extern crate ash;
extern crate winit;

use ash::extensions::{
    ext::DebugUtils,
    khr::{Surface, Swapchain},
};

use ash::{vk, Entry};
pub use ash::{Device, Instance};
use std::borrow::Cow;
use std::cell::RefCell;
use std::default::Default;
use std::ffi::{CStr, CString};
use std::ops::Drop;

// Simple offset_of macro akin to C++ offsetof
#[macro_export]
macro_rules! offset_of {
    ($base:path, $field:ident) => {{
        #[allow(unused_unsafe)]
        unsafe {
            let b: $base = mem::zeroed();
            (&b.$field as *const _ as isize) - (&b as *const _ as isize)
        }
    }};
}
/// Helper function for submitting command buffers. Immediately waits for the fence before the command buffer
/// is executed. That way we can delay the waiting for the fences by 1 frame which is good for performance.
/// Make sure to create the fence in a signaled state on the first use.
#[allow(clippy::too_many_arguments)]
pub fn record_submit_commandbuffer<F: FnOnce(&Device, vk::CommandBuffer)>(
    device: &Device,
    command_buffer: vk::CommandBuffer,
    command_buffer_reuse_fence: vk::Fence,
    submit_queue: vk::Queue,
    wait_mask: &[vk::PipelineStageFlags],
    wait_semaphores: &[vk::Semaphore],
    signal_semaphores: &[vk::Semaphore],
    f: F,
) {
    unsafe {
        device
            .wait_for_fences(&[command_buffer_reuse_fence], true, std::u64::MAX)
            .expect("Wait for fence failed.");

        device
            .reset_fences(&[command_buffer_reuse_fence])
            .expect("Reset fences failed.");

        device
            .reset_command_buffer(
                command_buffer,
                vk::CommandBufferResetFlags::RELEASE_RESOURCES,
            )
            .expect("Reset command buffer failed.");

        let command_buffer_begin_info = vk::CommandBufferBeginInfo::builder()
            .flags(vk::CommandBufferUsageFlags::ONE_TIME_SUBMIT);

        device
            .begin_command_buffer(command_buffer, &command_buffer_begin_info)
            .expect("Begin commandbuffer");
        f(device, command_buffer);
        device
            .end_command_buffer(command_buffer)
            .expect("End commandbuffer");

        let command_buffers = vec![command_buffer];

        let submit_info = vk::SubmitInfo::builder()
            .wait_semaphores(wait_semaphores)
            .wait_dst_stage_mask(wait_mask)
            .command_buffers(&command_buffers)
            .signal_semaphores(signal_semaphores);

        device
            .queue_submit(
                submit_queue,
                &[submit_info.build()],
                command_buffer_reuse_fence,
            )
            .expect("queue submit failed.");
    }
}

unsafe extern "system" fn vulkan_debug_callback(
    message_severity: vk::DebugUtilsMessageSeverityFlagsEXT,
    message_type: vk::DebugUtilsMessageTypeFlagsEXT,
    p_callback_data: *const vk::DebugUtilsMessengerCallbackDataEXT,
    _user_data: *mut std::os::raw::c_void,
) -> vk::Bool32 {
    let callback_data = *p_callback_data;
    let message_id_number: i32 = callback_data.message_id_number as i32;

    let message_id_name = if callback_data.p_message_id_name.is_null() {
        Cow::from("")
    } else {
        CStr::from_ptr(callback_data.p_message_id_name).to_string_lossy()
    };

    let message = if callback_data.p_message.is_null() {
        Cow::from("")
    } else {
        CStr::from_ptr(callback_data.p_message).to_string_lossy()
    };

    println!(
        "{:?}:\n{:?} [{} ({})] : {}\n",
        message_severity,
        message_type,
        message_id_name,
        &message_id_number.to_string(),
        message,
    );

    vk::FALSE
}

pub fn find_memorytype_index(
    memory_req: &vk::MemoryRequirements,
    memory_prop: &vk::PhysicalDeviceMemoryProperties,
    flags: vk::MemoryPropertyFlags,
) -> Option<u32> {
    memory_prop.memory_types[..memory_prop.memory_type_count as _]
        .iter()
        .enumerate()
        .find(|(index, memory_type)| {
            (1 << index) & memory_req.memory_type_bits != 0
                && memory_type.property_flags & flags == flags
        })
        .map(|(index, _memory_type)| index as _)
}

