#include "vk-renderer.hpp"
#include "utils.hpp"

#define VMA_IMPLEMENTATION
#include "thirdparty/vk_mem_alloc.h"

#include <iostream>
#include <vector>
#include <cstring>

#define VKRESULT(result) assert(result == VK_SUCCESS);

VKAPI_ATTR VkBool32 VKAPI_CALL DebugCallback(VkDebugUtilsMessageSeverityFlagBitsEXT severity,
                                             VkDebugUtilsMessageTypeFlagsEXT type,
                                             const VkDebugUtilsMessengerCallbackDataEXT *data,
                                             void *userData)
{
    std::cerr << data->pMessage << std::endl;
    return VK_FALSE;
}


vkrenderer::vkrenderer() {
    load_vulkan();

    create_instance();
    create_device();
    create_pipeline();
    create_memory_allocator();
    create_command_buffer();
    create_descriptor_set();
}

void vkrenderer::compute(const input_data& inputs, size_t width, size_t height) {
    fill_descriptor_set(inputs);

    VkCommandBufferBeginInfo cmd_buf_begin_info = {};
    cmd_buf_begin_info.sType                    = VK_STRUCTURE_TYPE_COMMAND_BUFFER_BEGIN_INFO;
    cmd_buf_begin_info.pNext                    = nullptr;
    cmd_buf_begin_info.flags                    = 0;
    cmd_buf_begin_info.pInheritanceInfo         = nullptr;

    vkBeginCommandBuffer(command_buffer, &cmd_buf_begin_info);

    vkCmdBindDescriptorSets(command_buffer, VK_PIPELINE_BIND_POINT_COMPUTE, compute_pipeline_layout, 0, 1, &compute_shader_input_set, 0, nullptr);

    vkCmdBindPipeline(command_buffer, VK_PIPELINE_BIND_POINT_COMPUTE, compute_pipeline);

    vkCmdDispatch(command_buffer, width, height, 1);

    vkEndCommandBuffer(command_buffer);

    VkSubmitInfo submit_info            = {};
    submit_info.sType                   = VK_STRUCTURE_TYPE_SUBMIT_INFO;
    submit_info.pNext                   = nullptr;
    submit_info.waitSemaphoreCount      = 0;
    submit_info.pWaitSemaphores         = nullptr;
    submit_info.signalSemaphoreCount    = 0;
    submit_info.pSignalSemaphores       = nullptr;
    submit_info.commandBufferCount      = 1;
    submit_info.pCommandBuffers         = &command_buffer;

    vkQueueSubmit(compute_queue, 1, &submit_info, VK_NULL_HANDLE);

    vkDeviceWaitIdle(device);
}

const color* const vkrenderer::output_image() {
    return mapped_data->output_image;
}


void vkrenderer::create_instance() {
    VkApplicationInfo app_info   = {};
    app_info.sType               = VK_STRUCTURE_TYPE_APPLICATION_INFO;
    app_info.pApplicationName    = "path-tracer"; 
    app_info.applicationVersion  = VK_MAKE_VERSION(1, 0, 0);
    app_info.pEngineName         = "gpu-path-tracer";
    app_info.engineVersion       = VK_MAKE_VERSION(1, 0, 0);
    app_info.apiVersion          = VK_API_VERSION_1_2;


    std::vector<const char*> layers = {
        "VK_LAYER_KHRONOS_validation",
    };
    std::vector<const char*> extensions = {
        VK_EXT_DEBUG_UTILS_EXTENSION_NAME
    };

    VkInstanceCreateInfo instance_create_info       = {};
    instance_create_info.sType                      = VK_STRUCTURE_TYPE_INSTANCE_CREATE_INFO;
    instance_create_info.pApplicationInfo           = &app_info;
    instance_create_info.enabledLayerCount          = layers.size();
    instance_create_info.ppEnabledLayerNames        = layers.data();
    instance_create_info.enabledExtensionCount      = extensions.size();
    instance_create_info.ppEnabledExtensionNames    = extensions.data();

