use std::sync::Arc;
use vulkano::command_buffer::allocator::StandardCommandBufferAllocator;
use vulkano::device::{Device, DeviceCreateInfo, DeviceExtensions, DeviceFeatures, Queue, QueueCreateInfo, QueueFlags};
use vulkano::device::physical::PhysicalDeviceType;
use vulkano::instance::{Instance, InstanceCreateFlags, InstanceCreateInfo};
use vulkano::memory::allocator::StandardMemoryAllocator;
use vulkano::swapchain::{acquire_next_image, Surface, SwapchainCreateInfo, SwapchainPresentInfo};
use vulkano::{sync, Validated, Version, VulkanError, VulkanLibrary};
use vulkano::command_buffer::{AutoCommandBufferBuilder, CommandBufferUsage, RenderingAttachmentInfo, RenderingInfo};
use vulkano::render_pass::{AttachmentLoadOp, AttachmentStoreOp};
use vulkano::sync::GpuFuture;
use winit::application::ApplicationHandler;
use winit::event::WindowEvent;
use winit::event_loop::{ActiveEventLoop, EventLoop};
use winit::window::WindowId;
use crate::renderer::render_context::RenderContext;
use crate::renderer::{window_size_dependent_setup, Scene};

pub struct App {
    instance: Arc<Instance>,
    device: Arc<Device>,
    queue: Arc<Queue>,
    memory_allocator: Arc<StandardMemoryAllocator>,
    command_buffer_allocator: Arc<StandardCommandBufferAllocator>,
    rcx: Option<RenderContext>,
    scene: Option<Scene>,
}

impl App {
    pub fn new(event_loop: &EventLoop<()>) -> Self {
        let library = VulkanLibrary::new().unwrap();

        let required_extensions = Surface::required_extensions(event_loop).unwrap();

        let instance = Instance::new(
            library,
            InstanceCreateInfo {
                // Enable enumerating devices that use non-conformant Vulkan implementations.
                // (e.g. MoltenVK)
                flags: InstanceCreateFlags::ENUMERATE_PORTABILITY,
                enabled_extensions: required_extensions,
                enabled_layers: vec![
                    String::from("VK_LAYER_KHRONOS_validation"),
                    String::from("VK_LAYER_MANGOHUD_overlay_x86_64"),
                    String::from("VK_LAYER_NV_optimus"),
                ],
                ..Default::default()
            },
        )
            .unwrap();

        let mut device_extensions = DeviceExtensions {
            khr_swapchain: true,
            ..DeviceExtensions::empty()
        };

        let (physical_device, queue_family_index) = instance
            .enumerate_physical_devices()
            .unwrap()
            .filter(|p| {
                p.api_version() >= Version::V1_3 || p.supported_extensions().khr_dynamic_rendering
            })
            .filter(|p| {
                p.supported_extensions().contains(&device_extensions)
            })
            .filter_map(|p| {
                p.queue_family_properties()
                    .iter()
                    .enumerate()
                    .position(|(i, q)| {
                        q.queue_flags.intersects(QueueFlags::GRAPHICS)
                            && p.presentation_support(i as u32, event_loop).unwrap()
                    })
                    .map(|i| (p, i as u32))
            })
            .min_by_key(|(p, _)| {
                match p.properties().device_type {
                    PhysicalDeviceType::DiscreteGpu => 0,
                    PhysicalDeviceType::IntegratedGpu => 1,
                    PhysicalDeviceType::VirtualGpu => 2,
                    PhysicalDeviceType::Cpu => 3,
                    PhysicalDeviceType::Other => 4,
                    _ => 5,
                }
            })
            .expect("no suitable physical device found");

        println!(
            "Using device: {} (type: {:?})",
            physical_device.properties().device_name,
            physical_device.properties().device_type,
        );

        if physical_device.api_version() < Version::V1_3 {
            device_extensions.khr_dynamic_rendering = true;
        }

        let (device, mut queues) = Device::new(
            physical_device,
            DeviceCreateInfo {
                queue_create_infos: vec![QueueCreateInfo {
                    queue_family_index,
                    ..Default::default()
                }],
                enabled_extensions: device_extensions,
                enabled_features: DeviceFeatures {
                    dynamic_rendering: true,
                    ..DeviceFeatures::empty()
                },
                ..Default::default()
            },
        )
            .unwrap();

        let queue = queues.next().unwrap();
        let memory_allocator = Arc::new(StandardMemoryAllocator::new_default(device.clone()));

        let command_buffer_allocator = Arc::new(StandardCommandBufferAllocator::new(
            device.clone(),
            Default::default(),
        ));

