#include "Components/MeshRendererComponent.h"

#include "Core/Asset/ResourceManager.h"

#include <sstream>

namespace XCEngine {
namespace Components {

namespace {

std::string ToStdString(const Containers::String& value) {
    return std::string(value.CStr());
}

std::vector<std::string> SplitMaterialPaths(const std::string& value) {
    std::vector<std::string> paths;
    std::stringstream stream(value);
    std::string item;
    while (std::getline(stream, item, '|')) {
        paths.push_back(item);
    }

    if (value.empty()) {
        paths.clear();
    }

    return paths;
}

} // namespace

Resources::Material* MeshRendererComponent::GetMaterial(size_t index) const {
    return index < m_materials.size() ? m_materials[index].Get() : nullptr;
}

const Resources::ResourceHandle<Resources::Material>& MeshRendererComponent::GetMaterialHandle(size_t index) const {
    static const Resources::ResourceHandle<Resources::Material> kNullHandle;
    return index < m_materials.size() ? m_materials[index] : kNullHandle;
}

void MeshRendererComponent::SetMaterial(size_t index, const Resources::ResourceHandle<Resources::Material>& material) {
    EnsureMaterialSlot(index);
    m_materials[index] = material;
    m_materialPaths[index] = MaterialPathFromHandle(material);
}

void MeshRendererComponent::SetMaterial(size_t index, Resources::Material* material) {
    SetMaterial(index, Resources::ResourceHandle<Resources::Material>(material));
}

void MeshRendererComponent::SetMaterials(const std::vector<Resources::ResourceHandle<Resources::Material>>& materials) {
    m_materials = materials;
    m_materialPaths.resize(materials.size());
    for (size_t i = 0; i < materials.size(); ++i) {
        m_materialPaths[i] = MaterialPathFromHandle(materials[i]);
    }
}

void MeshRendererComponent::ClearMaterials() {
    m_materials.clear();
    m_materialPaths.clear();
}

void MeshRendererComponent::Serialize(std::ostream& os) const {
    os << "materials=";
    for (size_t i = 0; i < m_materialPaths.size(); ++i) {
        if (i > 0) {
            os << "|";
        }
        os << m_materialPaths[i];
    }
    os << ";";
    os << "castShadows=" << (m_castShadows ? 1 : 0) << ";";
    os << "receiveShadows=" << (m_receiveShadows ? 1 : 0) << ";";
    os << "renderLayer=" << m_renderLayer << ";";
}

void MeshRendererComponent::Deserialize(std::istream& is) {
    ClearMaterials();
    m_castShadows = true;
    m_receiveShadows = true;
    m_renderLayer = 0;

    std::string token;
    while (std::getline(is, token, ';')) {
        if (token.empty()) {
            continue;
        }

        const size_t eqPos = token.find('=');
        if (eqPos == std::string::npos) {
            continue;
        }

        const std::string key = token.substr(0, eqPos);
        const std::string value = token.substr(eqPos + 1);

        if (key == "materials") {
            m_materialPaths = SplitMaterialPaths(value);
            m_materials.resize(m_materialPaths.size());
            for (size_t i = 0; i < m_materialPaths.size(); ++i) {
                if (!m_materialPaths[i].empty()) {
                    m_materials[i] = Resources::ResourceManager::Get().Load<Resources::Material>(m_materialPaths[i].c_str());
                }
            }
        } else if (key == "castShadows") {
            m_castShadows = (std::stoi(value) != 0);
        } else if (key == "receiveShadows") {
            m_receiveShadows = (std::stoi(value) != 0);
        } else if (key == "renderLayer") {
            m_renderLayer = static_cast<uint32_t>(std::stoul(value));
        }
    }
}

void MeshRendererComponent::EnsureMaterialSlot(size_t index) {
    if (index >= m_materials.size()) {
        m_materials.resize(index + 1);
        m_materialPaths.resize(index + 1);
    }
}

std::string MeshRendererComponent::MaterialPathFromHandle(const Resources::ResourceHandle<Resources::Material>& material) {
    return material.Get() != nullptr ? ToStdString(material->GetPath()) : std::string();
}

} // namespace Components
} // namespace XCEngine