    VKRESULT(vkCreateInstance(&instance_create_info, nullptr, &instance))

    load_instance_functions(instance);

    create_debugger();

    std::cerr << "Instance ready" << std::endl;
}

void vkrenderer::create_debugger() {
    VkDebugUtilsMessengerEXT debugMessenger;
    VkDebugUtilsMessengerCreateInfoEXT debugUtilsMessengeCreateInfo {
        VK_STRUCTURE_TYPE_DEBUG_UTILS_MESSENGER_CREATE_INFO_EXT,
        nullptr,
        0,
        VK_DEBUG_UTILS_MESSAGE_SEVERITY_ERROR_BIT_EXT | VK_DEBUG_UTILS_MESSAGE_SEVERITY_WARNING_BIT_EXT,
        VK_DEBUG_UTILS_MESSAGE_TYPE_GENERAL_BIT_EXT | VK_DEBUG_UTILS_MESSAGE_TYPE_PERFORMANCE_BIT_EXT
            | VK_DEBUG_UTILS_MESSAGE_TYPE_VALIDATION_BIT_EXT,
        DebugCallback,
        nullptr,
    };

    VKRESULT(vkCreateDebugUtilsMessengerEXT(
        instance,
        &debugUtilsMessengeCreateInfo,
        nullptr,
        &debugMessenger
    ))
}

void vkrenderer::create_device() {
    select_physical_device();
    select_compute_queue();

    VkDeviceQueueCreateInfo queue_create_info   = {};
    queue_create_info.sType                     = VK_STRUCTURE_TYPE_DEVICE_QUEUE_CREATE_INFO;
    queue_create_info.queueFamilyIndex          = compute_queue_index;
    queue_create_info.queueCount                = 1;

    float queue_priority                        = 1.f;
    queue_create_info.pQueuePriorities          = &queue_priority;

    VkPhysicalDeviceFeatures device_features    = {};

    VkDeviceCreateInfo device_create_info       = {};
    device_create_info.sType                    = VK_STRUCTURE_TYPE_DEVICE_CREATE_INFO;
    device_create_info.pQueueCreateInfos        = &queue_create_info;
    device_create_info.queueCreateInfoCount     = 1;
    device_create_info.pEnabledFeatures         = &device_features;
    device_create_info.enabledExtensionCount    = 0; // None yet
    device_create_info.enabledLayerCount        = 0; // Deprecated https://www.khronos.org/registry/vulkan/specs/1.2/html/chap31.html#extendingvulkan-layers-devicelayerdeprecation

    VKRESULT(vkCreateDevice(physical_device, &device_create_info, nullptr, &device))

    load_device_functions(device);

    vkGetDeviceQueue(device, compute_queue_index, 0, &compute_queue);

    std::cerr << "Device ready" << std::endl;
}

void vkrenderer::create_pipeline() {
    std::vector<uint8_t> shader_code = get_shader_code("./shaders/compute.comp.spv");
    if (shader_code.size() == 0) {
        exit(1);
    }

    VkShaderModule compute_shader_module;
    VkShaderModuleCreateInfo shader_create_info     = {};
    shader_create_info.sType                        = VK_STRUCTURE_TYPE_SHADER_MODULE_CREATE_INFO;
    shader_create_info.pNext                        = nullptr;
    shader_create_info.flags                        = 0;
    shader_create_info.codeSize                     = shader_code.size();
    shader_create_info.pCode                        = (uint32_t*)shader_code.data();

    VKRESULT(vkCreateShaderModule(device, &shader_create_info, nullptr, &compute_shader_module))

    VkPipelineShaderStageCreateInfo stage_create_info = {};
    stage_create_info.sType                         = VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_CREATE_INFO;
    stage_create_info.pNext                         = nullptr;
    stage_create_info.flags                         = 0;
    stage_create_info.stage                         = VK_SHADER_STAGE_COMPUTE_BIT;
    stage_create_info.module                        = compute_shader_module;
    stage_create_info.pName                         = "main";
    stage_create_info.pSpecializationInfo           = nullptr;

    VkDescriptorSetLayoutBinding binding            = {};
    binding.binding                                 = 0;
    binding.descriptorType                          = VK_DESCRIPTOR_TYPE_STORAGE_BUFFER;
    binding.descriptorCount                         = 1;
    binding.stageFlags                              = VK_SHADER_STAGE_COMPUTE_BIT;
    binding.pImmutableSamplers                      = 0;

