/*
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated
 * documentation files (the “Software”), to deal in the Software without restriction, including without
 * limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
 * of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT
 * LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 * Copyright © 2020 Charles Giessen (charles@lunarg.com)
 */

#pragma once

#include <cassert>
#include <cstdio>
#include <cstring>

#include <vector>
#include <string>
#include <system_error>

#include <vulkan/vulkan_core.h>

#include "VkBootstrapDispatch.h"

#ifdef VK_MAKE_API_VERSION
#define VKB_MAKE_VK_VERSION(variant, major, minor, patch) VK_MAKE_API_VERSION(variant, major, minor, patch)
#elif defined(VK_MAKE_VERSION)
#define VKB_MAKE_VK_VERSION(variant, major, minor, patch) VK_MAKE_VERSION(major, minor, patch)
#endif

#if defined(VK_API_VERSION_1_3) || defined(VK_VERSION_1_3)
#define VKB_VK_API_VERSION_1_3 VKB_MAKE_VK_VERSION(0, 1, 3, 0)
#endif

#if defined(VK_API_VERSION_1_2) || defined(VK_VERSION_1_2)
#define VKB_VK_API_VERSION_1_2 VKB_MAKE_VK_VERSION(0, 1, 2, 0)
#endif

#if defined(VK_API_VERSION_1_1) || defined(VK_VERSION_1_1)
#define VKB_VK_API_VERSION_1_1 VKB_MAKE_VK_VERSION(0, 1, 1, 0)
#endif

#if defined(VK_API_VERSION_1_0) || defined(VK_VERSION_1_0)
#define VKB_VK_API_VERSION_1_0 VKB_MAKE_VK_VERSION(0, 1, 0, 0)
#endif

namespace vkb {

    struct Error {
        std::error_code type;
        VkResult vk_result = VK_SUCCESS; // optional error value if a vulkan call failed
    };

    template <typename T> class Result {
    public:
        Result(const T& value) noexcept : m_value{ value }, m_init{ true } {}
        Result(T&& value) noexcept : m_value{ std::move(value) }, m_init{ true } {}

        Result(Error error) noexcept : m_error{ error }, m_init{ false } {}

        Result(std::error_code error_code, VkResult result = VK_SUCCESS) noexcept
            : m_error{ error_code, result }, m_init{ false } {
        }

        ~Result() noexcept { destroy(); }
        Result(Result const& expected) noexcept : m_init(expected.m_init) {
            if (m_init)
                new (&m_value) T{ expected.m_value };
            else
                m_error = expected.m_error;
        }
        Result& operator=(Result const& result) noexcept {
            m_init = result.m_init;
            if (m_init)
                new (&m_value) T{ result.m_value };
            else
                m_error = result.m_error;
            return *this;
        }
        Result(Result&& expected) noexcept : m_init(expected.m_init) {
            if (m_init)
                new (&m_value) T{ std::move(expected.m_value) };
            else
                m_error = std::move(expected.m_error);
            expected.destroy();
        }
        Result& operator=(Result&& result) noexcept {
            m_init = result.m_init;
            if (m_init)
                new (&m_value) T{ std::move(result.m_value) };
            else
                m_error = std::move(result.m_error);
            return *this;
        }
        Result& operator=(const T& expect) noexcept {
            destroy();
            m_init = true;
            new (&m_value) T{ expect };
            return *this;
        }
        Result& operator=(T&& expect) noexcept {
            destroy();
            m_init = true;
            new (&m_value) T{ std::move(expect) };
            return *this;
        }
        Result& operator=(const Error& error) noexcept {
            destroy();
            m_init = false;
            m_error = error;
            return *this;
        }
        Result& operator=(Error&& error) noexcept {
            destroy();
            m_init = false;
            m_error = error;
            return *this;
        }
        // clang-format off
        const T* operator-> () const noexcept { assert(m_init); return &m_value; }
        T*       operator-> ()       noexcept { assert(m_init); return &m_value; }
        const T& operator* () const& noexcept { assert(m_init);	return m_value; }
        T&       operator* () & noexcept { assert(m_init); return m_value; }
        T        operator* () && noexcept { assert(m_init); return std::move(m_value); }
        const T&  value() const&    noexcept { assert(m_init); return m_value; }
        T&        value() & noexcept { assert(m_init); return m_value; }
        T         value() && noexcept { assert(m_init); return std::move(m_value); }

        // std::error_code associated with the error
        std::error_code error() const { assert(!m_init); return m_error.type; }
        // optional VkResult that could of been produced due to the error
        VkResult vk_result() const { assert(!m_init); return m_error.vk_result; }
        // Returns the struct that holds the std::error_code and VkResult
        Error full_error() const { assert(!m_init); return m_error; }
        // clang-format on

        // check if the result has an error that matches a specific error case
        template <typename E> bool matches_error(E error_enum_value) const {
            return !m_init && static_cast<E>(m_error.type.value()) == error_enum_value;
        }

        bool has_value() const { return m_init; }
        explicit operator bool() const { return m_init; }

    private:
        void destroy() {
            if (m_init) m_value.~T();
        }
        union {
            T m_value;
            Error m_error;
        };
        bool m_init;
    };

    namespace detail {
        struct GenericFeaturesPNextNode {

            static const uint32_t field_capacity = 256;

            GenericFeaturesPNextNode();

            template <typename T> GenericFeaturesPNextNode(T const& features) noexcept {
                memset(fields, UINT8_MAX, sizeof(VkBool32) * field_capacity);
                memcpy(this, &features, sizeof(T));
            }

            static bool match(GenericFeaturesPNextNode const& requested, GenericFeaturesPNextNode const& supported) noexcept;

            void combine(GenericFeaturesPNextNode const& right) noexcept;

