/*
 *  This file is part of the KDE libraries
 *  Copyright (C) 2013 Bernd Buschinski <b.buschinski@googlemail.com>
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser 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
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */

#ifndef KJS_ARRAYBUFFERVIEW_H
#define KJS_ARRAYBUFFERVIEW_H

#include "ecma/kjs_arraybuffer.h"

#include <kjs/object.h>
#include <kjs/function.h>
#include <kjs/function_object.h>
#include <kjs/operations.h>
#include <kjs/array_instance.h>
#include <dom/dom_exception.h>

namespace KJS
{
class ArrayBuffer;

// Keep enum outside of template classes, for lut tables
namespace ArrayBufferViewBase
{
enum {
    Buffer, ByteLength, ByteOffset, Subarray, Length, Set, BytesPerElement
};
}

//type, TypedArrayClass
template <class T, class U>
class ArrayBufferViewConstructorImp : public KJS::FunctionPrototype
{
public:
    ArrayBufferViewConstructorImp(ExecState *exec, DOM::DocumentImpl *d);
    bool implementsConstruct() const override;
    using KJS::JSObject::construct;
    JSObject *construct(ExecState *exec, const List &args) override;

    JSValue *getValueProperty(ExecState *exec, int token) const;
    using KJS::JSObject::getOwnPropertySlot;
    bool getOwnPropertySlot(ExecState *exec, const Identifier &propertyName, PropertySlot &slot) override;
private:
    SharedPtr<DOM::DocumentImpl> doc;
};

//type, TypedArrayPrototype
template <class T, class P>
class ArrayBufferView : public JSObject
{
public:
    explicit ArrayBufferView(ExecState *exec, ArrayBuffer *buffer, size_t byteOffset, size_t byteLength);
    virtual ~ArrayBufferView();

    bool getOwnPropertySlot(ExecState *exec, unsigned i, PropertySlot &slot) override;
    bool getOwnPropertySlot(ExecState *exec, const Identifier &propertyName, PropertySlot &slot) override;
    JSValue *getValueProperty(ExecState *exec, int token) const;

    void put(ExecState *exec, const Identifier &propertyName, JSValue *value, int attr = None) override;
    void put(ExecState *exec, unsigned propertyName, JSValue *value, int attr = None) override;

    ArrayBuffer *buffer() const
    {
        return m_buffer;
    }
    size_t byteLength() const
    {
        return m_byteLength;
    }
    size_t byteOffset() const
    {
        return m_byteOffset;
    }
    size_t length() const
    {
        return m_length;
    }
    inline T *bufferStart() const
    {
        return m_bufferStart;
    }

private:
    // checks if the pos is a valid array index, returns false if not
    inline bool checkIndex(ExecState *exec, unsigned pos);

    ProtectedPtr<ArrayBuffer> m_buffer;
    size_t m_byteOffset;
    size_t m_byteLength;
    size_t m_length;
    T *m_bufferStart;
};

//unrolled KJS_DEFINE_PROTOTYPE(ArrayBufferViewProto), for template sake

//type, TypedArrayClass
template <class T, class U>
class ArrayBufferViewProto : public KJS::JSObject
{
public:
    bool getOwnPropertySlot(KJS::ExecState *, const KJS::Identifier &, KJS::PropertySlot &) override;
    using JSObject::getOwnPropertySlot;
protected:
    ArrayBufferViewProto(KJS::ExecState *exec);
};

//unrolled KJS_IMPLEMENT_PROTOFUNC(ArrayBufferViewProtoFunc), for template sake
template <class T, class U>
class ArrayBufferViewProtoFunc : public KJS::InternalFunctionImp
{
public:
    ArrayBufferViewProtoFunc<T, U>(KJS::ExecState *exec, int i, int len, const KJS::Identifier &name)
        : InternalFunctionImp(static_cast<KJS::FunctionPrototype *>(exec->lexicalInterpreter()->builtinFunctionPrototype()), name), id(i)
    {
        put(exec, exec->propertyNames().length, KJS::jsNumber(len), KJS::DontDelete | KJS::ReadOnly | KJS::DontEnum);
    }

