << Tag_Shift;
#else
    v.tag = _Null_Type;
    v.int_32 = 0;
#endif
    return v;
}

inline Value Value::emptyValue()
{
    Value v;
    v.tag = Value::_Empty_Type;
    v.uint_32 = 0;
    return v;
}


inline Value Value::fromBoolean(Bool b)
{
    Value v;
    v.tag = _Boolean_Type;
    v.int_32 = (bool)b;
    return v;
}

inline Value Value::fromDouble(double d)
{
    Value v;
    v.dbl = d;
    return v;
}

inline Value Value::fromInt32(int i)
{
    Value v;
    v.tag = _Integer_Type;
    v.int_32 = i;
    return v;
}

inline Value Value::fromUInt32(uint i)
{
    Value v;
    if (i < INT_MAX) {
        v.tag = _Integer_Type;
        v.int_32 = (int)i;
    } else {
        v.dbl = i;
    }
    return v;
}

inline Value Value::fromString(String *s)
{
    Value v;
#if QT_POINTER_SIZE == 8
    v.val = (quint64)s;
    v.val |= quint64(_String_Type) << Tag_Shift;
#else
    v.tag = _String_Type;
    v.s = s;
#endif
    return v;
}

inline Value Value::fromObject(Object *o)
{
    Value v;
#if QT_POINTER_SIZE == 8
    v.val = (quint64)o;
    v.val |= quint64(_Object_Type) << Tag_Shift;
#else
    v.tag = _Object_Type;
    v.o = o;
#endif
    return v;
}

inline bool Value::toBoolean() const
{
    switch (type()) {
    case Value::Undefined_Type:
    case Value::Null_Type:
        return false;
    case Value::Boolean_Type:
    case Value::Integer_Type:
        return (bool)int_32;
    case Value::String_Type:
        return stringValue()->toQString().length() > 0;
    case Value::Object_Type:
        return true;
    default: // double
        return doubleValue() && !std::isnan(doubleValue());
    }
}

inline uint Value::asArrayIndex() const
{
    if (isInteger() && int_32 >= 0)
        return (uint)int_32;
    if (!isDouble())
        return UINT_MAX;
    uint idx = (uint)dbl;
    if (idx != dbl)
        return UINT_MAX;
    return idx;
}

inline uint Value::asArrayLength(bool *ok) const
{
    *ok = true;
    if (isConvertibleToInt() && int_32 >= 0)
        return (uint)int_32;
    if (isDouble()) {
        uint idx = (uint)dbl;
        if ((double)idx != dbl) {
            *ok = false;
            return UINT_MAX;
        }
        return idx;
    }
    if (isString())
        return stringValue()->toUInt(ok);

    uint idx = toUInt32();
    double d = toNumber();
    if (d != idx) {
        *ok = false;
        return UINT_MAX;
    }
    return idx;
}

inline String *Value::asString() const
{
    if (isString())
        return stringValue();
    return 0;
}

inline Object *Value::asObject() const
{
    return isObject() ? objectValue() : 0;
}

inline FunctionObject *Value::asFunctionObject() const
{
    return isObject() ? managed()->asFunctionObject() : 0;
}

inline BooleanObject *Value::asBooleanObject() const
{
    return isObject() ? managed()->asBooleanObject() : 0;
}

inline NumberObject *Value::asNumberObject() const
{
    return isObject() ? managed()->asNumberObject() : 0;
}

inline StringObject *Value::asStringObject() const
{
    return isObject() ? managed()->asStringObject() : 0;
}

inline DateObject *Value::asDateObject() const
{
    return isObject() ? managed()->asDateObject() : 0;
}

inline ArrayObject *Value::asArrayObject() const
{
    return isObject() ? managed()->asArrayObject() : 0;
}

inline ErrorObject *Value::asErrorObject() const
{
    return isObject() ? managed()->asErrorObject() : 0;
}

// ###
inline ReturnedValue Managed::construct(CallData *d) {
    return vtbl->construct(this, d);
}
inline ReturnedValue Managed::call(CallData *d) {
    return vtbl->call(this, d);
}

struct Q_QML_PRIVATE_EXPORT PersistentValuePrivate
{
    PersistentValuePrivate(const Value &v, ExecutionEngine *engine = 0, bool weak = false);
    virtual ~PersistentValuePrivate();
    Value value;
    uint refcount;
    QV4::ExecutionEngine *engine;
    PersistentValuePrivate **prev;
    PersistentValuePrivate *next;

    void removeFromList();
    void ref() { ++refcount; }
    void deref();
    PersistentValuePrivate *detach(const QV4::Value &value, bool weak = false);

    bool checkEngine(QV4::ExecutionEngine *otherEngine) {
        if (!engine) {
            Q_ASSERT(!value.isObject());
            engine = otherEngine;
        }
        return (engine == otherEngine);
    }
};

class Q_QML_EXPORT PersistentValue
{
public:
    PersistentValue() : d(0) {}

    PersistentValue(const Value &val);
    PersistentValue(ReturnedValue val);
    PersistentValue(const PersistentValue &other);
    PersistentValue &operator=(const PersistentValue &other);
    PersistentValue &operator=(const Value &other);
    PersistentValue &operator =(const ReturnedValue &other);
    ~PersistentValue();

    Value value() const {
        return d ? d->value : Value::emptyValue();
    }

    ExecutionEngine *engine() {
        if (!d)
            return 0;
        Managed *m = d->value.asManaged();
        return m ? m->engine() : 0;
    }

    operator Value() const { return value(); }

    bool isEmpty() const { return !d || d->value.isEmpty(); }
    void clear() {
        *this = PersistentValue();
    }

private:
    friend struct ValueRef;
    PersistentValuePrivate *d;
};

class Q_QML_EXPORT WeakValue
{
public:
    WeakValue() : d(0) {}
    WeakValue(const Value &val);
    WeakValue(const WeakValue &other);
    WeakValue &operator=(const WeakValue &other);
    WeakValue &operator=(const Value &other);
    ~WeakValue();

    Value value() const {
        return d ? d->value : Value::emptyValue();
    }

    ExecutionEngine *engine() {
        if (!d)
            return 0;
        Managed *m = d->value.asManaged();
        return m ? m->engine() : 0;
    }

    operator Value() const { return value(); }

    bool isEmpty() const { return !d || d->value.isEmpty(); }
    void clear() {
        *this = WeakValue();
    }

    void markOnce();

private:
    friend struct ValueRef;
    PersistentValuePrivate *d;
};

} // namespace QV4

QT_END_NAMESPACE

#endif