            VkStructureType sType = static_cast<VkStructureType>(0);
            void* pNext = nullptr;
            VkBool32 fields[field_capacity];
        };

        struct GenericFeatureChain {
            std::vector<GenericFeaturesPNextNode> nodes;

            template <typename T> void add(T const& features) noexcept {
                // If this struct is already in the list, combine it
                for (auto& node : nodes) {
                    if (static_cast<VkStructureType>(features.sType) == node.sType) {
                        node.combine(features);
                        return;
                    }
                }
                // Otherwise append to the end
                nodes.push_back(features);
            }

            bool match_all(GenericFeatureChain const& extension_requested) const noexcept;
            bool find_and_match(GenericFeatureChain const& extension_requested) const noexcept;

            void chain_up(VkPhysicalDeviceFeatures2& feats2) noexcept;

            void combine(GenericFeatureChain const& right) noexcept;
        };

    } // namespace detail

    enum class InstanceError {
        vulkan_unavailable,
        vulkan_version_unavailable,
        vulkan_version_1_1_unavailable,
        vulkan_version_1_2_unavailable,
        failed_create_instance,
        failed_create_debug_messenger,
        requested_layers_not_present,
        requested_extensions_not_present,
        windowing_extensions_not_present,
    };
    enum class PhysicalDeviceError {
        no_surface_provided,
        failed_enumerate_physical_devices,
        no_physical_devices_found,
        no_suitable_device,
    };
    enum class QueueError {
        present_unavailable,
        graphics_unavailable,
        compute_unavailable,
        transfer_unavailable,
        queue_index_out_of_range,
        invalid_queue_family_index
    };
    enum class DeviceError {
        failed_create_device,
        VkPhysicalDeviceFeatures2_in_pNext_chain_while_using_add_required_extension_features,
    };
    enum class SwapchainError {
        surface_handle_not_provided,
        failed_query_surface_support_details,
        failed_create_swapchain,
        failed_get_swapchain_images,
        failed_create_swapchain_image_views,
        required_min_image_count_too_low,
        required_usage_not_supported
    };

    std::error_code make_error_code(InstanceError instance_error);
    std::error_code make_error_code(PhysicalDeviceError physical_device_error);
    std::error_code make_error_code(QueueError queue_error);
    std::error_code make_error_code(DeviceError device_error);
    std::error_code make_error_code(SwapchainError swapchain_error);

    const char* to_string_message_severity(VkDebugUtilsMessageSeverityFlagBitsEXT s);
    const char* to_string_message_type(VkDebugUtilsMessageTypeFlagsEXT s);

    const char* to_string(InstanceError err);
    const char* to_string(PhysicalDeviceError err);
    const char* to_string(QueueError err);
    const char* to_string(DeviceError err);
    const char* to_string(SwapchainError err);

    // Gathers useful information about the available vulkan capabilities, like layers and instance
    // extensions. Use this for enabling features conditionally, ie if you would like an extension but
    // can use a fallback if it isn't supported but need to know if support is available first.
    struct SystemInfo {
    private:
        SystemInfo();

    public:
        // Use get_system_info to create a SystemInfo struct. This is because loading vulkan could fail.
        static Result<SystemInfo> get_system_info();
        static Result<SystemInfo> get_system_info(PFN_vkGetInstanceProcAddr fp_vkGetInstanceProcAddr);

        // Returns true if a layer is available
        bool is_layer_available(const char* layer_name) const;
        // Returns true if an extension is available
        bool is_extension_available(const char* extension_name) const;

        std::vector<VkLayerProperties> available_layers;
        std::vector<VkExtensionProperties> available_extensions;
        bool validation_layers_available = false;
        bool debug_utils_available = false;
    };

    // Forward declared - check VkBoostrap.cpp for implementations
    const char* to_string_message_severity(VkDebugUtilsMessageSeverityFlagBitsEXT s);
    const char* to_string_message_type(VkDebugUtilsMessageTypeFlagsEXT s);

    // Default debug messenger
    // Feel free to copy-paste it into your own code, change it as needed, then call `set_debug_callback()` to use that instead
    inline VKAPI_ATTR VkBool32 VKAPI_CALL default_debug_callback(VkDebugUtilsMessageSeverityFlagBitsEXT messageSeverity,
        VkDebugUtilsMessageTypeFlagsEXT messageType,
        const VkDebugUtilsMessengerCallbackDataEXT* pCallbackData,
        void*) {
        auto ms = to_string_message_severity(messageSeverity);
        auto mt = to_string_message_type(messageType);
        printf("[%s: %s]\n%s\n", ms, mt, pCallbackData->pMessage);

        return VK_FALSE; // Applications must return false here
    }

    class InstanceBuilder;
    class PhysicalDeviceSelector;

    struct Instance {
        VkInstance instance = VK_NULL_HANDLE;
        VkDebugUtilsMessengerEXT debug_messenger = VK_NULL_HANDLE;
        VkAllocationCallbacks* allocation_callbacks = VK_NULL_HANDLE;
        PFN_vkGetInstanceProcAddr fp_vkGetInstanceProcAddr = nullptr;
        PFN_vkGetDeviceProcAddr fp_vkGetDeviceProcAddr = nullptr;

        // A conversion function which allows this Instance to be used
        // in places where VkInstance would have been used.
        operator VkInstance() const;

        // Return a loaded instance dispatch table
        InstanceDispatchTable make_table() const;

    private:
        bool headless = false;
        bool properties2_ext_enabled = false;
        uint32_t instance_version = VKB_VK_API_VERSION_1_0;
        uint32_t api_version = VKB_VK_API_VERSION_1_0;

        friend class InstanceBuilder;
        friend class PhysicalDeviceSelector;
    };

    void destroy_surface(Instance const& instance, VkSurfaceKHR surface); // release surface handle
    void destroy_surface(VkInstance instance, VkSurfaceKHR surface, VkAllocationCallbacks* callbacks = nullptr); // release surface handle
    void destroy_instance(Instance const& instance); // release instance resources

