#include "scripthandle.h"
#include <assert.h>
#include <new>
#include <string.h>

BEGIN_AS_NAMESPACE

static void Construct(CScriptHandle* self) { new (self) CScriptHandle(); }
static void Construct(CScriptHandle* self, const CScriptHandle& o) { new (self) CScriptHandle(o); }
// This one is not static because it needs to be friend with the CScriptHandle class
void Construct(CScriptHandle* self, void* ref, int typeId) { new (self) CScriptHandle(ref, typeId); }
static void Destruct(CScriptHandle* self) { self->~CScriptHandle(); }

CScriptHandle::CScriptHandle() {
    m_ref = 0;
    m_type = 0;
}

CScriptHandle::CScriptHandle(const CScriptHandle& other) {
    m_ref = other.m_ref;
    m_type = other.m_type;

    AddRefHandle();
}

CScriptHandle::CScriptHandle(void* ref, asITypeInfo* type) {
    m_ref = ref;
    m_type = type;

    AddRefHandle();
}

// This constructor shouldn't be called from the application
// directly as it requires an active script context
CScriptHandle::CScriptHandle(void* ref, int typeId) {
    m_ref = 0;
    m_type = 0;

    Assign(ref, typeId);
}

CScriptHandle::~CScriptHandle() { ReleaseHandle(); }

void CScriptHandle::ReleaseHandle() {
    if (m_ref && m_type) {
        asIScriptEngine* engine = m_type->GetEngine();
        engine->ReleaseScriptObject(m_ref, m_type);

        engine->Release();

        m_ref = 0;
        m_type = 0;
    }
}

void CScriptHandle::AddRefHandle() {
    if (m_ref && m_type) {
        asIScriptEngine* engine = m_type->GetEngine();
        engine->AddRefScriptObject(m_ref, m_type);

        // Hold on to the engine so it isn't destroyed while
        // a reference to a script object is still held
        engine->AddRef();
    }
}

CScriptHandle& CScriptHandle::operator=(const CScriptHandle& other) {
    Set(other.m_ref, other.m_type);

    return *this;
}

void CScriptHandle::Set(void* ref, asITypeInfo* type) {
    if (m_ref == ref)
        return;

    ReleaseHandle();

    m_ref = ref;
    m_type = type;

    AddRefHandle();
}

void* CScriptHandle::GetRef() { return m_ref; }

asITypeInfo* CScriptHandle::GetType() const { return m_type; }

int CScriptHandle::GetTypeId() const {
    if (m_type == 0)
        return 0;

    return m_type->GetTypeId() | asTYPEID_OBJHANDLE;
}

// This method shouldn't be called from the application
// directly as it requires an active script context
CScriptHandle& CScriptHandle::Assign(void* ref, int typeId) {
    // When receiving a null handle we just clear our memory
    if (typeId == 0) {
        Set(0, 0);
        return *this;
    }

    // Dereference received handles to get the object
    if (typeId & asTYPEID_OBJHANDLE) {
        // Store the actual reference
        ref = *(void**)ref;
        typeId &= ~asTYPEID_OBJHANDLE;
    }

    // Get the object type
    asIScriptContext* ctx = asGetActiveContext();
    asIScriptEngine* engine = ctx->GetEngine();
    asITypeInfo* type = engine->GetTypeInfoById(typeId);

    // If the argument is another CScriptHandle, we should copy the content instead
    if (type && strcmp(type->GetName(), "ref") == 0) {
        CScriptHandle* r = (CScriptHandle*)ref;
        ref = r->m_ref;
        type = r->m_type;
    }

    Set(ref, type);

    return *this;
}

bool CScriptHandle::operator==(const CScriptHandle& o) const {
    if (m_ref == o.m_ref && m_type == o.m_type)
        return true;

    // TODO: If type is not the same, we should attempt to do a dynamic cast,
    //       which may change the pointer for application registered classes

    return false;
}

bool CScriptHandle::operator!=(const CScriptHandle& o) const { return !(*this == o); }

bool CScriptHandle::Equals(void* ref, int typeId) const {
    // Null handles are received as reference to a null handle
    if (typeId == 0)
        ref = 0;

