#include "Core/EntityFilePreprocessor.h"

EntityFilePreprocessor::EntityFilePreprocessor(const EntityFile* entityFile) 
    : m_EntityFile(entityFile)
{
    EntityFileHandler handler;
    handler.SetStartComponentCallback(std::bind(&EntityFilePreprocessor::onStartComponent, this, std::placeholders::_1, std::placeholders::_2));
    m_EntityFile->Parse(&handler);

    LOG_DEBUG("___ COMPONENT DEFINITIONS ___");
    for (auto& kv : m_ComponentCounts) {
        LOG_DEBUG("%s: %i", kv.first.c_str(), kv.second);
    }

    parseComponentInfo();

    for (auto& kv : m_ComponentInfo) {
        auto& info = kv.second;
        LOG_DEBUG("Component: %s (%s)", info.Name.c_str(), info.Meta.Annotation.c_str());
        LOG_DEBUG("Stride: %i", info.Meta.Stride);
        LOG_DEBUG("Allocation: %i", info.Meta.Allocation);
        for (auto& kv : info.Fields) {
            auto& field = kv.second;
            LOG_DEBUG("\t%i\t%s %s", field.Offset, field.Type, kv.first.c_str());
        }
    }

    parseDefaults();
}

void EntityFilePreprocessor::RegisterComponents(World* world)
{
    for (auto& kv : m_ComponentInfo) {
        world->RegisterComponent(kv.second);
    }
}

void EntityFilePreprocessor::onStartComponent(EntityID entity, std::string type)
{
    //LOG_DEBUG("Component: %s", type.c_str());
    m_ComponentCounts[type]++;
}

void EntityFilePreprocessor::parseComponentInfo()
{
    using namespace xercesc;
    EntityFileXMLErrorHandler errorHandler;
    auto grammarPool = m_EntityFile->GrammarPool();
    bool whateverTheFuckThisIs;
    auto xsModel = grammarPool->getXSModel(whateverTheFuckThisIs);

    // Find component xsd element declarations
    std::cout << "Enumerating components..." << std::endl;
    // <xs:element name="ComponentName">
    auto topLevelElements = xsModel->getComponents(XSConstants::ELEMENT_DECLARATION);
    for (unsigned int i = 0; i < topLevelElements->getLength(); ++i) {
        auto element = static_cast<XSElementDeclaration*>(topLevelElements->item(i));

        std::string nameSpace = XS::ToString(element->getNamespace());
        if (nameSpace != "components") {
            continue;
        }

        ComponentInfo compInfo;

        // Name
        compInfo.Name = XS::ToString(element->getName());
        // Known allocation
        compInfo.Meta.Allocation = m_ComponentCounts[compInfo.Name];
        // Annotation
        auto componentAnnotation = element->getAnnotation();
        if (componentAnnotation != nullptr) {
            // Parse annotation XML
            char* annotationString = XMLString::transcode(componentAnnotation->getAnnotationString());
            MemBufInputSource annotationInput(reinterpret_cast<const XMLByte*>(annotationString), strlen(annotationString), "MemBuf: Annotation String");
            XercesDOMParser parser(nullptr, XMLPlatformUtils::fgMemoryManager, grammarPool);
            parser.setErrorHandler(&errorHandler);
            parser.parse(annotationInput);
            XMLString::release(&annotationString);
            auto doc = parser.getDocument();

            // TODO: Add allocation estimations from external file on map-to-map basis
            // Add allocation estimation(s)
            //auto allocationTags = doc->getElementsByTagName(XSTR("meta:allocation"));
            //for (int i = 0; i < allocationTags->getLength(); ++i) {
            //    auto allocation = dynamic_cast<DOMElement*>(allocationTags->item(i));
            //    auto child = allocation->getFirstChild();
            //    if (child == nullptr) {
            //        continue;
            //    }

            //    XSValue::Status status;
            //    XSValue* val = XSValue::getActualValue(child->getNodeValue(), XSValue::dt_integer, status);
            //    compInfo.Meta.Allocation += val->fData.fValue.f_int;
            //}

            // Save documentation string
            auto documentationTags = doc->getElementsByTagName(XS::ToXMLCh("xs:documentation"));
            if (documentationTags->getLength() != 0) {
                auto child = documentationTags->item(0)->getFirstChild();
                if (child != nullptr) {
                    compInfo.Meta.Annotation = XS::ToString(child->getNodeValue());
                }
            }
        } else {
            LOG_WARNING("Component is missing an annotation!");
        }

        // <xs:complexType>
        auto typeDefinition = element->getTypeDefinition();
        if (typeDefinition->getTypeCategory() != XSTypeDefinition::COMPLEX_TYPE) {
            LOG_ERROR("Type definition wasn't COMPLEX_TYPE! Skipping.");
            continue;
        }
        auto complexTypeDefinition = dynamic_cast<XSComplexTypeDefinition*>(typeDefinition);