    VkDescriptorSetLayoutCreateInfo descriptor_set_layout_create_info = {};
    descriptor_set_layout_create_info.sType         = VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_CREATE_INFO;
    descriptor_set_layout_create_info.pNext         = nullptr;
    descriptor_set_layout_create_info.flags         = 0;
    descriptor_set_layout_create_info.bindingCount  = 1;
    descriptor_set_layout_create_info.pBindings     = &binding;

    VKRESULT(vkCreateDescriptorSetLayout(device, &descriptor_set_layout_create_info, nullptr, &compute_shader_input_layout))

    VkPipelineLayoutCreateInfo layout_create_info   = {};
    layout_create_info.sType                        = VK_STRUCTURE_TYPE_PIPELINE_LAYOUT_CREATE_INFO;
    layout_create_info.pNext                        = nullptr;
    layout_create_info.flags                        = 0;
    layout_create_info.setLayoutCount               = 1;
    layout_create_info.pSetLayouts                  = &compute_shader_input_layout;
    layout_create_info.pushConstantRangeCount       = 0;
    layout_create_info.pPushConstantRanges          = nullptr;

    VKRESULT(vkCreatePipelineLayout(device, &layout_create_info, nullptr, &compute_pipeline_layout))

    VkComputePipelineCreateInfo create_info         = {};
    create_info.sType                               = VK_STRUCTURE_TYPE_COMPUTE_PIPELINE_CREATE_INFO;
    create_info.pNext                               = nullptr;
    create_info.flags                               = 0;
    create_info.stage                               = stage_create_info;
    create_info.layout                              = compute_pipeline_layout;

    VKRESULT(vkCreateComputePipelines(
        device,
        VK_NULL_HANDLE,
        1,
        &create_info,
        nullptr,
        &compute_pipeline
    ))

    std::cerr << "Compute pipeline ready" << std::endl;
}

void vkrenderer::create_memory_allocator() {
    VmaAllocatorCreateInfo allocator_info = {};
    allocator_info.vulkanApiVersion = VK_API_VERSION_1_2;
    allocator_info.physicalDevice = physical_device;
    allocator_info.device = device;
    allocator_info.instance = instance;
     
    vmaCreateAllocator(&allocator_info, &allocator);
}

void vkrenderer::create_command_buffer() {
    VkCommandPoolCreateInfo cmd_pool_create_info    = {};
    cmd_pool_create_info.sType                      = VK_STRUCTURE_TYPE_COMMAND_POOL_CREATE_INFO;
    cmd_pool_create_info.pNext                      = nullptr;
    cmd_pool_create_info.flags                      = 0;
    cmd_pool_create_info.queueFamilyIndex           = compute_queue_index;

    VKRESULT(vkCreateCommandPool(device, &cmd_pool_create_info, nullptr, &command_pool))

    VkCommandBufferAllocateInfo cmd_buf_allocate_info   = {};
    cmd_buf_allocate_info.sType                         = VK_STRUCTURE_TYPE_COMMAND_BUFFER_ALLOCATE_INFO;
    cmd_buf_allocate_info.pNext                         = nullptr;
    cmd_buf_allocate_info.commandPool                   = command_pool;
    cmd_buf_allocate_info.level                         = VK_COMMAND_BUFFER_LEVEL_PRIMARY;
    cmd_buf_allocate_info.commandBufferCount            = 1;

    vkAllocateCommandBuffers(device, &cmd_buf_allocate_info, &command_buffer);
}
void vkrenderer::create_descriptor_set() {
    VkDescriptorPoolSize descriptor_pool_size               = {};
    descriptor_pool_size.type                               = VK_DESCRIPTOR_TYPE_STORAGE_BUFFER;
    descriptor_pool_size.descriptorCount                    = 1;

    VkDescriptorPoolCreateInfo descriptor_pool_create_info  = {};
    descriptor_pool_create_info.sType                       = VK_STRUCTURE_TYPE_DESCRIPTOR_POOL_CREATE_INFO;
    descriptor_pool_create_info.pNext                       = nullptr;
    descriptor_pool_create_info.flags                       = 0;
    descriptor_pool_create_info.maxSets                     = 1;
    descriptor_pool_create_info.poolSizeCount               = 1;
    descriptor_pool_create_info.pPoolSizes                  = &descriptor_pool_size;