    // Dereference handles to get the object
    if (typeId & asTYPEID_OBJHANDLE) {
        // Compare the actual reference
        ref = *(void**)ref;
        typeId &= ~asTYPEID_OBJHANDLE;
    }

    // TODO: If typeId is not the same, we should attempt to do a dynamic cast,
    //       which may change the pointer for application registered classes

    if (ref == m_ref)
        return true;

    return false;
}

// AngelScript: used as '@obj = cast<obj>(ref);'
void CScriptHandle::Cast(void** outRef, int typeId) {
    // If we hold a null handle, then just return null
    if (m_type == 0) {
        *outRef = 0;
        return;
    }

    // It is expected that the outRef is always a handle
    assert(typeId & asTYPEID_OBJHANDLE);

    // Compare the type id of the actual object
    typeId &= ~asTYPEID_OBJHANDLE;
    asIScriptEngine* engine = m_type->GetEngine();
    asITypeInfo* type = engine->GetTypeInfoById(typeId);

    *outRef = 0;

    // RefCastObject will increment the refCount of the returned object if successful
    engine->RefCastObject(m_ref, m_type, type, outRef);
}

void CScriptHandle::EnumReferences(asIScriptEngine* inEngine) {
    // If we're holding a reference, we'll notify the garbage collector of it
    if (m_ref)
        inEngine->GCEnumCallback(m_ref);

    // The object type itself is also garbage collected
    if (m_type)
        inEngine->GCEnumCallback(m_type);
}

void CScriptHandle::ReleaseReferences(asIScriptEngine*) {
    // Simply clear the content to release the references
    Set(0, 0);
}

void RegisterScriptHandle_Native(asIScriptEngine* engine) {
    [[maybe_unused]] int r;

#if AS_CAN_USE_CPP11
    // With C++11 it is possible to use asGetTypeTraits to automatically determine the flags that represent the C++
    // class
    r = engine->RegisterObjectType("ref", sizeof(CScriptHandle),
                                   asOBJ_VALUE | asOBJ_ASHANDLE | asOBJ_GC | asGetTypeTraits<CScriptHandle>());
    assert(r >= 0);
#else
    r = engine->RegisterObjectType("ref", sizeof(CScriptHandle),
                                   asOBJ_VALUE | asOBJ_ASHANDLE | asOBJ_GC | asOBJ_APP_CLASS_CDAK);
    assert(r >= 0);
#endif
    r = engine->RegisterObjectBehaviour("ref", asBEHAVE_CONSTRUCT, "void f()",
                                        asFUNCTIONPR(Construct, (CScriptHandle*), void), asCALL_CDECL_OBJFIRST);
    assert(r >= 0);
    r = engine->RegisterObjectBehaviour("ref", asBEHAVE_CONSTRUCT, "void f(const ref &in)",
                                        asFUNCTIONPR(Construct, (CScriptHandle*, const CScriptHandle&), void),
                                        asCALL_CDECL_OBJFIRST);
    assert(r >= 0);
    r = engine->RegisterObjectBehaviour("ref", asBEHAVE_CONSTRUCT, "void f(const ?&in)",
                                        asFUNCTIONPR(Construct, (CScriptHandle*, void*, int), void),
                                        asCALL_CDECL_OBJFIRST);
    assert(r >= 0);
    r = engine->RegisterObjectBehaviour("ref", asBEHAVE_DESTRUCT, "void f()",
                                        asFUNCTIONPR(Destruct, (CScriptHandle*), void), asCALL_CDECL_OBJFIRST);
    assert(r >= 0);
    r = engine->RegisterObjectBehaviour("ref", asBEHAVE_ENUMREFS, "void f(int&in)",
                                        asMETHOD(CScriptHandle, EnumReferences), asCALL_THISCALL);
    assert(r >= 0);
    r = engine->RegisterObjectBehaviour("ref", asBEHAVE_RELEASEREFS, "void f(int&in)",
                                        asMETHOD(CScriptHandle, ReleaseReferences), asCALL_THISCALL);
    assert(r >= 0);
    r = engine->RegisterObjectMethod("ref", "void opCast(?&out)", asMETHODPR(CScriptHandle, Cast, (void**, int), void),
                                     asCALL_THISCALL);
    assert(r >= 0);
    r = engine->RegisterObjectMethod("ref", "ref &opHndlAssign(const ref &in)", asMETHOD(CScriptHandle, operator=),
                                     asCALL_THISCALL);
    assert(r >= 0);
    r = engine->RegisterObjectMethod("ref", "ref &opHndlAssign(const ?&in)", asMETHOD(CScriptHandle, Assign),
                                     asCALL_THISCALL);
    assert(r >= 0);
    r = engine->RegisterObjectMethod("ref", "bool opEquals(const ref &in) const",
                                     asMETHODPR(CScriptHandle, operator==,(const CScriptHandle&) const, bool),
                                     asCALL_THISCALL);
    assert(r >= 0);
    r = engine->RegisterObjectMethod("ref", "bool opEquals(const ?&in) const",
                                     asMETHODPR(CScriptHandle, Equals, (void*, int)const, bool), asCALL_THISCALL);
    assert(r >= 0);
}

