asset_library.h

#pragma once
 
#include <cstddef>
#include <cstdint>
#include <filesystem>
#include <string>
#include <unordered_map>
#include <vector>
 
#include <nlohmann/json_fwd.hpp>
 
#include "resource/asset_type.h"
 
namespace Vkm::Engine {

struct AssetRecord {
    AssetType   type = AssetType::Mesh;
    std::string name;
    uint64_t    recipeHash = 0;
    std::vector<std::string> sources;
};

class AssetLibrary {
    public:
        enum class Truth {
            Recipes,  
            Manifest  
        };
 
    public:
        ~AssetLibrary() = default;
 
        AssetLibrary(const AssetLibrary& other) = delete;
        AssetLibrary& operator=(const AssetLibrary& other) = delete;
 
        AssetLibrary(AssetLibrary && other) = delete;
        AssetLibrary& operator=(AssetLibrary && other) = delete;
 
    public:
        static AssetLibrary& get();

        void load(Truth truth);

        const AssetRecord* find(AssetType type, const std::string& name) const;

        std::vector<std::string> namesOf(AssetType type) const;

        static std::filesystem::path recipePath(AssetType type, const std::string& name);

        static std::filesystem::path cookedPath(AssetType type, const std::string& name, uint64_t recipeHash);

        static bool readRecipe(AssetType type, const std::string& name, nlohmann::json& outSource);

        [[nodiscard]] static bool writeRecipe(
            AssetType type,
            const std::string& name,
            const nlohmann::json& source
        );

        void upsert(AssetRecord record);

        void remove(AssetType type, const std::string& name);

        [[nodiscard]] bool save() const;

        size_t removeUnrecordedCooked() const;
 
    private:
        AssetLibrary() = default;
 
        static std::string key(AssetType type, const std::string& name);

        void loadManifest();

        void dropRowsWithoutRecipes();

        void adoptUnrecordedRecipes();

        static std::string uidFor(AssetType type, const std::string& name);
 
    private:
        std::unordered_map<std::string, AssetRecord> m_records;  
};
 
} // namespace Vkm::Engine