    KJS::JSValue *callAsFunction(KJS::ExecState *exec, KJS::JSObject *thisObj, const KJS::List &args) override;
private:
    int id;
};
}

#include "kjs_arraybufferview.lut.h"

namespace KJS
{

// unrolled KJS_IMPLEMENT_PROTOTYPE("ArrayBufferView", ArrayBufferViewProto, ArrayBufferViewProtoFunc, ObjectPrototype)
// for template sake
template <class T, class U>
bool ArrayBufferViewProto<T, U>::getOwnPropertySlot(KJS::ExecState *exec, const KJS::Identifier &propertyName, KJS::PropertySlot &slot)
{
    return KJS::getStaticFunctionSlot<ArrayBufferViewProtoFunc<T, U>, KJS::JSObject>(exec, &ArrayBufferViewProtoTable, this, propertyName, slot);
}

template <class T, class U>
ArrayBufferViewProto<T, U>::ArrayBufferViewProto(KJS::ExecState *exec)
    : KJS::JSObject(ObjectPrototype::self(exec))
{
}
// unroll end

// -------------------- ArrayBufferViewProtoFunc ---------------------

template <class T, class U>
JSValue *ArrayBufferViewProtoFunc<T, U>::callAsFunction(ExecState *exec, JSObject *thisObj, const List &args)
{
    if (!thisObj->inherits(&U::info)) {
        return jsUndefined();
    }
    U *view = static_cast<U *>(thisObj);

    switch (id) {
    case ArrayBufferViewBase::Subarray: {
        //Subarray takes max long/signed size_t
        // If start or end are negative, it refers to an index from the end of the array
        ssize_t begin = 0;
        ssize_t end = 0;
        double tmp;
        if (args[0]->getNumber(tmp)) {
            begin = static_cast<ssize_t>(tmp);
        }
        if (args.size() >= 2 && args[1]->getNumber(tmp)) {
            end = static_cast<ssize_t>(tmp);
        }

        // turn negative start/end into a valid positive index
        if (begin < 0 && view->length() > static_cast<size_t>(-begin)) {
            begin = view->length() + begin;
        }
        if (end < 0 && view->length() > static_cast<size_t>(-end)) {
            end = view->length() + end;
        }

        if (static_cast<size_t>(begin) > view->length()) {
            begin = view->length();
        }
        if (static_cast<size_t>(end) > view->length()) {
            end = 0;
        }

        size_t length = 0;
        if (begin < end) {
            length = (end - begin) * sizeof(T);
        }

        U *newView = new U(exec, view->buffer(), begin * sizeof(T), length);
        return newView;
    }
    case ArrayBufferViewBase::Set: {
        JSObject *obj = args[0]->getObject();
        if (!obj) {
            return jsUndefined();
        }
        if (obj->inherits(&U::info)) {
            U *other = static_cast<U *>(obj);
            double tmp;
            size_t offset = 0;
            if (args.size() >= 2 && args[1]->getNumber(tmp) && tmp > 0) {
                offset = static_cast<size_t>(tmp) * sizeof(T);
            }

            if (offset > other->byteLength() || other->byteLength() - offset > view->byteLength()) {
                setDOMException(exec, DOM::DOMException::INDEX_SIZE_ERR);
                return jsUndefined();
            }
            memcpy(view->buffer()->buffer(), other->buffer()->buffer() + offset, std::max<ssize_t>(static_cast<ssize_t>(other->byteLength()) - static_cast<ssize_t>(offset), 0));
            return jsUndefined();
        } else if (obj->inherits(&ArrayInstance::info)) {
            ArrayInstance *array = static_cast<ArrayInstance *>(obj);
            if (array->getLength() > view->length()) {
                setDOMException(exec, DOM::DOMException::INDEX_SIZE_ERR);
                return jsUndefined();
            }
            for (unsigned i = 0; i < array->getLength(); ++i) {
                view->put(exec, i, array->getItem(i));
            }
            return jsUndefined();
        } else {
            return jsUndefined();
        }
    }
    default:
        ASSERT_NOT_REACHED();
        return jsUndefined();
    }
}