    VKRESULT(vkCreateDescriptorPool(device, &descriptor_pool_create_info, nullptr, &descriptor_pool))

    VkDescriptorSetAllocateInfo descriptor_set_allocate_info    = {};
    descriptor_set_allocate_info.sType                          = VK_STRUCTURE_TYPE_DESCRIPTOR_SET_ALLOCATE_INFO;
    descriptor_set_allocate_info.pNext                          = nullptr;
    descriptor_set_allocate_info.descriptorPool                 = descriptor_pool;
    descriptor_set_allocate_info.descriptorSetCount             = 1;
    descriptor_set_allocate_info.pSetLayouts                    = &compute_shader_input_layout;

    vkAllocateDescriptorSets(device, &descriptor_set_allocate_info, &compute_shader_input_set);
}

void vkrenderer::select_physical_device() {
    uint32_t physical_devices_count = 0;
    vkEnumeratePhysicalDevices(instance, &physical_devices_count, nullptr);

    if (physical_devices_count < 1) {
        std::cerr << "No physical device found !" << std::endl;
        exit(1);
    }

    std::vector<VkPhysicalDevice> physical_devices { physical_devices_count };
    vkEnumeratePhysicalDevices(instance, &physical_devices_count, physical_devices.data());

    physical_device = physical_devices[0];
}

void vkrenderer::select_compute_queue() {
    uint32_t queue_properties_count = 0;
    vkGetPhysicalDeviceQueueFamilyProperties(physical_device, &queue_properties_count, nullptr);

    std::vector<VkQueueFamilyProperties> queue_properties { queue_properties_count };
    vkGetPhysicalDeviceQueueFamilyProperties(physical_device, &queue_properties_count, queue_properties.data());

    for (uint32_t properties_index = 0; properties_index < queue_properties_count; properties_index++) {
        if (queue_properties[properties_index].queueFlags & VK_QUEUE_COMPUTE_BIT) {
            compute_queue_index = properties_index;
            return;
        }
    }

    std::cerr << "No compute queue found !" << std::endl;
    exit(1);
}

void vkrenderer::fill_descriptor_set(const input_data& inputs) {
    VkBufferCreateInfo buffer_info  = { VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO };
    buffer_info.size                = sizeof(path_tracer_data);
    buffer_info.usage               = VK_BUFFER_USAGE_STORAGE_BUFFER_BIT;
     
    VmaAllocationCreateInfo alloc_create_info = {};
    alloc_create_info.usage = VMA_MEMORY_USAGE_GPU_TO_CPU;
     
    VmaAllocation allocation;
    vmaCreateBuffer(allocator, &buffer_info, &alloc_create_info, &compute_shader_buffer, &allocation, nullptr);

    vmaMapMemory(allocator, allocation, (void**) &mapped_data);
    std::memcpy(&mapped_data->inputs, &inputs, sizeof(inputs));

    VkDescriptorBufferInfo descriptor_buf_info      = {};
    descriptor_buf_info.buffer                      = compute_shader_buffer;
    descriptor_buf_info.offset                      = 0;
    descriptor_buf_info.range                       = VK_WHOLE_SIZE;

    VkWriteDescriptorSet write_descriptor_set       = {};
    write_descriptor_set.sType                      = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET;
    write_descriptor_set.pNext                      = nullptr;
    write_descriptor_set.dstSet                     = compute_shader_input_set;
    write_descriptor_set.dstBinding                 = 0;
    write_descriptor_set.dstArrayElement            = 0;
    write_descriptor_set.descriptorCount            = 1;
    write_descriptor_set.descriptorType             = VK_DESCRIPTOR_TYPE_STORAGE_BUFFER;
    write_descriptor_set.pImageInfo                 = nullptr;
    write_descriptor_set.pBufferInfo                = &descriptor_buf_info;
    write_descriptor_set.pTexelBufferView           = nullptr;

    vkUpdateDescriptorSets(device, 1, &write_descriptor_set, 0, nullptr);
}