use self::model::{Normal, Position, INDICES, NORMALS, POSITIONS};
use glam::{
    f32::{Mat3, Vec3},
    Mat4,
};
use std::{error::Error, sync::Arc, time::Instant};
use vulkano::{
    buffer::{
        allocator::{SubbufferAllocator, SubbufferAllocatorCreateInfo},
        Buffer, BufferCreateInfo, BufferUsage,
    },
    command_buffer::{
        allocator::StandardCommandBufferAllocator, CommandBufferBeginInfo, CommandBufferLevel,
        CommandBufferUsage, RecordingCommandBuffer, RenderPassBeginInfo,
    },
    descriptor_set::{
        allocator::StandardDescriptorSetAllocator, DescriptorSet, WriteDescriptorSet,
    },
    device::{
        physical::PhysicalDeviceType, Device, DeviceCreateInfo, DeviceExtensions, DeviceOwned,
        QueueCreateInfo, QueueFlags,
    },
    format::Format,
    image::{view::ImageView, Image, ImageCreateInfo, ImageType, ImageUsage},
    instance::{Instance, InstanceCreateFlags, InstanceCreateInfo},
    memory::allocator::{AllocationCreateInfo, MemoryTypeFilter, StandardMemoryAllocator},
    pipeline::{
        graphics::{
            color_blend::{ColorBlendAttachmentState, ColorBlendState},
            depth_stencil::{DepthState, DepthStencilState},
            input_assembly::InputAssemblyState,
            multisample::MultisampleState,
            rasterization::RasterizationState,
            vertex_input::{Vertex, VertexDefinition},
            viewport::{Viewport, ViewportState},
            GraphicsPipelineCreateInfo,
        },
        layout::PipelineDescriptorSetLayoutCreateInfo,
        GraphicsPipeline, Pipeline, PipelineBindPoint, PipelineLayout,
        PipelineShaderStageCreateInfo,
    },
    render_pass::{Framebuffer, FramebufferCreateInfo, RenderPass, Subpass},
    shader::EntryPoint,
    swapchain::{
        acquire_next_image, Surface, Swapchain, SwapchainCreateInfo, SwapchainPresentInfo,
    },
    sync::{self, GpuFuture},
    Validated, VulkanError, VulkanLibrary,
};
use winit::{
    event::{Event, WindowEvent},
    event_loop::EventLoop,
    window::WindowBuilder,
};

mod model;

fn main() -> Result<(), impl Error> {
    // The start of this example is exactly the same as `triangle`. You should read the `triangle`
    // example if you haven't done so yet.

    let event_loop = EventLoop::new().unwrap();

    let library = VulkanLibrary::new().unwrap();
    let required_extensions = Surface::required_extensions(&event_loop).unwrap();
    let instance = Instance::new(
        library,
        InstanceCreateInfo {
            flags: InstanceCreateFlags::ENUMERATE_PORTABILITY,
            enabled_extensions: required_extensions,
            ..Default::default()
        },
    )
    .unwrap();

    let window = Arc::new(WindowBuilder::new().build(&event_loop).unwrap());
    let surface = Surface::from_window(instance.clone(), window.clone()).unwrap();

    let device_extensions = DeviceExtensions {
        khr_swapchain: true,
        ..DeviceExtensions::empty()
    };
    let (physical_device, queue_family_index) = instance
        .enumerate_physical_devices()
        .unwrap()
        .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.surface_support(i as u32, &surface).unwrap_or(false)
                })
                .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,
        })
        .unwrap();

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

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

    let queue = queues.next().unwrap();

    let (mut swapchain, images) = {
        let surface_capabilities = device
            .physical_device()
            .surface_capabilities(&surface, Default::default())
            .unwrap();
        let image_format = device
            .physical_device()
            .surface_formats(&surface, Default::default())
            .unwrap()[0]
            .0;

        Swapchain::new(
            device.clone(),
            surface,
            SwapchainCreateInfo {
                min_image_count: surface_capabilities.min_image_count.max(2),
                image_format,
                image_extent: window.inner_size().into(),
                image_usage: ImageUsage::COLOR_ATTACHMENT,
                composite_alpha: surface_capabilities
                    .supported_composite_alpha
                    .into_iter()
                    .next()
                    .unwrap(),
                ..Default::default()
            },
        )
        .unwrap()
    };

    let memory_allocator = Arc::new(StandardMemoryAllocator::new_default(device.clone()));