pub struct ExampleBase {
    pub entry: Entry,
    pub instance: Instance,
    pub device: Device,
    pub surface_loader: Surface,
    pub swapchain_loader: Swapchain,
    pub debug_utils_loader: DebugUtils,
    pub window: winit::Window,
    pub events_loop: RefCell<winit::EventsLoop>,
    pub debug_call_back: vk::DebugUtilsMessengerEXT,

    pub pdevice: vk::PhysicalDevice,
    pub device_memory_properties: vk::PhysicalDeviceMemoryProperties,
    pub queue_family_index: u32,
    pub present_queue: vk::Queue,

    pub surface: vk::SurfaceKHR,
    pub surface_format: vk::SurfaceFormatKHR,
    pub surface_resolution: vk::Extent2D,

    pub swapchain: vk::SwapchainKHR,
    pub present_images: Vec<vk::Image>,
    pub present_image_views: Vec<vk::ImageView>,

    pub pool: vk::CommandPool,
    pub draw_command_buffer: vk::CommandBuffer,
    pub setup_command_buffer: vk::CommandBuffer,

    pub depth_image: vk::Image,
    pub depth_image_view: vk::ImageView,
    pub depth_image_memory: vk::DeviceMemory,

    pub present_complete_semaphore: vk::Semaphore,
    pub rendering_complete_semaphore: vk::Semaphore,

    pub draw_commands_reuse_fence: vk::Fence,
    pub setup_commands_reuse_fence: vk::Fence,
}

impl ExampleBase {
    pub fn render_loop<F: Fn()>(&self, f: F) {
        use winit::*;
        self.events_loop.borrow_mut().run_forever(|event| {
            f();
            match event {
                Event::WindowEvent { event, .. } => match event {
                    WindowEvent::KeyboardInput { input, .. } => {
                        if let Some(VirtualKeyCode::Escape) = input.virtual_keycode {
                            ControlFlow::Break
                        } else {
                            ControlFlow::Continue
                        }
                    }
                    WindowEvent::CloseRequested => winit::ControlFlow::Break,
                    _ => ControlFlow::Continue,
                },
                _ => ControlFlow::Continue,
            }
        });
    }

    pub fn new(window_width: u32, window_height: u32) -> Self {
        unsafe {
            let events_loop = winit::EventsLoop::new();
            let window = winit::WindowBuilder::new()
                .with_title("Ash - Example")
                .with_dimensions(winit::dpi::LogicalSize::new(
                    f64::from(window_width),
                    f64::from(window_height),
                ))
                .build(&events_loop)
                .unwrap();
            let entry = Entry::new();
            let app_name = CString::new("VulkanTriangle").unwrap();

            let layer_names = [CString::new("VK_LAYER_KHRONOS_validation").unwrap()];
            let layers_names_raw: Vec<*const i8> = layer_names
                .iter()
                .map(|raw_name| raw_name.as_ptr())
                .collect();

            let surface_extensions = ash_window::enumerate_required_extensions(&window).unwrap();
            let mut extension_names_raw = surface_extensions
                .iter()
                .map(|ext| ext.as_ptr())
                .collect::<Vec<_>>();
            extension_names_raw.push(DebugUtils::name().as_ptr());

            let appinfo = vk::ApplicationInfo::builder()
                .application_name(&app_name)
                .application_version(0)
                .engine_name(&app_name)
                .engine_version(0)
                .api_version(vk::make_api_version(0, 1, 0, 0));

            let create_info = vk::InstanceCreateInfo::builder()
                .application_info(&appinfo)
                .enabled_layer_names(&layers_names_raw)
                .enabled_extension_names(&extension_names_raw);

            let instance: Instance = entry
                .create_instance(&create_info, None)
                .expect("Instance creation error");