    /* If headless mode is false, by default vk-bootstrap use the following logic to enable the windowing extensions

    #if defined(_WIN32)
        VK_KHR_win32_surface
    #elif defined(__linux__)
        VK_KHR_xcb_surface
        VK_KHR_xlib_surface
        VK_KHR_wayland_surface
    #elif defined(__APPLE__)
        VK_EXT_metal_surface
    #elif defined(__ANDROID__)
        VK_KHR_android_surface
    #elif defined(_DIRECT2DISPLAY)
        VK_KHR_display
    #endif

    Use `InstanceBuilder::enable_extension()` to add new extensions without altering the default behavior
    Feel free to make a PR or raise an issue to include additional platforms.
    */

    class InstanceBuilder {
    public:
        // Default constructor, will load vulkan.
        explicit InstanceBuilder();
        // Optional: Can use your own PFN_vkGetInstanceProcAddr
        explicit InstanceBuilder(PFN_vkGetInstanceProcAddr fp_vkGetInstanceProcAddr);

        // Create a VkInstance. Return an error if it failed.
        Result<Instance> build() const;

        // Sets the name of the application. Defaults to "" if none is provided.
        InstanceBuilder& set_app_name(const char* app_name);
        // Sets the name of the engine. Defaults to "" if none is provided.
        InstanceBuilder& set_engine_name(const char* engine_name);

        // Sets the version of the application.
        // Should be constructed with VK_MAKE_VERSION or VK_MAKE_API_VERSION.
        InstanceBuilder& set_app_version(uint32_t app_version);
        // Sets the (major, minor, patch) version of the application.
        InstanceBuilder& set_app_version(uint32_t major, uint32_t minor, uint32_t patch = 0);

        // Sets the version of the engine.
        // Should be constructed with VK_MAKE_VERSION or VK_MAKE_API_VERSION.
        InstanceBuilder& set_engine_version(uint32_t engine_version);
        // Sets the (major, minor, patch) version of the engine.
        InstanceBuilder& set_engine_version(uint32_t major, uint32_t minor, uint32_t patch = 0);

        // Require a vulkan API version. Will fail to create if this version isn't available.
        // Should be constructed with VK_MAKE_VERSION or VK_MAKE_API_VERSION.
        InstanceBuilder& require_api_version(uint32_t required_api_version);
        // Require a vulkan API version. Will fail to create if this version isn't available.
        InstanceBuilder& require_api_version(uint32_t major, uint32_t minor, uint32_t patch = 0);

        // Overrides required API version for instance creation. Will fail to create if this version isn't available.
        // Should be constructed with VK_MAKE_VERSION or VK_MAKE_API_VERSION.
        InstanceBuilder& set_minimum_instance_version(uint32_t minimum_instance_version);
        // Overrides required API version for instance creation. Will fail to create if this version isn't available.
        InstanceBuilder& set_minimum_instance_version(uint32_t major, uint32_t minor, uint32_t patch = 0);

        // Prefer a vulkan instance API version. If the desired version isn't available, it will use the
        // highest version available. Should be constructed with VK_MAKE_VERSION or VK_MAKE_API_VERSION.
        [[deprecated("Use require_api_version + set_minimum_instance_version instead.")]] InstanceBuilder&
            desire_api_version(uint32_t preferred_vulkan_version);

        // Prefer a vulkan instance API version. If the desired version isn't available, it will use the highest version available.
        [[deprecated("Use require_api_version + set_minimum_instance_version instead.")]] InstanceBuilder&
            desire_api_version(uint32_t major, uint32_t minor, uint32_t patch = 0);

        // Adds a layer to be enabled. Will fail to create an instance if the layer isn't available.
        InstanceBuilder& enable_layer(const char* layer_name);
        // Adds an extension to be enabled. Will fail to create an instance if the extension isn't available.
        InstanceBuilder& enable_extension(const char* extension_name);
        InstanceBuilder& enable_extensions(std::vector<const char*> const& extensions);
        InstanceBuilder& enable_extensions(size_t count, const char* const* extensions);

        // Headless Mode does not load the required extensions for presentation. Defaults to true.
        InstanceBuilder& set_headless(bool headless = true);

        // Enables the validation layers. Will fail to create an instance if the validation layers aren't available.
        InstanceBuilder& enable_validation_layers(bool require_validation = true);
        // Checks if the validation layers are available and loads them if they are.
        InstanceBuilder& request_validation_layers(bool enable_validation = true);

        // Use a default debug callback that prints to standard out.
        InstanceBuilder& use_default_debug_messenger();
        // Provide a user defined debug callback.
        InstanceBuilder& set_debug_callback(PFN_vkDebugUtilsMessengerCallbackEXT callback);
        // Sets the void* to use in the debug messenger - only useful with a custom callback
        InstanceBuilder& set_debug_callback_user_data_pointer(void* user_data_pointer);
        // Set what message severity is needed to trigger the callback.
        InstanceBuilder& set_debug_messenger_severity(VkDebugUtilsMessageSeverityFlagsEXT severity);
        // Add a message severity to the list that triggers the callback.
        InstanceBuilder& add_debug_messenger_severity(VkDebugUtilsMessageSeverityFlagsEXT severity);
        // Set what message type triggers the callback.
        InstanceBuilder& set_debug_messenger_type(VkDebugUtilsMessageTypeFlagsEXT type);
        // Add a message type to the list of that triggers the callback.
        InstanceBuilder& add_debug_messenger_type(VkDebugUtilsMessageTypeFlagsEXT type);

        // Disable some validation checks.
        // Checks: All, and Shaders
        InstanceBuilder& add_validation_disable(VkValidationCheckEXT check);