// -------------------- ArrayBufferViewConstructorImp ---------------------

template <class T, class U>
ArrayBufferViewConstructorImp<T, U>::ArrayBufferViewConstructorImp(ExecState *exec, DOM::DocumentImpl *d)
    : KJS::FunctionPrototype(exec),
      doc(d)
{
}

template <class T, class U>
bool ArrayBufferViewConstructorImp<T, U>::implementsConstruct() const
{
    return true;
}

template <class T, class U>
JSObject *ArrayBufferViewConstructorImp<T, U>::construct(ExecState *exec, const List &args)
{
    JSType type = args[0]->type();

    switch (type) {
    case ObjectType: {
        JSObject *obj = args[0]->getObject();
        if (!obj) {
            return throwError(exec, TypeError);
        }
        if (obj->inherits(&ArrayBuffer::info)) {
            // new ArrayBufferView(ArrayBuffer, [byteOffset[, byteLength]])
            ArrayBuffer *buf = static_cast<ArrayBuffer *>(obj);

            size_t byteOffset = 0, byteLength = 0;
            double tmp;
            if (args.size() >= 2 && args[1]->getNumber(tmp) && tmp > 0) {
                byteOffset = static_cast<size_t>(tmp);
            }

            if (args.size() >= 3 && args[2]->getNumber(tmp) && tmp > 0) {
                byteLength = static_cast<size_t>(tmp) * sizeof(T);
            }

            return new U(exec, buf, byteOffset, byteLength);
        } else if (obj->inherits(&ArrayInstance::info)) {
            // new ArrayBufferView(Array)
            ArrayInstance *arr = dynamic_cast<ArrayInstance *>(obj);
            ArrayBuffer *buf = new ArrayBuffer(arr->getLength()*sizeof(T));
            U *view = new U(exec, buf, 0, 0);
            for (unsigned i = 0; i < arr->getLength(); ++i) {
                view->put(exec, i, arr->getItem(i));
            }
            return view;
        } else if (obj->inherits(&U::info)) {
            // new ArrayBufferView(ArrayBufferView)
            U *arr = static_cast<U *>(obj);
            ArrayBuffer *buf = new ArrayBuffer(arr->buffer()->buffer(), arr->byteLength());
            U *view = new U(exec, buf, 0, 0);
            return view;
        } else {
            break;
        }
    }
    case NumberType: {
        // new ArrayBufferView(Length)
        size_t length = 0;
        double lengthF = args[0]->getNumber();
        if (!KJS::isNaN(lengthF) && !KJS::isInf(lengthF) && lengthF > 0) {
            length = static_cast<size_t>(lengthF);
        }
        ArrayBuffer *buf = new ArrayBuffer(length * sizeof(T));
        return new U(exec, buf, 0, 0);
    }
    default:
        break;
    }
    // new ArrayBufferView(), create empty ArrayBuffer
    ArrayBuffer *buf = new ArrayBuffer(0);
    return new U(exec, buf, 0, 0);
}

template <class T, class U>
JSValue *ArrayBufferViewConstructorImp<T, U>::getValueProperty(ExecState *, int) const
{
    // switch (id)
    // {
    // case ArrayBufferViewFuncImp<T>::BytesPerElement:
    return jsNumber(sizeof(T));
    // }
}

template <class T, class U>
bool ArrayBufferViewConstructorImp<T, U>::getOwnPropertySlot(ExecState *exec, const Identifier &propertyName, PropertySlot &slot)
{
    return getStaticPropertySlot<ArrayBufferViewProtoFunc<T, U>, ArrayBufferViewConstructorImp<T, U>, KJS::FunctionPrototype>(exec, &ArrayBufferViewConstTable, this, propertyName, slot);
}