            let debug_info = vk::DebugUtilsMessengerCreateInfoEXT::builder()
                .message_severity(
                    vk::DebugUtilsMessageSeverityFlagsEXT::ERROR
                        | vk::DebugUtilsMessageSeverityFlagsEXT::WARNING
                        | vk::DebugUtilsMessageSeverityFlagsEXT::INFO,
                )
                .message_type(
                    vk::DebugUtilsMessageTypeFlagsEXT::GENERAL
                        | vk::DebugUtilsMessageTypeFlagsEXT::VALIDATION
                        | vk::DebugUtilsMessageTypeFlagsEXT::PERFORMANCE,
                )
                .pfn_user_callback(Some(vulkan_debug_callback));

            let debug_utils_loader = DebugUtils::new(&entry, &instance);
            let debug_call_back = debug_utils_loader
                .create_debug_utils_messenger(&debug_info, None)
                .unwrap();
            let surface = ash_window::create_surface(&entry, &instance, &window, None).unwrap();
            let pdevices = instance
                .enumerate_physical_devices()
                .expect("Physical device error");
            let surface_loader = Surface::new(&entry, &instance);
            let (pdevice, queue_family_index) = pdevices
                .iter()
                .map(|pdevice| {
                    instance
                        .get_physical_device_queue_family_properties(*pdevice)
                        .iter()
                        .enumerate()
                        .filter_map(|(index, info)| {
                            let supports_graphic_and_surface =
                                info.queue_flags.contains(vk::QueueFlags::GRAPHICS)
                                    && surface_loader
                                        .get_physical_device_surface_support(
                                            *pdevice,
                                            index as u32,
                                            surface,
                                        )
                                        .unwrap();
                            if supports_graphic_and_surface {
                                Some((*pdevice, index))
                            } else {
                                None
                            }
                        })
                        .next()
                })
                .flatten()
                .next()
                .expect("Couldn't find suitable device.");
            let queue_family_index = queue_family_index as u32;
            let device_extension_names_raw = [Swapchain::name().as_ptr()];
            let features = vk::PhysicalDeviceFeatures {
                shader_clip_distance: 1,
                ..Default::default()
            };
            let priorities = [1.0];

            let queue_info = vk::DeviceQueueCreateInfo::builder()
                .queue_family_index(queue_family_index)
                .queue_priorities(&priorities);

            let device_create_info = vk::DeviceCreateInfo::builder()
                .queue_create_infos(std::slice::from_ref(&queue_info))
                .enabled_extension_names(&device_extension_names_raw)
                .enabled_features(&features);

            let device: Device = instance
                .create_device(pdevice, &device_create_info, None)
                .unwrap();

            let present_queue = device.get_device_queue(queue_family_index as u32, 0);

            let surface_format = surface_loader
                .get_physical_device_surface_formats(pdevice, surface)
                .unwrap()[0];

            let surface_capabilities = surface_loader
                .get_physical_device_surface_capabilities(pdevice, surface)
                .unwrap();
            let mut desired_image_count = surface_capabilities.min_image_count + 1;
            if surface_capabilities.max_image_count > 0
                && desired_image_count > surface_capabilities.max_image_count
            {
                desired_image_count = surface_capabilities.max_image_count;
            }
            let surface_resolution = match surface_capabilities.current_extent.width {
                std::u32::MAX => vk::Extent2D {
                    width: window_width,
                    height: window_height,
                },
                _ => surface_capabilities.current_extent,
            };
            let pre_transform = if surface_capabilities
                .supported_transforms
                .contains(vk::SurfaceTransformFlagsKHR::IDENTITY)
            {
                vk::SurfaceTransformFlagsKHR::IDENTITY
            } else {
                surface_capabilities.current_transform
            };
            let present_modes = surface_loader
                .get_physical_device_surface_present_modes(pdevice, surface)
                .unwrap();
            let present_mode = present_modes
                .iter()
                .cloned()
                .find(|&mode| mode == vk::PresentModeKHR::MAILBOX)
                .unwrap_or(vk::PresentModeKHR::FIFO);
            let swapchain_loader = Swapchain::new(&instance, &device);