    let vertex_buffer = Buffer::from_iter(
        memory_allocator.clone(),
        BufferCreateInfo {
            usage: BufferUsage::VERTEX_BUFFER,
            ..Default::default()
        },
        AllocationCreateInfo {
            memory_type_filter: MemoryTypeFilter::PREFER_DEVICE
                | MemoryTypeFilter::HOST_SEQUENTIAL_WRITE,
            ..Default::default()
        },
        POSITIONS,
    )
    .unwrap();
    let normals_buffer = Buffer::from_iter(
        memory_allocator.clone(),
        BufferCreateInfo {
            usage: BufferUsage::VERTEX_BUFFER,
            ..Default::default()
        },
        AllocationCreateInfo {
            memory_type_filter: MemoryTypeFilter::PREFER_DEVICE
                | MemoryTypeFilter::HOST_SEQUENTIAL_WRITE,
            ..Default::default()
        },
        NORMALS,
    )
    .unwrap();
    let index_buffer = Buffer::from_iter(
        memory_allocator.clone(),
        BufferCreateInfo {
            usage: BufferUsage::INDEX_BUFFER,
            ..Default::default()
        },
        AllocationCreateInfo {
            memory_type_filter: MemoryTypeFilter::PREFER_DEVICE
                | MemoryTypeFilter::HOST_SEQUENTIAL_WRITE,
            ..Default::default()
        },
        INDICES,
    )
    .unwrap();

    let uniform_buffer = SubbufferAllocator::new(
        memory_allocator.clone(),
        SubbufferAllocatorCreateInfo {
            buffer_usage: BufferUsage::UNIFORM_BUFFER,
            memory_type_filter: MemoryTypeFilter::PREFER_DEVICE
                | MemoryTypeFilter::HOST_SEQUENTIAL_WRITE,
            ..Default::default()
        },
    );

    let render_pass = vulkano::single_pass_renderpass!(
        device.clone(),
        attachments: {
            color: {
                format: swapchain.image_format(),
                samples: 1,
                load_op: Clear,
                store_op: Store,
            },
            depth_stencil: {
                format: Format::D16_UNORM,
                samples: 1,
                load_op: Clear,
                store_op: DontCare,
            },
        },
        pass: {
            color: [color],
            depth_stencil: {depth_stencil},
        },
    )
    .unwrap();

    let vs = vs::load(device.clone())
        .unwrap()
        .entry_point("main")
        .unwrap();
    let fs = fs::load(device.clone())
        .unwrap()
        .entry_point("main")
        .unwrap();

    let (mut pipeline, mut framebuffers) = window_size_dependent_setup(
        memory_allocator.clone(),
        vs.clone(),
        fs.clone(),
        &images,
        render_pass.clone(),
    );
    let mut recreate_swapchain = false;

    let mut previous_frame_end = Some(sync::now(device.clone()).boxed());
    let rotation_start = Instant::now();

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

    event_loop.run(move |event, elwt| {
        match event {
            Event::WindowEvent {
                event: WindowEvent::CloseRequested,
                ..
            } => {
                elwt.exit();
            }
            Event::WindowEvent {
                event: WindowEvent::Resized(_),
                ..
            } => {
                recreate_swapchain = true;
            }
            Event::WindowEvent {
                event: WindowEvent::RedrawRequested,
                ..
            } => {
                let image_extent: [u32; 2] = window.inner_size().into();

                if image_extent.contains(&0) {
                    return;
                }

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

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

                    swapchain = new_swapchain;
                    let (new_pipeline, new_framebuffers) = window_size_dependent_setup(
                        memory_allocator.clone(),
                        vs.clone(),
                        fs.clone(),
                        &new_images,
                        render_pass.clone(),
                    );
                    pipeline = new_pipeline;
                    framebuffers = new_framebuffers;
                    recreate_swapchain = false;
                }

                let uniform_buffer_subbuffer = {
                    let elapsed = rotation_start.elapsed();
                    let rotation =
                        elapsed.as_secs() as f64 + elapsed.subsec_nanos() as f64 / 1_000_000_000.0;
                    let rotation = Mat3::from_rotation_y(rotation as f32);

                    // NOTE: This teapot was meant for OpenGL where the origin is at the lower left
                    // instead the origin is at the upper left in Vulkan, so we reverse the Y axis.
                    let aspect_ratio =
                        swapchain.image_extent()[0] as f32 / swapchain.image_extent()[1] as f32;

                    let proj = Mat4::perspective_rh_gl(
                        std::f32::consts::FRAC_PI_2,
                        aspect_ratio,
                        0.01,
                        100.0,
                    );
                    let view = Mat4::look_at_rh(
                        Vec3::new(0.3, 0.3, 1.0),
                        Vec3::new(0.0, 0.0, 0.0),
                        Vec3::new(0.0, -1.0, 0.0),
                    );
                    let scale = Mat4::from_scale(Vec3::splat(0.01));

                    let uniform_data = vs::Data {
                        world: Mat4::from_mat3(rotation).to_cols_array_2d(),
                        view: (view * scale).to_cols_array_2d(),
                        proj: proj.to_cols_array_2d(),
                    };

                    let subbuffer = uniform_buffer.allocate_sized().unwrap();
                    *subbuffer.write().unwrap() = uniform_data;

                    subbuffer
                };

                let layout = &pipeline.layout().set_layouts()[0];
                let set = DescriptorSet::new(
                    descriptor_set_allocator.clone(),
                    layout.clone(),
                    [WriteDescriptorSet::buffer(0, uniform_buffer_subbuffer)],
                    [],
                )
                .unwrap();