// -------------------- ArrayBufferView ---------------------

template <class T, class P>
ArrayBufferView<T, P>::ArrayBufferView(KJS::ExecState *exec, KJS::ArrayBuffer *buffer, size_t byteOffset, size_t byteLength)
    : JSObject(),
      m_buffer(buffer),
      m_byteOffset(byteOffset)
{
    if (byteLength == 0) {
        if (byteOffset < buffer->byteLength()) {
            m_byteLength = buffer->byteLength() - byteOffset;
        } else {
            m_byteLength = 0;
        }
    } else {
        m_byteLength = byteLength;
    }
    m_length = m_byteLength / sizeof(T);
    setPrototype(P::self(exec));
    m_bufferStart = reinterpret_cast<T *>(m_buffer->buffer() + m_byteOffset);
}

template <class T, class P>
ArrayBufferView<T, P>::~ArrayBufferView()
{
}

template <class T, class P>
bool ArrayBufferView<T, P>::getOwnPropertySlot(ExecState *exec, unsigned int i, PropertySlot &slot)
{
    if (!checkIndex(exec, i)) {
        return false;
    }

    slot.setValue(this, jsNumber(m_bufferStart[i]));
    return true;
}

template <class T, class P>
bool ArrayBufferView<T, P>::getOwnPropertySlot(ExecState *exec, const Identifier &propertyName, PropertySlot &slot)
{
    bool ok = false;
    unsigned i = propertyName.toArrayIndex(&ok);
    if (ok) {
        return ArrayBufferView<T, P>::getOwnPropertySlot(exec, i, slot);
    }

    return getStaticValueSlot< ArrayBufferView<T, P>, JSObject>(exec, &ArrayBufferViewTable, this, propertyName, slot);
}

template <class T, class P>
JSValue *ArrayBufferView<T, P>::getValueProperty(ExecState * /*exec*/, int token) const
{
    switch (token) {
    case ArrayBufferViewBase::Buffer:
        return m_buffer;
    case ArrayBufferViewBase::ByteLength:
        return jsNumber(m_byteLength);
    case ArrayBufferViewBase::ByteOffset:
        return jsNumber(m_byteOffset);
    case ArrayBufferViewBase::Length:
        return jsNumber(m_length);
    default:
        ASSERT_NOT_REACHED();
        qCWarning(KHTML_LOG) << "ArrayBufferView<T>::getValueProperty unhandled token " << token;
        break;
    }
    return nullptr;
}

template <class T, class P>
void ArrayBufferView<T, P>::put(ExecState *exec, const Identifier &propertyName, JSValue *value, int attr)
{
    bool ok = false;
    unsigned i = propertyName.toArrayIndex(&ok);
    if (ok) {
        ArrayBufferView<T, P>::put(exec, i, value, attr);
    } else {
        KJS::JSObject::put(exec, propertyName, value, attr);
    }
}

template <class T, class P>
void ArrayBufferView<T, P>::put(ExecState *exec, unsigned int i, JSValue *value, int /*attr*/)
{
    if (!checkIndex(exec, i)) {
        return;
    }
    if (value && value->type() != NumberType) {
        return;
    }
    m_bufferStart[i] = static_cast<T>(value->getNumber());
}

template <class T, class P>
bool ArrayBufferView<T, P>::checkIndex(KJS::ExecState * /*exec*/, unsigned int pos)
{
    if (m_byteOffset + (pos + 1)*sizeof(T) > m_buffer->byteLength()) {
        return false;
    }
    if (pos * sizeof(T) >= m_byteLength) {
        return false;
    }
    return true;
}

} // namespace KJS

#endif //KJS_ARRAYBUFFERVIEW_H