            let swapchain_create_info = vk::SwapchainCreateInfoKHR::builder()
                .surface(surface)
                .min_image_count(desired_image_count)
                .image_color_space(surface_format.color_space)
                .image_format(surface_format.format)
                .image_extent(surface_resolution)
                .image_usage(vk::ImageUsageFlags::COLOR_ATTACHMENT)
                .image_sharing_mode(vk::SharingMode::EXCLUSIVE)
                .pre_transform(pre_transform)
                .composite_alpha(vk::CompositeAlphaFlagsKHR::OPAQUE)
                .present_mode(present_mode)
                .clipped(true)
                .image_array_layers(1);

            let swapchain = swapchain_loader
                .create_swapchain(&swapchain_create_info, None)
                .unwrap();

            let pool_create_info = vk::CommandPoolCreateInfo::builder()
                .flags(vk::CommandPoolCreateFlags::RESET_COMMAND_BUFFER)
                .queue_family_index(queue_family_index);

            let pool = device.create_command_pool(&pool_create_info, None).unwrap();

            let command_buffer_allocate_info = vk::CommandBufferAllocateInfo::builder()
                .command_buffer_count(2)
                .command_pool(pool)
                .level(vk::CommandBufferLevel::PRIMARY);

            let command_buffers = device
                .allocate_command_buffers(&command_buffer_allocate_info)
                .unwrap();
            let setup_command_buffer = command_buffers[0];
            let draw_command_buffer = command_buffers[1];

            let present_images = swapchain_loader.get_swapchain_images(swapchain).unwrap();
            let present_image_views: Vec<vk::ImageView> = present_images
                .iter()
                .map(|&image| {
                    let create_view_info = vk::ImageViewCreateInfo::builder()
                        .view_type(vk::ImageViewType::TYPE_2D)
                        .format(surface_format.format)
                        .components(vk::ComponentMapping {
                            r: vk::ComponentSwizzle::R,
                            g: vk::ComponentSwizzle::G,
                            b: vk::ComponentSwizzle::B,
                            a: vk::ComponentSwizzle::A,
                        })
                        .subresource_range(vk::ImageSubresourceRange {
                            aspect_mask: vk::ImageAspectFlags::COLOR,
                            base_mip_level: 0,
                            level_count: 1,
                            base_array_layer: 0,
                            layer_count: 1,
                        })
                        .image(image);
                    device.create_image_view(&create_view_info, None).unwrap()
                })
                .collect();
            let device_memory_properties = instance.get_physical_device_memory_properties(pdevice);
            let depth_image_create_info = vk::ImageCreateInfo::builder()
                .image_type(vk::ImageType::TYPE_2D)
                .format(vk::Format::D16_UNORM)
                .extent(vk::Extent3D {
                    width: surface_resolution.width,
                    height: surface_resolution.height,
                    depth: 1,
                })
                .mip_levels(1)
                .array_layers(1)
                .samples(vk::SampleCountFlags::TYPE_1)
                .tiling(vk::ImageTiling::OPTIMAL)
                .usage(vk::ImageUsageFlags::DEPTH_STENCIL_ATTACHMENT)
                .sharing_mode(vk::SharingMode::EXCLUSIVE);

            let depth_image = device.create_image(&depth_image_create_info, None).unwrap();
            let depth_image_memory_req = device.get_image_memory_requirements(depth_image);
            let depth_image_memory_index = find_memorytype_index(
                &depth_image_memory_req,
                &device_memory_properties,
                vk::MemoryPropertyFlags::DEVICE_LOCAL,
            )
            .expect("Unable to find suitable memory index for depth image.");

            let depth_image_allocate_info = vk::MemoryAllocateInfo::builder()
                .allocation_size(depth_image_memory_req.size)
                .memory_type_index(depth_image_memory_index);

            let depth_image_memory = device
                .allocate_memory(&depth_image_allocate_info, None)
                .unwrap();

            device
                .bind_image_memory(depth_image, depth_image_memory, 0)
                .expect("Unable to bind depth image memory");

            let fence_create_info =
                vk::FenceCreateInfo::builder().flags(vk::FenceCreateFlags::SIGNALED);

            let draw_commands_reuse_fence = device
                .create_fence(&fence_create_info, None)
                .expect("Create fence failed.");
            let setup_commands_reuse_fence = device
                .create_fence(&fence_create_info, None)
                .expect("Create fence failed.");