void CScriptHandle_Construct_Generic(asIScriptGeneric* gen) {
    CScriptHandle* self = reinterpret_cast<CScriptHandle*>(gen->GetObject());
    new (self) CScriptHandle();
}

void CScriptHandle_ConstructCopy_Generic(asIScriptGeneric* gen) {
    CScriptHandle* other = reinterpret_cast<CScriptHandle*>(gen->GetArgAddress(0));
    CScriptHandle* self = reinterpret_cast<CScriptHandle*>(gen->GetObject());
    new (self) CScriptHandle(*other);
}

void CScriptHandle_ConstructVar_Generic(asIScriptGeneric* gen) {
    void* ref = gen->GetArgAddress(0);
    int typeId = gen->GetArgTypeId(0);
    CScriptHandle* self = reinterpret_cast<CScriptHandle*>(gen->GetObject());
    Construct(self, ref, typeId);
}

void CScriptHandle_Destruct_Generic(asIScriptGeneric* gen) {
    CScriptHandle* self = reinterpret_cast<CScriptHandle*>(gen->GetObject());
    self->~CScriptHandle();
}

void CScriptHandle_Cast_Generic(asIScriptGeneric* gen) {
    void** ref = reinterpret_cast<void**>(gen->GetArgAddress(0));
    int typeId = gen->GetArgTypeId(0);
    CScriptHandle* self = reinterpret_cast<CScriptHandle*>(gen->GetObject());
    self->Cast(ref, typeId);
}

void CScriptHandle_Assign_Generic(asIScriptGeneric* gen) {
    CScriptHandle* other = reinterpret_cast<CScriptHandle*>(gen->GetArgAddress(0));
    CScriptHandle* self = reinterpret_cast<CScriptHandle*>(gen->GetObject());
    *self = *other;
    gen->SetReturnAddress(self);
}

void CScriptHandle_AssignVar_Generic(asIScriptGeneric* gen) {
    void* ref = gen->GetArgAddress(0);
    int typeId = gen->GetArgTypeId(0);
    CScriptHandle* self = reinterpret_cast<CScriptHandle*>(gen->GetObject());
    self->Assign(ref, typeId);
    gen->SetReturnAddress(self);
}

void CScriptHandle_Equals_Generic(asIScriptGeneric* gen) {
    CScriptHandle* other = reinterpret_cast<CScriptHandle*>(gen->GetArgAddress(0));
    CScriptHandle* self = reinterpret_cast<CScriptHandle*>(gen->GetObject());
    gen->SetReturnByte(*self == *other);
}