        // Enables optional parts of the validation layers.
        // Parts: best practices, gpu assisted, and gpu assisted reserve binding slot.
        InstanceBuilder& add_validation_feature_enable(VkValidationFeatureEnableEXT enable);

        // Disables sections of the validation layers.
        // Options: All, shaders, thread safety, api parameters, object lifetimes, core checks, and unique handles.
        InstanceBuilder& add_validation_feature_disable(VkValidationFeatureDisableEXT disable);

        // Provide custom allocation callbacks.
        InstanceBuilder& set_allocation_callbacks(VkAllocationCallbacks* callbacks);

    private:
        struct InstanceInfo {
            // VkApplicationInfo
            const char* app_name = nullptr;
            const char* engine_name = nullptr;
            uint32_t application_version = 0;
            uint32_t engine_version = 0;
            uint32_t minimum_instance_version = 0;
            uint32_t required_api_version = VKB_VK_API_VERSION_1_0;
            uint32_t desired_api_version = VKB_VK_API_VERSION_1_0;

            // VkInstanceCreateInfo
            std::vector<const char*> layers;
            std::vector<const char*> extensions;
            VkInstanceCreateFlags flags = static_cast<VkInstanceCreateFlags>(0);
            std::vector<VkBaseOutStructure*> pNext_elements;

            // debug callback - use the default so it is not nullptr
            PFN_vkDebugUtilsMessengerCallbackEXT debug_callback = default_debug_callback;
            VkDebugUtilsMessageSeverityFlagsEXT debug_message_severity =
                VK_DEBUG_UTILS_MESSAGE_SEVERITY_WARNING_BIT_EXT | VK_DEBUG_UTILS_MESSAGE_SEVERITY_ERROR_BIT_EXT;
            VkDebugUtilsMessageTypeFlagsEXT debug_message_type = VK_DEBUG_UTILS_MESSAGE_TYPE_GENERAL_BIT_EXT |
                VK_DEBUG_UTILS_MESSAGE_TYPE_VALIDATION_BIT_EXT |
                VK_DEBUG_UTILS_MESSAGE_TYPE_PERFORMANCE_BIT_EXT;
            void* debug_user_data_pointer = nullptr;

            // validation features
            std::vector<VkValidationCheckEXT> disabled_validation_checks;
            std::vector<VkValidationFeatureEnableEXT> enabled_validation_features;
            std::vector<VkValidationFeatureDisableEXT> disabled_validation_features;

            // Custom allocator
            VkAllocationCallbacks* allocation_callbacks = VK_NULL_HANDLE;

            bool request_validation_layers = false;
            bool enable_validation_layers = false;
            bool use_debug_messenger = false;
            bool headless_context = false;

            PFN_vkGetInstanceProcAddr fp_vkGetInstanceProcAddr = nullptr;
        } info;
    };

    VKAPI_ATTR VkBool32 VKAPI_CALL default_debug_callback(VkDebugUtilsMessageSeverityFlagBitsEXT messageSeverity,
        VkDebugUtilsMessageTypeFlagsEXT messageType,
        const VkDebugUtilsMessengerCallbackDataEXT* pCallbackData,
        void* pUserData);

    void destroy_debug_utils_messenger(
        VkInstance const instance, VkDebugUtilsMessengerEXT const messenger, VkAllocationCallbacks* allocation_callbacks = nullptr);

    // ---- Physical Device ---- //
    class PhysicalDeviceSelector;
    class DeviceBuilder;

    struct PhysicalDevice {
        std::string name;
        VkPhysicalDevice physical_device = VK_NULL_HANDLE;
        VkSurfaceKHR surface = VK_NULL_HANDLE;

        // Note that this reflects selected features carried over from required features, not all features the physical device supports.
        VkPhysicalDeviceFeatures features{};
        VkPhysicalDeviceProperties properties{};
        VkPhysicalDeviceMemoryProperties memory_properties{};

        // Has a queue family that supports compute operations but not graphics nor transfer.
        bool has_dedicated_compute_queue() const;
        // Has a queue family that supports transfer operations but not graphics nor compute.
        bool has_dedicated_transfer_queue() const;

        // Has a queue family that supports transfer operations but not graphics.
        bool has_separate_compute_queue() const;
        // Has a queue family that supports transfer operations but not graphics.
        bool has_separate_transfer_queue() const;

        // Advanced: Get the VkQueueFamilyProperties of the device if special queue setup is needed
        std::vector<VkQueueFamilyProperties> get_queue_families() const;

        // Query the list of extensions which should be enabled
        std::vector<std::string> get_extensions() const;

        // Query the list of extensions which the physical device supports
        std::vector<std::string> get_available_extensions() const;

        // Returns true if an extension should be enabled on the device
        bool is_extension_present(const char* extension) const;

        // Returns true if all the features are present
        template <typename T> bool are_extension_features_present(T const& features) const {
            return is_features_node_present(detail::GenericFeaturesPNextNode(features));
        }

        // If the given extension is present, make the extension be enabled on the device.
        // Returns true the extension is present.
        bool enable_extension_if_present(const char* extension);

        // If all the given extensions are present, make all the extensions be enabled on the device.
        // Returns true if all the extensions are present.
        bool enable_extensions_if_present(const std::vector<const char*>& extensions);

        // If the features from VkPhysicalDeviceFeatures are all present, make all of the features be enable on the device.
        // Returns true if all the features are present.
        bool enable_features_if_present(const VkPhysicalDeviceFeatures& features_to_enable);

        // If the features from the provided features struct are all present, make all of the features be enable on the
        // device. Returns true if all of the features are present.
        template <typename T> bool enable_extension_features_if_present(T const& features_check) {
            return enable_features_node_if_present(detail::GenericFeaturesPNextNode(features_check));
        }