            record_submit_commandbuffer(
                &device,
                setup_command_buffer,
                setup_commands_reuse_fence,
                present_queue,
                &[],
                &[],
                &[],
                |device, setup_command_buffer| {
                    let layout_transition_barriers = vk::ImageMemoryBarrier::builder()
                        .image(depth_image)
                        .dst_access_mask(
                            vk::AccessFlags::DEPTH_STENCIL_ATTACHMENT_READ
                                | vk::AccessFlags::DEPTH_STENCIL_ATTACHMENT_WRITE,
                        )
                        .new_layout(vk::ImageLayout::DEPTH_STENCIL_ATTACHMENT_OPTIMAL)
                        .old_layout(vk::ImageLayout::UNDEFINED)
                        .subresource_range(
                            vk::ImageSubresourceRange::builder()
                                .aspect_mask(vk::ImageAspectFlags::DEPTH)
                                .layer_count(1)
                                .level_count(1)
                                .build(),
                        );

                    device.cmd_pipeline_barrier(
                        setup_command_buffer,
                        vk::PipelineStageFlags::BOTTOM_OF_PIPE,
                        vk::PipelineStageFlags::LATE_FRAGMENT_TESTS,
                        vk::DependencyFlags::empty(),
                        &[],
                        &[],
                        &[layout_transition_barriers.build()],
                    );
                },
            );

            let depth_image_view_info = vk::ImageViewCreateInfo::builder()
                .subresource_range(
                    vk::ImageSubresourceRange::builder()
                        .aspect_mask(vk::ImageAspectFlags::DEPTH)
                        .level_count(1)
                        .layer_count(1)
                        .build(),
                )
                .image(depth_image)
                .format(depth_image_create_info.format)
                .view_type(vk::ImageViewType::TYPE_2D);

            let depth_image_view = device
                .create_image_view(&depth_image_view_info, None)
                .unwrap();

            let semaphore_create_info = vk::SemaphoreCreateInfo::default();

            let present_complete_semaphore = device
                .create_semaphore(&semaphore_create_info, None)
                .unwrap();
            let rendering_complete_semaphore = device
                .create_semaphore(&semaphore_create_info, None)
                .unwrap();

            ExampleBase {
                events_loop: RefCell::new(events_loop),
                entry,
                instance,
                device,
                queue_family_index,
                pdevice,
                device_memory_properties,
                window,
                surface_loader,
                surface_format,
                present_queue,
                surface_resolution,
                swapchain_loader,
                swapchain,
                present_images,
                present_image_views,
                pool,
                draw_command_buffer,
                setup_command_buffer,
                depth_image,
                depth_image_view,
                present_complete_semaphore,
                rendering_complete_semaphore,
                draw_commands_reuse_fence,
                setup_commands_reuse_fence,
                surface,
                debug_call_back,
                debug_utils_loader,
                depth_image_memory,
            }
        }
    }
}

impl Drop for ExampleBase {
    fn drop(&mut self) {
        unsafe {
            self.device.device_wait_idle().unwrap();
            self.device
                .destroy_semaphore(self.present_complete_semaphore, None);
            self.device
                .destroy_semaphore(self.rendering_complete_semaphore, None);
            self.device
                .destroy_fence(self.draw_commands_reuse_fence, None);
            self.device
                .destroy_fence(self.setup_commands_reuse_fence, None);
            self.device.free_memory(self.depth_image_memory, None);
            self.device.destroy_image_view(self.depth_image_view, None);
            self.device.destroy_image(self.depth_image, None);
            for &image_view in self.present_image_views.iter() {
                self.device.destroy_image_view(image_view, None);
            }
            self.device.destroy_command_pool(self.pool, None);
            self.swapchain_loader
                .destroy_swapchain(self.swapchain, None);
            self.device.destroy_device(None);
            self.surface_loader.destroy_surface(self.surface, None);
            self.debug_utils_loader
                .destroy_debug_utils_messenger(self.debug_call_back, None);
            self.instance.destroy_instance(None);
        }
    }
}