// Copyright (c) 2016 The vulkano developers
// Licensed under the Apache License, Version 2.0
// <LICENSE-APACHE or
// https://www.apache.org/licenses/LICENSE-2.0> or the MIT
// license <LICENSE-MIT or https://opensource.org/licenses/MIT>,
// at your option. All files in the project carrying such
// notice may not be copied, modified, or distributed except
// according to those terms.

use cgmath::{Matrix3, Matrix4, Point3, Rad, Vector3};
use examples::{Normal, Vertex, INDICES, NORMALS, VERTICES};
use std::{sync::Arc, time::Instant};
use vulkano::{
    buffer::{BufferUsage, CpuAccessibleBuffer, CpuBufferPool, TypedBufferAccess},
    command_buffer::{
        allocator::StandardCommandBufferAllocator, AutoCommandBufferBuilder, CommandBufferUsage,
        RenderPassBeginInfo, SubpassContents,
    },
    descriptor_set::{
        allocator::StandardDescriptorSetAllocator, PersistentDescriptorSet, WriteDescriptorSet,
    },
    device::{
        physical::PhysicalDeviceType, Device, DeviceCreateInfo, DeviceExtensions, QueueCreateInfo,
    },
    format::Format,
    image::{view::ImageView, AttachmentImage, ImageAccess, ImageUsage, SwapchainImage},
    instance::{Instance, InstanceCreateInfo},
    pipeline::{
        graphics::{
            depth_stencil::DepthStencilState,
            input_assembly::InputAssemblyState,
            vertex_input::BuffersDefinition,
            viewport::{Viewport, ViewportState},
        },
        GraphicsPipeline, Pipeline, PipelineBindPoint,
    },
    render_pass::{Framebuffer, FramebufferCreateInfo, RenderPass, Subpass},
    shader::ShaderModule,
    swapchain::{
        acquire_next_image, AcquireError, Swapchain, SwapchainCreateInfo, SwapchainCreationError,
        SwapchainPresentInfo,
    },
    sync::{self, FlushError, GpuFuture},
    VulkanLibrary,
};
use vulkano_win::VkSurfaceBuild;
use winit::{
    event::{Event, WindowEvent},
    event_loop::{ControlFlow, EventLoop},
    window::{Window, WindowBuilder},
};

fn main() {
    // 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 library = VulkanLibrary::new().unwrap();
    let required_extensions = vulkano_win::required_extensions(&library);
    let instance = Instance::new(
        library,
        InstanceCreateInfo {
            enabled_extensions: required_extensions,
            // Enable enumerating devices that use non-conformant vulkan implementations. (ex. MoltenVK)
            enumerate_portability: true,
            ..Default::default()
        },
    )
    .unwrap();

    let event_loop = EventLoop::new();
    let surface = WindowBuilder::new()
        .build_vk_surface(&event_loop, instance.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.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 = Some(
            device
                .physical_device()
                .surface_formats(&surface, Default::default())
                .unwrap()[0]
                .0,
        );
        let window = surface.object().unwrap().downcast_ref::<Window>().unwrap();

        Swapchain::new(
            device.clone(),
            surface.clone(),
            SwapchainCreateInfo {
                min_image_count: surface_capabilities.min_image_count,
                image_format,
                image_extent: window.inner_size().into(),
                image_usage: ImageUsage {
                    color_attachment: true,
                    ..ImageUsage::empty()
                },
                composite_alpha: surface_capabilities
                    .supported_composite_alpha
                    .iter()
                    .next()
                    .unwrap(),
                ..Default::default()
            },
        )
        .unwrap()
    };

    let vertex_buffer = CpuAccessibleBuffer::from_iter(
        device.clone(),
        BufferUsage {
            vertex_buffer: true,
            ..BufferUsage::empty()
        },
        false,
        VERTICES,
    )
    .unwrap();
    let normals_buffer = CpuAccessibleBuffer::from_iter(
        device.clone(),
        BufferUsage {
            vertex_buffer: true,
            ..BufferUsage::empty()
        },
        false,
        NORMALS,
    )
    .unwrap();
    let index_buffer = CpuAccessibleBuffer::from_iter(
        device.clone(),
        BufferUsage {
            index_buffer: true,
            ..BufferUsage::empty()
        },
        false,
        INDICES,
    )
    .unwrap();

    let uniform_buffer = CpuBufferPool::<vs::ty::Data>::new(
        device.clone(),
        BufferUsage {
            uniform_buffer: true,
            ..BufferUsage::empty()
        },
    );