        // A conversion function which allows this PhysicalDevice to be used
        // in places where VkPhysicalDevice would have been used.
        operator VkPhysicalDevice() const;

    private:
        uint32_t instance_version = VKB_VK_API_VERSION_1_0;
        std::vector<std::string> extensions_to_enable;
        std::vector<std::string> available_extensions;
        std::vector<VkQueueFamilyProperties> queue_families;
        detail::GenericFeatureChain extended_features_chain;

        bool defer_surface_initialization = false;
        bool properties2_ext_enabled = false;
        enum class Suitable { yes, partial, no };
        Suitable suitable = Suitable::yes;
        friend class PhysicalDeviceSelector;
        friend class DeviceBuilder;

        bool is_features_node_present(detail::GenericFeaturesPNextNode const& node) const;
        bool enable_features_node_if_present(detail::GenericFeaturesPNextNode const& node);
    };

    enum class PreferredDeviceType { other = 0, integrated = 1, discrete = 2, virtual_gpu = 3, cpu = 4 };

    enum class DeviceSelectionMode {
        // return all suitable and partially suitable devices
        partially_and_fully_suitable,
        // return only physical devices which are fully suitable
        only_fully_suitable
    };

    // Enumerates the physical devices on the system, and based on the added criteria, returns a physical device or list of physical devies
    // A device is considered suitable if it meets all the 'required' and 'desired' criteria.
    // A device is considered partially suitable if it meets only the 'required' criteria.
    class PhysicalDeviceSelector {
    public:
        // Requires a vkb::Instance to construct, needed to pass instance creation info.
        explicit PhysicalDeviceSelector(Instance const& instance);
        // Requires a vkb::Instance to construct, needed to pass instance creation info, optionally specify the surface here
        explicit PhysicalDeviceSelector(Instance const& instance, VkSurfaceKHR surface);

        // Return the first device which is suitable
        // use the `selection` parameter to configure if partially
        Result<PhysicalDevice> select(DeviceSelectionMode selection = DeviceSelectionMode::partially_and_fully_suitable) const;

        // Return all devices which are considered suitable - intended for applications which want to let the user pick the physical device
        Result<std::vector<PhysicalDevice>> select_devices(
            DeviceSelectionMode selection = DeviceSelectionMode::partially_and_fully_suitable) const;

        // Return the names of all devices which are considered suitable - intended for applications which want to let the user pick the physical device
        Result<std::vector<std::string>> select_device_names(
            DeviceSelectionMode selection = DeviceSelectionMode::partially_and_fully_suitable) const;

        // Set the surface in which the physical device should render to.
        // Be sure to set it if swapchain functionality is to be used.
        PhysicalDeviceSelector& set_surface(VkSurfaceKHR surface);

        // Set the name of the device to select.
        PhysicalDeviceSelector& set_name(std::string const& name);
        // Set the desired physical device type to select. Defaults to PreferredDeviceType::discrete.
        PhysicalDeviceSelector& prefer_gpu_device_type(PreferredDeviceType type = PreferredDeviceType::discrete);
        // Allow selection of a gpu device type that isn't the preferred physical device type. Defaults to true.
        PhysicalDeviceSelector& allow_any_gpu_device_type(bool allow_any_type = true);

        // Require that a physical device supports presentation. Defaults to true.
        PhysicalDeviceSelector& require_present(bool require = true);

        // Require a queue family that supports compute operations but not graphics nor transfer.
        PhysicalDeviceSelector& require_dedicated_compute_queue();
        // Require a queue family that supports transfer operations but not graphics nor compute.
        PhysicalDeviceSelector& require_dedicated_transfer_queue();

        // Require a queue family that supports compute operations but not graphics.
        PhysicalDeviceSelector& require_separate_compute_queue();
        // Require a queue family that supports transfer operations but not graphics.
        PhysicalDeviceSelector& require_separate_transfer_queue();

        // Require a memory heap from VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT with `size` memory available.
        PhysicalDeviceSelector& required_device_memory_size(VkDeviceSize size);
        // Prefer a memory heap from VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT with `size` memory available.
        [[deprecated]] PhysicalDeviceSelector& desired_device_memory_size(VkDeviceSize size);

        // Require a physical device which supports a specific extension.
        PhysicalDeviceSelector& add_required_extension(const char* extension);
        // Require a physical device which supports a set of extensions.
        PhysicalDeviceSelector& add_required_extensions(std::vector<const char*> const& extensions);
        PhysicalDeviceSelector& add_required_extensions(size_t count, const char* const* extensions);

        // Prefer a physical device which supports a specific extension.
        [[deprecated("Use vkb::PhysicalDevice::enable_extension_if_present instead")]] PhysicalDeviceSelector&
            add_desired_extension(const char* extension);
        // Prefer a physical device which supports a set of extensions.
        [[deprecated("Use vkb::PhysicalDevice::enable_extensions_if_present instead")]] PhysicalDeviceSelector&
            add_desired_extensions(const std::vector<const char*>& extensions);

        // Prefer a physical device that supports a (major, minor) version of vulkan.
        [[deprecated("Use set_minimum_version + InstanceBuilder::require_api_version.")]] PhysicalDeviceSelector&
            set_desired_version(uint32_t major, uint32_t minor);

        // Require a physical device that supports a (major, minor) version of vulkan.
        PhysicalDeviceSelector& set_minimum_version(uint32_t major, uint32_t minor);

        // By default PhysicalDeviceSelector enables the portability subset if available
        // This function disables that behavior
        PhysicalDeviceSelector& disable_portability_subset();

        // Require a physical device which supports a specific set of general/extension features.
        // If this function is used, the user should not put their own VkPhysicalDeviceFeatures2 in
        // the pNext chain of VkDeviceCreateInfo.
        template <typename T> PhysicalDeviceSelector& add_required_extension_features(T const& features) {
            criteria.extended_features_chain.add(features);
            return *this;
        }

