mod functions;
use functions::{
    create_instance, create_logical_device, create_pipeline, create_swapchain,
    create_swapchain_image_views, pick_physical_device,
};

use crate::VALIDATION_ENABLED;
use ::anyhow::{anyhow, Result};
use ::log::*;
use ::thiserror::Error;
use ::vulkanalia::loader::{LibloadingLoader, LIBRARY};
use ::vulkanalia::prelude::v1_0::*;
use ::vulkanalia::vk::{ExtDebugUtilsExtension, KhrSurfaceExtension, KhrSwapchainExtension};
use ::vulkanalia::window as vk_window;
use ::winit::window::Window;

pub(crate) const VALIDATION_LAYER: vk::ExtensionName =
    vk::ExtensionName::from_bytes(b"VK_LAYER_KHRONOS_validation");
pub(crate) const DEVICE_EXTENSIONS: &[vk::ExtensionName] = &[vk::KHR_SWAPCHAIN_EXTENSION.name];

/// Our Vulkan app.
#[derive(Clone, Debug)]
pub struct App {
    entry: Entry,
    instance: Instance,
    data: AppData,
    device: Device,
}

impl App {
    /// Creates our Vulkan app.
    pub unsafe fn create(window: &Window) -> Result<Self> {
        let loader = LibloadingLoader::new(LIBRARY)?;
        let entry = Entry::new(loader).map_err(|b| anyhow!("{}", b))?;

        let mut data = AppData::default();
        let instance = create_instance(window, &entry, &mut data)?;
        data.surface = vk_window::create_surface(&instance, window)?;

        pick_physical_device(&instance, &mut data)?;
        let device = create_logical_device(&instance, &mut data)?;

        create_swapchain(window, &instance, &device, &mut data)?;
        create_swapchain_image_views(&device, &mut data)?;
        create_pipeline(&device, &mut data)?;

        Ok(Self {
            entry,
            instance,
            data,
            device,
        })
    }

    /// Renders a frame for our Vulkan app.
    pub unsafe fn render(&mut self, _window: &Window) -> Result<()> {
        Ok(())
    }

    /// Destroys our Vulkan app.
    pub unsafe fn destroy(&mut self) {
        self.data
            .swapchain_image_views
            .iter()
            .for_each(|v| self.device.destroy_image_view(*v, None));
        self.device.destroy_swapchain_khr(self.data.swapchain, None);
        self.device.destroy_device(None);
        self.instance.destroy_surface_khr(self.data.surface, None);

        if VALIDATION_ENABLED {
            self.instance
                .destroy_debug_utils_messenger_ext(self.data.messenger, None);
        }

        self.instance.destroy_instance(None);
    }
}

/// The Vulkan handles and associated properties used by our Vulkan app.
#[derive(Clone, Debug, Default)]
pub struct AppData {
    // Debug
    messenger: vk::DebugUtilsMessengerEXT,
    // Surface
    surface: vk::SurfaceKHR,
    // Physical Device / Logical Device
    physical_device: vk::PhysicalDevice,
    graphics_queue: vk::Queue,
    present_queue: vk::Queue,
    // Swapchain
    swapchain_format: vk::Format,
    swapchain_extent: vk::Extent2D,
    swapchain: vk::SwapchainKHR,
    swapchain_images: Vec<vk::Image>,
    swapchain_image_views: Vec<vk::ImageView>,
}

impl AppData {}

#[derive(Debug, Error)]
#[error("Missing {0}.")]
pub struct SuitabilityError(pub &'static str);

#[derive(Copy, Clone, Debug)]
pub(crate) struct QueueFamilyIndices {
    graphics: u32,
    present: u32,
}

impl QueueFamilyIndices {
    unsafe fn get(
        instance: &Instance,
        data: &AppData,
        physical_device: vk::PhysicalDevice,
    ) -> Result<Self> {
        let properties = instance.get_physical_device_queue_family_properties(physical_device);

        let graphics = properties
            .iter()
            .position(|p| p.queue_flags.contains(vk::QueueFlags::GRAPHICS))
            .map(|i| i as u32);

        let mut present = None;
        for (index, _properties) in properties.iter().enumerate() {
            if instance.get_physical_device_surface_support_khr(
                physical_device,
                index as u32,
                data.surface,
            )? {
                present = Some(index as u32);
                break;
            }
        }

        if let (Some(graphics), Some(present)) = (graphics, present) {
            Ok(Self { graphics, present })
        } else {
            Err(anyhow!(SuitabilityError(
                "Missing required queue families."
            )))
        }
    }
}

#[derive(Clone, Debug)]
pub(crate) struct SwapchainSupport {
    capabilities: vk::SurfaceCapabilitiesKHR,
    formats: Vec<vk::SurfaceFormatKHR>,
    present_modes: Vec<vk::PresentModeKHR>,
}

impl SwapchainSupport {
    unsafe fn get(
        instance: &Instance,
        data: &AppData,
        physical_device: vk::PhysicalDevice,
    ) -> Result<Self> {
        Ok(Self {
            capabilities: instance
                .get_physical_device_surface_capabilities_khr(physical_device, data.surface)?,
            formats: instance
                .get_physical_device_surface_formats_khr(physical_device, data.surface)?,
            present_modes: instance
                .get_physical_device_surface_present_modes_khr(physical_device, data.surface)?,
        })
    }
}