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

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

    let (mut pipeline, mut framebuffers) =
        window_size_dependent_setup(device.clone(), &vs, &fs, &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 = StandardDescriptorSetAllocator::new(device.clone());
    let command_buffer_allocator = StandardCommandBufferAllocator::new(device.clone());

    event_loop.run(move |event, _, control_flow| {
        match event {
            Event::WindowEvent {
                event: WindowEvent::CloseRequested,
                ..
            } => {
                *control_flow = ControlFlow::Exit;
            }
            Event::WindowEvent {
                event: WindowEvent::Resized(_),
                ..
            } => {
                recreate_swapchain = true;
            }
            Event::RedrawEventsCleared => {
                let window = surface.object().unwrap().downcast_ref::<Window>().unwrap();
                let dimensions = window.inner_size();
                if dimensions.width == 0 || dimensions.height == 0 {
                    return;
                }

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

                if recreate_swapchain {
                    let (new_swapchain, new_images) =
                        match swapchain.recreate(SwapchainCreateInfo {
                            image_extent: dimensions.into(),
                            ..swapchain.create_info()
                        }) {
                            Ok(r) => r,
                            Err(SwapchainCreationError::ImageExtentNotSupported { .. }) => return,
                            Err(e) => panic!("Failed to recreate swapchain: {:?}", e),
                        };

                    swapchain = new_swapchain;
                    let (new_pipeline, new_framebuffers) = window_size_dependent_setup(
                        device.clone(),
                        &vs,
                        &fs,
                        &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 = Matrix3::from_angle_y(Rad(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 = cgmath::perspective(
                        Rad(std::f32::consts::FRAC_PI_2),
                        aspect_ratio,
                        0.01,
                        100.0,
                    );
                    let view = Matrix4::look_at_rh(
                        Point3::new(0.3, 0.3, 1.0),
                        Point3::new(0.0, 0.0, 0.0),
                        Vector3::new(0.0, -1.0, 0.0),
                    );
                    let scale = Matrix4::from_scale(0.01);

                    let uniform_data = vs::ty::Data {
                        world: Matrix4::from(rotation).into(),
                        view: (view * scale).into(),
                        proj: proj.into(),
                    };

                    uniform_buffer.from_data(uniform_data).unwrap()
                };

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

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

                if suboptimal {
                    recreate_swapchain = true;
                }

                let mut builder = AutoCommandBufferBuilder::primary(
                    &command_buffer_allocator,
                    queue.queue_family_index(),
                    CommandBufferUsage::OneTimeSubmit,
                )
                .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(),
                            )
                        },
                        SubpassContents::Inline,
                    )
                    .unwrap()
                    .bind_pipeline_graphics(pipeline.clone())
                    .bind_descriptor_sets(
                        PipelineBindPoint::Graphics,
                        pipeline.layout().clone(),
                        0,
                        set,
                    )
                    .bind_vertex_buffers(0, (vertex_buffer.clone(), normals_buffer.clone()))
                    .bind_index_buffer(index_buffer.clone())
                    .draw_indexed(index_buffer.len() as u32, 1, 0, 0, 0)
                    .unwrap()
                    .end_render_pass()
                    .unwrap();
                let command_buffer = builder.build().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 {
                    Ok(future) => {
                        previous_frame_end = Some(future.boxed());
                    }
                    Err(FlushError::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());
                    }
                }
            }
            _ => (),
        }
    });
}

/// This method is called once during initialization, then again whenever the window is resized
fn window_size_dependent_setup(
    device: Arc<Device>,
    vs: &ShaderModule,
    fs: &ShaderModule,
    images: &[Arc<SwapchainImage>],
    render_pass: Arc<RenderPass>,
) -> (Arc<GraphicsPipeline>, Vec<Arc<Framebuffer>>) {
    let dimensions = images[0].dimensions().width_height();

    let depth_buffer = ImageView::new_default(
        AttachmentImage::transient(device.clone(), dimensions, Format::D16_UNORM).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 = GraphicsPipeline::start()
        .vertex_input_state(
            BuffersDefinition::new()
                .vertex::<Vertex>()
                .vertex::<Normal>(),
        )
        .vertex_shader(vs.entry_point("main").unwrap(), ())
        .input_assembly_state(InputAssemblyState::new())
        .viewport_state(ViewportState::viewport_fixed_scissor_irrelevant([
            Viewport {
                origin: [0.0, 0.0],
                dimensions: [dimensions[0] as f32, dimensions[1] as f32],
                depth_range: 0.0..1.0,
            },
        ]))
        .fragment_shader(fs.entry_point("main").unwrap(), ())
        .depth_stencil_state(DepthStencilState::simple_depth_test())
        .render_pass(Subpass::from(render_pass, 0).unwrap())
        .build(device)
        .unwrap();

    (pipeline, framebuffers)
}

mod vs {
    vulkano_shaders::shader! {
        ty: "vertex",
        path: "src/bin/teapot/vert.glsl",
        types_meta: {
            use bytemuck::{Pod, Zeroable};

            #[derive(Clone, Copy, Zeroable, Pod)]
        },
    }
}

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