        // Require a physical device which supports the features in VkPhysicalDeviceFeatures.
        PhysicalDeviceSelector& set_required_features(VkPhysicalDeviceFeatures const& features);
#if defined(VKB_VK_API_VERSION_1_2)
        // Require a physical device which supports the features in VkPhysicalDeviceVulkan11Features.
        // Must have vulkan version 1.2 - This is due to the VkPhysicalDeviceVulkan11Features struct being added in 1.2, not 1.1
        PhysicalDeviceSelector& set_required_features_11(VkPhysicalDeviceVulkan11Features const& features_11);
        // Require a physical device which supports the features in VkPhysicalDeviceVulkan12Features.
        // Must have vulkan version 1.2
        PhysicalDeviceSelector& set_required_features_12(VkPhysicalDeviceVulkan12Features const& features_12);
#endif
#if defined(VKB_VK_API_VERSION_1_3)
        // Require a physical device which supports the features in VkPhysicalDeviceVulkan13Features.
        // Must have vulkan version 1.3
        PhysicalDeviceSelector& set_required_features_13(VkPhysicalDeviceVulkan13Features const& features_13);
#endif

        // Used when surface creation happens after physical device selection.
        // Warning: This disables checking if the physical device supports a given surface.
        PhysicalDeviceSelector& defer_surface_initialization();

        // Ignore all criteria and choose the first physical device that is available.
        // Only use when: The first gpu in the list may be set by global user preferences and an application may wish to respect it.
        PhysicalDeviceSelector& select_first_device_unconditionally(bool unconditionally = true);

    private:
        struct InstanceInfo {
            VkInstance instance = VK_NULL_HANDLE;
            VkSurfaceKHR surface = VK_NULL_HANDLE;
            uint32_t version = VKB_VK_API_VERSION_1_0;
            bool headless = false;
            bool properties2_ext_enabled = false;
        } instance_info;

        // We copy the extension features stored in the selector criteria under the prose of a
        // "template" to ensure that after fetching everything is compared 1:1 during a match.

        struct SelectionCriteria {
            std::string name;
            PreferredDeviceType preferred_type = PreferredDeviceType::discrete;
            bool allow_any_type = true;
            bool require_present = true;
            bool require_dedicated_transfer_queue = false;
            bool require_dedicated_compute_queue = false;
            bool require_separate_transfer_queue = false;
            bool require_separate_compute_queue = false;
            VkDeviceSize required_mem_size = 0;
            VkDeviceSize desired_mem_size = 0;

            std::vector<std::string> required_extensions;
            std::vector<std::string> desired_extensions;

            uint32_t required_version = VKB_VK_API_VERSION_1_0;
            uint32_t desired_version = VKB_VK_API_VERSION_1_0;

            VkPhysicalDeviceFeatures required_features{};
            VkPhysicalDeviceFeatures2 required_features2{};

            detail::GenericFeatureChain extended_features_chain;
            bool defer_surface_initialization = false;
            bool use_first_gpu_unconditionally = false;
            bool enable_portability_subset = true;
        } criteria;

        PhysicalDevice populate_device_details(
            VkPhysicalDevice phys_device, detail::GenericFeatureChain const& src_extended_features_chain) const;

        PhysicalDevice::Suitable is_device_suitable(PhysicalDevice const& phys_device) const;

        Result<std::vector<PhysicalDevice>> select_impl(DeviceSelectionMode selection) const;
    };

    // ---- Queue ---- //
    enum class QueueType { present, graphics, compute, transfer };

    namespace detail {
        // Sentinel value, used in implementation only
        inline const uint32_t QUEUE_INDEX_MAX_VALUE = 65536;
    } // namespace detail

    // ---- Device ---- //

    struct Device {
        VkDevice device = VK_NULL_HANDLE;
        PhysicalDevice physical_device;
        VkSurfaceKHR surface = VK_NULL_HANDLE;
        std::vector<VkQueueFamilyProperties> queue_families;
        VkAllocationCallbacks* allocation_callbacks = VK_NULL_HANDLE;
        PFN_vkGetDeviceProcAddr fp_vkGetDeviceProcAddr = nullptr;
        uint32_t instance_version = VKB_VK_API_VERSION_1_0;

        Result<uint32_t> get_queue_index(QueueType type) const;
        // Only a compute or transfer queue type is valid. All other queue types do not support a 'dedicated' queue index
        Result<uint32_t> get_dedicated_queue_index(QueueType type) const;

        Result<VkQueue> get_queue(QueueType type) const;
        // Only a compute or transfer queue type is valid. All other queue types do not support a 'dedicated' queue
        Result<VkQueue> get_dedicated_queue(QueueType type) const;

        // Return a loaded dispatch table
        DispatchTable make_table() const;

        // A conversion function which allows this Device to be used
        // in places where VkDevice would have been used.
        operator VkDevice() const;

    private:
        struct {
            PFN_vkGetDeviceQueue fp_vkGetDeviceQueue = nullptr;
            PFN_vkDestroyDevice fp_vkDestroyDevice = nullptr;
        } internal_table;
        friend class DeviceBuilder;
        friend void destroy_device(Device const& device);
    };


    // For advanced device queue setup
    struct CustomQueueDescription {
        explicit CustomQueueDescription(uint32_t index, std::vector<float> priorities);
        uint32_t index = 0;
        std::vector<float> priorities;
    };

    void destroy_device(Device const& device);

    class DeviceBuilder {
    public:
        // Any features and extensions that are requested/required in PhysicalDeviceSelector are automatically enabled.
        explicit DeviceBuilder(PhysicalDevice physical_device);

        Result<Device> build() const;

        // For Advanced Users: specify the exact list of VkDeviceQueueCreateInfo's needed for the application.
        // If a custom queue setup is provided, getting the queues and queue indexes is up to the application.
        DeviceBuilder& custom_queue_setup(std::vector<CustomQueueDescription> queue_descriptions);