        // <xs:all>
        auto modelGroupParticle = complexTypeDefinition->getParticle();
        if (modelGroupParticle->getTermType() != XSParticle::TERM_MODELGROUP) {
            LOG_ERROR("Model group particle wasn't TERM_MODELGROUP! Skipping.");
            continue;
        }
        auto modelGroup = modelGroupParticle->getModelGroupTerm();

        // <xs:element... 
        // <xs:attribute...
        unsigned int fieldOffset = 0;
        auto particles = modelGroup->getParticles();
        for (unsigned int i = 0; i < particles->size(); ++i) {
            auto particle = particles->elementAt(i);
            if (particle->getTermType() != XSParticle::TERM_ELEMENT) {
                LOG_ERROR("Particle wasn't TERM_ELEMENT! Skipping.");
                continue;
            }
            auto elementDeclaration = particle->getElementTerm();

            std::string name = XS::ToString(elementDeclaration->getName());
            std::string type = XS::ToString(elementDeclaration->getTypeDefinition()->getName());

            size_t stride = EntityFile::GetTypeStride(type);
            if (stride == 0) {
                std::cout << "Warning: Field \"" << name << "\" in component \"" << compInfo.Name << "\" uses unexpected field type \"" << type << "\". Skipping." << std::endl;
                continue;
            }

            auto& field = compInfo.Fields[name];
            field.Type = type;
            field.Offset = fieldOffset;
            field.Stride = stride;
            compInfo.FieldsInOrder.push_back(&field);

            fieldOffset += stride;
        }

        compInfo.Meta.Stride = fieldOffset;
        m_ComponentInfo[compInfo.Name] = compInfo;
    }
}

void EntityFilePreprocessor::parseDefaults()
{
    using namespace xercesc;

    EntityFileXMLErrorHandler errorHandler;

    for (auto& ci : m_ComponentInfo) {
        // Allocate memory for default values
        ci.second.Defaults = std::shared_ptr<char>(new char[ci.second.Meta.Stride]);
        memset(ci.second.Defaults.get(), 0, ci.second.Meta.Stride);

        XercesDOMParser parser(nullptr, XMLPlatformUtils::fgMemoryManager);
        parser.setErrorHandler(&errorHandler);

        std::string componentName = ci.first;
        LOG_DEBUG("Parsing defaults for component %s", componentName.c_str());
        boost::filesystem::path defaultsFile = "Schema/Components/" + componentName + ".xml";

        parser.parse(defaultsFile.string().c_str());
        auto doc = parser.getDocument();
        if (doc == nullptr) {
            LOG_ERROR("%s not found! Skipping.", defaultsFile.string().c_str());
            continue;
        }

        // Find the node in the components namespace matching the component name
        std::string tagName = "c:" + componentName;
        auto rootNodes = doc->getElementsByTagName(XS::ToXMLCh(tagName));
        if (rootNodes->getLength() == 0) {
            LOG_ERROR("Couldn't find defaults for component \"%s\"! Skipping.", componentName.c_str());
            continue;
        }
        auto componentElement = dynamic_cast<DOMElement*>(rootNodes->item(0));

        // Fill the default value buffer with values
        for (auto& kv : ci.second.Fields) {
            std::string fieldName = kv.first;
            auto& field = kv.second;
            auto fieldNodes = componentElement->getElementsByTagName(XS::ToXMLCh(fieldName));
            auto fieldNode = fieldNodes->item(0);
            if (fieldNode == nullptr) {
                LOG_ERROR("Defaults for component \"%s\" is missing field \"%s\"!", componentName.c_str(), fieldName.c_str());
                continue;
            }
            auto fieldElement = dynamic_cast<DOMElement*>(fieldNode);

            char* data = ci.second.Defaults.get() + field.Offset;

            // Handle potential field attributes
            if (fieldElement->hasAttributes()) {
                std::map<std::string, std::string> attributes;
                auto attributeMap = fieldElement->getAttributes();
                for (int i = 0; i < attributeMap->getLength(); ++i) {
                    auto attribItem = attributeMap->item(i);
                    attributes[XS::ToString(attribItem->getNodeName())] = XS::ToString(attribItem->getNodeValue());
                }
                EntityFile::WriteAttributeData(data, field, attributes);
            }

            // Handle potential field values
            auto childNode = fieldElement->getFirstChild();
            if (childNode != nullptr && childNode->getNodeType() == DOMNode::TEXT_NODE) {
                char* cstrValue = XMLString::transcode(childNode->getNodeValue());
                EntityFile::WriteValueData(data, field, cstrValue);
                XMLString::release(&cstrValue);
            }
        }
    }
}