        Self {
            instance,
            device,
            queue,
            memory_allocator,
            command_buffer_allocator,
            rcx: None,
            scene: None,
        }
    }
}

impl ApplicationHandler for App {
    fn resumed(&mut self, event_loop: &ActiveEventLoop) {
        let window_attributes = winit::window::Window::default_attributes()
            .with_title("Rust ASH Test")
            .with_inner_size(winit::dpi::PhysicalSize::new(
                f64::from(800),
                f64::from(600),
            ));

        let window = Arc::new(
            event_loop
                .create_window(window_attributes)
                .unwrap(),
        );

        let surface = Surface::from_window(self.instance.clone(), window.clone()).unwrap();

        self.rcx = Some(RenderContext::new(window, surface, &self.device));
        self.scene = Some(Scene::initialize(&self.device, &self.rcx.as_ref().unwrap().swapchain, &self.memory_allocator));
    }

    fn window_event(&mut self, event_loop: &ActiveEventLoop, _id: WindowId, event: WindowEvent) {
        let rcx = self.rcx.as_mut().unwrap();

        match event {
            WindowEvent::CloseRequested => {
                log::debug!("The close button was pressed; stopping");
                event_loop.exit();
            }
            WindowEvent::Resized(_) => {
                rcx.recreate_swapchain = true;
            }
            WindowEvent::RedrawRequested => {
                let window_size = rcx.window.inner_size();

                if window_size.width == 0 || window_size.height == 0 {
                    return;
                }

                rcx.previous_frame_end.as_mut().unwrap().cleanup_finished();

                if rcx.recreate_swapchain {
                    let (new_swapchain, new_images) = rcx
                        .swapchain
                        .recreate(SwapchainCreateInfo {
                            image_extent: window_size.into(),
                            ..rcx.swapchain.create_info()
                        })
                        .expect("failed to recreate swapchain");

                    rcx.swapchain = new_swapchain;
                    rcx.attachment_image_views = window_size_dependent_setup(&new_images);
                    rcx.viewport.extent = window_size.into();
                    rcx.recreate_swapchain = false;
                }

                let (image_index, suboptimal, acquire_future) = match acquire_next_image(
                    rcx.swapchain.clone(),
                    None,
                )
                    .map_err(Validated::unwrap)
                {
                    Ok(r) => r,
                    Err(VulkanError::OutOfDate) => {
                        rcx.recreate_swapchain = true;
                        return;
                    }
                    Err(e) => panic!("failed to acquire next image: {e}"),
                };

                if suboptimal {
                    rcx.recreate_swapchain = true;
                }

                let mut builder = AutoCommandBufferBuilder::primary(
                    self.command_buffer_allocator.clone(),
                    self.queue.queue_family_index(),
                    CommandBufferUsage::OneTimeSubmit,
                )
                    .unwrap();

                builder
                    .begin_rendering(RenderingInfo {
                        color_attachments: vec![Some(RenderingAttachmentInfo {
                            load_op: AttachmentLoadOp::Clear,
                            store_op: AttachmentStoreOp::Store,
                            clear_value: Some([0.0, 0.0, 0.0, 1.0].into()),
                            ..RenderingAttachmentInfo::image_view(
                                rcx.attachment_image_views[image_index as usize].clone(),
                            )
                        })],
                        ..Default::default()
                    })
                    .unwrap()
                    .set_viewport(0, [rcx.viewport.clone()].into_iter().collect())
                    .unwrap();

                if let Some(scene) = self.scene.as_ref() {
                    scene.render(&mut builder);
                }

                builder
                    .end_rendering()
                    .unwrap();

                let command_buffer = builder.build().unwrap();

                let future = rcx
                    .previous_frame_end
                    .take()
                    .unwrap()
                    .join(acquire_future)
                    .then_execute(self.queue.clone(), command_buffer)
                    .unwrap()
                    .then_swapchain_present(
                        self.queue.clone(),
                        SwapchainPresentInfo::swapchain_image_index(
                            rcx.swapchain.clone(),
                            image_index,
                        ),
                    )
                    .then_signal_fence_and_flush();

                match future.map_err(Validated::unwrap) {
                    Ok(future) => {
                        rcx.previous_frame_end = Some(future.boxed());
                    }
                    Err(VulkanError::OutOfDate) => {
                        rcx.recreate_swapchain = true;
                        rcx.previous_frame_end = Some(sync::now(self.device.clone()).boxed());
                    }
                    Err(e) => {
                        println!("failed to flush future: {e}");
                        rcx.previous_frame_end = Some(sync::now(self.device.clone()).boxed());
                    }
                }
            }
            _ => {}
        }
    }

    fn about_to_wait(&mut self, _event_loop: &ActiveEventLoop) {
        let rcx = self.rcx.as_mut().unwrap();
        rcx.window.request_redraw();
    }
}