void CScriptHandle_EqualsVar_Generic(asIScriptGeneric* gen) {
    void* ref = gen->GetArgAddress(0);
    int typeId = gen->GetArgTypeId(0);
    CScriptHandle* self = reinterpret_cast<CScriptHandle*>(gen->GetObject());
    gen->SetReturnByte(self->Equals(ref, typeId));
}

void CScriptHandle_EnumReferences_Generic(asIScriptGeneric* gen) {
    CScriptHandle* self = reinterpret_cast<CScriptHandle*>(gen->GetObject());
    self->EnumReferences(gen->GetEngine());
}

void CScriptHandle_ReleaseReferences_Generic(asIScriptGeneric* gen) {
    CScriptHandle* self = reinterpret_cast<CScriptHandle*>(gen->GetObject());
    self->ReleaseReferences(gen->GetEngine());
}

void RegisterScriptHandle_Generic(asIScriptEngine* engine) {
    [[maybe_unused]] int r;

    r = engine->RegisterObjectType("ref", sizeof(CScriptHandle),
                                   asOBJ_VALUE | asOBJ_ASHANDLE | asOBJ_GC | asOBJ_APP_CLASS_CDAK);
    assert(r >= 0);
    r = engine->RegisterObjectBehaviour("ref", asBEHAVE_CONSTRUCT, "void f()",
                                        asFUNCTION(CScriptHandle_Construct_Generic), asCALL_GENERIC);
    assert(r >= 0);
    r = engine->RegisterObjectBehaviour("ref", asBEHAVE_CONSTRUCT, "void f(const ref &in)",
                                        asFUNCTION(CScriptHandle_ConstructCopy_Generic), asCALL_GENERIC);
    assert(r >= 0);
    r = engine->RegisterObjectBehaviour("ref", asBEHAVE_CONSTRUCT, "void f(const ?&in)",
                                        asFUNCTION(CScriptHandle_ConstructVar_Generic), asCALL_GENERIC);
    assert(r >= 0);
    r = engine->RegisterObjectBehaviour("ref", asBEHAVE_DESTRUCT, "void f()",
                                        asFUNCTION(CScriptHandle_Destruct_Generic), asCALL_GENERIC);
    assert(r >= 0);
    r = engine->RegisterObjectBehaviour("ref", asBEHAVE_ENUMREFS, "void f(int&in)",
                                        asFUNCTION(CScriptHandle_EnumReferences_Generic), asCALL_GENERIC);
    assert(r >= 0);
    r = engine->RegisterObjectBehaviour("ref", asBEHAVE_RELEASEREFS, "void f(int&in)",
                                        asFUNCTION(CScriptHandle_ReleaseReferences_Generic), asCALL_GENERIC);
    assert(r >= 0);
    r = engine->RegisterObjectMethod("ref", "void opCast(?&out)", asFUNCTION(CScriptHandle_Cast_Generic),
                                     asCALL_GENERIC);
    assert(r >= 0);
    r = engine->RegisterObjectMethod("ref", "ref &opHndlAssign(const ref &in)",
                                     asFUNCTION(CScriptHandle_Assign_Generic), asCALL_GENERIC);
    assert(r >= 0);
    r = engine->RegisterObjectMethod("ref", "ref &opHndlAssign(const ?&in)",
                                     asFUNCTION(CScriptHandle_AssignVar_Generic), asCALL_GENERIC);
    assert(r >= 0);
    r = engine->RegisterObjectMethod("ref", "bool opEquals(const ref &in) const",
                                     asFUNCTION(CScriptHandle_Equals_Generic), asCALL_GENERIC);
    assert(r >= 0);
    r = engine->RegisterObjectMethod("ref", "bool opEquals(const ?&in) const",
                                     asFUNCTION(CScriptHandle_EqualsVar_Generic), asCALL_GENERIC);
    assert(r >= 0);
}

void RegisterScriptHandle(asIScriptEngine* engine) {
    if (strstr(asGetLibraryOptions(), "AS_MAX_PORTABILITY"))
        RegisterScriptHandle_Generic(engine);
    else
        RegisterScriptHandle_Native(engine);
}

END_AS_NAMESPACE