        // Add a structure to the pNext chain of VkDeviceCreateInfo.
        // The structure must be valid when DeviceBuilder::build() is called.
        template <typename T> DeviceBuilder& add_pNext(T* structure) {
            info.pNext_chain.push_back(reinterpret_cast<VkBaseOutStructure*>(structure));
            return *this;
        }

        // Provide custom allocation callbacks.
        DeviceBuilder& set_allocation_callbacks(VkAllocationCallbacks* callbacks);

    private:
        PhysicalDevice physical_device;
        struct DeviceInfo {
            VkDeviceCreateFlags flags = static_cast<VkDeviceCreateFlags>(0);
            std::vector<VkBaseOutStructure*> pNext_chain;
            std::vector<CustomQueueDescription> queue_descriptions;
            VkAllocationCallbacks* allocation_callbacks = VK_NULL_HANDLE;
        } info;
    };

    // ---- Swapchain ---- //
    struct Swapchain {
        VkDevice device = VK_NULL_HANDLE;
        VkSwapchainKHR swapchain = VK_NULL_HANDLE;
        uint32_t image_count = 0;
        VkFormat image_format = VK_FORMAT_UNDEFINED; // The image format actually used when creating the swapchain.
        VkColorSpaceKHR color_space = VK_COLOR_SPACE_SRGB_NONLINEAR_KHR; // The color space actually used when creating the swapchain.
        VkImageUsageFlags image_usage_flags = 0;
        VkExtent2D extent = { 0, 0 };
        // The value of minImageCount actually used when creating the swapchain; note that the presentation engine is always free to create more images than that.
        uint32_t requested_min_image_count = 0;
        VkPresentModeKHR present_mode = VK_PRESENT_MODE_IMMEDIATE_KHR; // The present mode actually used when creating the swapchain.
        uint32_t instance_version = VKB_VK_API_VERSION_1_0;
        VkAllocationCallbacks* allocation_callbacks = VK_NULL_HANDLE;

        // Returns a vector of VkImage handles to the swapchain.
        Result<std::vector<VkImage>> get_images();

        // Returns a vector of VkImageView's to the VkImage's of the swapchain.
        // VkImageViews must be destroyed.  The pNext chain must be a nullptr or a valid
        // structure.
        Result<std::vector<VkImageView>> get_image_views();
        Result<std::vector<VkImageView>> get_image_views(const void* pNext);
        void destroy_image_views(std::vector<VkImageView> const& image_views);

        // A conversion function which allows this Swapchain to be used
        // in places where VkSwapchainKHR would have been used.
        operator VkSwapchainKHR() const;

    private:
        struct {
            PFN_vkGetSwapchainImagesKHR fp_vkGetSwapchainImagesKHR = nullptr;
            PFN_vkCreateImageView fp_vkCreateImageView = nullptr;
            PFN_vkDestroyImageView fp_vkDestroyImageView = nullptr;
            PFN_vkDestroySwapchainKHR fp_vkDestroySwapchainKHR = nullptr;
        } internal_table;
        friend class SwapchainBuilder;
        friend void destroy_swapchain(Swapchain const& swapchain);
    };

    void destroy_swapchain(Swapchain const& swapchain);

    class SwapchainBuilder {
    public:
        // Construct a SwapchainBuilder with a `vkb::Device`
        explicit SwapchainBuilder(Device const& device);
        // Construct a SwapchainBuilder with a specific VkSurfaceKHR handle and `vkb::Device`
        explicit SwapchainBuilder(Device const& device, VkSurfaceKHR const surface);
        // Construct a SwapchainBuilder with Vulkan handles for the physical device, device, and surface
        // Optionally can provide the uint32_t indices for the graphics and present queue
        // Note: The constructor will query the graphics & present queue if the indices are not provided
        explicit SwapchainBuilder(VkPhysicalDevice const physical_device,
            VkDevice const device,
            VkSurfaceKHR const surface,
            uint32_t graphics_queue_index = detail::QUEUE_INDEX_MAX_VALUE,
            uint32_t present_queue_index = detail::QUEUE_INDEX_MAX_VALUE);

        Result<Swapchain> build() const;

        // Set the oldSwapchain member of VkSwapchainCreateInfoKHR.
        // For use in rebuilding a swapchain.
        SwapchainBuilder& set_old_swapchain(VkSwapchainKHR old_swapchain);
        SwapchainBuilder& set_old_swapchain(Swapchain const& swapchain);


        // Desired size of the swapchain. By default, the swapchain will use the size
        // of the window being drawn to.
        SwapchainBuilder& set_desired_extent(uint32_t width, uint32_t height);

        // When determining the surface format, make this the first to be used if supported.
        SwapchainBuilder& set_desired_format(VkSurfaceFormatKHR format);
        // Add this swapchain format to the end of the list of formats selected from.
        SwapchainBuilder& add_fallback_format(VkSurfaceFormatKHR format);
        // Use the default swapchain formats. This is done if no formats are provided.
        // Default surface format is {VK_FORMAT_B8G8R8A8_SRGB, VK_COLOR_SPACE_SRGB_NONLINEAR_KHR}
        SwapchainBuilder& use_default_format_selection();

        // When determining the present mode, make this the first to be used if supported.
        SwapchainBuilder& set_desired_present_mode(VkPresentModeKHR present_mode);
        // Add this present mode to the end of the list of present modes selected from.
        SwapchainBuilder& add_fallback_present_mode(VkPresentModeKHR present_mode);
        // Use the default presentation mode. This is done if no present modes are provided.
        // Default present modes: VK_PRESENT_MODE_MAILBOX_KHR with fallback VK_PRESENT_MODE_FIFO_KHR
        SwapchainBuilder& use_default_present_mode_selection();