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

                if suboptimal {
                    recreate_swapchain = true;
                }

                let mut builder = RecordingCommandBuffer::new(
                    command_buffer_allocator.clone(),
                    queue.queue_family_index(),
                    CommandBufferLevel::Primary,
                    CommandBufferBeginInfo {
                        usage: CommandBufferUsage::OneTimeSubmit,
                        ..Default::default()
                    },
                )
                .unwrap();

                builder
                    .begin_render_pass(
                        RenderPassBeginInfo {
                            clear_values: vec![
                                Some([0.0, 0.0, 1.0, 1.0].into()),
                                Some(1f32.into()),
                            ],
                            ..RenderPassBeginInfo::framebuffer(
                                framebuffers[image_index as usize].clone(),
                            )
                        },
                        Default::default(),
                    )
                    .unwrap()
                    .bind_pipeline_graphics(pipeline.clone())
                    .unwrap()
                    .bind_descriptor_sets(
                        PipelineBindPoint::Graphics,
                        pipeline.layout().clone(),
                        0,
                        set,
                    )
                    .unwrap()
                    .bind_vertex_buffers(0, (vertex_buffer.clone(), normals_buffer.clone()))
                    .unwrap()
                    .bind_index_buffer(index_buffer.clone())
                    .unwrap();

                unsafe {
                    builder
                        .draw_indexed(index_buffer.len() as u32, 1, 0, 0, 0)
                        .unwrap();
                }

                builder.end_render_pass(Default::default()).unwrap();

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

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

/// This function is called once during initialization, then again whenever the window is resized.
fn window_size_dependent_setup(
    memory_allocator: Arc<StandardMemoryAllocator>,
    vs: EntryPoint,
    fs: EntryPoint,
    images: &[Arc<Image>],
    render_pass: Arc<RenderPass>,
) -> (Arc<GraphicsPipeline>, Vec<Arc<Framebuffer>>) {
    let device = memory_allocator.device().clone();
    let extent = images[0].extent();

    let depth_buffer = ImageView::new_default(
        Image::new(
            memory_allocator,
            ImageCreateInfo {
                image_type: ImageType::Dim2d,
                format: Format::D16_UNORM,
                extent: images[0].extent(),
                usage: ImageUsage::DEPTH_STENCIL_ATTACHMENT | ImageUsage::TRANSIENT_ATTACHMENT,
                ..Default::default()
            },
            AllocationCreateInfo::default(),
        )
        .unwrap(),
    )
    .unwrap();

    let framebuffers = images
        .iter()
        .map(|image| {
            let view = ImageView::new_default(image.clone()).unwrap();
            Framebuffer::new(
                render_pass.clone(),
                FramebufferCreateInfo {
                    attachments: vec![view, depth_buffer.clone()],
                    ..Default::default()
                },
            )
            .unwrap()
        })
        .collect::<Vec<_>>();

    // In the triangle example we use a dynamic viewport, as its a simple example. However in the
    // teapot example, we recreate the pipelines with a hardcoded viewport instead. This allows the
    // driver to optimize things, at the cost of slower window resizes.
    // https://computergraphics.stackexchange.com/questions/5742/vulkan-best-way-of-updating-pipeline-viewport
    let pipeline = {
        let vertex_input_state = [Position::per_vertex(), Normal::per_vertex()]
            .definition(&vs.info().input_interface)
            .unwrap();
        let stages = [
            PipelineShaderStageCreateInfo::new(vs),
            PipelineShaderStageCreateInfo::new(fs),
        ];
        let layout = PipelineLayout::new(
            device.clone(),
            PipelineDescriptorSetLayoutCreateInfo::from_stages(&stages)
                .into_pipeline_layout_create_info(device.clone())
                .unwrap(),
        )
        .unwrap();
        let subpass = Subpass::from(render_pass, 0).unwrap();

        GraphicsPipeline::new(
            device,
            None,
            GraphicsPipelineCreateInfo {
                stages: stages.into_iter().collect(),
                vertex_input_state: Some(vertex_input_state),
                input_assembly_state: Some(InputAssemblyState::default()),
                viewport_state: Some(ViewportState {
                    viewports: [Viewport {
                        offset: [0.0, 0.0],
                        extent: [extent[0] as f32, extent[1] as f32],
                        depth_range: 0.0..=1.0,
                    }]
                    .into_iter()
                    .collect(),
                    ..Default::default()
                }),
                rasterization_state: Some(RasterizationState::default()),
                depth_stencil_state: Some(DepthStencilState {
                    depth: Some(DepthState::simple()),
                    ..Default::default()
                }),
                multisample_state: Some(MultisampleState::default()),
                color_blend_state: Some(ColorBlendState::with_attachment_states(
                    subpass.num_color_attachments(),
                    ColorBlendAttachmentState::default(),
                )),
                subpass: Some(subpass.into()),
                ..GraphicsPipelineCreateInfo::layout(layout)
            },
        )
        .unwrap()
    };

    (pipeline, framebuffers)
}

mod vs {
    vulkano_shaders::shader! {
        ty: "vertex",
        path: "vert.glsl",
    }
}

mod fs {
    vulkano_shaders::shader! {
        ty: "fragment",
        path: "frag.glsl",
    }
}