        // Set the bitmask of the image usage for acquired swapchain images.
        // If the surface capabilities cannot allow it, building the swapchain will result in the `SwapchainError::required_usage_not_supported` error.
        SwapchainBuilder& set_image_usage_flags(VkImageUsageFlags usage_flags);
        // Add a image usage to the bitmask for acquired swapchain images.
        SwapchainBuilder& add_image_usage_flags(VkImageUsageFlags usage_flags);
        // Use the default image usage bitmask values. This is the default if no image usages
        // are provided. The default is VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT
        SwapchainBuilder& use_default_image_usage_flags();

        // Set the number of views in for multiview/stereo surface
        SwapchainBuilder& set_image_array_layer_count(uint32_t array_layer_count);

        // Convenient named constants for passing to set_desired_min_image_count().
        // Note that it is not an `enum class`, so its constants can be passed as an integer value without casting
        // In other words, these might as well be `static const int`, but they benefit from being grouped together this way.
        enum BufferMode {
            SINGLE_BUFFERING = 1,
            DOUBLE_BUFFERING = 2,
            TRIPLE_BUFFERING = 3,
        };

        // Sets the desired minimum image count for the swapchain.
        // Note that the presentation engine is always free to create more images than requested.
        // You may pass one of the values specified in the BufferMode enum, or any integer value.
        // For instance, if you pass DOUBLE_BUFFERING, the presentation engine is allowed to give you a double buffering setup, triple buffering, or more. This is up to the drivers.
        SwapchainBuilder& set_desired_min_image_count(uint32_t min_image_count);

        // Sets a required minimum image count for the swapchain.
        // If the surface capabilities cannot allow it, building the swapchain will result in the `SwapchainError::required_min_image_count_too_low` error.
        // Otherwise, the same observations from set_desired_min_image_count() apply.
        // A value of 0 is specially interpreted as meaning "no requirement", and is the behavior by default.
        SwapchainBuilder& set_required_min_image_count(uint32_t required_min_image_count);

        // Set whether the Vulkan implementation is allowed to discard rendering operations that
        // affect regions of the surface that are not visible. Default is true.
        // Note: Applications should use the default of true if they do not expect to read back the content
        // of presentable images before presenting them or after reacquiring them, and if their fragment
        // shaders do not have any side effects that require them to run for all pixels in the presentable image.
        SwapchainBuilder& set_clipped(bool clipped = true);

        // Set the VkSwapchainCreateFlagBitsKHR.
        SwapchainBuilder& set_create_flags(VkSwapchainCreateFlagBitsKHR create_flags);
        // Set the transform to be applied, like a 90 degree rotation. Default is no transform.
        SwapchainBuilder& set_pre_transform_flags(VkSurfaceTransformFlagBitsKHR pre_transform_flags);
        // Set the alpha channel to be used with other windows in on the system. Default is VK_COMPOSITE_ALPHA_OPAQUE_BIT_KHR.
        SwapchainBuilder& set_composite_alpha_flags(VkCompositeAlphaFlagBitsKHR composite_alpha_flags);

        // Add a structure to the pNext chain of VkSwapchainCreateInfoKHR.
        // The structure must be valid when SwapchainBuilder::build() is called.
        template <typename T> SwapchainBuilder& add_pNext(T* structure) {
            info.pNext_chain.push_back(reinterpret_cast<VkBaseOutStructure*>(structure));
            return *this;
        }

        // Provide custom allocation callbacks.
        SwapchainBuilder& set_allocation_callbacks(VkAllocationCallbacks* callbacks);

    private:
        void add_desired_formats(std::vector<VkSurfaceFormatKHR>& formats) const;
        void add_desired_present_modes(std::vector<VkPresentModeKHR>& modes) const;

        struct SwapchainInfo {
            VkPhysicalDevice physical_device = VK_NULL_HANDLE;
            VkDevice device = VK_NULL_HANDLE;
            std::vector<VkBaseOutStructure*> pNext_chain;
            VkSwapchainCreateFlagBitsKHR create_flags = static_cast<VkSwapchainCreateFlagBitsKHR>(0);
            VkSurfaceKHR surface = VK_NULL_HANDLE;
            std::vector<VkSurfaceFormatKHR> desired_formats;
            uint32_t instance_version = VKB_VK_API_VERSION_1_0;
            uint32_t desired_width = 256;
            uint32_t desired_height = 256;
            uint32_t array_layer_count = 1;
            uint32_t min_image_count = 0;
            uint32_t required_min_image_count = 0;
            VkImageUsageFlags image_usage_flags = VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT;
            uint32_t graphics_queue_index = 0;
            uint32_t present_queue_index = 0;
            VkSurfaceTransformFlagBitsKHR pre_transform = static_cast<VkSurfaceTransformFlagBitsKHR>(0);
#if defined(__ANDROID__)
            VkCompositeAlphaFlagBitsKHR composite_alpha = VK_COMPOSITE_ALPHA_INHERIT_BIT_KHR;
#else
            VkCompositeAlphaFlagBitsKHR composite_alpha = VK_COMPOSITE_ALPHA_OPAQUE_BIT_KHR;
#endif
            std::vector<VkPresentModeKHR> desired_present_modes;
            bool clipped = true;
            VkSwapchainKHR old_swapchain = VK_NULL_HANDLE;
            VkAllocationCallbacks* allocation_callbacks = VK_NULL_HANDLE;
        } info;
    };

} // namespace vkb


namespace std {
    template <> struct is_error_code_enum<vkb::InstanceError> : true_type {};
    template <> struct is_error_code_enum<vkb::PhysicalDeviceError> : true_type {};
    template <> struct is_error_code_enum<vkb::QueueError> : true_type {};
    template <> struct is_error_code_enum<vkb::DeviceError> : true_type {};
    template <> struct is_error_code_enum<vkb::SwapchainError> : true_type {};
} // namespace std